speedballin

So I drive a 94 2 door lifted on 32s but performance wise no air intake only exhaust work is a thrush muffler no fuel injectors nothing, well I drive my dads 98 lifted on 16 rim equivalent of 31s and has a Gibson cat back exhaust other than that all stock performance wise

My question is I drove mine then drive his and his feels like way better throttle response a lot more pick up and with a/c on in mine it feels like a dog but his it doesn't really affect it? Is there something that was upgraded between the years or is the cat back that awesome lol??????

72mustang

I believe there were some changes between then. Starting in 96, I believe the head was changed as well as some of the electronics. Someone help me out on this

VTJeep

AC clutch could be slipping. In 97 they changed the manifold setup, I believe, giving it better response and a little more HP.. Also, if your running 32x11.50's (just a guess on the width) then there is more rotational weight/drag/resistance, than even a 31x10.50. Maybe there are other factors like gearing (but I don't think so) or engine wear (far more likely) that are contributing. Tune up time- plugs, wires, cap, rotor ++?

speedballin

Well I'm pretty sure the guy I bought it from redid all the AC stuff? And I had another xj with bfg 32x11.5 and it didn't really seem so bad I never used the AC in it tho but I was thinking a tune up to just wasn't sure how much it would help if the newer xjs got all there power from a newer head or updated ecu.....

hankthetank

gears? i've got 32's w/ 3.07's...its a dog all around....plus its a renix.

speedballin

Believe I have 3.73 so it shouldn't be like wtf!!! Hahaha

speedballin

I think I'm gonna do a quick tume-up and buy some new injectors

VTJeep

3.55's ya mean?

speedballin

Yea that's what I said lol

VTJeep

...hard to tell if your joking... :/

speedballin

I wasn't hahaha

F1Addict

Unsprung weight has a big impact on performance. 31s on 16s will be much lighter than 32s on 15s. Other factors like steel vs. aluminum wheels and width also make a difference.

Sneak over to your dad's and swap wheels and tires, see if that makes a difference. Also, figure out what your gearing is (rather than guessing). If you're running steel 11.5" wheels with 32s on stock 3.55 it's gonna be a dog. Doing the tune-up will definitely help and should be done, anyway.

What's your RPM at 65 MPH? You'll probably have to use a GPS or have someone lead you in a car with a known accurate speedo unless you're sure the speedo gear has been swapped in your TC.

speedballin

Well I am 3.55 since I'm not the up country and I'm rocking 15x7 aluminium. Rims with 32 and he's got Rubi rims I gotta check rpm when I get it back

F1Addict

I'm guessing the stock 3.55 ratio is responsible for your sluggish performance. Combine that with bigger tires (greater rotational mass) and no performance upgrades and you've got yourself a recipe for slow

speedballin

Not that I disagree but I had on my previous xj 32s with same gear ratio felt like more ***** Idk maybe I'll do this tune- up and go from there

I was already planning on air intake and then new down pipe back basically..