I discovered how much of a difference this makes today. When I did my HO swap I installed a 155 l/hr fuel pump. I never knew how much of a difference this makes.
My buddy has an 86 Mark VII that was a SEFI 5.0 SO that we converted to a HO with a 3.55 Traction-Lok. We used the stock SO pump and the car seemed to run good. After my HO swap was done we noticed how much stronger my T-bird felt vs. his Mark VII and we chalked that up to lighter weight/GT-40P heads/and the Comp cam. So just for fun we decided to swap in a 155l /hr pump today (which went well except when we broke the passenger side strap bolt and had to get a new bolt :hick: ). After we were done we took it out for a drive. The car responded MUCH, MUCH better. It acclelerated much better and passing power was so much better than it was before. With the stock SO pump the car responded better than stock but now it just jumps forward like someone kicked it in the ass:D . It runs soooooo much better. That stock 69 l/hr SO pump must be working overtime trying to feed a HO. If you have a HO swap car put in a HO pump. I swear you'll be amazed at the difference this will make.
ill agree on noticeable power, the stock pumps are configured as "good nuff" from the oem.
I went with the 3.8L supercharge fuel pump because it was better than stock (90 lph).
Does anyone in our local auto parts world carry the 155lph pump over the counter?
perhaps you might wann point out what LPH pump an actual HO car has so no one is confussing or associating standard equipment with aftermarket.
I did the H.O. swap,and the fuel pump was changed at that time.I figured that went without question.There's a reason that Ford used a different fuel pump with the H.O engines.
Ah good point. A stock HO pump is 88 l/hr where as the SO pump he was using was 69 l/hr.
As for finding a 155 l/hr pump at a parts store it might be hard. I think Advance can order one but it ends up being cheaper to just order one from Summit or some other source.
I had a 155 holley pump in my bird, but it shiznit the bed and I now am running just a SO pump. Have had nothing but stuttering problems accelerating hard with it since. I knew you needed a bigger pump with the HO but figured I would try a stock one and see first hand the effects. you can actually feel it fall on it's face at around 4-4500, it actually feels like I am letting off the throttle.
hmm might look into this. id really like my car to have what it needs. *flies over to ebay*
What size are the pumps from a '90/'91 4.6 Crown Vic?I have a couple of them lying around.I knew they had 19# injectors s well.Anybody have any idea?
thanks for the tip i wonder if that is the reason that some times when running my bird that it runs like a dream and some times when i stop at a redlight or stop sign when it idling it dies
The fuel pumps in the 96-97 DOHC cobras were standard 150lph pumps. Should be able to get em at most auto parts chains.
You have to watch the newer style fuel pumps.They have an electrical plug that ours don't.Ours have the two wires that plug onto the blades.The newer ones are designed for a small plug.
Dont mean to hijack but I have a question and this seems like a good thread for it. Is there such a thing as too much fuel pump for the car? I am planning on putting in a Walbro #GSS340 255 LPH (http://"http://www.jdsperformance.com/index.asp?initemuid=436&fcmd=item&inmake=all") fuel pump. I am thinking it will be fine but unfortunately we didnt do any high performance classes at school and i figured i would ask all of you more experienced people.
Thanks
I could see why; thats the next thing I plan to do on my car.
unless your running Turbos, a supercharger or lots of Nitrous, a 255 is WAY overkill.
Well a supercharger may be in the future, after the trick flow kit. I figure it wont hurt anything though until then.
It'll be fine, slap it in.
Back on topic, I'm suprised, it seems like everybody had problems with the SO pump when HO converted...I drove around with the T-bird for 2 1/2 years on the SO pump and never had a problem with it being lazy anywhere in the rpm range(FWIW-these engines are done making power past 4700rpm)....I had the SO pump out one day(sock fell off) so I installed a Walbro 190lph pump that I bought and noticed no difference...except that the Walbro was a little louder when you were low on gas. The car even went 14.50's before I installed the Walbro pump in horrible conditions...the following year after adding an electric fan and U/D pulley, it went 14.30's in perfect temps(but into a silly stong headwind).
The pump made no discernable difference for me.
It made no difference because for some reason you did not experience the problems we are having.
Trust me, if you were here I would take you for a rip and show you first hand the problem with a stock pump on an HO swap with slight mods. Hell maybe I will go to Welland and Take baXo for a rip this weekend and he can tell you what it feels like.:hick:
I'm going to have to reinforce that statement. My 3700lb 20th went 13.7 @ 102 MPH (~ 270 RWHP) when it was N/A using the stock SO pump. That was a 9.7:1 compression P-headed combo that had excellent accleration too (as the track times verify).
OTOH, since technically a 70 lph pump is only good for about 225 flywheel HP, I would advise upgrading the pump to at least a 110 lph pump (~350 FWHP) on N/A HO conversions. :hick:
If you're talking about the top end buck, that's not due to your fuel pump.
