Print Page - What Octane?

Title: What Octane?
Post by: 88 Blackbird 5.0 on December 26, 2011, 12:55:43 PM

Hey guys. I think there are a lot of us here that are running very similar engine combos. The engine combo I'm talking about is 5.0 with GT40 heads & intake with TFS stage 1 cam. If you're running this combo, or GT40 iron heads & intake with an alphabet cam, what octane gas do you fill up with? Just curious.

Title: What Octane?
Post by: TOM Renzo on December 26, 2011, 08:36:29 PM

Title: What Octane?
Post by: 88 Blackbird 5.0 on December 26, 2011, 08:43:30 PM

Quote from: TOM Renzo;376289

That depends on many factors??? Need a build sheet. Normally an octane rating is a direct result of Pre ignition or Knock.

Thanks Tom, but I know that. Things like rod-ratio, the shape of the combustion chamber, whether you're running aluminum heads, or not, all factor in to what octane is required to prevent detonation. Hell, I can even go into detail on stoichiometric mixtures (fuel/air ratios) if you'd like. I'm just curious to see what people here who are running that pretty common combo are putting in the their tanks. That's all. :)

Title: What Octane?
Post by: TOM Renzo on December 26, 2011, 09:21:52 PM

Title: What Octane?
Post by: 88 Blackbird 5.0 on December 26, 2011, 10:22:18 PM

I think you either misread, or misunderstood my question Tom. I didn't ask what the octane requirement of my engine would be. I simply asked what octane fuel guys here who are running that combo are using. Dynamic stacking can obviously vary from engine to engine. Even if the engines are using identical parts. Dynamic stacking however will NOT cause those two engines to have appreciably different octane requirements if the engines are timed the same. That just doesn't happen.
I appreciate you trying to help, but you're answering questions I've known the answers to for a long time. I'mjust asking to see what guys here are running. That's all. I've wrenched on everything from jet engines (I'm a licensed Aircraft Mechanic), to heavy equipment, quads and cars. It's safe to assume I have all the basic mechanical theories like "use enough octane to keep your engine from pinging" down.

Title: What Octane?
Post by: Haystack on December 27, 2011, 02:12:46 AM

With stock engine and h.o. intake/throttle body, I was running 14-16* with no pinging on 85 woth "up to 10%" ethonal. My alttitude was. Between 4200-5000ft above sea level or so. I never advanced it until it pinged, but left my dist loose and ran up and down a hill until it felt good and until just before my mph going up the hill started to decrease.

The hill I ran was about 6% incline with a traffic light at its base and a 60mph speed limit. I would guess just under 1/4 mile. Just playing with the timing and some stock style $1.99 copper plugs gapped at .40-.45I went from 64mph on the hill up to 76mph. However, I did have to pull my dist out when I had a leaky timing chain cover. I replaced the timing chain while I hade it all apart, and didn't have a timing light to verify timing until later.

Most of what you run has more to do with cranking cylinder pressure and alttitude then anything else. I left my car lower then it had to be because I did over 100miles a day commute, and in a day could go from 3200ft to just over 10000ft in a single day. I did try to run higher octane gas and did not notice any real improvement, or change in power or pinging from different grades.

I would check your compression pressures and make an educated guess from there. You can gain some power by having the heads milled down and usually not have to worry too much about ptv.

Title: What Octane?
Post by: TOM Renzo on December 27, 2011, 06:48:44 AM

Title: What Octane?
Post by: TOM Renzo on December 27, 2011, 07:10:18 AM

Title: What Octane?
Post by: ZondaC12 on December 27, 2011, 08:52:05 AM

My silver POS has GT40P's, an E303, 1.7 RR's. Mustang H.O. block with reliefs in the pistons, stock pistons, just to be thorough. Explorer intake. Have the timing at 16 degrees, runs like an animal. One day about a month after I bought the car, accidentally put 87 in it instead of 93. Made no difference. LOL!!!! Sooooo a cheap as I am, been running it like that since, for over a year now, beating the living daylights out of the thing...no observed ill effects so far. My friend's 90 Vette L98 TPI motor pings with regular gas on a hot summer day if he's got the timing bumped a couple degrees, forget what those run. Naturally he hates me. As said, clearly a case by case thing, but there you go there's my case.

Actually, another case. The red car, S.O. bottom end, flat top pistons, E7 heads explorer intake bone stock valvetrain. Timing again 16 deg, always careful with that engine, always have 93 in it, but once or twice I tried 87 and same result, couldn't get it to ping.

Title: What Octane?
Post by: 88 Blackbird 5.0 on December 27, 2011, 11:56:18 AM

Since most 5.0 engines run well on 87 octane, I'm not surprised to hear about your cars both running well on it. Since you get more power out of a lower octane fuel than you do a higher octane fuel, it makes no sense at all to run a higher than necessary octane fuel in your car. There are a lot of guys out there who advance their timing tot he point where they have to run a higher octane fuel to keep their engine from pinging. That's counterproductive and is a practice that should be avoided. The higher octane fuel doesn't burn as fast, or completely as a lower octane fuel would. That means less power and more carbon deposits in your engine. The higher octane fuel is more expensive. It's best to run as much timing as you can without causing your engine to ping while running the lowest octane fuel possible. Doing so delivers the most power/cleanest running engine.

You've got a win/win scenario Zonda.

Title: What Octane?
Post by: ZondaC12 on December 27, 2011, 12:17:09 PM

Yeah exactly. I'll probably mess around with it some more in the red car...like I said up until May of 2010 when I started to tear it down, so about 4 years and maybe 20k miles of running that timing and always 93 octane for fear of even trying, because it's very important to me that the original block and bottom end stay with this car and stay in unmolested condition for the rest of my life. It has great compression, all is fine, 134k miles and all is well. No reason why it can't stay that way. And once it's back together, it'll be driven far less than it was before. Car will probably never see 150k. It did great and the spark plugs were clean and red-ish, which indicates some fuel additives so I've heard. But everything nice upon inspection. It's a good idea though, and if it does good with 87 it'll go over to 87.

I love these engines. And I love Ford EEC-IV and their fuel injection LOL. It's like old guys that won't drive anything without a carburetor. I'll probably never update past this stuff!!!

Title: What Octane?
Post by: thunderjet302 on December 27, 2011, 03:06:06 PM

I'm running 93 with the timing at 16* BTDC. I haven't tried 87 yet. It may or may not work with 87. All combinations respond differently. Try it and see what happens ;).

Title: What Octane?
Post by: TOM Renzo on December 27, 2011, 07:47:55 PM

Title: What Octane?
Post by: TurboCoupe50 on December 27, 2011, 07:59:55 PM

I ran 93 in mine when I first built it cause I didn't know any better... A years or so later, I found it had better throttle response and didn't ping on lower octane, so I generally ran 89... Of course mine has alu heads so I could likely run it on 87...

Title: What Octane?
Post by: 88 Blackbird 5.0 on December 27, 2011, 08:32:42 PM

Quote from: TurboCoupe50;376353

I ran 93 in mine when I first built it cause I didn't know any better... A years or so later, I found it had better throttle response and didn't ping on lower octane, so I generally ran 89... Of course mine has alu heads so I could likely run it on 87...

Hey Tom. Where have you been? This place hasn't been the same without you.

Yea. There are a lot of canards floating around about cars like the mistaken idea you'll get more power by using a higher octane fuel. As your experience with switching to a lower ocatne gasoline proved, you get more power by running less octane.

There are obviously situations where running higher octane is worth it. I'm not saying that can't be the case. Being able to run higher compression is a perfect example of a favorable trade off for having to run higher octane. For nothing more than bumping the timing, it's not a worth-while trade off.

As far as higher octane fuels not burning as cleanly as lower octane fuels. That's easy to prove too. Say you had some extremely bored Aircraft Mechanics that decided to do a little test one day. Let's say they took two blue and yellow 55 gallon drums next to the hangar and put super high octane AvGas in on drum. They then put an equal amount of 87 octane gas in the other and then lit the fuels off. When they looked into the barrels, it was obvious the AvGas didn't burn as cleanly as the 87 octane gas did.

Everything I claimed can be and HAS been proven. It's not speculation.

Title: What Octane?
Post by: Bruce M on December 27, 2011, 09:38:55 PM

My car has ported E7s with GT40 valves, speed pro flat tops, heads are milled (9.5-1 compression), HO cam advance 2*, 1.6 roller rockers, and trickflow valve springs and I run 89 at 16* advanced. When I had the SO motor I couldnt run more than 12* of timing on 93. The only thing I can think that would cause that is carbon build up.

