how bad are the 2.5L's in a tj?

GSRswapandslow

GSRswapandslow

Well-Known Member
Joined
Dec 20, 2005
Location
Taylorsville
so i'm dying to get another trail truck.....and came across a seemingly good deal on a TJ. THe only thing is...it's a 4cylinder hooked to a 5speed. I'm not wanting to get anything super cereal but want something i can drive to URE or Moutain City or Harlan....and have fun following people (bypassing is always an option for me...since i have such little wheel time) and it'll still get my home. So i figure i'll prob not go over 33's and keep the d30 up front and switch to an 8.8/disk in the rear and a detroit if i can luck up on one. So with that said....and i'm rambling like usual, will the 4 cylinder be ok...or should i just look for a 4.0 right off?
 
I have been super impressed with Getstucksomes 4cyl TJ.

Think I can find a vid maybe..
 
It'll work. With 33s it would be nice to have 4.56 or 4.88 gears. My son had 35's on his 2.5 with 4.88s, worked OK on trails. Definitely not a burner on the interstate though :)
 
the first time i ever went serious off roading was in a tj 4 cyl. the only difference between what you want and he had was that 1) he was running 35's 2) he trailered it 3) he redlined it in mud and beat the living snot out of it.

i was impressed but i knew something had to go eventually.

you never know man. i was once looking at a four cyl cherokee. test drove it and did pretty nice in 4LO.

but a tj is lighter so you may be good
 
I built my wifes tj with a 4cyl, it is running 4;88s with 33s and does great, top speed on the interstate is a little low though , i would go 4;88 on a 5 spd and 4;56 on an auto
 
i have a 1997 4 cycl Tj with a 4 inch lift and 33 with stock 410 dana 30 and 35 but soon will be going to an 8.8 in the rear but i haven't had any prob. out of mine. it does great off road and ok on the interstate streets, highway speed it about 65 to 70 in 4th gear so not the fastest but i am very satisfied with mine.
 
I have a YJ & TJ both w/2.5L 4cyl. Great motor but not much out there to increase HP> The weak link would be the AX-5 tranny. Advance Adapters sells a kit to swap in a AX-15.
 
GSRswapandslow said:
what kind of mileage do you get running the 33's?
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I've drivin 3 wranglers with the 2.5 and bigger tires. I'd say they each got around 10-12ish MPG and were gutless. I'd go with a 4.0.

3rd gear seems to disapear quickly in those AX-5s.
 
I ran 4.88's and 35's for awhile, dd'ing it. I got around 13-15 mpg or so. With the tcase geared 4:1 and the gears in the axles it does well and I think if I had a 6 cyl I would have broken a lot more parts!
 
1stgenxxx said:
I've drivin 3 wranglers with the 2.5 and bigger tires. I'd say they each got around 10-12ish MPG and were gutless. I'd go with a 4.0.
3rd gear seems to disapear quickly in those AX-5s.
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i'd love to....but the price difference is astounding! the TJ i'm looking at is only $3000...the motor has been completely rebuilt with only 6k on that....so maybe i could get lucky and sell it off for a 4.0/ax15...but i'd just have to look.
 
Stick to a cherokee like you first intended and it will be in your range, with a 4.0 included. Your jumping into a whole step higher realm of spending when you get to a tj vs. a cherokee.

Cherokee = cheap to build, beat on it til you get wheel time and learn where exactly a tj would be beneficial, or if history repeats itself, you may not even wanna stay in this hobby that long and your not out as much cash.

Not busting your balls rob, just keepin it simple.
 
well, i just came across a good deal which is why i was considering it. i just came across another toyota i'm gonna look at as well.....but, i've gone through a LOOOOT of hobbies, but i've always regretted getting rid of my trucks, so i figure i'll be sticking to this one.
 
33s i get about 12-14 mpg, with a locker in the rear it gets about 10 to 12 mpg and my 1997 Tj 4 cycl has 184,000 miles, 4 inch lift and no problems
 
Ray VanBuren said:
I have a YJ & TJ both w/2.5L 4cyl. Great motor but not much out there to increase HP> The weak link would be the AX-5 tranny. Advance Adapters sells a kit to swap in a AX-15.
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The Dodge Dakota came with the ax-15 behind the 2.5L in 96-98. I would think a JY would be cheaper the AA on that swap. XJ's are much cheaper to build and cheaper to buy then a TJ. I ran the 2.5L in an 84 xj for 5 years and enjoyed it, but with the ease of finding 4.0 xj's IMHO its a waste to settle for less.
 
