Topic: A few Questions You probably already answered.

[joe_sojka]

Tried to look up some past posts but came up with no luck. Just read a bit on another jeep forum and as usual everyone was downing the 4 cylinder and bashing all my hopes and dreams for my jeep. So I came away with a few questions for the guys who've built em and know whats worth it and whats not.

So here we go.

Will putting in an 8.8 really dog down the jeep greatly with the extra weight?
Also is it worth installing since every 6 cylinder guy wants to tell me otherwise on putting it in.

I've got a 4.0 throttle body on it but will a spacer help?

Is a performance chip worth putting in?

Will the 2.5 always be too underpowered for pretty decent difficulty of rock courses?

Should I go out tomorrow and start looking to find a 350 to put in it?

That last one won't happen but I'm just looking to see how well the engine upgrades available for the jeep help. If its worth it I plan to upgrade it and run it till it don't wanna run no more.

[Jeffy]

No.  In fact, if you re-gear it properly for the tires, it will regain any pep lost from the larger tires.

A spacer will change the torque band a little but it doesn't give you a lot more HP if any.  You can pick up spacers for $60 or less.  Otherwise, pass.

No, performance chips don't do enough to make it worth it.

Rocks are done slowly so HP isn't a big deal.  If you re-gear properly it will do fine.  A double crawler box can really make a difference if you're going slow.

I'd probably go with a 5.7L Vortec at minimum if you're going to be doing an engine swap.  The new LS's like the 5.3L or even a 4.8L are cheap to come by.  There's a lot of support out there for swaps.

[jagular7]

Yep on Jeffy's response.

[95 Lowbuck]

I also agree with Jeffy,
The little 2.5 is built like a tractor motor, great for rocks and technical stuff.
If you plan on a lot of mud or sand it will be challenged, but If you can be patient on the highway
it's a great little engine.
Gearing is critical, try to build a lite rig, and don't spend too much modifying the 2.5.
If you you need even lower gears you could also get a 4:1 kit for your transfer case.

[VA_YJ]

Just a few additional thoughts on the 8.8 swap.  If you're going to run 31s, it's not really necessary to upgrade.  Bigger tires put more stress on the axle and require deeper gearing.  Advantages of 8.8 from Explorer over the D35:

1) Stronger tubes
2) Deeper gearing available
3) Disk brakes
4) Stronger shafts (31 spline)
5) Many have limited slip from the factory (e.g., 3LS73 axle code = 3.73 ratio with limited slip)
6) Larger ring gear provides more tooth contact (stronger)

Available Super88 kit from Superior Axle offers c-clip elimination, chromoly shafts, bigger wheel bearings (Ford 9" size), stock width
Good lockers (Detroit, ARB, etc.) are available and recommended as the stock carrier is one of the weak links

[stan98tj]

8.8 is totally worth it. I run 35s on mine.
My 2.5 has the 3spd auto and 4.56 gears. It's lethargic. I do pretty well in rock gardens-for the most part, especially with both axles being locked and long travel suspension. But, i don't have a prayer on hill climbs that require a little power or wheel speed. Just totally gutless. West coast guys seem to fare better with all that sticky rock, but out here in the NE we often are required to apply a bit of skinny pedal to get up over obstacles or climb hills. I guess i could just keep it in 1st gear and wind it up, but given my awful luck with these motors, i'd rather not pushing it hard. That was the motivating train of thought that led me to buying a 4.0 motor to swap into the Jeep.
As far as performance or go-fast parts for the 2.5, i haven't really had any luck with those and i don't feel they really work. Gearing is your best bet to regain power. Given the smaller engine, you need to gear pretty deep and that could affect its daily drivability.