Engine replacement

mike f

New Member
Joined
Jul 18, 2022
Messages
1
Location
Utah
Hey, I have a n 88 yj. It has the 2.5L but only has 16k total miles. I am looking for a little more power. I have looked into a small block V8 swap, but that is involving more than I think I'd like to do at this point and cost. Is there a simple drop in motor option (v6?, 4.0L) for this YJ, or is it a big undertaking whichever direction I go? This car does have a sentimental value to me so selling is not an option, and I do want to keep this for a very long time.
 

Gilaguy23

YJ Enthusiast
Joined
Apr 12, 2021
Messages
650
Location
Q town New Mexico
Dont quote me here but I think an 88 4 banger YJ will have a AX5. Not worthy of more HP or a swap to. Doing a 4.0 AX15 would be nice but lots of electrics due to the FI. I see a 327 or 350 swap in your future.
 

Stoopid Jeep

YJ Enthusiast
Joined
Dec 25, 2021
Messages
196
Location
North Idaho
Have you considered regearing?
I put 4.88 gears in my 4banger jeep and am quite happy with the results.
Running 31x10.5s it will drive 85mph, no problem.
Cheaper & easier than an engine swap.
 

Moon

New Member
Joined
Aug 1, 2022
Messages
1
Location
Alabama
Have you considered regearing?
I put 4.88 gears in my 4banger jeep and am quite happy with the results.
Running 31x10.5s it will drive 85mph, no problem.
Cheaper & easier than an engine swap.
that's what i am considering, wasn't sure which gears to use, sounds like 4.88's may do the trick. Where did you get the gears?
 

Stoopid Jeep

YJ Enthusiast
Joined
Dec 25, 2021
Messages
196
Location
North Idaho
What tire size? 2.5 5-speed?
This begs a question.
I'm running 31s with 4.88 gears. How much performance loss will there be by moving to 33s?
Specifically to 33x12.5s as 33x10.5s are considerably more expensive.

I've been thinking about getting a set of basically offroad dedicated 33's, but there are always big mountain passes between me and the trail. 31s with 4.10 gears sucked. Would 33s with 4.88s be the same?

Kinda want to find a set of 33's borrow before I buy 🤔
 

machoheadgames

Certified YJ Researcher
Supporting Member
Joined
May 19, 2020
Messages
1,371
Location
Dallas, TX
This begs a question.
I'm running 31s with 4.88 gears. How much performance loss will there be by moving to 33s?
Specifically to 33x12.5s as 33x10.5s are considerably more expensive.

I've been thinking about getting a set of basically offroad dedicated 33's, but there are always big mountain passes between me and the trail. 31s with 4.10 gears sucked. Would 33s with 4.88s be the same?

Kinda want to find a set of 33's borrow before I buy 🤔
You'll definitely feel it. I would do the borrow thing before buying. You may find it bearable, There are plenty out there on 4.88's who choose it as their regear ratio from 4.10 specifically for 4.88. Most of that though stems from the age old reason which was that for the longest time, 4.88 was the lowest you could go. So it was the "right" ratio for 33+ and everybody adjusted the other tires like 31's down to 4.56, etc.

33 and 4.88 will be similar to 31 and 4.56. So probably better than the sucky 31 & 4.10. the borrow method will tell you if you can tolerate it or not. I would expect to drop about 200 rpm on the highway from what you're doing now.