Been toying with the notion of making this thread for awhile now.. but this little semi-emergency road trip I just got back from a little while ago (and more specifically, all the time we spent monitoring the IN MPG reading on the Mark's trip computer) has me finally posting it. This isn't limited to a discussion about my (or any) Mark.. it's about all these bigger Foxes. I'm actually getting the EPA rated 24 highway for that thing, at 75 mph.. but improvement wouldn't be a bad thing with gas prices the way they are.
From time to time I hear people claim part X or modification Y *MIGHT* actually improve mileage. Things like superchargers improving mileage when you don't have your foot in it, the logic being that it still helps pull air through the filter/intake system. (I'm not saying it's true or false.. just recounting things I've read)
There's also the comparison of the V6 vs. V8 T-birds/Cougars.. how they get roughly the same mileage with different horsepower ratings and different engines.
Sometimes I wonder if putting in something with a bit more torque (like my 351W, but converted to EFI and maybe using 5.0 HO brains and fuel delivery and all that, for example) would be a bit more efficient at getting two tons of LSC and myself moving from a dead stop. This isn't really a specific question, (although it's open to discussion) it's meant more to add some direction to this post.
One thing I'd like to say before I continue is that this discussion pre-supposes that tune-ups are done as required. We already know that keeping the tires inflated, the filters clean, the plugs fresh, the idle down, your foot out of the engine compartment, and all that other stuff helps.
Another thing this pre-supposes is that any car modified in an attempt to make it more fuel efficient will be kept (barring accident, theft, catastrophic breakdown, etc.) for a long enough time to make the expense of the modifications pay off in savings. We'll say at least 5-10 years. With only 92k on the clock for my LSC, I could see keeping it quite some time.
So, any ideas on improvement? Is there a discussion to be made out of this? Please try to avoid instant negative responses like "it can't be done, don't bother even thinking about it" and think about possible ways to imrpove things before dismissing it. Sorry for the long post.
as far as making more power with better milage I cant think of a whole lot. You could maybe try getting a customer chip burned to give you a higher ration of 14.7 : 1. That is the only thing that I can really think of.
More power isn't necessarily the goal here. I'm thinking equivalent power, or mild increases, but mainly I'm concerned with efficiency.
So pretty much you would like to keep the economy and hp about even
Don't mind horsepower staying in the low-200s.. (HO is stock in the LSC, remember) Just looking for a bit more efficiency (beyond what a tune-up can provide) without getting outrageous. I actually got like 23.9 MPG highway today at 75 MPH with the A/C on full blast on a 92-93 degree day.. so I'm getting what I should be getting, at least on highway mileage. Wouldn't mind a little help in the city mileage department. But I'm not entirely talking about myself.. I had this in mind for anyone who might be facing a decision about continuing to drive their Bird/Cat/Mark or finding something more fuel efficient. I might be starting work here this week, and my fiance starts training for a job tomorrow morning.. so I'll definitely be putting in more time behind the wheel of the Mark.
There are some things that you can do that will increase mileage while negatively impacting other areas:
You can install skinnier tires - instead of, say, a 225/60R15 you could put on 205/70R15. Wider tires increase rolling resistance. You can also install harder tires with stiffer sidewalls, and if you want to go extreme, a set of drag-style skinnies up front would help. Anything to decrease rolling resistance will help mileage. Of course, your handling would suffer.
You can also install a steeper rear gear, such as a 2.73 (I think Marks came with a 3.27) - this may net you a MPG or two but of course acceleration will suffer.
Using all synthetic fluids (rear, tranny, engine) will decrease frictional losses but will likely cost more than the fuel you're saving, given the limited life span of fluids
Swapping a t-5 into the car will free up some MPG's by decreasing parasitic drivetrain loss. This will make the car more fun to drive, but of course could result in a decrease in mileage if you drive it harder than you normally would
Swapping the BMW 2.4-liter turbodiesel inline six that was offered in 84-86 Marks would greatly increase mileage (plus allow you to use biodiesel), but finding one could be difficult. And your car would become a dog.
Lower the weight of the car. Remove the spare (and bring along a can of fix-a-flat or a plug kit), and lose some of the insulation. The car will be noisier without it, but the quietness you're used to costs money. If you carry a heavy tool box wherever you go, lose it.
Keep the A/C. It may burn some fuel, but most fuel economy experts will tell you that it takes less energy than it does to drive at 65+ MPH with the windows open. Aerodynamic drag is a big fuel burner. Around town, turn off the A/C and open the windows (likely not much of an option down there in Florida).
