MILEAGEMAX Build Thread

[JMPVW73]

MILEAGEMAX
2005 Chevrolet
Silverado 2500HD 2wd Regular Cab W/T
6.6L DURAMAX Turbo Diesel, 5 speed auto Allison transmission
5177 lbs.

I hope to merge form and function with '50's custom car inspired build and maximizing MPG with improved aerodynamics and gear ratio changes.

I will be doing most of these modifications in the next three months.
NO FOAM or COROPLAST CRAP!!!!!!

Goal: 20+ MPG Combined, 30+ MPG Highway
Current: 16 Combined, 20 Highway


PLANNED MODIFICATIONS LIST
IDDI= I done did it
###= Post number for details

SUSPENSION/WHEELS
17" MOON disks
6" Lowered control arms
Lowered Torsion Keys???
8" Rear axel flip
Lowering blocks???

BODY/CHASSIS
2" Lowered body mounts
Grill blocks
#2 1500 bumper top pad
Front bumper lift
Fabricate/replace bumper bottom/air dam
Fabricate/replace front skid plate
Low profile transmission cross-member
Belly pans
IDDI#2 Remove side molding and badges
IDDI#2 Remove fender flares
Enclosed rear wheel wells
Rear fender skirts
1949 Chevrolet Fleetline inspired aero bed cap
Wiper cowl fairing???
Outside mirror delete???

ENGINE/DRIVETRAIN
3.42 Ring and pinion swap (3.73 stock)
Air intake and turbo, mods to stock
Exhaust, mods to stock (not “green” ones!)

WISH LIST
6 speed Allison transmission w/ manual gear selector (Final drive .61, 5sp is .71)
Engine tuner/programmer
Air intake
Turbo
Exhaust
Bio-diesel

[JMPVW73]

These photos are of a 1500 4x4 Hybrid and a 2500HD 4x4 and are the best I could find to see differences clearly. Note the following:

1. Difference between a truck with fender flairs and one without.
2. Bumper pad on the 2500HD is 2.25" taller than the 1500.
3. Large gap between the bumper and headlights/fender on both models.
4. Hood profile on the HD is taller by about 2".
5. Fender gap of HD is double that of 1500. 1500 is 4" front 6" rear and 2500HD is 9" and 11".
6. Frame visible below body on 1500 is around 2" and 2500 is 6".
7. Lower A-arms and skid plate are visible below bumper on 2500 HD.

[Frank Lee]

If the primary goal is to merge form and function, can you reveal what the function is e.g. hauling/towing 15,000 lbs, or x cu. ft. of cargo at x speed over x distances, and so on?

[JMPVW73]

Form is that it looks good. The modifications are primarily done for aesthetics.
Function is that it saves fuel. The secondary effect of modifications is improved aerodynamics which I will monitor as much as possible.

Some of the build will include unnecessary weight or rolling resistance and not the pursuit optimum drag coefficients.

I have not been able to find any mileage competitions for production cars and trucks.
I would like to eventually make a version of the truck with a bullet nose, full boat tail, narrow highway rib tires and a removable fuel cell.
I'd like to test Mythbusters style; testing within a set distance at a set speed by switching to fuel cell and weighing before and after.
This would also provide the plumbing for running an auxiliary biodiesel tank.


This vehicle does not regularly haul a load. It will haul less than 10000 pounds with an open dual axel car trailer between 16' and 20’ long across distances of no more than 1000 miles. I may eventually haul an open gooseneck trailer.
I will eventually work on a nose fairing, wheel skirts and other aerodynamic improvements for the trailer and share those as well.


I don’t always know what I’m talking about. Feel free critique anything I share and provide or direct me to information that will help. I may edit previous postings in response rather than making a new one; In which case you will be notified.

[RobertSmalls]

Originally Posted by JMPVW73

I'd like to test Mythbusters style;

Badly? :-P

A vehicle as large and heavy as a full-size pickup probably can't be modded to get better mileage than a bone-stock Civic. Therefore, there will be many people on this forum who will tell you you're selecting the wrong tool for the job. If this does not discourage you, then by all means, proceed! I think a sketch or two of what the finished product will look like is in order.

Originally Posted by JMPVW73

I have not been able to find any mileage competitions for production cars and trucks.

Check the Events and Meetups forum here. I'll be attending the Green Grand Prix and Hybridfest this year.

[JMPVW73]

Originally Posted by RobertSmalls

A vehicle as large and heavy as a full-size pickup probably can't be modded to get better mileage than a bone-stock Civic.

