kissthis66

Looking to get some more horse power / torque out of the XJ. seen a post that had a few bolt on after market ideas to increase both. What I need help with is understanding how and with what type of ignition upgrades I could do to improve HP/Tq. If anyone can point me in the right direction would really appreciate it. Don't know much about ignition products to help improve HP/TQ.

Thanks!

XJwonders

Upgrades u can do is to get distributor cap that has brass terminals, and NGK copper core spark plugs. And good wires. That's all!

JJCIII

Just make sure that the resistance In the plugs your putting in matches the champions that are recommended. I've seen some serious running problems due to the wrong plugs in jeeps. I myself do prefer ngk but I've yet to come across a line that is fully compatible with jeeps.

Click-Click-Pull

Sorry but there's really no HP/torque gain with ignition upgrades~ that will just make it run smooth. Jegs makes a performance cap and rotor, Accel performance coil and a good set of 8mm wires is a good start and for the plugs just stick with Champion coppers are all you need in the 4.0L. Just my opinions. If you want to upgrade the 4.0L look into a good CAI, injector upgrades and exhaust upgrades such as: header and cat back with 2.25in all the way back. There's lots of great info here on all of these. I've done all of them...and that makes the XJ rock...

JJCIII

This is true. Upgrade ignition really only helps getting the fuller potential of other upgrades. Like click click said, intake exhaust, injection upgrades and maybe a cam and lifter kit. The stock ignition can handle in the max range off 400hp. Don't quote me on that but that being said the inline 6 isn't an ignition hungry engine. If your not red lining through gears in a race then there's not really a point. Quality stock is fine for now. The inline 6 biggest power chokers are the intake manifold and exhaust. For the fuel managment issue go with the 4 hole injectors for a more mist like injection instead of the stock which almost looks like a super soaker water gun when it fires.

kissthis66

Alright thanks guys. I'll look into some injector upgraded. Already have plans in place for a new header and full new exhaust/muffler/cat. Also read some have taken a newer (1999/2000) intake and installed it into the older XJs. Supposedly it's a direct bolt on. Still researching this. Anyways, thanks for the info everyone, I'll save my money and put it to good use in other areas.

JJCIII

That is correct about the 99 manifold. The older ones have longer ports into a smaller area under the throttle body, basically cylinders 1 and 6 have to pull air farther where as the newer manifold which is compatable, all of the ports are relatively the same length.