Title: What Octane?
Post by: TOM Renzo on December 27, 2011, 10:04:20 PM

All

Title: What Octane?
Post by: thewestie on December 27, 2011, 10:28:46 PM

87 cause I'm cheap. And the guy with the right foot thinks its supposed to go to the floor regularly. Once in a while Ill throw in some 89 for the detergents. What do I know I'm no engine builder when this one falls apart we'll look inside and see what I did wrong.
:burnout:

Title: What Octane?
Post by: 88 Blackbird 5.0 on December 27, 2011, 11:16:14 PM

You're misunderstanding me Tom Renzo. There are reward/drawback situations where modifying and engine to the point where you have to use higher octane fuel ISN'T worth it and there are modifications you can make to an engine that require you to use higher octane fuel that ARE worthwhile. Installing a power adder like a blower, nitrous or turbo would be a situation where you would experience a gain in power even though you'd have to run a fuel with lower combustability (higher octane fuel). In my last post, I used the example of raising your compression ratio as being another worthwhile and effective way to improve the power of an engine, even though you'd have to run higher octane fuel if you raised the comression ratio much. Situations like advancing your timing so much, you have to run higher octane fuel to keep pinging at bay, are NOT worthwhile however. All I was trying to convey, is the point that you've got to pick your battles. The reason why octane is added to fuels, is to decrease their volatility. If you decrease the volatility of a fuel, you've decreased how much energy is released when it combusts.

AvGas is gasoline with a super high octane rating. Other than having tons of octane, it IS gasoline, just like what you fill your car's tank with. With that in mind, the little test I mentioned in my last post was a comparison of a low octane gasoline to a very high octane gasoline. In other words, it was an apples, to apples test. Gas to gas.

To address your tailpipe example; if you used Zonda's car as a test platform and ran it on 87 octane gasoline, an emissions test WOULD detect more polutants than it would if Zonda had his car tested with 87 octane in the tank. Hell, do the test yourself and the spark plugs will tell you that. When you run a higher than required octane fuel in your car, you WILL build up more deposits in your engine than you would with a lower octane. Like I covered earlier, higher octane fuels are DESIGNED to burn slower and with less energy. The drawback is that they don't burn as completely as lower grades. It's no different than setting your car on 10 tons of dynamite and lighting the fuse. You're car is going to be more thoroughly destroyed from the explosion, than it would be if you only used 2 tons of dynamite. Whether you're talking dynamite, or fuel, more energy being released means more thorough destruction.

To get my powerplant license, I had to sit through way too many classes on fuel theory. You could say I'm more than a little familiar with how all this works Tom. :)

Title: What Octane?
Post by: TOM Renzo on December 28, 2011, 07:07:26 AM

Title: What Octane?
Post by: 88 Blackbird 5.0 on December 28, 2011, 09:54:10 AM

Good morning Tom. Considering that EGR valves are part-throttle devices, anyone who removes their EGR valve in hopes of gaining horsepower doesn't know much about cars. At idle and full-throttle, the EGR isn't even working. The only things you'll accomplish by removing your EGR valve would be 1. Increasing the amount of polutants your car puts out. 2. Worsening your gas mileage and 3. Cleaning up the looks of your engine compartment. You DON'T improve performance by removing your EGR. That's NOT how cars work.

If you're looking for maximum horse, you SHOULD advance your timing as much as you can. As much as you can without increasing the octane requirements of your car. If you've been reading car blogs and magazine articles for so long Tom, you should have noticed how many times people reported an IMPROVEMENT in power/throttle response when they switched to using a lower octane fuel.

To address your comment about carbon being off the table; are you trying to tell me that hydrocarbons AREN'T tested for when an emmissions test is performed? Please tell me you're not trying to tell me that. YES. Modern gasolines do have additives that are designed to reduce carbon emmissions, but they don't totally remove carbon emmissions.

Title: What Octane?
Post by: 88 Blackbird 5.0 on December 28, 2011, 09:54:37 AM

Title: What Octane?
Post by: ZondaC12 on December 28, 2011, 10:01:18 AM

This is all chemistry. And chemistry is a nice can o' worms with a lot of hard data to chew through. If we really want to understand this issue we need to know the potential energies of compounds, the energy densities as these compounds exist, and in what ratios they're found at the pump.

http://motorcycleinfo.calsci.com/Gasoline.html Read "Octane Ratings"...Some history, and an "a-ha!!!!" moment, yes that is how industry tells you 0-100 the rating. Keep that maximum in mind.
http://books.google.com/books?id=J_AkNu-Y1wQC&pg=PA62&lpg=PA62&dq=1927+graham+edgar+105+octane&source=bl&ots=j0Au5QzTbq&sig=DLNHRF3MqfgkuoAdyEAix6euKTQ&hl=en&sa=X&ei=Ax_7TtCmAcXt0gHIrJibCg&ved=0CCYQ6AEwAQ#v=onepage&q=1927%20graham%20edgar%20105%20octane&f=false (http://"http://books.google.com/books?id=J_AkNu-Y1wQC&pg=PA62&lpg=PA62&dq=1927+graham+edgar+105+octane&source=bl&ots=j0Au5QzTbq&sig=DLNHRF3MqfgkuoAdyEAix6euKTQ&hl=en&sa=X&ei=Ax_7TtCmAcXt0gHIrJibCg&ved=0CCYQ6AEwAQ#v=onepage&q=1927%20graham%20edgar%20105%20octane&f=false")
Read page 62. 100 Octane, classically, should be the maximum you ever see. Adding other things, *mainly* lead, brought the performance you could make ABOVE "100% octane", equivalent to dumping 100% iso-octane in your tank. That was the best anti-knocking combustible one could technically "use" at the time.

NOW......here is our biggest talking point!!!!!!!!!!!!!!!!!
Low octane we're arguing is potentially more energetic but too volatile. High octane, low volatility is apparently less energetic. We can take advantage of the good part and bump timing and compression...maybe make a net gain, is it enough though?
http://en.wikipedia.org/wiki/Octane_rating

Look down at the chart of different materials, from actual pure compounds to end products you buy at the pump. Lets compare Methane and 2,2,4-Trimethylpentane. That mouthful is actually pure iso-octane, 100% Octane as we would say.
http://en.wikipedia.org/wiki/2,2,4-Trimethylpentane
http://en.wikipedia.org/wiki/Methane

(now yes I am grossly overusing Wikipedia....but I'll give it the benefit of the doubt for chemical pages...enough people in the know watch those pages carefully)

Iso-octane has 5461 Kilo-joules of energy per mole. Methane has only 891. Methane has a Research Octane Number of 120 and Iso-octane is as we know 100. So, this case supports our argument. Higher octane and less energy. But wait.
Look at the g/mol rating. Grams per mole. This tells you how dense the material is. Divide the energy per mole by the grams per mole, you get the energy density. Iso-octane has an energy density of about 44 KJ/mole. 5461/114 = 44

..........Methane has a density of 55.7 KJ/mole.

So IN THIS CASE, the one with lower volatility actually is more "powerful" as well! This is one case. And gasoline is composed of as many as 500 different hydrocarbons. You would have to at least have a rough idea of the majority of the makeup of any given gallon of gasoline, know each energy and energy density of each....and come to a conclusion on the overall effect. For a scientist or an engineer like me, it's interesting and frighteningly....beckoning.

FOR A HOTRODDER?

Quote from: "thewestie"

we'll look inside and see what i did wrong

I think this is much more reasonable and prudent. :rollin: Slam it together, stand on the shoulders of giants as much as you can, run it, see what happens. Build it, hammer down, grenade it, and build it better.

Title: What Octane?
Post by: 88 Blackbird 5.0 on December 28, 2011, 10:49:02 AM

That's some good reading Zonda.

Title: What Octane?
Post by: ZondaC12 on December 28, 2011, 10:55:03 AM

I....do have an excuse lol. I'm on the third and final day of being paid to do absolutely nothing at my new job. Long story short, some BS happened, so now I have to wait til tomorrow for my safety training, then I can go back in the cleanroom and LEARN STUFF again!!! For now I'm wasting taxpayers' and investor's money :(

Title: What Octane?
Post by: 88 Blackbird 5.0 on December 28, 2011, 10:59:59 AM

Well... I think I'm gonna start calling you "Easy Money!" :P

Title: What Octane?
Post by: ZondaC12 on December 28, 2011, 11:05:22 AM

No just call me "Tweek" from south park like my friend and his dad do because I can't sit the hell still, can't ever get comfortable, have to adjust my seatbelt like 1,233,895 times and fidget endlessly during a 15 minute drive.

EDIT: If you're reeeeeeaaalllly bored this is a good read too http://www.faqs.org/faqs/autos/gasoline-faq/part3/preamble.html

Quote from: "Aviation Fuel stuff"

The
Performance Number indicates the maximum knock-free power obtainable from a
fuel compared to iso-octane = 100. Thus, a PN = 150 indicates that an engine
designed to utilise the fuel can obtain 150% of the knock-limited power of
iso-octane at the same mixture ratio. This is an arbitrary scale based on
iso-octane + varying amounts of TEL, derived from a survey of engines
performed decades ago.

Title: What Octane?
Post by: Haystack on December 28, 2011, 05:01:01 PM

I could not tell any differance or emissions change between egr working and not. Best mileage I averaged over my 100 miles commute, was 35mpg without functioning egr at between 55 and 70mph.

Title: What Octane?
Post by: 88 Blackbird 5.0 on December 28, 2011, 05:30:32 PM

By recirculating exhaust gasses the way it's designed to do, an EGR valve will decrease the amount of polutants comming out the tailpipe Haystack. That's why you have to have one on your car to pass the visual inspection part of an emmissions test. You might not have been able to notice a difference with your nose, by an emmission sniffer would detect the difference.

