mikep_95133

The entire reason for me buying this truck ('93 D250 2wd, ex-cab, 3.54 posi) was to get better mileage towing my 19' cargo trailer around town. I'm glad to find out that what I was told around 1990 was true about these vehicle's fuel economy. Especially with this flat bed. It sure looks heavier than a stock long bed. With my first tank of fuel after the pump rebuild being 25.8 mpg, I'm happy. But that was pure highway driving.

The next step is to squeeze some more mpg's out of it at slow speeds the trailer will be towed at. My electric truck responded well to having the toe set to zero and synthetic put in the trans and differential. 10% improvement the next day.

Low rolling resistance tires are too costly for me on this Dodge. But they really helped my electric truck. It even pushes easier.

I would like to hear what mechanical changes others have actually made for better mileage. Pump tweaks? Exhaust? Gears? Torque Converters?

GIT-R-DONE

What air pressure do you normally run?

I run between 50-60 lbs on my tires. The more air that you put in them, the better it rolls (without going over the tire rated air pressure). Some of the 'E' rated tires are very high, although you may suffer some tire wear with it though.

Bruce M

What speed are you running to get that mileage?
Also what transmission do you have?

mikep_95133

I always run full rated pressure stated on the side walls. 80psi in this case. Trans is a stock 1993 518.

Mike

downhome

Count your blessings... that's a nice mpg. Best I've ever calculated was 18.6? from memory. That was at 60 with a tail wind and a hundred miles of straightaway. Same year but W250, same trans, everything. Turning the extra gears and carrying axle... I may need a tune though.

Your mileage sounds about optimum, hard to do better. You can do some proven funky aerodynamic stuffs to get your highway mpg's better (30 mpg?), but sounds like you aren't interested in that. And it would make your truck look like a space pod.

Lot's of threads on better mpg's, fuel mileage, etc. From memory, you are doing about as good as you can with the D250. Can brew your own fuel... knock your fuel cost per gallon down to 7 cents gallon? Maybe it was 70 cents.

Buddy Stewert

Downhome
What can i do for my D350 to be more aerodynamic. Would lowering the truck help?

Jklawinsky

Make it look like the TIV or Dominator on Storm Chasers

downhome

Buddy Stewart - can make your truck look like this http://www.evworld.com/article.cfm?storyid=870

Comprehensive study on saving fuel. For big rigs, but compatible. Every vehicle owner has to be concerned about the same talking points. http://cumminsengines.com/assets/pdf...whitepaper.pdf

The fuel saving fanatics website - http://ecomodder.com/

Comprehensive fuel saving punch list - http://ecomodder.com/forum/fuel-econ...ifications.php

Don't know if lowering the truck will help. But I know skirting the whole undercarriage, make it all smooth underneath, will.

Santaclaus

Water/methanol injection would help primarily on acceleration where most of the fuel is consumed. Driving with an egg on under your right foot seems to help. Turning to pump timing up a little is supposed to help. I doubt lowering the truck or covering the underside with help at low speed. Just my two cents, Mike.

SORTIE

thank you for posting the Cummins MPG guide, Downhome.

the modifications seen in evworld are unrealistic for most of us as we need unrestricted access to the bed and under-frame moldings rob us of clearance

the suggestions for the big rigs are more in-line with the realities of pickup ownership

skinny tires, properly inflated, make a big difference

so do driving habits

on a recent 500 mile round-trip to Gloucester, MA, I got 23.5 mpg on the way up (with 1,500# in the bed). my wife's Volvo XC-90 is lucky to get 18 on the highway, with that permanent 4WD.

this past weekend I towed a small utility trailer from Greenwich to Lyndhurst, NJ on Saturday and my boat locally on Sunday and let's face it, nothing tows like these old 1st gens.

when you tow with a gasser, your MPGs absolutely plummet

dieselJon

For the record, and I followed pulltilbroke to and from the same station (and 30 miles home) before I filled up. I got 23.x mpg in a W250 5spd, DennyT Stage 2, 33x12.5x16.5 tires, 4.10's, rebuilt pump and injectors. I even added a 4200 rpm spring before I made a return trip. Miles was 527.x and filled with 22.6 gallons.

2 things come to mind on this...

EASY throttle usage!
Knowing when to shift and what gear to be in!
Not going above 2k rpms consistently
A properly tuned pump, meaning not stock
Good cooling system, you need to be warm to help combustion

Autos are going to suck the life out of the truck no matter what.

If I were to build a MPG freak:

D250 Reg cab long bed
D150 springs
Big air dam in the front
3.42's gears in a AAM 11.5" axle
G56 6spd trans
Gear Vendors OD unit
5x.16's or 7x10's injectors
HY35 over a HT3B
PS intercooler
3" charge pipes
4" Diamond Eye exhaust with muffler
265/70/16 wheels
Tonnuea (sp?) cover
A/C that works
Special hood mods for removing the giant parachute that is called the engine bay

Long and low...

mikep_95133

In keeping with the title of the thread, has anyone experienced a fuel economy increase due to changes made?

I will change my diff fluid here at some point. It looks like it may need a yoke seal. When I drop the pan on the trans I'll adjust the bands and use synthetic fluid.

Synthetic in both of those locations will help. I need to find a highway around here to verify my odometer against. There may also be an app for my Android that could provide some bench marking.

On my 25.8 mpg run, I went over 2 1000 foot passes, twice. The A/C was running 3/4 of the 207 miles. On the way back it was cooling off after sunset, so I shut the A/C off. Plus the tank had it's fuel/electrical assembly on top very loose and leaking fuel. Still may be some better numbers to come.

stillsmokin209

23mpg cruising at 60-65. 1990 d250, 3 spd. 727, 265/75/16.

With the addition of the new converter and a518, along with progressive water injection I am hoping to see ~28mpg. When it all gets installed that is...

pulltilbroke

When Jon followed me I got 21 we were usually right around the 60mph mark went 525 miles on that tank,I did a little more running around when we got to SOP though. But like Jon said we were easy on the skinny pedal.This was in my 90 W250 with lot of pump adjustments a 4" lift and bad injectors I also ran the air on the way out. and was loaded about 1000 lbs heavier on the way back.

And just cause I like pics

Me on the far right Jon on the far left and Ike in the middle

crewcabxlt

timing bump and smaller exhaust housing have improved my mpg. i tow alot in the mountians. (nice pics pulllitbroke)