1972 Wagoneer 4x fuel economy

[joggerfogger]

Tiny bit of clickbait, but seems to follow suit with some of these titles.

I don't know the actual mpg this Jeep got with it's original motor, but 30 years ago we had an '83 Grand Wagoneer and it got 6-8 mpg, so I'm basing my title on that.

I bought the Jeep without a motor, and put a 1989 Isuzu 4bd1t Turbo Diesel in it over the last 2 years. I'm now driving it, and the last tank I got 24.3 mpg. The first tank was 19.7, but there was a lot of idling, tuning, and fuel leaks.

I built a fuel tank for it and my goal was 30 gallons. The first fill up was 31 gallons, so I'm guessing it's 32-33 gallons at least. So I'm getting 600+ miles between fill-ups with a complete variety of driving speeds.

If you want to burn 30 min checking out my build I have it mostly documented. I know it's still a dino fuel burning machine, but it's the most fuel efficient vehicle I now own. (all big diesel trucks).

1972 Jeep Wagoneer Diesel Conversion

Cheers,
Kevin

[cRiPpLe_rOoStEr]

Why did you resort to an Isuzu engine and what other engines have you considered prior to fitting it?

[joggerfogger]

Originally Posted by cRiPpLe_rOoStEr

Why did you resort to an Isuzu engine and what other engines have you considered prior to fitting it?

Cummins 6BT is doable, but a little too big/heavy. Then looked at Cummins 4BT, but they're very loud and getting harder to find. The 4BT does have huge aftermarket support as most 6BT go fast goodies work on the 4BT.

The Isuzu 4BD1t is less favored in the diesel swap world, but I believe there are many times more units available in the world. It's quieter, and the IP supports close about 250hp turned all the way up. Rebuild kits are cheap, ~$900. It's very similar to the 4BT in displacement and size and although rare, adapters are available.

I have a different turbo, charged air cooler (intercooler) and hoping for 200HP. This isn't a typical ecomodder build as I'm not primarily going for economy. When I made this plan, I was making biodiesel at home. Now it's just a fun project. I still buy B99, but stopped making it.

-Kevin

[MeteorGray]

Good deal, Jogger!

That's the engine the factory should have chosen in the first place.

Going from 8 to 24 mpg is real progress!

[cRiPpLe_rOoStEr]

Originally Posted by joggerfogger

Cummins 6BT is doable, but a little too big/heavy.[][]Then looked at Cummins 4BT, but they're very loud and getting harder to find.

Surprisingly, in my country (Brazil) it's been more common to see 4-cyls below 5-litre fitted to medium-duty trucks instead of a 6BT or similar other engines. When it comes to the U.S. it seems like Cummins is putting higher hopes on the more rev-happy R2.8 crate engine program, but I'm surprised the ISF3.8 didn't spawn into some U.S.-spec version similar to how the R2.8 evolved from the ISF2.8 which has been quite popular among Chinese truck factories and had even been factory-fitted to some versions of the Ford F-350 in my country.

The Isuzu 4BD1t is less favored in the diesel swap world, but I believe there are many times more units available in the world.

Well, maybe the 4JB1/4JB1-T/4JB1-TC outnumber it, not to mention the many Chinese copies