When an EGR valve recirculates exhaust gasses through your engine, that leans out your mixture a little. When you lean the mixture, you burn less fuel. Less fuel also means less power though. A hair less power cruising down the road doesn't matter. At full throttle though, it does. That's why your car's EGR valve is closed by the ECM when the engine is at full throttle.

If you didn't lose a little gas mileage when you removed your EGR valve, your EGR wasn't working properly. Increasing gas mileage and decreasing emmissions is what a properly working EGR does and is designed to do.

Title: What Octane?
Post by: Chrome on December 28, 2011, 05:31:08 PM

It is best to have highest timing possible prior to ping. As for EGR, I have found that more power can be found without it. I understand it does not function at idle or full throttle, however when you first go to full throttle, the mixture that is remaining in the cylinder is diluted. Not to mention, if it is malfunctioning it could cause all sorts of issues. I have never had the privledge of using a dyno on anything I have worked on. Just going by power difference that I have felt. Normally only minor improvements, but had a major improvemet with a 350 Chevy a friend of mine owns. Have never had gas milage decrease from removing EGR. I would think the lower octane would burn more completely as it is more volitile thus decreasing emmissions as long as there is no detination.

Title: What Octane?
Post by: TOM Renzo on December 28, 2011, 05:55:38 PM

[qu

Title: What Octane?
Post by: TOM Renzo on December 28, 2011, 06:03:14 PM

Title: What Octane?
Post by: Haystack on December 28, 2011, 06:19:58 PM

My car actually hit the same on both the 15 and 25mph dyno sniffer tests. It passed visual fine, because the egr was still there. The vacuum line controlling it broke making it not function. It also did better with the smog pump bypassed when it locked up on me then it did functioning. They still ran the test, but failed me when they notice the pulley seized and bypassed.

After repairing my egr gas mileage stayed the same as before. I was averaging 25-27 freeway, and near 30mpg if I did 5 under(70mph). I also averaged 14-19 city, but generally about 16. 14 being worst average, and 19 being best while driving careful. Never could crack 19mpg city though.

Emissions, in my opinion, are useless. 3 of 4 years I drove my car without a functioning egr. No differance in fuel or emissions. Best mileage I was getting was with the smog pump bypassed.

Title: What Octane?
Post by: TOM Renzo on December 28, 2011, 06:26:42 PM

Suu

Title: What Octane?
Post by: Haystack on December 28, 2011, 08:22:39 PM

Her you go
http://www.foxtbirdcougarforums.com/showthread.php?11193-Failed-emissions-got-a-new-cat-convert-and-got-WORSE!!!&highlight=

Right there, paid $800 for a new cat and smog pump, and emissions got worse.

The problem ended up being two bad map sensors, two bad fuel pressure regulators, and one bad o2 sensor. Actually, the emissions didn't change after swapping everything, except the map sensor, but all of the other sensors were bad.

What is a dynamic or active test?

Until this year cars were ran from 15mph to 30mph on a loaded dyno with the sniffer hooked up. Starting this year, now it is a idle and 1500rpm stationary test.

My 87 bird I junked in march, ran better emissions with the smog pump bypassed then when I fixed it a week later. The egr did not function the first three years I drove the car. 4th year I replaced the vacuum lines and fixed my egr. Emissions were actually slightly worse with functioning egr then the previous 3 years.I also put about 40k on that car between the 3rd and 4th year. Nothing changed emissions wise except the nox going up slightly.

I do not have all the paper work anymore. I threw it away when I junked the car. Long story short, here is two examples where a working smog pump and egr raised emissions. I honestly do not believe they do anything for the car, as long as it is running correctly. The gas mileage is definately not effected, in my cars at least. I drove between 200 and 400 miles a day, 7 days a weeks. I was down right buttstuff about my mileage.

I worked 50 miles away from my home, and drove an additional 10 miles for a car pool each way. Then I drove back, and then did pizza delivery 25 miles from my home and 50 to 100 miles a day on the job. I could tell everytime I filled up if my tire pressures changed, and remedy it and be right back where I was before. The smog pump seizing and being bypassed gave me 1-3mpg and the egr being repaired did nothing. Getting the smog pump working again got me down that same 1-3 mpg freeway.

I am not trying to argue anything, I just think that there is more to this then either of us are seeing.

Title: What Octane?
Post by: TOM Renzo on December 29, 2011, 05:52:28 AM

Title: What Octane?
Post by: TOM Renzo on December 29, 2011, 06:02:51 AM

Title: What Octane?
Post by: TOM Renzo on December 29, 2011, 06:11:17 AM

Title: What Octane?
Post by: TOM Renzo on December 29, 2011, 06:41:25 AM

Title: What Octane?
Post by: Haystack on December 29, 2011, 06:45:26 AM

Actually, that engine had either 297 or 397k on it. Never did figure out which. I rolled the odometer over 199k twice. A 30 year emissins tech is the person, after running codes, told me it was my cat. I ended up passing by hollowing out my new cat, and replacing the map sensor. The origonal map sensor failed, and the one I replaced it with was also badout of the box. I ruled out that code thinking it was just stuck in memory and was already replaced. Third one, swapped off of a good running car cleared everything up. Passed emissions fine the very next day, with a hollowed out cat and new map sensor. That car had quite a few issues. Not too many $110 police impounds that you can get 150k out of. To give you an idea of how screwed up that car was, and not well maintained, it still had 1985 motorcraft wires on it. I learned quite a bit from that car. What actually killed that car was they wanted me to have an ignition key on it. I guess its against the law to drive with a busted out ignition key. I swapped in a floor shift colum and added the colum shifter to it and theshifter ended up snapping off.

So, how did a new cat make my emissions worse if there so good for the engine and emissions? I never claimed to be an emissions tech, or be an expert, I am just giving you my experiances. Overall, the more emissions componets functioning on every car I have had, theemissions got worse, not better. Just saying. The egr definately will not effect gas mileage, in my experiance, and hasn't helped me any with emissions either.

Title: What Octane?
Post by: Haystack on December 29, 2011, 06:59:03 AM

Oh and tom, if you would like to replicate my test, you can do the same thing by pulling the vacuum line off of the map sensor. When I had my motor mounts go bad on my last tbird, it would pull the vacuum line off the intake. It would shoot black smoke out of the tail pipe and leave black soot on the ground.

Title: What Octane?
Post by: 88 Blackbird 5.0 on December 29, 2011, 01:08:52 PM

You never saw me say that there aren't times when running higher octane fuel isn't in your best interest Tom. If you modify your engine so that it will still make more power, even though the fuel you're running has to have higher octane to avoid detonation, the modification was well worth it. Definitelu run higher octane. If the Engineers who designed your engine tell you to run 91 octane in the car, I'd never recommend running a lower octane fuel than what they recommended.

What I have been saying all along is it's possible to think you're improving power by doing something that's supposed to add power, but actually doesn't. A perfect example of this ia advancing your timing so much that you have to run higher octane fuel. When you do that, power levels don't increase. You gained power by bumping the timing, but you lost the same amount of power by having to run a less potent fuel. I can't make this any easier to understand Tom. I've already made it perfectly clear that I think that running a higher octane fuel is fine if the modification you did results in a power gain even though your now using higher octane fuel.

Higher octane+engine mod that equals a net gain in power=GOOD

Higher octane+engine mod that equals less, or no net gain in power=BAD

Having to run higher octane is not always bad.

Title: What Octane?
Post by: TOM Renzo on December 30, 2011, 08:21:13 AM

Title: What Octane?
Post by: TOM Renzo on December 30, 2011, 08:30:30 AM

Title: What Octane?
Post by: Haystack on December 30, 2011, 07:08:59 PM

Well tom, I am not trying to pretend to be an expert, and true I am practically cutting teeth compared to you. My emissions issues from that link were basically the first trouble shooting I did to any car. I was 18 years old, and I'm not even 25 yet. I do not come from an automotive back ground, nor do I think I know everything. Almost everything I learned was from forums or first hand experiance. When you talk I listen, and look into it. But I can prove one out of two times I replaced a cat, and both times my emissions go worse. In my opinion, the egr will not positively effect emissions. I ran my last car hard and kept it running good. In a 12 hour day, I was driving it at least 6 hours a day. I can tell you which gas stations in my area were the last to use ethonal, based purely off of gas mileage. In my experiance at least, there isn't a doubt in my mind that I am right.

Maybe my cat wasn't working at all on either of my last two cars, and maybe my egr was clogged on one of them. But on my thunder bird I swapped both my intake and egr to a h.o. unit, and I cleaned the out of it and made sure it functioned, after they failed me for a seized smog pump. The emissions were worse, not better. I don't have any other explaination, do you?

Title: What Octane?
Post by: TOM Renzo on December 30, 2011, 11:56:57 PM

Title: What Octane?
Post by: Chrome on December 31, 2011, 12:13:55 AM

Tom, I know you know this stuff, this post is for those who don't. Cat converters reduce HCs. EGR valves reduce combustion temps by introducing non-combustable gas into the combustion chambers, thus reducing the combustion temps that cause NOX. The sole purpose of the smog pump is to assist the cat converters. The fresh air keeps them cooler which helps them catalize.