It could also have to do with the age of the pump. The pump in his Mark VII was 21 years old so I doubt it was still working at full capacity;)
no, I am talking mid rpm and up, say around 3000-6000rpm, sometimes it starts sooner, depending on how hard it hooks. or if I spin it bad you can feel it just die.
oh really? sure about that?
if so, do you know if the aftermarket matches oem? as far as LPH?
Hmm I'm not sure. His Mark VII just felt low on power till about 3,000 rpms then it would wake up till about 4,500 rpms. If you floored it at 60 mph it would lag off as rpms climbed due to lack of fuel. New fuel pump solved it all though.
I got a 255HP pump I gotta install one of these days...just not particularly looking forward to dropping the tank.
It's fun:hick: . Just make sure you have a helper as you'll need it taking the tank down and putting it back up.
OK, it's math time again!
1 gallon = 3.8 liters. = approximately 6.5-6.8 pounds for one gallon/liter of gasoline. I like to use 6.8 so here goes........
SO injectors = 14 lbs/hr = 2.06 Gal/hr = 7.824 liters/hr
8 SO injectors = 62.592 liters/hr
HO injectors = 19 lbs/hr = 2.79 gal/hr = 10.62 liters/hr
8 HO injectors = 84.96 liters/hr
using 6.5 pounds to the gallon we get:
SO injectors = 14 lbs/hr = 2.15 Gal/hr = 8.185 liters/hr
8 SO injectors = 65.486 liters/hr
HO injectors = 19 lbs/hr = 2.92 gal/hr = 11.108 liters/hr
8 HO injectors = 88.862 liters/hr
Now, gasoline does expand and contract a decent amount with temperature (colder gas is denser gas -- a gallon will weigh more when cold) Believe me on this one. You can ask anyone who has worked on aircraft and had them filled up overnight only to watch them vent gas an hour or so after sunrise.
14 pound injectors have been proven to sufficiently feed a stock HO motor at stock fuel pressure on a dyno. There is almost no safety margin though. I'm gonna guess with a 270 RWHP combo, that at part throttle and idle conditions the car ran fine with an SO pump. At full tilt I bet she started runnin real lean after 4500 RPM.
Also, let me add that changing fuel pressure changes flow rates for both injectors AND pumps. As you raise pressure, injectors will actually flow more, however a fuel pump will flow less. More pressure on the pump means more restriction upstream. More pressure to an injector means more force behind the gas coming out of it, simply put anyway........
A chart for reference
Paul sometimes you amaze me.
So for a TC;
1 gallon = 3.8 liters. = approximately 6.5-6.8 pounds for one gallon/liter of gasoline. I like to use 6.8 so here goes........
"Green Top" injectors = 30 lbs/hr = 4.41 Gal/hr = 16.758 liters/hr
4 x injectors = 67.032 liters/hr
"Brown Top" injectors = 36 lbs/hr = 5.29 gal/hr = 20.118 liters/hr
4 x injectors = 80.472 liters/hr
That's a LOT less then I would have figured! WOW! I have a 255 pump in my car, and I have a set of 56# injectors...
"56"s = 56 lbs/hr = 8.235 gal/hr = 31.3 liters/hr
4 x injectors = 125.2 liters/hr
I have 100 extra lph for nothing! In fact, by these calculations, 255 / 4 = 63.75 / 3.8 = 16.77 gal/hr x 6.8 = 114# injectors!!??!
You have to account for your fuel pressure at boost in a turbo or blower application. Again higher pressure = more injector flow, but less pump flow. TC injectors are still rated at 40 or so PSI when in fact at full boost they see more.
It's especially fun when you DON'T have a helper and a little more than 1/2 tank...it's amazing what you can do when you're doing it out of necessity.
yeah, try doing exactly that 3 times in one week like I had to. NOT FUN.:flame:
yeah, try doing exactly that 3 times in one week like I had to. NOT FUN.:flame: and I didn't have this problem until I went back to a stock SO 88'tbird pump, so I would have to believe it is the culprit, since none of the other variables have changed for me.
So, since the FP rises 1:1 with boost, I'd have to add maximum boost # to the total? Like this?
"Green Top" injectors = 30 lbs/hr + 22psi (T3) = 52 lbs/hr = 7.65 Gal/hr = 29.06 liters/hr
4 x injectors = 116.24 liters/hr
"Brown Top" injectors = 36 lbs/hr + 18psi (IHI) = 54 lbs/hr = 7.94 gal/hr = 30.12 liters/hr
4 x injectors = 120.7 liters/hr
"56"s = 56 lbs/hr + 28psi (SC50R) = 84 lbs/hr = 12.35 gal/hr = 46.9 liters/hr
4 x injectors = 187.8 liters/hr
Wow, that's a lot tighter, and definitely makes more sense. So a 155lph is pretty much required for any stock TC, and even a 255HP is barely adequate for me.
its called using a transmission jack. wussies! :slap: :D
BINGO! Now we're starting to get it! Just one thing though. Looking at the chart I posted, at 62 PSI a 30 pound injector would flow about 38 pounds per hour. You can't just add the pressure as you did. The actual formula is:
New flow rating = [square root of (new pressure /old pressure)] x old flow rating
Example:
New flow rating = [square root of (45 PSI / 39.6 PSI)] x 20.0 lbs./hr = 21.3 lbs./hr
You also have to take into account that a forced induction engine almost always has a higher BSFC than a N/A engine of similar size and power (I.E stock motor w/ a centrifugal blower vs. a H/C/I motor both producing equal peak power.)
