232 to 2.5L swap

[eprobe]

I know I'm going to catch some flack for this but I want to take my carbureted 232 out of my

'81 CJ-5 and put in a 2.5 L. Reasons:

My CJ-5 is my daily driver and always will be
The 232 gets about 15 mpg and it's killing me
The 232 has no emissions stuff and I'm going to need it soon

What would I need to do to swap in a 2.5 plus a five speed? Note: I'm not interested in

upgrading to a 4.0 unless there's a way to get 25 mpg. That's why I want a five-speed

behind the 2.5L.

[Dukes69]

Maybe a Chevy V6 would be a better way to go. I think someone on here has swapped in Chevy V6, maybe they can offer some suggestions.

[YJEric]

My 2.5 only gets about 18 mpg with 30" tires on a 90 YJ. Not the most gas effecient motors ever built. stick with 6cyl and you won't be sorry.

[rick]

See this thread: 4 cyl mileage

It is not likely you will get 25 mpg... Keep in mind that a brand new 2.4L Wrangler with a 5 speed is rated at 18/21 mpg.

A Chevy V-6 in a Jeep could get 20 or better depending on tire size, gearing, and the way you drive it. You will get better mileage with the V-6 because you won't have to have your foot in it all the time. A Chevy swap is not for the weak of heart however... You basically need the entire donor vehicle to avoid nickel and diming yourself to death with the things you forget to pull or that don't come with the engine if you buy one that is already pulled. I had a '95 S-10 that got 23 on the freeway at 70 mph with an automatic trans. It was a long bed extended cab, so I imagine it was similar in weight to a CJ.

A 4.0L mated to a 5 speed on stock tires and gears can get 17-18 if driven gingerly...

[blkTJ]

FYI, I just did the math and came out with 15.6 mpg coming home from moab with a 5 speed, 4.56s and 35s. not to bad.

[JeepGal]

I didnt really watch on the way back, but on the way there...I averaged over 20mpg. Thats with the front driveshaft taken out, 5 sp 3.73s and 33's

Tam

[eprobe]

232 to Chevy v6?

Maybe the 2.5 isn't the way to go. Getting a lot of negative feedback from other forums. So where is the golden mean between power/torque and mileage? My 151 got 25 mpg and had zero power and my 232 and 258 had great torque/power but I'm lucky if I get 15 mpg w/ 31" tires and 3.73 gears.

Maybe the 4.0 is the way to go.


Thanks,
Eric

[Dukes69]

Originally posted by JeepGal
I didnt really watch on the way back, but on the way there...I averaged over 20mpg. Thats with the front driveshaft taken out, 5 sp 3.73s and 33's

Tam

This is at about 2000 RPM and 65 MPH . . . because thats how fast my Jeep can go!

[RangerRick]

Have you ever thought about Fuel Injecting the 6? It will pick up a couple of MPG right there plus give you that new Jeep driveability you seek. Just a thought as the two I have converted from carb to F.I. turned out great and both owners are happy they went that route instead of reconfiguring and moving stuff around to stick in some other engine. Smog will be a benefit as well because the F.I. models pass better especially if you live in a state like California with tough laws. One was a Throttle Body Injection conversion (about $1300) using the existing intake manifold and the other was a Head Swap M.P.F.I. conversion ($2000) to a 4.0L head. This combined with an O.D. gear in the final drive will give you better HWY miles guaranteed....

[eprobe]

Reply to OllllllO

First off, that's a cool logo of a name. Second, what do you have to do to swap a 4.0 head on a 232? I know the 4.0 has a more efficient head-- something about eliminating a 90-degree turn in the channel the fuel has to take--but don't you have to do some drilling, etc, and how would the valves on a 4.0 match up w/ the displacement on a bored-out 232? Would I have to do some reprogramming? Would I have to adjust the valves? You can see why I'm scared to get involved w/ this. Was the $2000 mostly labor or parts? What labor was involved? What kind of mileage do these two guys get and how else were their Jeeps set up (i.e. axle gear ratio, tranny, # of gears, tire size, etc.). Can you just pull a head and EFI system off a newer Cherokee sitting in a wrecking yard?

I've done some very scientific experimentation since my first post and my 232 (w/ 1bbl carb, 3.31 gears, 4 speed SR-4, 31.5" tires) gets about 16.1 mpg when I drive it as if there was a wood block beneath the accelerator. I guess I would be satisfied w/ 21 mpg under the same circumstances. Can EFI give me that?

Thanks,

Eric

[drivenhardse]

my 04 se 2.4 with 4.10 gears and 33 inch tires averages about 17 miles per gal on the highway or in town it dont matter of course my odometer is off i loose a mile about every 12 miles so could be off a bit, but my question in is the anyway to get more torque out of my 2.4 with out spending gobs of money, dont really want to regear unless that is my only option. any help would be great. thanks