As for timing... manufactures are conservative about timing. They will keep the timing a little on the low side because of differences in engine tolerances caused by the manufacturing process. Also, the outer ring on the harmonic balancers do slip. The best way to time these things is with a vac gauge. The more vac the better. Once you have reached the max vac, do not advance any further or it will be to far advanced. As we all know, too much advance causes knocks and pings that can be hushed with higher octane. Higher octane should only be used to hush the pinging if the car is timed correctly.

As for Haystack's sniffer numbers... with that kind of mileage, who knows what is going on in that engine. blow-by... low vac... I salute him for making it pass his state's emission tests. My state only does those tests in counties that have large cities in them, so I don't have to worry about passing them. I was a state inspector for 2 years and all we had to do for emission testing was test the gas cap and do a visual. Make sure components are not altered or missing. 81 and older cars don't even have to have cat converters.

Title: What Octane?
Post by: Chrome on December 31, 2011, 12:16:49 AM

Sorry Tom, your last post was sent as I was typing mine.

Title: What Octane?
Post by: TOM Renzo on December 31, 2011, 12:33:09 AM

Title: What Octane?
Post by: Chrome on December 31, 2011, 12:53:10 AM

OK Tom, can't slam that post. Most of the work I have performed with cats has been due to them overheating caused by too much fuel or the fuel not getting burned. Did not have to use cat performance theory much. Your post is more accurate. Facinating that Ford dampers spin more.

Title: What Octane?
Post by: Chrome on December 31, 2011, 01:04:34 AM

I do have to add that we are working on cars that are 88 and older. Factory cats on these cars do restrict, especially if they haven't been tuned up regularly their whole life. I have had HP gain from disabling EGR. I claim that to be from the theory I mentioned at the start of this thread. Diluted mixture still in cylinders when you hit the throttle. However, it could just be because of a EGR valve malfunction.

And I will never claim that emission components don't work. They do!

Title: What Octane?
Post by: Haystack on December 31, 2011, 02:19:17 AM

Tom, I was harsh in my posts as well. Were all on the same team here. I read and re-read every post by you before making any response. Words aren't conveyed very well through text all of the time. I am glad to have someone with experiance greater then mine to be shared.

That engine had quite a few issues. It didn't leak a drop of oil, but used 2-3 quarts a tank. I have a feeling that it was really near 397k. I never did check the kilometers on the digi dash because I didn't know about that trick. In the time I owned that car, I made many mistakes and wasted quite a bit of money because I didn't know what to do to fix it. I decided the prroblems steamed around the high mileage. I litterly swapped every sensor I knew about trying to get it pass. Until my second 86 5.0 broke the vacuum manifold. Then iit started running the same and shooting black smoke all over everything.

I swapped the map sensor onto the other car and the smoke cleared right up, 3 days after I layed down $1k for a rebuilt block. Took it in and it barely failed. Replaced the gas cap, and hollowed out my new $600 clogged cat and passed emissions with flying colors, less then 1/3rd of max on nox. They failed me on saftey for having a busted out colum and non-working electric windows. It was a police impound and I took out a fire hydrant on the drivers side door. Swapped in a floor shift colum and wired new switches to my windows and passed.

Drove the car for about a week, trying to milk it through the winter to swap in my new 85 gt block and replace my aod missing od. Well got it stuck in a 6ft snow drift and busted off the shifter banging it in and out gear getting it unstuck. Pulled it infront of my house instead of the driveway so my dad could get to work the next day. Ended up getting towed for being parked on the street with a snow accumulation while I was working 4 days straight out of town. Sucks too because I already bought the new shifter and correct colum shifter colum on my way home and was going to swap it in on over 4 days without sleep so that I could park it in the driveway.

Had quite a bit of love for that car and I would have done anything to get it back, even today. Hell I was into it over $4k just trying to get it through emissions that year alone. They wouldn't give me a emissions waiver because I did most of the work my self and had to be repaired by a state certified mechanic, which was the whole reason I had the cat and smog pump put into it.

I would rather it ran good and would pass emissions too.

Title: What Octane?
Post by: Chrome on December 31, 2011, 02:56:15 AM

:rollin:Cats really do have 9 lives!

This has been a wild thread. Tom and Haystack fighting like cats and birds. Original thread starter trying to keep it on subject, and me sticking my nose in it! We should all be careful. Written word can be misunderstood very easily.

Haystack, Tom has the knowledge and experiance we all wish we had, but when it comes down to it ur no dummy. Sometimes a poor mans view can be more helpful. Not saying you are poor, just that we don't all have access to the equipment and more complicated info that Tom does, and that changes the views dramaticly.

Title: What Octane?
Post by: TOM Renzo on December 31, 2011, 07:47:09 AM

Title: What Octane?
Post by: 88 Blackbird 5.0 on December 31, 2011, 12:05:43 PM

The stance I took on dynamic stacking was correct Tom. Dynamic stacking IS a reality. I never said it wasn't. What you don't seem to realize is that in two, absolutely identical engines, dynamic stacking WILL NOT cause those two engines to have radically different octane requirements.
Through this whole thread, you've been misunderstanding what I've said for some reason.

Title: What Octane?
Post by: Chrome on December 31, 2011, 12:42:28 PM

I think altitude plays a big roll in octain requirements. When I visit my brothers in Kansas, whatever I am driving takes on a whole new attitude. More power and even sounds better. Kansas has a much lower altitude than the panhandle of Texas. My question is, how would altitude affect octane? Does higher altitude require more or less octain?

Title: What Octane?
Post by: 88 Blackbird 5.0 on December 31, 2011, 12:49:57 PM

High altitude lowers your compression. That means you can run lower octane without pinging.

Title: What Octane?
Post by: Chrome on December 31, 2011, 01:05:22 PM

:punchballs:I should have thought about it before posting that question. Lower altitude, thicker air.

Title: What Octane?
Post by: Haystack on December 31, 2011, 01:15:51 PM

85 is our low octane, and 91 is our high octane. I doubt there would be much of a differance. They still have to make the car run good at any elevation. My work trucks at least didn't ping going from 4500ft to whatever kansas was on a tank of gas. Here you can also go from 3200ft to just over 1000ft in just about 2 hours drive. I personally never ran my bird with my bumped toming above 5ooo, but I am sure it would have been fine. Still had quite a bit to go before I would ping.

Another thing I haven't seen mentioned at all, is most places have an ethonal blend now. That should raise your octane a bit too.

Title: What Octane?
Post by: Haystack on December 31, 2011, 01:16:06 PM

Title: What Octane?
Post by: 88 Blackbird 5.0 on December 31, 2011, 01:20:45 PM

That's no big deal. You just had a brain fart. Everyone has those.

Imagine trying to get a plane to perform well at low altitudes AND high altitudes. P51 Mustangs (the later models) had 2-speed superchargers (the pilots hated the superchargers, because they were junk) on their engines to compensate for the thinner air at higher altitudes. That thin air can really change how an engine performs.

Title: What Octane?
Post by: Haystack on December 31, 2011, 04:44:33 PM

Same reason why avaiation fuel is higher octane, and most airplane engines had a timing advanced control in them. Have not read much past worl war 2 planes, but they ran those as lean as possible with high timing to help with mileage and power. I'll have to ask my dad what he knows about aviation fuels, but I can't imagine he would say much different.

Title: What Octane?
Post by: thunderjet302 on December 31, 2011, 05:32:21 PM

Quote from: 88 Blackbird 5.0;376585

That's no big deal. You just had a brain fart. Everyone has those.

Imagine trying to get a plane to perform well at low altitudes AND high altitudes. P51 Mustangs (the later models) had 2-speed superchargers (the pilots hated the superchargers, because they were junk) on their engines to compensate for the thinner air at higher altitudes. That thin air can really change how an engine performs.

The Rolls Royce (Packard) Merlin with the supercharger was faaaar superior to the Alison V16 it replaced in the P-51A.

Title: What Octane?
Post by: TOM Renzo on December 31, 2011, 06:18:30 PM

Title: What Octane?
Post by: 88 Blackbird 5.0 on December 31, 2011, 07:57:27 PM

The Merlin engine was far superior in power, but the 2-speed superchargers that were on the Merlins were pr0ne to sticking. That left the pilots who flew Mustangs in the war (like my Dad) in some touchy situations at times. Imagine being in a dogfight and the supercharger on your plane's engine is stuck in the wrong gear. You need 1st gear and the supercharger is stuck in 2nd. Not good. I remember asking Dad what he and the other pilots that flew Mustangs thought about the Merlin engines when they first came out. The first thing he said about them, was that they were junk. When they worked correctly, they were a dream though. I think dad said they finally resolved that problem though.

I wish I could have gotten him to tell me more stories about the war though. He sure seemed to hate talking about it.

Title: What Octane?
Post by: Chrome on December 31, 2011, 08:00:18 PM

Yes it was poorly worded, but I knew what he was trying to say. I suppose a different kind of cam is why Chrysler was able to have so many of the newer cars without EGR. I think this would be a better way of controlling emissions because it does not leave a point of failure. Had no idea cam selection was so critical when it comes to compression ratio. I would love to learn more about this.