Fuel requirement in lbs./hr = (Max HP x BSFC) / (number of injectors x duty cycle) Most OEM manufacturers like to keep duty cycle at .80 to .85
1) I was using 24# injectors in the 270 RWHP engine
2) I have a spreadsheet to calculate fuel needs - I estimate BSFC based on AFR (N/A = 12.5-13:1, blown = 11.5:1) & static compression
3) injectors still have exactly the same 40 psi across them even under boost (10psi example - 50 on top, 10 on bottom 50 - 10 = 40). Oops, you are correct that the pump has more backpressure, thus lowering flow potential.
4) I've maxed 36# injectors in my current setup - I logged 105% duty cycle (calculated based on pulsewidth & RPM) - that was something that caught my attention! :D (thus my current 42# injectors)
I figured you were using larger than stock.
Can you send me that spread sheet?
What size pump are you
currently using?
I'm running a 255 pump with 19's at 64 PSI (24.5 lbs/hr static flow). I'm 95% certain I go static at WOT and even at that pressure I'm most likely very close ro 100% duty cycle. The low speed driveability is just too good right now and she pulls like a raped ape up top with no lean codes. I tried to go bigger on the injectors, but she idled like poo. I attribute most of that to the MAF meter that I tried using (GMS sux!).
I opted to go with a C&L 73 mm setup for 19's instead for the time being. I plan on going bigger again, but it'll be properly dynotuned when I do so. It should happen sometime in July. I'd like to find about 15 or so hidden horsepower.
Heh, you got to it before I finished my edits - I am buttstuff about posting material that reads a certain way (properly) - lol.
I'll get you that spreadsheet - where to send it to? It's actually a modified sheet I got from the web somewhere - you'll like it - there are other tabs for doing blown engine calcs.
Funny, I was using a 155lph pump w/Boost-a-pump but I used a Mustang kit and the sock did not reach the bottom of the tank - thus I would uncover it at the track unless I had like 1/2 tank - very annoying. I also had a leak at the filler neck that prevented me from filling the tank - ever. I got a 190lph Cougar/Bird specific kit that someone provided a link to here (this is what makes a site like this great) and recently replaced the 155lph (anybody want the old pump?). Now I can turn down the BAP to about 20% and see no drop-off in fuel pressure (I log fuel pressure, boost, AFR & 16 other engine parameters using the TwEEcer).
Paul_Flockhart@hotmail.com
How is the B.A.P. kit? where does it mount? The reason I ask is because if this tranny ever goes, I'm throwing in a Lentech and some type of centrifugal blower will be used with my current combo to assault that new Lentech properly.
So my 255HP might not be enough for the 56#s? Argh!
I still need to control it all somehow too...
The flow would be 171 liter/hr for the 4 injectors using 6.5 lb/gal. At max fuel pressure your pump should flow at just around 200 LPH. You should be fine.
Explain....
I can't just plug the 56#s into the harness and hope the EEC knows what to do :hick:
I have a Kirban AFPR, and a Gillis Boostvalve, so I can adjust fuel pressure and boost along with base timing. I have no wideband or data-logging and still run 35#s (temporary) until the 56#s and something to control them go in. It's a toss-up between a TwEECer ($$$) or a Moates J3 ($). I want the new MSD Blaster EFI, but $1000 on a stand-alone is out of my league.
Seems like a nice piece. Here's the link:
http://www.msdignition.com/2007/blasterefi.html
The Megasquirt CAN be programmed to SEFI, correct?
The BAP is nice. I mounted it just behind the rear seat under the rug in the trunk - real close to the fuel pump :) . I mounted the adjustment dial near one of the hinges in the trunk - I get looks from people who wonder what I'm doing when I open the trunk & turn a dial - it's kinda stealthy. It activates on boost and you can dial it in - since there is always some loss in the system, increasing pump voltage via BAP will actually let you tweak open loop AFR just by rotating the dial one way or the other. I don't like to pump more fuel than needed (just heats it up) so I added an RPM switch in series with the Boost switch so the BAP will only activate >3psi & >3k RPM (I also have the H2O injection triggered off this same setup. Works nice - when cruising all that is off and only activates if someone asks for it :evilgrin:
MegaSquirt = no way
I suck at wiring and after adding up the $$$ of everything my combo needs to run, the TwEECer is cheaper. I'd like to keep the VAm or go MAF for now, but I LOVE the Blaster EFI as it's TRUE Speed Density, so I don't need to upgrade MAF's and there's nothing in front of the turbo.