How bad is relative to what your planning to do with it. If your planning to DD it I think the 4.0l only gets 1 mpg less on the highway.
- For a trail rig it depends on several things. What kind of stuff your planning to run. Mud or rocks. Also what your max tires size as well as axles etc..
- I do everything different so, I'm specifically building my TJ w/ the 4cyl for a few reasons. Its a little lighter and a good bit shorter in length. I will be able to fit a triangulated 4 link up front just clearing the front of the engine.

The AX5 has a bad wrap but personally I think they are fair transmissions, they just are only good for some much wear/tear before they need a rebuild. I think a good rebuild with good bearings can help them last a good bit. I've seen/heard of many problems with them but to me its mainly loosing gears and shifting issues. Which I think a good rebuild and proper oil would correct. (when a bearing goes out it breaks other stuff). How many are truly broken ? Blown inputs or outputs, gears spit out the side etc?

All that said, I'm running a W56 up to the 2.5L so I get the benefits of the toy trans/t-case (and axles) and will be pushing 35-36s

HP- Based on my homework I've seen numbers around 140hp. I think its easy to hurt power on these engines with the wrong parts or not properly matched parts. Some recent discussion on the jeepforum about swapping 4 hole injectors (fords) in for better fuel atomization. No real improvement on max HP but reportedly helps throttle response and better MPG really do to more efficiency.

I have a goal to get 140hp. Stock is 120 so I feel its a realistic goal with intake/injection and exhaust work. I'm also gonna look in to roller top end, that's relatively cheep (only 4cyls) and can free up 5-10hp all by it self.

So all that said, if you try to run with the V8 guys you will be disappointed. If your gonna run huge tires you will be disappointed. If your rig is built in line w/ what the 4cly is capable of handling I think they are actually pretty good engines.
 
well like i said....goals are:
33" tires as a max, probably
wanna get all over URE type stuff (only place i've really driven all over)
wanna DRIVE there, do it, and DRIVE home
would like to follow buggies,and just use the bypass at places i'm not capable of doing
stick with a d30 up front, and maybe swap to an 8.8 out back


but from more and more talking...it seems an xj would be the smarter choice...i just keep getting shafted when it comes to buying one haha. I'm still gonna look at the tj, and if it's in really good shape i might just buy it and keep it stock and flip it when i can. while looking for another XJ........

thanks for the help and suggestions
 
I have a YJ that had a 2.5 in it. I drove it like that for about 9 years I ran 33's with the stock 4.10 gearing and did fine I even ran 36's for about a year or so before I got an 8.8 and 4.88 gears It did pretty well. now I have been talked into going bigger so I'm doing the v8, tons, and 40's. I would recommend a 2.5l jeep to anyone I had a great time with mine and had very little problems with it.
 
GSRswapandslow said:
but from more and more talking...it seems an xj would be the smarter choice...i just keep getting shafted when it comes to buying one haha.
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Well you get a 96 or 97 xj and they have the 8.25 and the 4.0L with an aw4 and its damn near bullitproof if you drive smart on the trails. What do you mean shafted? People selling them before you can get to it?
 
Aforbes704 said:
I have a YJ that had a 2.5 in it. I drove it like that for about 9 years I ran 33's with the stock 4.10 gearing and did fine I even ran 36's for about a year or so before I got an 8.8 and 4.88 gears It did pretty well. now I have been talked into going bigger so I'm doing the v8, tons, and 40's. I would recommend a 2.5l jeep to anyone I had a great time with mine and had very little problems with it.
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Sorry for the highjack. Do you still have the 2.5?
 
Well I have a 4.0 with 3.07's.....its got plenty of power but i need lower gears...with that said a 4 cyl wouldn't be bad if geared right....just don't expect it to overachieve on the highway haha
 
My buddy has a 2.5 YJ on 33's w/ 4.88 gears. I've driven it several times and it's not too bad. Never had any trouble with it on the mild wheeling it's done. He's taken it to Uwharrie also with no trouble.

Not a speed demon or anything but it will get you there. I prefer the 4.0 but thats just me.
 
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