Install underdrive pulleys. Less drag on the engine will equal less fuel burned. This may create overheating or charging issues, though...
And of course, the simplest way to increase mileage: Slow down. At 75 MPH you're probably burning 10% more fuel than you would at 65 MPH. Might not be much fun, but the laws of physics are indisputable, and it takes a certain amount of energy to move two tons through the air at a given speed. Decrease the speed and it takes less energy. Use the cruise control to optimize efficiency - it can maintain a steady speed better than your right foot, and varying speeds burns more fuel.
To address a few parts of that:
- Yes, this has a 3.27 open rear, according to the codes.. if they're the same as Bird/cat codes.
- I've thought about going to a 4R70W and going with a numerically lower rear gear. Right now a stick is out of the question.. my fiance drives this from time to time, and I haven't taught her how to drive a stick yet. (mainly 'cause I don't have one) Current concern is getting work for both of us, which should be taken care of this week.. lessons like that can come later.
- Only I6 I'll be using in anything is a Ford one. :p (I could always track down one of the diesel Marks.. but there's no real point)
- After this weekend, I am NOT losing the spare. Mind you, when I bought this car, it had four new tires on it. (but unlike with the battery, came with no receipt) Within a week, one of them got a nail in the sidewall. Had that replaced at Sam's for about $100 total. Well, when I was about 130 miles away from home this weekend, I got a flat in that exact tire. Drove it long enough flat (trying to figure out what the hell that noise was) that the sidewall took some damage, and a chunk also got taken out of it aside from the initial puncture. (we didn't know about the chunk until the next day, today) The spare got us the 7 miles back to my uncle's house, where he proceeded to rawhide-patch the hole. Put the damaged tire back on and went off to their Sam's, to replace the tire. Ended up paying 78 cents (plus tax and a new road hazard policy, $12.50 for everything) for a brand new tire, no grief given or questions asked. Maybe a can of Fix-A-Flat would've worked, maybe not.. but I know the spare did its job and bailed me out on a very bad weekend, so it keeps its job.
- I am wondering about something: I am going to replace the funky oversized Mark VII 100A/external reg. alternator with a 3G at some point.. but should I see about buying a 200A alt and underdriving it, or get a 130A and leave it as is?
- As for slowing down: I don't think 65 vs. 75 makes a difference, to be honest. We spent a lot of time watching (my fiance more than me, for obvious reasons.. I had to drive) the trip computer.. and we were getting the same mileage at 75 as just about any speed. 75 in OD is only about 2200 RPM. Car had no problems with that. Calculated it out to about 23.9 MPG.. and the EPA rating on an '89 Mark is 24 highway. Honestly, I think most of the gas gets wasted getting it to a certain speed quickly.. once you get that car going, it stays going, and doesn't give you trouble about it.
At any rate, going any slower than 75 mph here is almost foolish. Speed limit in Florida on rural Interstates is 70, and flow of traffic is often 80+ on I-75. I spent far more time today worrying about the crazies coming up on my rear bumper than I did worrying about the crazies off my front bumper.
This thread is more of a general improvement thread. Focusing on the highway (which I rarely do, although with things being as screwed up as they are right now might become more common) detracts from trying to pick up something here and there for city driving. Even when I baby it, I don't do much better than 10-11 MPG city. I know there are some things to take care of to improve that, but I'd like to see just how far I can push that improvement. Like I said, I think sometimes about adapting the 351W to take the place of the 5.0 HO, in the hopes that a little more torque would equate to a little less pedal travel to get the same acceleration.
Assuming that you're car is completely box stock, I would recommend a K&N air filter, off-road h-pipe(with turbo style lers if you don't want it too loud) and set the base timing(with SPOUT connector removed) to 12-14 degrees. That should help with fuel economy and throttle response as well.
Bumping the timing would also require higher octane fuel... thus sort of negating the efficiency goal.
if it;s totally tock the hpipe would hurt him. the offroad anyway. motor has no work to breathe 2.5 inch pipe from the headers back. you could find beter ways to get gas mileage. how about an explorer cam you may loose some rpm's but you would get tourqe which pushes the car. or the whole elplorer /gt40/cobra pacage or cam n intake. but could get expensive
or he could go back to e6 head and the stock s.o. cam shaft and smaller fuel injectors.
Do this?
I believe I said I wanted to try to maintain performance.. not eliminate it. :p
The Marks came with 2.5in exhaust from the factory. Remember it has the HO 5.0 no the SO.
