MPG approximation 6.5 N/A

[Chevrolet4x4s]

I have a 1996 6.5 N/A non computer controlled diesel engine.I am thinking about putting this engine into a 73-87 half-ton, 2 wheel drive,Chevy or GMC pickup. I am thinking about this as a college vehicle so mainly a commuter not a pulling rig .I am thinking of the rearend ratio being either 2.76 or 3.08 stock tire size and highway type tread,with either a 5-speed manual out of a 88-98 gm truck or a 700r4 with lockup converter.What are the ratios of the 5-speed esp 5th...are all the 5-speeds overdrive?What type of milage should I expect,the truck would have a low restriction daul exhaust(either straight pipes or glasspacks),Fliped breather lid if this woudl help on a diesel, probably a tonnau cover and a spindle/shackle drop(3"front/4"rear)? Would 30mpg(or more I want all I can get) be easily obtainable driving at a moderate speed (50-55mph)on mostly flat ground?Anyone who has 2wd diesels feel free to chime in along with anyone else.
Thank you for your help,
Shane

[Robyn]

18-20 is not at all out of the question here.

[Chevrolet4x4s]

21.9 highway 19ish(by the ripoff pump) in town 700r4 4wd 3.08 gears......Converted truck to gas still have the motor at my disposial......and the diesel pump was puting in like 20 gallons into a 16 gallon tank(rip off) :eek:
now the truck gets like 14mpg on gas
Thanks
Shane

[moondoggie]

Good Day!

My 82 (see signature below) has 31-10.5x15 tires, 3.08 gears, & the goofy 4 speed - the one where 3rd is direct & 4th is OD. This truck was obviously built to make mpg. With the original engine, it ALWAYS returned 26.0 - 27.9 mpg. (All mpg corrected to < 1% error.) The mpg was so good I never bothered to figure it out tank-by-tank. It has two 20 gallon tanks, so I'd switch every 400 miles. When I fueled the low tank, I had a lool-up chart on the visor: so many gallons was 27.0 - 27.9, a little more was 26.0 - 26.9, etc. So, I quickly knew within 1 mpg what the last tank returned.

Before I knew anything about diesels, & before the Page, I was given bad advice & junked this engine (head gasket leak) & installed one from an 84. The mpg was never as good as before, but still pretty good - mid-20's all the time, at least in summer.

A few years ago, it had been sitting for 2 1/2 years & we needed another vehicle right quick. I put 'er back on the road for three months during the winter (MN), & it returned 24.something every tank.

I wish I had the time - I'd try what you're thinking of doing. I've got a hunch that if the drivetrain from my now-rusted-out 82 was moved into a 2WD with stock-size tires, 30 mpg is not out of the realm of possibility.

Blessings!

[Chevrolet4x4s]

Yeehaw!!!!!!!!! Thats awesome.........thoughts of doing this are becoming more and more serious.Now to convince my parents that this would be more practical than a car or a small truck...........Thanks for your help keep the suggestions and ideas coming.Would a 6 speed camaro/firebird/trans am 6speed bolt up as easily as the 5 speed If I am not mistaken arent 5th and 6th in the six speeds overdrives 5th .78ish and 6th .50 : 1.......The truck 5 speeds overdrive is .74:1 isnt it?Arent tonnau covers worth 1-3 mpgs and a drop another 1-2.
Thank yall
Shane

[NH2112]

I'm averaging 21mpg with my signature truck, driving the speed limit for the most part but still making use of the turbo regularly :) Before changing my driving habits, having the front end aligned, paying closer attention to tire pressure, etc, I was getting 15mpg. Since then my best single-tank mileage was 24mpg. I'm thinking of going synthetic in the rearend and tranny, maybe that'll give me another 1-2mpg. I'm sure the new exhaust will help when I finally get it done, too.

[Chevrolet4x4s]

How hard was it to convert the gasser to a diesel?What trans and gear ratio are you running?
Thanks
Shane

[NH2112]

Well, the swap was done by the friend who had the truck before me (4.3l V6 to 6.2l NA) but it's really not that hard. The engine mounts and trannies are the same, you need to change flywheels or flexplates, and the radiator & radiator support are different as well. Use the +coil wire to energize the injector pump and run a manual glow plug switch. I'm running a 4-speed manual w/granny gear, and a 2.73:1 10-bolt rear. Future plans include an airbag-sprung 14-bolt FF w/3.73s and a 700R4 built to handle the engine's power (I've heard they can be built to handle 450HP and 700+ lb-ft.)

[Guipo]

You know I've been wondering this myself. I just am finishing up a install of a 93 6.5 in my 85 Blazer. I have 3.08 gears and I installed a nv4500. I am hoping for low 20's MPG wise.

Guipo

[More Power]

If fuel economy is important, gear the truck to run at 1800-rpm at the speed you've chosen to drive. I'll be talking more about this is an article before long, but we learned this past June while in Michigan that the 6.5L NA (small precups) we tested produced its best fuel economy (bmsfc) at 1800 rpm.

Jim

[Chevrolet4x4s]

Thats partly the reason I am wanting to have the M/T so that it could be downshifted into a lower gear to turn optimal rpms at both slow speeds to and from college(NTI after I graduate High School{senior}) and then be able to drop it into overdrive and run 65-70 @1800 on the interstate from NC to WV when I come home from school


Also is anyone running a hood scoop or other ram air setup?does it help you economy.I'm thinking along the lines of a ramcharger or 440+6 type scoop to help it breathe easier on the Intake side and free flowing dauls on the exhaust side

Thanks for all your help
Shane