Calgary Jeep Association

4x4 Related Groups => Tech Talk => Topic started by: chrispl on July 28, 2007, 01:37:20 AM

Title: 2.5 4cyl in early YJ's
Post by: chrispl on July 28, 2007, 01:37:20 AM

how are the early 2.5 4cyl's with 5spd trannies in the early YJ's? hold up well with 35's? hows the reliability? and mods to make them better?

Title: 2.5 4cyl in early YJ's
Post by: dukabor on July 28, 2007, 03:36:47 PM

you want Fuel Injection for sure.....

mine is still going strong, but I am a bit of a freak for maintenance, I run synthetic oil in the motor, and Syncromesh in the tranny.... I have only minor mods to the motor (4.ol TB, header, minor airbox mod) and have no issues at all.... though I will be the first to admit I do not break land speed records, I am able to cruise at 75 mph..... not sure if I want to go any fater in an SOA YJ on 35's

....Another major factor is gearing, the 5spds came with 4:10's and while that may be OK to get by with 33's, I went to 4:88's and have never looked back.....

If I were to do any more mods, it would be an electric fan, and maybe a cold air intake..... and when it was time for a rebuild I would go to a bit stronger camshaft (Hesco makes a few different options)

Many people will tell you to bypass a 4banger and do a 4.o or even a v-8 swap.... but my bang for the buck is on the 2.5 4cyl.... I can crawl like a bandit with the gears and the 4:1 in the Transfer case, and it does not eat parts!

my 0.02$ .... but I am biased ;)

Title: 2.5 4cyl in early YJ's
Post by: chrispl on July 28, 2007, 04:05:04 PM

i'm mostly concerned about power..

Title: 2.5 4cyl in early YJ's
Post by: dukabor on July 28, 2007, 05:37:55 PM

It does have less power than the 6cyl for sure..... IIRC it is like 140 horse to 190 horse.... I think..  someone will correct me if I am wrong on those numbers

Title: 2.5 4cyl in early YJ's
Post by: Gearhead on July 29, 2007, 01:15:50 AM

I've got a 2.5 YJ as well as a 4.7 stroker YJ , The 2.5 has a 4.0 throttle body and a flowmaster muffler , 4.88 gears . It's easy on fuel and will go as fast as it needs to go ( spring over on 33's ). The stroked 4.0 is a beast , only runs on premium and is thirsty. I like em both. The 2.5 is a cool little engine , I wouldn't turn my nose up at one ,............ well , ...... the throttle body version is not as powerfull as the later mpi model , my 88 Comanche has that engine , it uses more fuel and is less fun to drive.