You could look into getting a set of equal length shortie headers for the car.
Converting to mass air is also an option.
The shorty-header thing is doable. Mass air, (I almost typed out "Ass air") I could do that too.. maybe when I attempt that DIY CAI from the article over at LoL:
http://www.lincolnsonline.com/article137.html
OK, so maybe I SHOULD ask about the 351 thing. Do you think that converting one to EFI but leaving it otherwise stock would get the Mark moving from a dead stop a little more efficiently vs. the 5.0 HO in it now? (my 351 is 210 horses as-is, carbed)
I've also considered things like switching to a 4R70W for the wider gear ratios, and then using a numerically-lower rear gear. (not that you can go much lower than 3.27s) Unfortunately, I haven't even run the numbers on that one yet.. and even if I did, it would probably be pretty expensive for a marginal gain on the highway. (and most of my driving right now is city-type driving anyway)
EDIT: Remember, when I contemplate any of these changes, I do so with the intent of trying to hang onto the car for at least 10 years.. so spread the costs vs. benefits out over that time.
As far as the exhaust goes it depends on where you do most of your driving. A set of Free flowing headers and H-pipe will help you on the highway. Probably won't do much of anything around town.....
well the difference between 76 and 70 on the hwy for my cobalt has been about 4 mpg on average. so it does make a pretty big difference, at least in that 4 banger.
Short version: Moving up to a 351 is going to hurt your in-town gas mileage unless you regularly go WOT.
I can give you the long version if you want.
Speed makes a big difference in my T-Bird too - I got 33 MPG driving like a granny on a 60-mile trip, and I got 28 driving like I normally do on a 200 mile trip. The 33MPG trip was all back roads, so speeds rarely got over 70. The 28MPG trip was on open highway with speeds constantly in the 75-80 range.
Unfortunately it's not an option for highway driving here. Even at 74-75 mph I'm regularly passed like I'm standing still, and get passed (by people going more normal speeds) more than I pass others. Even the cops here will tell you flow of traffic is 5-10 over the limit, and that limit is 70 on rural Interstates down here. I will not go so slow that I increase my risk of having some idiot in an Excursion turn my LSC into a subcompact from behind.
At any rate, even at 75 with the cruise on, I'm still getting what the EPA rating suggests for the car. I can't complain about that mileage much.
The LSC's have the 3.27 gear for a reason... Better performance AND fuel economy. Whaattt? you say... Yep The HO engines peak efficiency is 300-400 rpms higher than the SO(this is due mainly to the camshaft). You go stickin' 2.73s in it, and my bet is you'll actually loose milage. But you say the Mustangs had HOs and 2.73 gears. Yea and they are 800-900lbs lighter as well, so the engine isn't working as hard to cruse the same speed. The 351 probably won't do any better on the highway, and will only suck more gas in town, so don't even think about it(My 5.8 Lightning is a real gas hog).
If you really want more MPG, swap in a SO 5.0(or 2v mod motor[shudder]) and then go with the 2.73s. Otherwise use synthetics, keep it in tune, the tires pumped up and don't worry about it.
One thing thhat will help is to install a vaccum gage and drive by it... The higher you keep the vac, the better the fuel economy.
Me, I just ordered some new race tires......
Someone made a comment that a bump in the timing would require a higher octane fuel...such is not the case on these HO engines. We drove my T-bird around at 25 degrees BASE on 87 octane just for the hell of it...but that was before it was my t-bird and it still had to SO...After I put the HO in, I ran the base timing at 14 degrees. The timing pointer decided to disappear on my way to the track and I proceeded to advance the timing even more so, probably in the area of 5 degrees. I have no problems at any engine speed or load. Very rarely will I put anything higher than 87 in my car.
The idea wasn't just to swap 2.73s in, but to put in a 4R70W (an AOD-E w/ a wide-ratio gear set, for anyone else following along who doesn't keep up on slushboxes much) along with it.
http://www.becontrols.com/tech/ch3aodeupgrade.htm
Either w/ or w/o the 3.27s, I still wouldn't mind going to a 4R70W.. it's supposedly much more durable than its AOD ancestor.. and can be had in the right bellhousing pattern. (and yes, I am aware it would not be inexpensive to do)
The pic I'm including is of the gear ratio calculator spreadsheet we whipped up some time ago, for when I had a strong desire to mess around with a gear splitter and alternate gearing. (hence the "Please ignore column B" statement.. that was the splitter's column) Whipped up those numbers using Baumann as a source, plus the FordMuscle RPM calculator and some random tire size calculator.
