Gentleman,
I'm looking for your opinions / advice.
I've just purchased a '97 powerstroke with 5spd and 4.10 gears.
I am upgrading from my '88 7.3 IDI with 5spd and 3.55 gears.
I'm tempted to swap front and rear axles to put the 3.55 gears in the '97 for improved highway fuel economy.
This is a lot of work.
I just pulled the '88 on my 3500lb trailer through the smokeys from Atlanta to Detroit, 1 fill up got 10.5mpg, one fill up got 13.2mpg.
I've heard of some guys getting over 19mpg with these trucks, but reports of mileage are as widely varied and sometimes not very accurate.
What is the mileage difference between 3.55 and 4.10 all other things held equal? [img]/ubbthreads/images/graemlins/shrug.gif[/img]
Would it be worth all the trouble of swapping both axles truck to truck?
__________________
Belleville, MI (Detroit / Ann Arbor)
'01 F350 cc lwb srw, Rebuilt engine, Rosewood rebuilt injectors, rebuilt turbo, soon to have 3.5"dp and 4" magnaflow exhaust, gauges, etc.
'69 Mustang 428CJ(ongoing project)
'86 Ranger 302/aod/8.8
'02 Focus wagon commuter
'86 Supra classic ski boat 351W PCM power
'54 Belair sedan, all original
I dont think your axle swap would work due to the speed sensor & hole needed in the top of the rear diff. I seem to recall that wasnt added till about 89 or 90.
__________________
Brian
95 F-250 XLT,SC,4x4,TDE1,LWB,4:56's,Dana 60,E4OD(lightly tuned),Tymared,Swamped,Lifted,rear disc brakes,6 pos chipped & a pile of other odd & end mods.Trucks,Parts & Misc. Pics 05 F250 V10 too
I have a 97 auto with 3:55 gears and at 65mph on the highway I average no less than 21.5 mpg and as much as 23 mpg. I tow a 9000lb fifth wheel but have not had a chance to check my mileage towing but I seem to be getting around 13 mpg or so.
__________________
1997 F-250 4X4 Powerstroke, ext cab, 3:55 gears, E4OD tranny, DiPricol gauges and 3 pillar pod,Tru-Cool 4739 Max trans cooler, 3" downpipe, dead kitty, Rotella Synthetic,Mobil-1 synthetic ATF,Warn manual lockouts, ..1995 29'Carri-Lite fifth wheel.
Considering how much work it would be, assuming your rear end would even work, it might not pay off unless you drive a lot!! Another option is to get taller tires for the newer truck, and effectively lower your gear ratio. I've got 4.10's in my truck, but with the 35" tires, my final ratio is 3.73:1. I also get 19-20mpg on the freeway empty.
__________________ Quadzilla
'95 F-350XLT Crew Cab SRW 4X4 PSD, 35X12.50X16.5's, LS 4.10's, Air bags front and rear, PS 2000 propane, TYMAR intake, 1.0AR turbine housing,
gutted EBPV, downpipe, 5" exhaust system, DP chip, Autometer gauges, Fumoto valve, Tru-Cool, HX mod, Tricumulator springs, Sonnax valve, 4R100 pan,
Magnefine tranny filter, reverse shackle kit, Big_Fig power pedal. Pictures I'm not affilitated with the vendor "Quadzilla" in any way.
Well I sure appreciate all your thoughts on this.
I have considered the possibility of taller tires, however, generally you can't go taller without also going wider, which, usually results in less fuel economy due to more rolling resistance and aerodynamic drag.
My '88 axle does have a speed sensor on top, but I'll obviously have to look at the whole swap thing a lot more before I really consider actually doing it. You're all right, the number of miles driven in order to pay back the pain in the backside factor may never be achieved.
As far as getting 21.5 to 23 mpg with a power stroke automatic with 3.55 gears..... what tires (highway tread 235 85 16?) ??
2wd??
Cap at cab height to maximize aero?
that seems too good to be true?!
__________________
Belleville, MI (Detroit / Ann Arbor)
'01 F350 cc lwb srw, Rebuilt engine, Rosewood rebuilt injectors, rebuilt turbo, soon to have 3.5"dp and 4" magnaflow exhaust, gauges, etc.
'69 Mustang 428CJ(ongoing project)
'86 Ranger 302/aod/8.8
'02 Focus wagon commuter
'86 Supra classic ski boat 351W PCM power
'54 Belair sedan, all original
That is not unrealistic. I did most highway driving to work until I sprung an oil leak yesterday and on the front tank I got 315 miles. Assuming I used at least the 15 gallons that it carries that is 21MPG. That is with 315/75/16's, Baby Swamps, and the chip in the highest setting. Kept it at 65-70MPH, and air condition only on in the afternoon. At 5AM I dont really need it [img]/ubbthreads/images/graemlins/grin.gif[/img]. Auto tranny with 3.55's soon to be 4.10's [img]/ubbthreads/images/graemlins/biggrin.gif[/img]. Alot of these mods that are done to our trucks all add up to some pretty decent MPG gains. I drove to New Orleans once and still had a little left last year at this time...I think it was something like 750 miles or so. Again at 65-70 but I did not have the 315's, I had 285's at that time and stock injectors.
