Just took a 3.5 hour trip from central MA to Burlington VT and got 14.3mpg. It was all highway. I have 4:10s and the truck is completely stock, all the way around (reg. cab xl). I know the low gears really kill the milage, but that was pretty bad. I'm at 2500rpm @ 75mph. I was really light on the throttle the whole way. Maybe my tymar intake and downpipe that will be in next week will help a little.
Seems like anything over 2000rpm mileage goes to crap, if I get 16-17 I roll about 65mph but usually just get tired of driving slow and go 75 and just take what I get.
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1997 F250 FireTruck Red,CC SB,auto( Prescion TC, HD-2Tugger),5" exhaust, custom Swamp 195cc Hybrid injectors, TWildman 4-pos chip,open air cleaner, I/C w Banks intake, 225,000km,AIC,dual electric fans,Sky mfg RSK w/ D60w/ARB locker,Ramsey 15k# winch, BFG/AT 315's, F450 rear springs, home of Craig's Performance Diesel pictures
" lying is a cheap way out of reality, the real cost is the loss of respect and trust"
I have the 4.10's as well, and I can't keep it below 2,000 RPM's anything after 65 MPH...it sucks but, oh well.
As for the bigger tires, I asked Dale about the same thing and he said that it wouldn't give you any gains in the MPG department because you need more force to roll the bigger tires even though your RPM's may go down....has anyone actually seen a mileage gain from running bigger tires? I, personally, haven't seen one or heard of it.
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'96 F250 ExCab 4x4, 4" exhaust,Shimmed FPR, Tymar intake, 4" lift, front end replacment, soon to have a rear end and a headache rack, 315/75R16 BFG All Terrain KO's, Optima Red Tops...
you'll loose mileage with the 315s, that's a wide tire which creates not only more rolling resistance (larger tire contact patch with the road) but also significantly increases your aerodynamic drag (which goes up with the square of speed) which will hurt you at highway speed.
I think the 255 85 is the best scenario for these trucks if you're trying to help mileage, I can't get them locally unfortunately.
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Belleville, MI (Detroit / Ann Arbor)
'97 F250 4x4 7.3PSD ZF5spd 4L10
PA2818 diy intake, wicked wheel diy turbo rebuild, .84 turbo housing, no muffler, I LOVE MY BEANS TS'ers! ;-), new pedal box bushings, Fleetgaurd coolant filter, Seat Mod, electric fan, Eagle 16x8 w/265 75 Firestone Steeltex AT, cooling pkg front bumper
'69 Mustang 428CJ(ongoing project)
'99 escort zx2 commuter
'86 Supra classic ski boat 351W PCM power
'54 Belair sedan, all original
Last trip I took from Flag to Payson to see the slot canyons, we got ~14mpg. The wind was HOWLING tho, so that may have had something to do with it... I'm hoping next trip, its a little better.
M
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Not all who wander are lost. Sometimes we're out looking for hares (its a hashing thing. ask me about it sometime)
You don't say if you have 4x4, but I have 4.10 and 35's and @ 2000rpm turn about 70mph. On an open highway run I can get a best of 15-15.2, so I don't think your going to see much better mileage by a tire increase.
Like said above best mileage is obtained keeping it under 2000rpms.
I know people always post mpg of 18-19-21-22 and such, but there are just too many variables, to expect to get what others are getting.
I have 3.55s and 315 75 and the best I have ever seen was 15mpg and 12mpg normal. I'm hoping to swap to 4.10 and see if it helps. 75mph @ 2000rpm just is a little to high geared for me. And it would be nice to get some low end again.
Rusty
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1995 F-350, Auto (stock), 4x4, Crewcab, Longbed, 4" superlift, 35" BFG's All Terrains, E12000 Milemarker Winch, 5" miter stacks, 160cc Injectors, Shimmed FPR, Tymar Intake, Tyamr HPX, 7.3L Intercooler , 6.0L Tranny Cooler(Thanks Jon), ISSPRO Guages Trany/Boost/Pyro, Built tranny in garage being built.
I lost 1-1.5mpg highway on the '94 when going from stock to 33/12.50-16.5 BFG Mud Terrains. I went from factory steel to aluminum wheels to keep the unsprung weight down as much as possible in an effort to save the fuel mileage. The lower RPM is nice. I'd like to note that I did correct my speedometer so I know my figures are accurate.
To the original poster: Is this your first road trip since the switch to ULSD? It has slightly less energy content per gallon so mileage will lower. Your mileage sounds about right to me for the speed/gear/truck combo.
I used to get between 18-20 mpg on the road in my 97 super cab lwb. 2wd.It had 4.10s with stock size rubber. I had an open element air cleaner,4" straight ex.Bully dog 3"dp, and an edge evolution set on kill.
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97 F-250 H/D 4 door 4X4 6'bed.Broke block building new engine! Oh well it ran14.96 at 89mph at Baytown!
Kenworth T-600 aerodyne 3406c CAT, with 18* "B" modle injection pump(was a freakin peak yuk),10 over trans,4.10 rears,Dual 150 gal. fuel tanks,Budwieser inspired custom hot rod flames.Going to work real soon Leasing to Landstar yeah!
89 mustang coupe single turbo 302 ,built c-4,running little rubber.
I hate Dodges, straight piped common rail cummings sound like crap!
I just blazed from Morristown, TN to Elwood, IN on Monday and averaged 17.5 mpg with the cruise locked in at 75mph. I have gotten as much as 20 mpg on the highway taking it easy of course.
I have a 2wd dually with 4.10's and i get about 13.5 mpgs @ 75 mph driving nice, and about 18 mpgs @ between 55 and 65 mph. that was last summer driving all stock.
Have a new 6.0 F350 CrewCab with 4.33 gears and last trip not pulling got 15.1 at 65mph. Pulling 14K, I got 9.4 at 62mph and I live in Northern California with some hills.
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