XJ's~For~Life

I have a 99 XJ with the 4.0L! I want some more ponies. Whats the best and proven things I could do to get some more umphhhh?

lifted1994xj

Cold air intake and Cat back exhaust that is what JP magazine says they have seen on the dyno to improve HP and torque. I don't have the article handy but i think they said those will give you 10-15 horsepower and about the same in torque.

bigbadxj

Build or buy a stroker.

cherokeefreak

the main upgrades I would recommend would be a bored out throttle body, upgraded computer system, have your injectors cleaned, Cold air intake. It's hard to get much of anything out of a 4.0 they're just not that capable without a stroker kit.

XJ's~For~Life

I dont have the time or the money to buy or build a stroker. I know the cold air's are not worth the money and only make sound imo!

XJ's~For~Life

I want a bored throttle body. Anyone have a 62mm TB? I think a bored TB and a cool custom snorkel which = actual cold air intake. and I already have the exhaust done so that should do it. Oh and I need to tune up.

XJ's~For~Life

I am doing a tuneup this week, Gonna see if that helps. It still has stock Plugs,Wires,Dist Cap,Button on it with 162k on it. That might not being helping it I drove a 96 HO XJ the other night and it seemed to have alot more power then my 99 which it should be the same HP wise. I just wonder!