Title: What Octane?
Post by: 88 Blackbird 5.0 on December 31, 2011, 08:04:33 PM

Tom's just being pedantic. I did word that poorly, but knew you'd understand what I was saying was that there is less air being compressed in your engine's cylinders at high altitudes than at lower ones.

Title: What Octane?
Post by: Haystack on December 31, 2011, 08:13:23 PM

The compression ratio does not change. But the cylinder pressures do.

Title: What Octane?
Post by: 88 Blackbird 5.0 on December 31, 2011, 08:26:06 PM

That's right. That's what I should have said. :)

Title: What Octane?
Post by: TOM Renzo on January 01, 2012, 12:50:01 AM

Title: What Octane?
Post by: jcassity on January 01, 2012, 01:17:32 AM

with our older motors and to answer the original post, I tend to stay clear of higher octanes as of the past couple of years.
I tend to stick to the middle grade but now I am seeing EPA fuels (test bed areas like Indiana) where there are like 4 or 5 fuel selections and even one selection that had a different nozzle on the end but it was not diesel. It was some sort of Eco fuel or something... so much to choose from all i know is that the the higher the octane, the odds are against my motor being capable of putting up with it for long periods of time.

answer, im using 87 and 89.

Title: What Octane?
Post by: Haystack on January 01, 2012, 01:29:43 AM

When you know the actual cylinder compression, and the compression ratio, you know almost exactly what you can and cannot run. Even though the cam does help with cranking pressures, it is not the sole determining factor. You might have a big cam with 8.5 to one compression, or lots and lots of overlap, which will run completely differently then another engine, all else being equal, but with 11 to 1 compression ratio. Then there is the style of piston, heads, quench area ect. There really is no other way to know exactly what octane you can or can't run, until it is running. But guessing off of you compression ratio and actual cylinder pressures, you will be right 99% of the time.

Title: What Octane?
Post by: TOM Renzo on January 01, 2012, 10:17:08 AM

Title: What Octane?
Post by: TOM Renzo on January 01, 2012, 10:23:05 AM

Title: What Octane?
Post by: Chrome on January 01, 2012, 03:47:03 PM

Tom, the thing to keep in mind is most of us are running well under 400 HP. Most of us would be happy with 350 HP. For these numbers, we don't have to spend the kind of money that the engines you are building cost. Most of us have no access to a dyno! This is why we share what works for us and what doesn't. I don't know about anyone else, but I don't want to visit Dallas every time I build an engine.

Title: What Octane?
Post by: Haystack on January 01, 2012, 04:37:56 PM

Most engine builders I do know don't use a dyno for anything, except for top power, find everything the engine caan get out of them. I guess there all idiots too for telling people what octane to try, and what compression their engine is. Or the people getting their engines built what octane they want to hit.

The only correct answer is what your engine will tollerate. Period. There are lots of bullshiznit computer calculations and smoke and mirrors to hide behind, but until its running, you don't even know where to start. As a matter of fact, every dyno rates hp differently, and depends heavily on the person running it. You can make any motor look good. You can see that in every mustang magizine.

Title: What Octane?
Post by: TOM Renzo on January 01, 2012, 06:01:25 PM

Title: What Octane?
Post by: Chrome on January 01, 2012, 08:21:49 PM

:dunno:

Quote from: TOM Renzo;376651

so much to choose from all i know is that the the higher the octane, the odds are against my motor being capable of putting up with it for long periods of time.

Why ???? Can you explain this to ME!!!!! What would be the issue???? So you are saying your engine will expload with a higher octane on a regular diet. I find this extremely odd and would like to know why?????

To put it in perspective. Toyota recommends regular 87 in the camry V6. But in the lexus with the same exact engine and tune they recommend premium 91. Can anyone explain this to ME??????

Title: What Octane?
Post by: 88 Blackbird 5.0 on January 01, 2012, 08:59:21 PM

The reasons why running more octane than you need to is a bad idea have been clearly explained to you numerous times in this thread Tom. Those reasons don't mesh with the opines you've shared in this thread, because your opines on the effect octane has on engines are totally wrong. You apparently lack the self esteem to admit when you're wrong, or are one of those guys who will never see the light, even if there's tons of evidence to prove you're wrong about something. You were rude as hell to Haystack for what he said earlier in this thread about emissions components and their effect on engines, but that was AFTER you made totally screwed up statements about octane's effect on engines yourself. Anyone who REALLY knows as much as you claim to know about cars would know the truth of this matter. Also; common sense should tell you that most people don't want to spend the extra money on a higher grade fuel than their vehicle requires.

Title: What Octane?
Post by: TOM Renzo on January 01, 2012, 10:19:30 PM

Title: What Octane?
Post by: Chrome on January 01, 2012, 11:12:11 PM

Tom, it is understandable if you feel the need to dyno those. I would too. Our cars are not nearly as costly. The power levels that we are working with, we can discover and repair detonation way before it causes major damage. Not saying your ideas are wrong. Just saying they are overkill for what most of us do..........just like if we put that first engine in one of are cats or birds. Local law enforcement would have a field day!

Title: What Octane?
Post by: TOM Renzo on January 01, 2012, 11:25:03 PM

[im

Title: What Octane?
Post by: TOM Renzo on January 01, 2012, 11:31:27 PM

[qu

Title: What Octane?
Post by: TOM Renzo on January 01, 2012, 11:34:55 PM

[qu

Title: What Octane?
Post by: Chrome on January 01, 2012, 11:54:34 PM

Quote from: TOM Renzo;376788

Chrome an engine is an engine they are all air pumps!!!!! Once again hope i got you thinking about sweep compression and how it effects compression pressures. I seem to think i taught you something and that is good. That is why i post on sites. Remember an engine is an air pump. And as they get older and build some deposits they can require higher octane. Also engineers are so worried about detonation in modern engines the y monitor and adjust it with the Knock sensor and the O2 . If i made a difference how you thimk or if you learned something i am happy. That is why i post. Thank you

I have been told engines are nothing but air pumps half my life. We just need enough air pump to move a car, not a planet. lol I will look more into sweep compression. Never covered in school, and I have never seen anything about it in books or magazines. I plan on looking into it more. I have always wondered about dual pattern cams and what they were supposed to accomplish. Cams are the most hard to understand part of an engine........funny since they are just one piece of metal, and only have the purpose of opening valves.

Title: What Octane?
Post by: Chrome on January 02, 2012, 12:05:02 AM

Quote from: TOM Renzo;376791

This was my first post and sums it up pretty correctly i would think

Guess what his reply to that should have been. GT40p heads, and intake. and a E cam with fly-cut pistons. That is the most popular configuration in this forum, and what I will most likely do to my bird. I think he wanted to see what octane is being used with this configuration. As a side question, have you dynoed this config? What is the most probable HP for this set up?

Title: What Octane?
Post by: TOM Renzo on January 02, 2012, 12:12:09 AM

I re

Title: What Octane?
Post by: Haystack on January 02, 2012, 03:04:56 AM

I swapped the the headlight on a mazerati, as a matter of fact, I was paid to do it. Doesn't sound impressive when I tell you I was the shop gopher, and noone else had long enough arms. I guess it took them 5 or 6 hours the first time, taking off basically the whole front end.

I've also worked on a 28 studebaker police car, model t rat rod, some kind of ferarri, and a w12 bentley. Even a 4 seater 2.3 turbo sand rail with an eslinger head and big turbo.

So what was in this 328rwhp 347? Which head transmission ect? And 1/4 miles times? 328 at the wheels sounds like a good number, but as I said earlier, the dyno results are only as good as the person running them.

Title: What Octane?
Post by: TOM Renzo on January 02, 2012, 07:19:59 AM

Title: What Octane?
Post by: Chrome on January 02, 2012, 09:57:16 AM

Sure is a lot of fancy stuff to just show exprieance. A car is a car. Simply put, this has gone way too far. The thread posted a simple question "What octane do you use?", not "What octane should be used?"

Title: What Octane?
Post by: 88 Blackbird 5.0 on January 02, 2012, 10:17:41 AM

Quote from: Chrome;376811

Sure is a lot of fancy stuff to just show exprieance. A car is a car. Simply put, this has gone way too far. The thread posted a simple question "What octane do you use?", not "What octane should be used?"

You're exactly right Chrome. It's safe to say that Tom has impressed himself. I thought it was a simple question that would give us something to talk about in a friendly way. Things had gotten really slow here in this forum and I thought I might be able to wake things up a little bit by starting a conversation that EVERYONE here could respond to. That's all.

Title: What Octane?
Post by: Haystack on January 02, 2012, 06:01:04 PM

Its kinda fun to share information, while dodging any and all questions. So do you think that means some one is to smart to communicate with others, or smart enough to know they can't answer questions?

Its easy to look smart when you have the answer to the question you ask yourself.

Title: What Octane?
Post by: DVP on January 02, 2012, 07:00:29 PM

On the note of octane, local shop ran a car on the dyno with QT fuel, then Shell IIRC. Loss of 25 horsepower just on fuel.

Title: What Octane?
Post by: TOM Renzo on January 02, 2012, 07:48:18 PM

Title: What Octane?
Post by: Chrome on January 02, 2012, 08:24:51 PM

:sorry:

Quote from: 88 Blackbird 5.0;376813

You're exactly right Chrome. It's safe to say that Tom has impressed himself. I thought it was a simple question that would give us something to talk about in a friendly way. Things had gotten really slow here in this forum and I thought I might be able to wake things up a little bit by starting a conversation that EVERYONE here could respond to. That's all.