Deleted inserted photos because they are not working please see attached.
31.07MPG has been achieved with this at highway speeds!
The truck is 9300lbs!
It runs a compound turbo set up and has other performance modifications to the engine as well as a programmable tuner.
He has a 6x8” lowered suspension and a 3” body drop.
The MPG is mostly thanks to the six speed conversion with a .61 final drive from the transmission and 3.42 ring and pinion ratio. That is cruising 70MPH at 1600RPM!
The truck owner also pulls a 53’ enclosed trailer with two cars inside. I don’t know the MPG with it in tow.

The truck weighs 4183lbs (a Honda Civic and then some) more than mine does at 5177lbs!
I will be performing many of the same modifications.

Take the energy required to move that amount of weight. Hypothetically if it being 1/3 the weight made it capable of 3 times the MPG it would be a 3100lb vehicle that gets 93.21MPG. That’s about 50% more efficient than your Honda.

Originally Posted by RobertSmalls

people on this forum who will tell you you're selecting the wrong tool for the job.

The fact is I need a truck; a truck that can that can haul. It is the right tool for the job.

Originally Posted by RobertSmalls

I think a sketch or two of what the finished product will look like is in order.

My beliefs probably differ from most of the people on this forum. I will refrain from expressing those here and hope we can respectfully disagree. The tread is a work in progress and you will see sketches or actual forms as it continues. Please note the Fleetline photos in the first post.

[JMPVW73]

My tire selection was set prior to owning the truck at 275/55R17 D rated (28.9” dia.) with a 3” white wall applied by Diamond Back Classic. It also dictates the wheel choice as Dodge 2500 17x8” wheels.
Wheels will be covered by 17” MOON disk.
Bridgestone Dueler H/L Alenza
Diamond Back Classic Radial Tires

Wheel and tire combination weight is 80lbs.
Wheels increase rolling resistance and reduce drive ratio from stock 3.73 to effectively a 3.93. It may be counterintuitive but it is what I have. See future post on gear ratios.


Stock tire is 245/75R16 (30.5” dia.). Truck is currently running 285/75R16 E rated BFG A/T (57lbs 32.8” dia.). I’m trying to get some 245/75R16 E rated for baseline testing and hauling.

Chevrolet 2500HD steel wheel is 16x6.5”. I have not found a weight.
Dodge 2500 steel wheel is 17x8”. Weight is close to 40 lbs.

Dodge has a 17x7” 2500 wheel and I think may also have a 6.5”. Dodge 1500 17x8 is 40lbs. Dodge 1500 17x7 weights 10-15% less so 2500 version should be the same.
Weights are approximate and provided by me standing on a cheap bathroom scale with and without holding parts.


Potential LLR tire choices are highway rib tires in the following sizes (may have negative effect on towing stability):
215/85R16 (30.5” dia.)
235/85R16 (31.7” dia.)
245/75R16 (30.5” dia.)
225/75R17 (30.3” dia.)
235/80R17 (31.8” dia.)
245/75R17 (31.5” dia.)

[Frank Lee]

Trucks are the correct tool for certain hauling and towing. Am I correct in that your need is more for trailer towing than filling the truck box? Is it a box trailer or a flatbed with tall loads? How often?

[RH77]

Look into getting an aero bed cover and maybe lowering the ride unless you absolutely plan to go off-road (imagine owning a sub-compact car -- would you take it off road? Remember to check how much it is to rent if you need off-road capability once in a while).

To JPMVW73, sorry, but I'm skeptical. Is the 31.x MPG average across an entire tank? If you have receipts, we would love to know the location, fuel price, route, and details of each fill. I have cruised at 70 mph with the Ford E-350 with a 5.4L SOHC, 3-Valve "Triton" Modular V-8 rated at 300 hp and 365 ft-lb torque from Ohio to Missouri. Transmission: 5-Speed Heavy Duty with Tow/Haul mode (helped to auto-downshift for slowdown and held the revs higher before shift for better response). Chassis: Ford E-350 (formerly Econoline) with "dualie" rear axle and box . Payload: 10,000 lbs. FE 9.2.

RH77

[JMPVW73]

You guys need to go back to the top and read this again. Frank, see Post#4. Thanks for your interest.
An E350 with a box is no streamliner. Do you have a 4.10 rear end?

The 31+MPG truck is not mine and he didn’t back up the number with much or share any running adverage. It may also be a fluke ideal conditions result. Here is the Diesel forum tread on the claim. 31.07 Mpg - Diesel Place : Chevrolet and GMC Diesel Truck Forums

A stock truck can get 25+MPG at 55MPH. The problem is they run out of gears at 55MPH and everyone drives at 65-75MPH anyway.

I see 20MPG at 65MPH with 285/75R16 BFG AT’s.

I like the cap design in this video.

http://www.youtube.com/watch?v=pEEzbnT5dKs

It looks like one of my all time favorite cars; the 1971 Buick Riviera. Note the caption under photo.