Topic: regear question

[pioneer4x4]

hello, Ive got a 86 Cherokee, 2.5 TBI, 3spd auto trans, 31" tires, msd ignition, blaster coil, 30over, decked, ported, slightly larger cam,header, higher flow injector, and have recently re-geared from 3.54 to 4.56 and don't really notice any difference but loosing top end, was wondering if yall had any comments as to why this is. i thought it should feel a lot more peppier from stop to start, but still sluggish? not sure what trans or tcase i have there aren't any tags or #'s anywhere,anyone know what i might have? was thinking about swapping a manual in, anyone know what options i have for trans and tcase for this conversion? also my spedo gear is probably stock which i think could have an effect on the pcm, just cant seem to find right gear without knowing what trans or tcase i have? i know the 2.5 usually runs around the 2500-2800 rpm range, but can i exceed this safely say 3500-4000, at 60mph i'm a 3k, moving soon and have to drive jeep and don't want to over rev for 3 hrs, what rpm should i run? Ive read posts about re-gearing and spedo calibrations but they weren't on xj's. sorry for so many questions on one post. any input would be appreciated, thanks in advance.

[Mr_Random]

Sounds like you have a good set up there, swap out that crappy 3 speed! It doesn't hurt to bring your 2.5 into the high revs you need, it's a short stroke motor and doesn't run into harmonics that high like 4.0's do!

Sorry you didn't feel any kind of help from the regear, but it's probably due to the horrible combination of the tbi2.5, 3spd auto, and 31" tires.

Here are some (oem) 5 speed options;
t-5
ax-5
ax-15

The ax-15 is the best choice. You will have to find a 95+ 2.5L Dakota ax-15 bellhousing and use the clutch kit/slave cylinder from it to mount an ax-15/np231 from an 89-90 jeep cherokee (not sure if YJ's had them at the time) in order to retain your cable driven speedometer. On top of this you'll need a new crossmember, clutch pedal, all the mounts, master cylinder, and new driveshafts to tie it all together.

The ax-5 isn't as strong as the t-5, but is more readily available for a jeep swap. I would just buy a whole donor 2.5 jeep to pull everything off of. Your current t-case should mount up the same to the ax-5 due to it having a 21 spline input shaft, so it wont matter what year (just avoid 87-90 because they have an internal slave cylinder) donor you get. Heck, if you get an MPI year you can probably do the swap for even more power!

[aw12345]

If it sluggish, check the engine does it run the way it should no plugged cat and such, on the trans when is the last time you had the bands adjusted and is the kickdown properly adjusted? this kinda stuff can make a big difference

[pioneer4x4]

the trans was rebuilt less than a year ago. yea cheched the engine, compression was good.  what are my options with auto trans?

[oldjeep]

i know the 2.5 usually runs around the 2500-2800 rpm range, but can i exceed this safely say 3500-4000, at 60mph i'm a 3k, moving soon and have to drive jeep and don't want to over rev for 3 hrs, what rpm should i run? Ive read posts about re-gearing and spedo calibrations but they weren't on xj's. sorry for so many questions on one post. any input would be appreciated, thanks in advance.

I run mine at nearly 4K down the highway, it has no power at all down in the 2500 - 2800 range.

[DodgeMudder]

If you do want to swap it over to a stick I do have everything except formaybe driveshafts that you would need, (I might have the driveshafts too but not sure if there in the back or not), if your anywhere near nw PA I could get you all fixed up on what you need.

[Bounty Hunter]

Could be running too rich with an oversized injector, this would cause it to be sluggish.  A rich condition will also ruin the catalytic converter, which will choke the exhaust and make it even more sluggish.

I'd recommend an air/fuel ratio gauge with a wide-band o2 sensor so you can properly tune that hopped up 4banger.