ART
__________________
2005 Dodge Durango Limited w/HEMI.
2006 Chevrolet Cobalt LT.
SOLD 1996 F250 CC 4X4- Stage 1, Tymar, 4" exhaust, BDP chip...etc.
On my 96 2wd 4:10's I have stock size tires. All this talk about taller tires has me confused. Up front I only have about one inch clearance between the tire and front bumper. I would like to get taller tires but don't see how you guys do it! I would also like to knock down my ratio with taller tires. You guys don't mean taller in back and stock in front, do you? Wouldn't that be a little funkie? I understand that 4by4's have a lot more clearance in front. I have a 80 & 91 4by4 Ford gassers, I use my PSD for towing my 5er.
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96 PSD 2WD ExCab LWB F250 E40D 4:10's. 4" Bassani exhaust with 3 1/2 DP, napa6637 air filter, HX hose, all gauges, tru-cool 4739 trans cooler & BD deep dish pan & shift kit, radiator filter, FS2500 bypass oil filter, 99 IC, RV TC, 6 position TW, 1" turbo housing, all synthetic, SD HPOP, modded IDM, TSM rear disk brakes. Electric fuel pump. Beans Tranny Savers, 203*, 'the cure', Bilsteins
Nope, I think the most I have ever put is about 17. Probably cause I dont let it go too far on E. I dont want to run the engine out of fuel. So I am pretty sure I still have a little left when I fill up.
ART
__________________
2005 Dodge Durango Limited w/HEMI.
2006 Chevrolet Cobalt LT.
SOLD 1996 F250 CC 4X4- Stage 1, Tymar, 4" exhaust, BDP chip...etc.
When I run both of my tanks to the red line they are right at 15 gallons per tank to fill them up. Expinsive proposition when diesel is over 2 a gallon
I get an even 20 at 70 mph at about 1900 rpm. 3.55 rear end with 265/75-16 tires. 4X4 Crew Cab. Can't give a towing milage yet, but will be able to soon. Will be pulling a 26' Prowler at about 7,000 gross from central TX out west to Ft Davis and back, the 1st week of May.
Maybe I'm optimistic, but would hope for 12-13 mpg.
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Basic truck: 1997 F-250 XLT HD, 7.3 L PS, 4X4, 200,441 miles, CrewCab, Short bed, White w/Silver belt, E40D Auto, 3.55 limited slip, 265/75X16, Tru-Cool 4590 Trans oil cooler, City Muffler 3" SS Downpipe, T&S 6 position chip, Trans, Pyro and Boost gauges
I have also found that fuel mileage really depends on your right foot, I can loose 3-4 mpg really easy with a heavy foot. I rarely see over 2000 rpm and I think that has a lot to do with my fuel mieage.
__________________
1997 F-250 4X4 Powerstroke, ext cab, 3:55 gears, E4OD tranny, DiPricol gauges and 3 pillar pod,Tru-Cool 4739 Max trans cooler, 3" downpipe, dead kitty, Rotella Synthetic,Mobil-1 synthetic ATF,Warn manual lockouts, ..1995 29'Carri-Lite fifth wheel.
[ QUOTE ]
That is not unrealistic. I did most highway driving to work until I sprung an oil leak yesterday and on the front tank I got 315 miles. Assuming I used at least the 15 gallons that it carries that is 21MPG
[/ QUOTE ]
It's pretty difficult to be accurate calculating fuel mileage based on needle position on the gauge. If you actually burned 17 gallons of fuel instead of 15, your fuel mileage would be 18.5.
The front tank is listed at a 19.0 gallon capacity, but actually holds 22.0 gallons. On a side note, the rear tank has a listed capacity of 18.7 gallons, and actually holds 21.0. I just switched off the back tank on my truck, after driving 350 miles. If I assumed that I used 18 gallons, I'd think I was getting 19.4mpg, but I actually burned close to 20, for 17.5. Knowing the true capacities of my tanks, I've gone 425 miles on the front tank, and an additional 400 on the rear before stopping for fuel, which came out to 19.3 mpg. I've backed those numbers up with several other trips over 19mpg, and a few over 20, but it's always after using a calculator to figure the mileage, not an estimate based on how much fuel I assume I've burned. I also fill up to the top of the filler neck every time for consistency.
__________________ Quadzilla
'95 F-350XLT Crew Cab SRW 4X4 PSD, 35X12.50X16.5's, LS 4.10's, Air bags front and rear, PS 2000 propane, TYMAR intake, 1.0AR turbine housing,
gutted EBPV, downpipe, 5" exhaust system, DP chip, Autometer gauges, Fumoto valve, Tru-Cool, HX mod, Tricumulator springs, Sonnax valve, 4R100 pan,
Magnefine tranny filter, reverse shackle kit, Big_Fig power pedal. Pictures I'm not affilitated with the vendor "Quadzilla" in any way.
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