(I think it ran somewhere around 2200-2250 RPM on the gauge, at 75 MPH.. so it doesn't completely mesh with what the calculators tell me)
Hmmm, that was me. In my experience, with my '85, too much timing advance gives great power results, but it pings real easily. I guess results vary based on mileage and engine condition.
Not necessarily true. Although aerodynamics plays a pretty big role in efficiency, the a/c compressor will drag down the motor more than having your windows open will. I won't say I believe everything I see on TV, but on mythbusters, they tested the a/c versus open windows theory and the open windows lasted a lot longer than a/c. Given these were suvs, the results should be about the same for most cars unless they're super aerodynamic to begin with and rely completely on that factor to attain higher efficiencies. Since the test wasn't performed with fox cars, I cannot say with a great degree of accuracy that open windows will net you better mileage, but I don't see why it wouldn't.
My 88 XR7 with its almighty 3.08 and 235/60R15 will run down the interstate at 80 only running 2000rpm.
I wouldn't go with a 2.73 just because it would take so much more to get the car rolling from a stop.
The A/C is a keeper here. Especially since I can't roll down either window, now.
That must suck, whats wrong with them?
A AOD can be built using the 4R70W gear set... As for swapping in a Electronic tranny, I'd use a 94-95 Mustang automatic EEC that can shift the tranny and operate a electric fan. The fan is something not mentioned that does help fuel economy.
Its not hard to get the car moving with 2:73's. I have two 5.0 cougars with then and a crown vic. Its not hard to make the car move. My 87 3.8 has higher gears, I forget what now. Its really not that much diffrent between 2,73's and a 3.08
Passenger one hasn't worked since I got the car. Driver's side one went bad recently.. started sticking in the seals. I've tried pulling down on them while someone leans on the switch, tried spraying some silicone spray lube up into the seals, but it's a no-go. I have one more thing I'll try, but I'm not optimistic about it.
Since I may be working again starting later this week, I'll just replace the motors when I can afford to. We know the switches aren't the problem.. we've tested that before.
Yeah, I know about the AOD case/4R70W gear set thing. That is also a possibility.
If I go electronic, I was thinking about a Baumannator TCS or whatever the hell it was called. I think one of its stated purposes was to allow for putting electronic trannies into older vehicles.. plus it's programmable.
As for controlling a fan, I had planned to do the modified Mark VIII fan + control box thing that was posted here awhile back. (the one that gradually powers it up and down on demand, vs. just on/off) I'll probably do that no matter what else I do to the car.
OK, lemme try this:
Doing the 4R70W swap while leaving in the 3.27 rear gears would give me (as that quote above stated) the same effect in 1st gear as if I had 3.87 rear gears plus the AOD.. but the OD would remain pretty much the same (maybe a difference of 100 RPM or so) as it is now. Would that be beneficial from an efficiency standpoint? I see lots of talk about being hard to get the car moving with numerically lower rear gears.. well this *seems* to counteract that. Does it go too far?
Even if it isn't the most effective solution, I still like the thought of using the 4R70W. It's supposed to be upgraded in every necessary way vs. an AOD. Bigger OD band, etc. Yes, I could rebuild an AOD to close to 4R70W levels.. but if I could manage to find a 4R70W that I could use, why not use it?
I've also contemplated a stick.. but if I went that route, honestly I would want to go T56.. and that ain't gonna be cheap either. That debate is a whole other can of worms I won't go into at this time.
Two questions...are you sure you have 3.08's? if so, did you get a different speedo driven gear or no?
With 2.73's you should be running 80@2000rpm. With 3.08's, you would actually be running more like 71-73mph@2000rpm...if you haven't changed speedo gears, then you are going slower than your speedo reads.
Sidebar: The change from 2.73 to 3.08 was quite noticable in the seat of the pants...can't wait to put in my 3.55's.
Well, my current mileage is about to be put to the test.. because I start work 7 hours and 57 minutes from the time of this posting. :p
Well there isn't that much of difference between the 235/60 and 225/60. No I didn't change the speedo gear.
225/60R15 = 25.63
235/60R15 = 26.10
Next the 3.08 was stasndard with the XR7.
78.3mph by my calculations.
equaltion goes like this.
((235/25.4*((60/100)*2+15))*2000)/(3.08*.67+346) = 78.3
close enough to 80 for me.
So 80mph at 2000rpm.
