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2.5 vs. 4.0

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in_motion

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Discussion starter · #1 ·
hey, newbie jeep owner here. i got my XJ this summer and it has the 2.5 engine. i bought it because i'm driving daily for student teaching but also needed to combat the northern IN winters. i do have plans for it whenever i can put some money back in my pocket and i'm wondering if there are any considerable power deficincies when wheeling with a 4 banger. i'm not planning on any strenuous rock crawling, but i would like to put a lift on it (stock at the moment) and was wondering if that would drag me down at all.

i also would like to know if my engine compartment is big enough to jam a 4.0 in if it ever comes to that.

:thumbsup:
 
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#2 ·
you definitely do not have the power and torque of the 4.0 but it will get you by i guess. A 4.0 is drop in but as for the tranny i do not know.
 
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#5 ·
I wheel the crap out of my 88, it has the 2.5, 5spd, and 33's. Its not fast, and its no torque monster, but it will do what it does all day long. I've had a 4.0 sitting in the shop for it for over two years now, I figured the 2.5 wasn't going to last long, and when I blew it up I'd swap in the 4.0. Problem is that the little 4 cylinder runs great, and has shown no sign of giving up the ghost any time soon, so it may be awhile before I get to do the swap. To be honest, I'm kinda proud of the little thing considering what its been through.
 
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#6 ·
Also forgot, spend the cash on gears and a crawl box if you lift it and go with bigger tires. 4to1 with the right gears and the interia ring, you should be able to idle up and over.













 
Discussion starter · #7 ·
balloo93 said:
Inertia ring
http://www.4x4wire.com/tech/clutch/inertiaring/

Stock 4.0L throttle body.

K&N replacement panel filter.

That's all I'd do with it.
Click to expand...
Ooh, i like that idea. 'Course, it's going to be a while before anything like this happens, but i like knowing what my options are. would there be any adjustments needed to fuel flow with the bigger intake? or would it be regulated by the throttle body itself? (also pretty much a mechanical newb)
 
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#8 ·
The stock 4.0L TB is only a little larger, so the equivilant to boring the 4.0L to 60mm. Should improve throttle repnse and help with a little more umph in the higher RPMs.

Shop around and you should be abl eto pick up a 4.0L from a yard for around $30. Not sure if he TPS and IAC are the same or not, but swapping those two things is easy. The TB swap is a pretty bolt on.













 
Discussion starter · #10 ·
i also have another question about the power behind the Renault 2.1L 4cyl. Turbo Diesel. the reason i ask is because i know diesel's have great torque but don't suck down the fuel quite as hard as their gas operated counterparts. can anyone give me some details, or am i spouting stupidity?
 
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#11 ·
4.0 and tranny drop in, but you'll change the input on your tcase. i had a 4banger in my wrangler for a while, and it was ok off road, but just ok. i was gonna swap for the 4.0. i actually get better mileage out of the 4.0 in my xj then i ever did in the 4 banger...
 
#14 ·
diskman_1 said:
Ok, I have a 1984 with the 2.5. Can I swap in a 4.0 and tranny from a later year??? If so, what all do I need?!?

Eagerly awaiting! Can't stand my 2.5.. Love the 4wd though.
Click to expand...
84-86 had a different firewall lay out and it is a PITA to make a 87+ 4.0L fit.
 
#15 ·
I had a 1986 MJ with the 2.5 and TBI. If it hadn't been wrecked it'd still be running today, I'd be willing to bet on that. It only put out 117 HP, torque was ok, and they only had a 4-spd back then. Actually, when you stop to think about it, back then about the only option on the MJ was, "Buy it or don't." Only engine choices that year were the AMC 2.5L TBI or the POS carburetted V-6. With the gearing and all, it did fine. It was a pickup and I used it like one ALL the time. Hunting, construction, surveying - I took that li'l pup places where ATV's wouldn't even think about going. I had chain sets for all wheels but never once HAD to use them; I used them, but just so's I'd know how to put 'em on in a blizzard in the pitch black night, and to know what I could expect from them. The only tires I ever had on it were Goodyear Wranglers, and back then the Wrangler was fairly new to the scene and there was only the one (original) tread pattern. I loved that little truck. It never let me down. Even when it was hit, it saved my life - the cops and the wrecker driver all said the same thing...

That said, I'd still take the 4.0 over the 2.5 any day. In fact, I get better mpg with ALL of the 4.0's I've had than that 2.5 TBI ever gave me; granted, it wasn't in a Cherokee, but still -- I mean, I'm not sure, but I think it was lighter? Whatever... I only ever got around 17mpg, I average better than that with every 4.0 I've ever had. And more power, too. So while I liked my old 2.5, I wouldn't necessarily go out looking for another one today.
 
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#17 ·
Chuck I am in agreement on the fact that it would be easier/better to run the 86 with TBI than attempt a 4.0L swap. If I remember correctly though, the 84-84 2.5 was not offered with TBI, so that sucker would probably benefit from a 3.4" V6 swap and trans that will work with it.













 
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Ryan949
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