2.5L 4cyl Mods

ok so i know that it's not a popular choice. i know that not many people are running them, but i have found some mods and aftermarket parts out there. Intakes, headers, carbs, ect. Lets hear what you have done with your 4 banger? What worked, what didn't good and bad. I'm not looking to hear get different jeep or swap it for a 4.0L. i know that people are running these motors and i want to hear from them. What size tires are you running, what gears do you have, how much lift and how it's all working for you? let's hear it guys.

One of my xj's is a 98 2.5 5 speed. I havent even driven it yet because I bought it with a cracked head. I'm taking out the 4.10 rear end and putting in a 4.56 and it has 235/75/15 tires. I hear that a 4.0 throttle body is a good mod, that with intake/exhaust/headers it should give it a decent bump in power. Some of the old chryslers had turbos that might work with it if you want to do something crazy.

I build an 85 2.5L into a nice little motor. I went with the Mopar Purple cam. I decked the block, did some porting, added headers, and switched from carb to TBI. It was sweet on the trails but just didn't have the poop over the 13,000 foot passes around here. At lower altitude it would probably been fine. I liked the 28mpg.

Been there. If you are set on keeping the 4cyl, put your money into gears. 5spd, 33's and 4.88's were OK. About 10% deep but it needed it to drive decently on the street. Offroad, I had to use more RPM and wheel spin than I liked, just didn't have the low end torque that a 6 cyl does. And once it was lifted with some decent sized tires, MPGs sucked too.

I think the 4cyls are decent stock rigs where MPGs are a high priority but in retrospect, spending money to modify a 4cyl jeep was a mistake.

a quick hijack for those who've owned the 2.5l-- are they usually as reliable as the 4.0l once they reach 200,000 miles, or is it just the 4.0l that's good for 300,000? I just picked up a '94 with the 2.5l as a DD, and was not sure if she'll hang in there like the old '88. I've never sold a DD with less than 250,000 on it and was hoping this one wouldn't disappoint (not that she's very far from it already)

oh, and the other quickie:

is there any noticeable increase in the top end with the 4.0l throttle body? I would expect some loss of throttle response from the larger throttle bore and lower air velocity, but is there enough from the top end to make it a worth wild investment (with steeper gears)

'96 4 cyl. 5 speed, stock 4.11 gears, 235/75 15 AT tires, 2 w.d. I really enjoy it like it is and plan on keeping it for a long time.

I'll throw in my OPINION. Probably not worth modifying the engine/drivetrain. Breathes fine as is. 3000 rpm at 68 mph is busier than I really like, the '89 6 cyl, auto is around 2100 at the same speed so the actual number of spark firings / cylinder strokes is about the same.

I don't "think" the 4 cyl. mileage much better in real world use, but it sure is more entertaining to drive.

One more thing, don't forget the AX-5 trans will be a weak link. I'm thinking of changing to an AX-15, but it's not a simple swap.