Efficient 4WD Jeep

[SOURKRAUT]

New to the forum and I thought I'd share my plans to make an efficient Jeep.

my plans are to start with a 1992 Jeep Comanche 2wd, I love Jeeps and will only own Jeeps (except maybe an air cooled VW), my goal is to make a realistic, functional truck that I can use as my daily driver, to replace my current thirsty lifted Cherokee. I figured the Comanche would be the best Jeep platform to start with as it is one of the few somewhat aerodynamic models, plus they got decent mpgs stock, with torque minded motors made when mpg ratings were a practical way to fill up empty space on window stickers.

1986 Jeep Comanche 2.1 4cyl Diesel 2WD 5spd Manual-24 city 29 highway
1986 Jeep Comanche 2.5 4cyl 2WD 5spd Manual-19 city 24 highway
1992 Jeep Comanche 2.5 4cyl 2WD 5spd Manual-18 city 22 highway

My plans are:
Engine-VW 1.9 TDI, equipped with a hydrogen generator, maybe a veggie oil/ used oil conversion later.

Drivetrain-5spd Manual from a Geo Tracker (cant adapt Jeep trans to TDI without custom work) and two auxiliary overdrives. With the gears in the spare axle I have laying around I'll be doing 70 at roughly 1700 rpms

Aeromods- Remove fender flares and smooth out mounting surface, fill grill (I'll be upgrading the cooling system to utilize less airflow), a 3" chop top, a coroplast slantback bed cover, 2" lowered and many more here & there aero mods

My naive, mpg hungry heart is aching for 40 MPG.

[ecomodded]

With the 1.9 tdi you will see 40 mpg, easy.
I bet you could throw that motor in a full size pick up or your Cherokee and get 40 mpg.
I say that because my beetle gets 62 mpg on the hwy with that motor.

[SOURKRAUT]

I think I'm going to use My Jeep M38 instead, it's less aerodynamic but quite a bit lighter, it weighs a little more than a Metro. After more research on the hydrogen generator I think 60 MPG is attainable.

[Ryland]

Now your title says 4 wheel drive... is that going to work with that engine and transmission set up?
After seeing an electric front wheel drive, gasoline rear wheel drive pickup truck last week, I really like that as a home built hybrid design and you get your 4 wheel drive as well, not that most people need it but it works.

[SOURKRAUT]

Yes it will be 4WD, it is a must in Minnesota, we had over 100" of snow last year and it's supposed to be significantly more this year. Front wheel drive is useless in our winters, especially on the highway. I was considering a Geo but want something that I can drive year round that will get me there alive on long winter trips.

[brucepick]

Originally Posted by SOURKRAUT

...
Aeromods- Remove fender flares and smooth out mounting surface, fill grill (I'll be upgrading the cooling system to utilize less airflow), a 3" chop top, a coroplast slantback bed cover, 2" lowered and many more here & there aero mods

My naive, mpg hungry heart is aching for 40 MPG.

Are you up to building new aerodynamic body onto the frame? Yes you'll need steering and suspension spring movement clearance to match the Jeep's specs but the body doesn't have to be a box with protrusions.

I'm assuming the Jeep is a body-on-frame construction?? So removing the body doesn't affect the base structure??

[slowmover]

Uni-body

[SOURKRAUT]

The idea of building my own body is making me think about building a sand rail, I have enough drivetrain, suspension, etc parts laying around and I could "borrow" steel tubing from my friends farm. I also discovered that HPA Motorsports makes a Jeep TDI swap kit so I could use a Wrangler 6spd, I thought the only RWD adapters were for Suzuki samurai/sidekick trans which are better suited to the VW 1.6td, the TDI has too much torque for them. The Jeep trans has a wider gear spread as well.

Does anyone have pics of a aerodynamic sand rail or similar vehicle?

I'm thinking a lightweight, low profile frame with a coroplast and fiberglass body.

[trooper Tdiesel]

knowing what my mid size suv gets, id say 40 is really up there.

looking at major aro mods to get that.
doable yea, but no cake walk.

mine is about 4,300LBs with 4.55 gears, 450LB engine and really bad aro. 33mpg is as good as ive gotten.
that's in flat land in warmer temps....with no cargo.
its old school diesel with a turbo added at the factory, so its not ideal as far as the power band, its rather narrow.....2,300 to 2,800rpms its very much suited to the gearing they put in the autos....and the fed 55 speed back in the day..

29 mpg is common as a year round avrege, running at 60 or less, with many steep roads day in and day out.

its rated at 28 city 28 highway

un like your jeep, im limited to 4.55 or 4.11s with the stock axils in a 87 or older ZOO.
my aveter is one of my loads, it sucked mpg down to 17. CGVW was about 9,000LBs, thus why i stay with the 4.55s


for the jeep if i remember right there's many different 3rd member gears that fit the dana 35 that the jeeps are common with.

[Frank Lee]

I'm thinking of a lifted Zoltanbod with Monster Mudders.