This thread took a bad turn from the very start. I am ashamed to have gotten involved at all. I don't even have a constructive answer to your simple question. Bought my bird in October. It was bone stock. So far my modifications include a tune up and bumping up the timing. I didn't use a timing light, vac gauge, or dyno.(OMG!) It starts fine, runs fine, has no pings. As for octane, I use the lowest grade I can possibly find. I am sorry to have perpetuated the slaughter of your innocent and constructive thread.

Title: What Octane?
Post by: 88 Blackbird 5.0 on January 02, 2012, 08:31:45 PM

Lol. You didn't perpetuate the slaughter of this thread. I thought what you had to say was constructive. :)

Title: What Octane?
Post by: 88 Blackbird 5.0 on January 02, 2012, 08:33:33 PM

Quote from: DVP;376849

On the note of octane, local shop ran a car on the dyno with QT fuel, then Shell IIRC. Loss of 25 horsepower just on fuel.

Wow Dillon! That's a big drop in power!

Title: What Octane?
Post by: Chrome on January 02, 2012, 08:34:58 PM

Tom, sorry you couldn't dumb it down for us "GOOD OL BOYS". Maybe we should join a different forum. Perhaps one about tractors, or cow, or chickens or something!

Title: What Octane?
Post by: Chrome on January 02, 2012, 08:38:16 PM

Quote from: 88 Blackbird 5.0;376857

Lol. You didn't perpetuate the slaughter of this thread. I thought what you had to say was constructive. :)

Thank U.

Title: What Octane?
Post by: TOM Renzo on January 02, 2012, 09:22:50 PM

Title: What Octane?
Post by: Chrome on January 02, 2012, 10:40:38 PM

:disappoinThe man's been working on cars longer than I've been alive and can't tell what an engine is doing by listening to it.

Title: What Octane?
Post by: Haystack on January 02, 2012, 10:49:14 PM

Mr. Tom, I do not have any problem with a majority or what was said here, however. A discussion usually revolves around those having experiance on a subject, sharing it with others. I am not part of an un-ruly mob, nor am I going to consider myself to be an expert. I was not here to brag, until you started taking shots at me to make me look like an un-educated idiot. Which by the way I am. I still don't understand why you are/were so threatened by me.

Octane was brought up, I mentined what I run, and somewhere someone mentioned that no egr with obviously effect both gas mileage and emissions. Me being stupid as I am, decided to share several of my own experiances. I was personally attacked and made fun of, and called out for everyone to see as an idiot. When I asked you specific questions, you conveineantly changed the subject, made fun of me, or bragged about how you work in the automotive feild, and that I don't.

Why even bother drilling and tapping a brake line? There is going to be almost no flow whatsoever going through it, and it would more likely draw more air through your single exhaust port then to you intake, especially at lower rpm's. The air will be introduced, and dillute air, not clean it. All emissions are tested by parts per million. You add air into that, and it is going to seem cleaner, no matter what. An old hot rod trick to pass emissions was to drill lots of small 1/8th inch holes into your tail pipe because it would suck air into your entire exhaust sytem, "cleaning " it, and getting you passed on emissions. I don't see what your doing with brake lines as being any different, or an egr for that matter. If your just going to ignore me and act high and mighty, let me know, and you can be the first ever person in about 6 or 7 years to make it into my ignored filter.

If you are here to share information, go ahead. I would appreciate it if you could answer one of many questions that you asked throughout this entire thread, as I have answered many of yours.

Title: What Octane?
Post by: Haystack on January 02, 2012, 10:49:32 PM

Title: What Octane?
Post by: Chrome on January 02, 2012, 11:04:45 PM

:stupid:

Just kidding Haystack, you are far from.

Title: What Octane?
Post by: TOM Renzo on January 03, 2012, 05:37:00 AM

Ok if y

Title: What Octane?
Post by: Haystack on January 03, 2012, 07:03:58 AM

I have been told that my car cannot be tested before for having holes in my exhaust. One thing that I find funny about emissions, is that in my experiance, they really don't do anything to help. Note, I did say in MY experiance, not that it is law, or anyone that disagrees with me shouldn't. A number of emissions components were deleted in the 1990's when cars switched to obd2. Also, many imported cars in the 80's didn't have cats, or egr valves. Many had no emissions. Those cars had to pass the same tests as mine, and I have seen them get better then cars with emissions functioning. Anothing thing I found funny. A friend of mine run a sniffer test on a obd2 vehicle, when her worked at a shop, just for fun. It didn't pass at all. Not even close. Yet as long as it doesn't throw a code, its fine, in my state. I knew another kid that had a carbed 460 in a later 90's mustang. He passed every year with a $40 fake obd2 computer.

In my state, they went to the idle rev test. Not sure what you call that, but now, in my opinion, it should be impossible not to pass. I am still not to see a single person fail this test. Now remember I did say in my opinion.

So, I have blown through a brake line before, and there really isn't much of any air passed through. The only way that this could work is if the car had a very restrictive exhaust system. Otherwise it would suck cooler air out of the intake. Not trying to be mean, but I really don't see it making much of any differance.

Also, why did my emissions get so much worse with a functioning cat? Why didn't my emissions get quite a bit better with my repaired egr on my thunderbird? I know every engine is different, but I can't come up with any explaination for anything I have experianced.

Title: What Octane?
Post by: TOM Renzo on January 03, 2012, 12:42:29 PM

Fir

Title: What Octane?
Post by: shame302 on January 03, 2012, 04:24:30 PM

Quote from: 88 Blackbird 5.0;376813

You're exactly right Chrome. It's safe to say that Tom has impressed himself.

Quite obviously this is what most of his posts are ever about. Loves to hear himself go on.

Quote from: TOM Renzo;376774

So be it as it may i always tune for 93. But not always.

:hick:

Quote from: TOM Renzo;376862

No problem i am moving on. Sorry you dont understand what i was saying.

Have a good DAY Y'all

:bowdown:

No you won't.

Tom Renzo, possibly the MOST narcissistic, arrogant, self riotous and obnoxious post w to date.

:evilgrin:

Seems to me Tom, any quality info you bring to the site is muddied of not nullified for the above reasons. Keep it up though, it's entertaining. So what's the name of this amazing shop you run?

Title: What Octane?
Post by: shame302 on January 03, 2012, 04:38:01 PM

Quote from: thunderjet302;376598

The Rolls Royce (Packard) Merlin with the supercharger was faaaar superior to the Alison V16 it replaced in the P-51A.

Not that I claim to have much knowledge in regards to them, aircraft engines always impressed and intrigued me one way or another. One that stands out in mind is the Pratt & Whitney R-4360 Wasp Major.

Title: What Octane?
Post by: Haystack on January 03, 2012, 06:05:45 PM

First and foremost OBD2 Did not really come to play until 1996. But some Fords actually had a dummy plug that was not hooked to anything as far as i know

Time to start picking things apart. This is rather time consuming on my cell phone but here we go. Actually most fords were compliant in early 94, except for certain 5.0 engines, such as the 94-95 mustang. In my state, if you have an obd2 plug, you are required to meet those requirements.

So a 1990 Mustang would not be OBD2 Compliant. If the inspector inspected that car as an OBD2 Vehicle the guy should be stacking shelves in wall mart. Also it would be impossible to pass with a dummy computer any way. How would he set the monitors!!! I know it can be Dun but highly unlikely. Also a lot of foreign cars got exemptions like HONDA. Honda got a 1 year extension on OBD2 Compliance. And some other foreign cars also got wavers. Example Volvo had an exemption for obd 2 because their ECM did not retain monitor memory hold over. So they had to get wavered.

I said a 1990's mustang, not a 1990. Once again, only hearing the part of the response you want to. I was not sure of the year of mustang, but I believe it was a 96-98 v-6. The engine blew and he found a loop hole. As long as they didn't get a failed code from the computer, it passed. Actually a problem with the way emissions laws were written in my state. They knew the car shouldn't pass, but passed all of the rules under the new obd2 laws.

Now on the brake line. First i showed clearly the pass paper work my machine printed out. Remember the engine is under vacuum and actually sucks the exhaust in to the intake. If you dont believe me open an egr valve while a car is idling and see what happens to an idling engine. It stalls out. But i used a 1/4 inch pipe and the engine did not stall or fail an ASM 25-25. Reason being the test starts at 25 and not idle. Now an idle 15/25 is very bad because you need to be lean and clean at idle. That is where most engines fail.

If the computer is functioning correctly, it will throw an egr code, which will automatically disable the egr , as well as how the egr is not used at idle until the car is warmed up. To be honest, I don't think the egr is used period at idle.