OD ratio is .68 not .67
:hick:
http://www.foxtbirdcougarforums.com/showthread.php?t=3772&page=3&pp=40&highlight=.67
My car.....1988 Thunderbird.
Statistics...1987 5.0 H.O.,Explorer intake,60mm throttlebody,Factory headers (for now),H Pipe,Removed the air silencer,Locker rear with 3.45 gears.I got 26 miles per gallon at nearly 80 at 2000 rpms,without using the cruise control.If I would've used the cruise,probably a little better,if I would've used cruise at 70,then I can only wonder what the MPG woul be.Hmmmmmmmmmmm................
back to the mythbusters, that was a failed experiment and had no controls, I don't trust it, it is a cool show (and i watch it when I can), but they are by no means scientific in the least most of the time.
but they had 2 different vehicle with two differend drivers and just filled em and ran em till they stopped. not a good test of actual mpg at all. so that one holds no wait with me.
Uhh... I don't know which show you watched, but that wasn't the experiment at all. They used two identical suvs, I think they were Tahoes or something similar. They pumped all the gas out and put exactly the same amount of gas back into both and drove on a track until one ran out. One with windows open and one with a/c on.
Okay, good supporting info on the OD ratio. But, you're speed is still a few mph high @2000rpm in OD with the 3.08's. Did you measure the diameter of the tire at the recommended inflation pressure while loaded(i.e.-on the car). Or are you using tire manufacturer's specs...some measure diameter with the tires loaded, others don't. A 10mm width difference equates to a sidewall height difference of 6mm. Six millimeters is not equivalent to .47", so something in your equation isn't happy. Six millimeters is closer to 1/2 of .47". I'm not trying to break balls, but I'd like to know where you got your tire diameters from because you're equation is all in order.
With a 25.6" tire(the 225) according to your specs, you would be going 74mph(rounded up 2 tenths). With a 26.1" tire(the 235), again according to your specs, you'd actually be going 75mph(round down 3 tenths). Unfortunately I can't remember what I measured my old cobra 225's at...I'll measure my 225's and my 265's tomorrow.
This is what I used- http://www.4lo.com/calc/gearratio.htm
235/60r15
235/25.4*.6*2+15=26.95
225/60r15
225/25.4*.6*2+15=25.63
Heres another to ponder. With the 235/60R16 the 3.08 ratio turns into 3.03
(20800/((235/25.4)*(60/100)*2+15))/(20800/((225/25.4)*(60/100)*2+15))*3.08=3.03
:hick:
I understand your thinking, but that equation is worthless for figuring tire diameter. I used that formula in the past and it just didn't seem right, the more I looked at it, the more flawed it was. My 225/60's(full tread, 32psi) measured out at 24.5"(within 1/32") while on the car. My 265/50's measured the same within the same accuracy but with 28psi and nearly full tread. Metric tire sizes are always rounded...I'll bet you've never heard of a 221/58R15.
The only accurate way to find the tire diameter is to measure the diameter of the tire while it's on the car(with the wheels on the ground, no cheating). The easiest way is to take a ruler or similar object and lay it across the top of the tire so it extends out toward the wheel well. Take a tape measure and measure from the ground to the bottom side of the ruler or whatever you may be using. That is the ONLY way to get true tire diameters.
That equation cam from a "Mast Fittment Guide" that was at the shop I worked at. The book is put out by Michilen of North America.
Not to be pissy but try telling them their wrong. :rolleyes:
I also understand what you are saying. But what about cyntrifical force pulling on that tire when its do 80mph. Its not going to have the same dia when its moving.
OK, somewhat closer to the topic:
Perhaps I should look into getting a nice clean 4-door Fairmont or Zephyr, swapping in some more comfortable seats from one of the bigger Fox bodies, and trying to make that a little more efficient? (and keep the Mark for road trips)
How well, efficiency-wise, would a 2.3T do in something as (relatively) light as a Fairmont? I think it's been said before that the TCs aren't the most efficient of cars, gas-wise.. but is that mainly due to performance of the engine while not under boost? (trying to move a heavier car, etc.)