Now i dont know the numbers in your state for a pass fail by year of manufacturing parameters but the state sets the limits to a degree. Now i dont know why your vehicle failed and had higher numbers with a cat or EGR. What were the numbers and what were the previous numbers. I have to see what it was. Just saying it failed means nothing. Now as for an OBD 2 car to fail an asm or dyno test would be basically very hard to do. Reason being when an obd2 is working properly it is 1.5% cleaner than fed specks. Thank you

So when everything was new from the factory, emissions were 1.5% of maximum allowable. So may car was running quite a bit better then a new obd2 vehicle. And if someone hasn't been maintaining their car, but it still dooesn't throw any codes, it will still pass emissions, while failing the actual emissions tests. Or does obd2 run its own emissions? And you do know the numbers in my state. That post that you got such a kick out of my car hitting 5000nox showed what it was until the begining of this year. I am not sure what it is now, but my state has the same emissions requirements from 1967 to 1995. And yes, there is no emissions waiver in my state forr any vehicle that came with emissions equipment. A 1967 mustang has the exact same emissions requirements as my 88 crown victoria station wagon.

NOTE the EGR valve on most newer cars of non obd2 design will not allow the EGR to operate unless the car is in gear and up to a pre determined speed. So they dont test for it. Plain and simple. Now what do they test?? It depends on the state. But most states that do pre OBD2 Normally do a dyne asm test. But normally up to and including cars that are under 25 years old only older vehicles are exempt in most states. Now some states like NY only do OBD2 compliant cars. Hope this helps.

So in most states the dyno is used. In my state it is not. So my egr would not even function, nor do most cars to begin with on most emissions tests.

But we all have to remember, I am the moron here because I don't work in the industry.

Title: What Octane?
Post by: shame302 on January 03, 2012, 07:22:04 PM

Quote from: Haystack;376928

Once again, only hearing the part of the response you want to.

That's his "thing". Also, he says thank you after every post. It comes off as arrogant and obnoxious Tom, just in case you were un-aware.

Quote

I was not sure of the year of mustang, but I believe it was a 96-98 v-6. The engine blew and he found a loop hole. As long as they didn't get a failed code from the computer, it passed. Actually a problem with the way emissions laws were written in my state. They knew the car shouldn't pass, but passed all of the rules under the new obd2 laws.

1996. It was like this in MA till this year when they wised up to it. Guys with everything turned off in the tune were passing because they were showing no mil lights. Now they won't pass. I believe you are now allowed 2 to be turned off (2001 and older anyway) and still pass if no MIL indicator. This works for me as I only have my rear O2s turned off. My buddy with his boosted 04 GT got nailed hard. Had to go to a separate entity after failing in order to be approved for a re-test. We de-modded the car back to stock and flashed the stock tune back into it. For next year he is going to need a new tune (expensive) or de-mod again (pita).

Title: What Octane?
Post by: 20thanniver-ls on January 03, 2012, 08:07:46 PM

Quote from: TOM Renzo;376902

First and foremost OBD2 Did not really come to play until 1996. But some Fords actually had a dummy plug that was not hooked to anything as far as i know. So a 1990 Mustang would not be OBD2 Compliant. If the inspector inspected that car as an OBD2 Vehicle the guy should be stacking shelves in wall mart. Also it would be impossible to pass with a dummy computer any way. How would he set the monitors!!! I know it can be Dun but highly unlikely. Also a lot of foreign cars got exemptions like HONDA. Honda got a 1 year extension on OBD2 Compliance. And some other foreign cars also got wavers. Example Volvo had an exemption for obd 2 because their ECM did not retain monitor memory hold over. So they had to get wavered. Now on the brake line. First i showed clearly the pass paper work my machine printed out. Remember the engine is under vacuum and actually sucks the exhaust in to the intake. If you dont believe me open an egr valve while a car is idling and see what happens to an idling engine. It stalls out. But i used a 1/4 inch pipe and the engine did not stall or fail an ASM 25-25. Reason being the test starts at 25 and not idle. Now an idle 15/25 is very bad because you need to be lean and clean at idle. That is where most engines fail. Now i dont know the numbers in your state for a pass fail by year of manufacturing parameters but the state sets the limits to a degree. Now i dont know why your vehicle failed and had higher numbers with a cat or EGR. What were the numbers and what were the previous numbers. I have to see what it was. Just saying it failed means nothing. Now as for an OBD 2 car to fail an asm or dyno test would be basically very hard to do. Reason being when an obd2 is working properly it is 1.5% cleaner than fed specks. Thank you

NOTE the EGR valve on most newer cars of non obd2 design will not allow the EGR to operate unless the car is in gear and up to a pre determined speed. So they dont test for it. Plain and simple. Now what do they test?? It depends on the state. But most states that do pre OBD2 Normally do a dyne asm test. But normally up to and including cars that are under 25 years old only older vehicles are exempt in most states. Now some states like NY only do OBD2 compliant cars. Hope this helps

'94 and up T-birds and Cougars are in fact OBD-2, no dummy plugs.

Title: What Octane?
Post by: thunderjet302 on January 03, 2012, 09:38:37 PM

Quote from: shame302;376925

Not that I claim to have much knowledge in regards to them, aircraft engines always impressed and intrigued me one way or another. One that stands out in mind is the Pratt & Whitney R-4360 Wasp Major.

The R-4360 is a awesome engine. Another cool Pratt & Whitney engine is the R-2800 Double Wasp used in the P-47 and F6F Hellcat: http://en.wikipedia.org/wiki/Pratt_%26_Whitney_R-2800_Double_Wasp

Title: What Octane?
Post by: thunderjet302 on January 03, 2012, 09:44:25 PM

Quote from: 20thanniver-ls;376936

'94 and up T-birds and Cougars are in fact OBD-2, no dummy plugs.

The 3.8 was OBD I till '96 when it went OBD II. I know because I use to own a 95 T-bird and it ran EEC-IV and was OBD I.

Title: What Octane?
Post by: Chrome on January 03, 2012, 10:12:31 PM

Quote from: shame302;376924

Quite obviously this is what most of his posts are ever about. Loves to hear himself go on.

:hick:

:bowdown:

No you won't.

Tom Renzo, possibly the MOST narcissistic, arrogant, self riotous and obnoxious post w to date.

:evilgrin:

Seems to me Tom, any quality info you bring to the site is muddied of not nullified for the above reasons. Keep it up though, it's entertaining. So what's the name of this amazing shop you run?

I feel cheated. I was planning on posting the same thing.

Title: What Octane?
Post by: Chrome on January 03, 2012, 10:29:53 PM

Quote from: TOM Renzo;376862

No problem i am moving on. Sorry you dont understand what i was saying. Octane is determined by many things built in to a particular combination . Example Axle ratio transmission Altitude induction system with or without EGR injector size. Thermostat so on and so forth. Anyone that does not know their exact timing and claims to set it without a light or whatever is beyond my even commenting. You should know exactly where your timing parameters are. Either way i messed with the regulars and got hammered because of the click. Well thanks i will remember all the knowledge i learned by this post. I am going to throw my SNAP ON timing light away tomorrow when i open my business. After all it is not needed right Chrome. The silliest thing i have ever heard in my life.

I do understand what you are saying. It is not the purpose of this thread. He wanted to know what octane these fellas ran with similar setups. Not identical setups, not what octane is needed. He was starting conversation. How come so many threads you post in results in fighting? How come you have posted the high dollar builds in three posts that I know of in order to prove experiance? WE GET THE POINT TOM! As for the timing.... I knew you would be appalled by that. Timing by ear is not for the squeemish. As long as it runs fine, sounds fine, and plugs look fine, there is no problem. A dyno would show it is in much better shape now, and although the timing would not show perfect, it would be close. That is all one can ask for without a dyno.....timing light or not.

Title: What Octane?
Post by: TOM Renzo on January 04, 2012, 05:34:46 AM

[qu

Title: What Octane?
Post by: shame302 on January 04, 2012, 01:45:24 PM

Quote from: TOM Renzo;376968

On 1996 and later vehicles, you can tell which protocol is used by examining the OBD II connector:

Uhhh moot point? your entire post is moot because again, you fail to address what YOU quoted and responded to:

Quote from: 20thanniver-ls;376936

'94 and up T-birds and Cougars are in fact OBD-2, no dummy plugs.

The V6 cars are OBDI the 4.6 cars are in fact OBDII. Just because your state may not require them to be OBDII compliant does not mean they aren't.

Was that so difficult Tom?

What's the name of this elite shop again Tom?

Oh:

Quote

Just for the record as posted 1990 was not obd 2 nor would it be tested as so. That is without a doubt of being incorrect.

Nobody said they were. You mis-understood/read and then got all excited..

Thank you.

Title: What Octane?
Post by: Haystack on January 04, 2012, 03:08:26 PM

Tom, you are an entertaining guy. I think the internet is ruinging our relation ship though. I think if we had this same discussion over a beer or two, we would be freinds after. In the mean time, I will read what you post, and remember that it is always a loaded answer, and that you will not answer any questions. You are useful, and very knowledgeabe, but not someone to be trusted without double checking virtially everything you say.

Good thing there isn't so much politics thrown into wiring. Otherwise nothing would ever get done.

Title: What Octane?
Post by: 20thanniver-ls on January 04, 2012, 05:46:56 PM

Quote from: thunderjet302;376944

The 3.8 was OBD I till '96 when it went OBD II. I know because I use to own a 95 T-bird and it ran EEC-IV and was OBD I.

Yep. I meant to put V-8 Birds and cats '94 and up....

Title: What Octane?
Post by: Chrome on January 08, 2012, 01:20:00 AM

:DThis thread was a good idea, but has gone majorly awry. Can we start fresh? Please post the octane you use if you have similar set up! As Tom has so painfully expressed over and over, octane has many contributing factors. Please post your octane and the factors that may be the reason for your octane use. Let's not get side tracked with arguments over emission requirements or OBD2 or such.

Title: What Octane?
Post by: jcassity on January 08, 2012, 09:39:44 AM

Quote from: TOM Renzo;376651

so much to choose from all i know is that the the higher the octane, the odds are against my motor being capable of putting up with it for long periods of time.

Why ???? Can you explain this to ME!!!!! What would be the issue???? So you are saying your engine will expload with a higher octane on a regular diet. I find this extremely odd and would like to know why?????

To put it in perspective. Toyota recommends regular 87 in the camry V6. But in the lexus with the same exact engine and tune they recommend premium 91. Can anyone explain this to ME??????

i thought,,(perhaps that may be the problem ) that the higher octane results in the following:

~more heat
~more miles to the gallon

I have gotten better miles to the gallon but with the fuel changes, i am pretty certain (based on zero facts) that the original design was not based on fuels to be invented two decades from now.

For the purposes of too much heat, and the age of the motor pieces parts, again i "thought" the higher octane would eventually cause some harm.

I cant explain technically why i feel this way, i just do. After reading all this though, its been educational. I dont mind the ball busting, it happens , just as long as there is something informative. Trust me , i know how to bicker but reading between the lines, it makes me wonder if running the higherst octane would actually help and also offer additional life to an engine. You said a couple things that lean to that direction but never really came out and explained it.

Title: What Octane?
Post by: Chrome on January 08, 2012, 11:44:13 AM

Quote from: jcassity;377226

i thought,,(perhaps that may be the problem ) that the higher octane results in the following:

~more heat
~more miles to the gallon

I have gotten better miles to the gallon but with the fuel changes, i am pretty certain (based on zero facts) that the original design was not based on fuels to be invented two decades from now.

For the purposes of too much heat, and the age of the motor pieces parts, again i "thought" the higher octane would eventually cause some harm.

I cant explain technically why i feel this way, i just do. After reading all this though, its been educational. I dont mind the ball busting, it happens , just as long as there is something informative. Trust me , i know how to bicker but reading between the lines, it makes me wonder if running the higherst octane would actually help and also offer additional life to an engine. You said a couple things that lean to that direction but never really came out and explained it.

That is a common misconception. Higher octane has quite the opposite affect. Less heat and fewer miles to the gallon. With it producing less heat, perhaps it could extend engine life....never thought about it. I always thought the higher octane fuels had more cleaning agents in them, but that could be wrong. Why else would they call it "premium"? As for the bickering, I think it has scared away potential posters, and has shortened the life of this thread. I just wanted to keep the thread going because I have an intrest in this engine configuration. Would like to see the possibility of having to switch to higher octane if I use this engine combo.

Title: What Octane?
Post by: TOM Renzo on January 08, 2012, 07:11:39 PM

Title: What Octane?
Post by: TOM Renzo on January 08, 2012, 07:15:13 PM

Title: What Octane?
Post by: TOM Renzo on January 08, 2012, 07:17:22 PM

Title: What Octane?
Post by: TOM Renzo on January 08, 2012, 07:18:47 PM

Title: What Octane?
Post by: TOM Renzo on January 08, 2012, 07:20:36 PM

Title: What Octane?
Post by: Chrome on January 08, 2012, 09:13:30 PM

:DThank U Tom. That was very informative. Goes to show how much we can learn if we don't argue. I hope we can get past our previous issues. I do believe U have much knowledge we can all learn from. You might be able to learn a little from us too.

Title: What Octane?
Post by: sarjxxx on January 08, 2012, 10:44:39 PM

holy this thread's been here for 2 weeks and 13 pages and I just realized it exiested....

anyway, I don't have the engine setup you originally posted, but just for kicks.... I run 93 in mine. But I also have timing advanced to 14*btdc. I was getting some loping at 10* on 87 so I played with timing and got a much better idle at 13-14*and decided to go with 14* and run 93 due to its ability to perform better with advanced timings. I did actually make a noticeable difference in seat of the pants acceleration, unfortunately I have not had access to a dyno in the last 3 years, as much as I would have liked to, so I can't say for sure what difference it did make. However, it did have a negligible negative impact on mpg's though. Well, maybe not negligible since it does cost me another ~$4.00 to fill up my tank with 93....

Also, the reason I run 93 and not 91 is that in my area the only grades available are 87 89 and 93

Title: What Octane?
Post by: Chrome on January 08, 2012, 10:58:50 PM

Quote from: sarjxxx;377286

holy this thread's been here for 2 weeks and 13 pages and I just realized it exiested....

anyway, I don't have the engine setup you originally posted, but just for kicks.... I run 93 in mine. But I also have timing advanced to 14*btdc. I was getting some loping at 10* on 87 so I played with timing and got a much better idle at 13-14*and decided to go with 14* and run 93 due to its ability to perform better with advanced timings. I did actually make a noticeable difference in seat of the pants acceleration, unfortunately I have not had access to a dyno in the last 3 years, as much as I would have liked to, so I can't say for sure what difference it did make. However, it did have a negligible negative impact on mpg's though. Well, maybe not negligible since it does cost me another ~$4.00 to fill up my tank with 93....

Also, the reason I run 93 and not 91 is that in my area the only grades available are 87 89 and 93

I think the reason your thread was shut down so fast is because the battles on this one spilled onto yours. Sorry about that. Welcome to the bloodbath.lol

Title: What Octane?
Post by: sarjxxx on January 08, 2012, 11:07:59 PM

Quote from: Chrome;377288

I think the reason your thread was shut down so fast is because the battles on this one spilled onto yours. Sorry about that. Welcome to the bloodbath.lol

lol I thought that was funny that he shut it down. It was clearly a joke but I guess everyone (3 people) took it seriously. I though it was funny as hell. The guy did it to HIS OWN CAR for crying out loud. Whatever. My feelings aren't hurt.;)

Title: What Octane?
Post by: shame302 on January 09, 2012, 02:59:09 AM

:rollin:I forgot I even posted in that threat. My bad (for my part in getting it closed). It's because I'm so pissed that Tom Renzo has all the goods and the toys. I'm so jealous uber honda and I'm intimidated by his E-dick swinging. :bowdown:Thank you.

Title: What Octane?
Post by: TOM Renzo on January 09, 2012, 06:19:27 AM

Tha

Title: What Octane?
Post by: Kitz Kat on January 09, 2012, 04:10:50 PM

Hey Tom, how come when you answer with quotes, it's not in Quotes? You need to fix that.

Title: What Octane?
Post by: TOM Renzo on January 09, 2012, 05:21:55 PM

Title: What Octane?
Post by: sarjxxx on January 09, 2012, 06:30:26 PM

Quote from: TOM Renzo;377347

Sorry English is not my strong point by any means. Basically i cant compose sentences very well. I read things differently than others
.I am told i am Dislectic So please excuse that. . Sorry My girls set up this computer to correct all the miss spelled words i print. When they are wrong it puts a red line through it. Then it corrects it. I think i know what you mean is this quotes (cars i own) (SUNOCO SAYS SUCH AND SUCH) Thanks

Use of quotes doesn't bother me so much but the CAPITALIZATION does. It seems to me that you've gotten a lot better about it since you've been here though. I don't know if anyone has told you before, but when carrying on conversation over the internet, CAPITALIZING WORDS OTHER THAN ABBREVIATIONS will usually be taken as the equivalent of yelling at someone.

I noticed a while back that you usually don't mean it that way, and that's just how you type, but that can be a part of why some people are quick to jump at you, because they might think your are already jumping on them. Just giving a friendly tip;)

Title: What Octane?
Post by: TOM Renzo on January 09, 2012, 08:49:36 PM

I did

Title: What Octane?
Post by: Chrome on January 10, 2012, 08:16:02 AM

Quote from: TOM Renzo;377357

I did not know that thanks. So yelling is caps. Well i apologize for that it is good to know. My girls did not tell me that. I will have to correct that asap. I am glad you told me that. I see i have a lot to learn about posting. Thanks

Wow! I feel like a bit of an ass. I thought all that yelling was intentional. I know now that I have read ur posts way wrong on many occasions. Please accept my opologize. Posting is kind of new to me also. Most of my internet communication thus far has been with E-mail.

Title: What Octane?
Post by: Chrome on January 10, 2012, 08:21:43 AM

:rollin:

Quote from: shame302;377316

:rollin:I forgot I even posted in that threat. My bad (for my part in getting it closed). It's because I'm so pissed that Tom Renzo has all the goods and the toys. I'm so jealous uber honda and I'm intimidated by his E-dick swinging. :bowdown:Thank you.

"E-dick swinging" lol. That's epic. I'll have to remember that one.

Fox T-Bird/Cougar Forums

General => General Fox T-Bird/Cougar Discussion => Topic started by: 88 Blackbird 5.0 on December 26, 2011, 12:55:43 PM