I see a few Fairmonts/Zephyrs running around town now and again. (including that Fairmont Ranchero I saw awhile back)
get the 200 CI inline six and then when that brakes down you can test fit the super charged 300
or you could find a 83-86 xr7/TC for cheap and just turn the boost down to 5 or 6 pounds
Yeah, but also keep in mind centrifugal force won't cause it to grow that much...if it were a drag slick, sure...but 6 or 8 ply tires won't grow an inch in diameter, maybe a quarter inch at the absolute most. The equation, in theory, is good but it doesn't calculate for a loaded tire or differences in tread depth or inflation pressures. Give me their contact info, I'll tell'em their wrong...lol. :hick:
the 200's only get in the 20's around town normally 18-22 mpg
I get far better fuel mileage with 3.73s than I did with 2.73s (especially in town- probably only 1 mpg on the hwy). The car moves like it weighs 800lbs. less and on the hwy I'm only doing 23-2400 at 70mph. Best mod yet. Better Acceleration and mileage.
:canada:
OK, I had to resurrect this because I actually sat down and ran some numbers I've been toying with for awhile now.
One of the things I've thought about doing was tracking down a used 4R70W (wide-ratio AOD-E, more or less) in the 3.8/4.2/300/5.0/5.8/etc. bellhousing bolt pattern (I'm led to believe they exist.. and putting that in place of the LSC's AOD along with a Baumannator TCS (http://www.becontrols.com/products/tcs.htm) to control it. Eh, maybe.. until I saw you guys talking about rear end gears and getting mileage improvements (city mileage, anyway) with switching to a numerically higher rear gear.
I whipped up a new piece of my infamous (to the people I regularly annoy with it, anyway) gear ratio calculator spreadsheet. Listed my current rear gear, (3.27) and the gear ratios of the 4R70W and the AOD, and it calculated out the final drive ratios for each gear in each transmission. I also did some lines below that for comparison: using the 1st, 2nd, and OD gears from the AOD along with differing rear gear ratios for comparison to the numbers the 4R70W generates.
How does this look to those of you who mess around with (or think about messing around with) alternate gearing? Unless I'm doing this all wrong, it looks like the 4R70W with my current rear gear would be roughly the equivalent (I'm approximating in this example) having an AOD with close to a 3.89 rear gear for 1st gear, close to a 3.73 rear gear for 2nd gear, my current 3.27 for 3rd, and again up to between my stock gear and a 3.55 for OD.
(and I pulled the 3.89 ratio from Summit.. they have one for sale.. didn't know that there was something between a 3.73 and a 4.10)
In addition to that, this setup would allow me to tweak all shift points, keep a second set of shift points that can be switched to, tweak line pressures and torque converter clutch settings, (not stuff I'd be ready to mess with) and other such nifty things like being able to use the cruise control buttons for manual shifting in an alternate function mode. That is, if Baumann delivers everything they say they deliver.
Yes, it would cost a pretty penny.. but again, this is an expense I would consider as spread out over the lifetime of the car.. and as I see it, it would also save me from tinkering with rear gears and shift kits and other stuff like that. The 4R70W is also supposed to have some stronger components than the AOD, like the input shaft and the OD servo.
You're basically ' in the wind if you think playing with tranny ratios is going to give any noticable gas milage improvement. Yea you might get 2-3 TENTHS... ought to be able to recoup that in 25 years or so...
The ONLY modification that may help, is to run a milder cam that lets the engine make peak torque at a lower rpm. Then with fewer revolutions per mile, there is less internal friction. For instance there may be enough friction to rob 25 hp at 2000 rpm but only 20 hp at 1600.. That's five hp less the engine has to produce just to run, and that will save fuel. Years ago after the oil embargo and rising prices, several cam vendors offered "econmy" cams that were just mild cams that proudced good low end torque.
As I stated some posts back, the greatest improvement will be to install a vaccum gage and drive by it. Never let the vac fall below 5-6" and you'll get a noticable improvement. The gage will likely pay for itself in 4-5 tanks.
I have a vacuum gauge.. can't really read it while I'm driving because I can't mount it in a way that allows me to see it easily while moving.. not without mangling the dash. (at least until I figure out a more creative mounting solution)
What about an Explorer's cam?
EDIT: I still think I might do the 4R70W conversion even if it isn't much better mileage-wise, just for all the other little benefits. (the ones I see, anyway.. heh)
As a side note, not addressed to anyone, I'll sort of repeat this from the other night:
Please avoid any "just get this" types of comments. This is about ideas on improving the fuel efficiency of a car I already own.. and doesn't necessarily mean a project will happen because of this thread. (although the 4R70W swap is likely at some point, efficient or not) Besides.. I confess, I started looking for 1989-90 Honda Civics/CRXes in the state, for a beater work car. Checking into a $500 CRX HF 5-speed I stumbled across. It would mean I'd have to get the '88 T-bird out of the yard to make room for it, though.