Hi I recently bought a 2004 jaguar xjr and i was wondering what could I do to get more Hp ? Thanks

 

Wow, power not enough for you ? Anyway, I believe you can buy a different diameter pulley wheel for the supercharger that makes it spin faster and pump more air.

 

Have a look at "quest for 450 hp" in this forum.

https://www.jaguarforums.com/forum/s...rchid=13819028

 

Instead of more HP, consider taking the back seat out, remove the headlining, leave the wife behind, and anything else that saves weight.

Seriously, Jazzyjags has nitrous injection or something, look up his posts. Story is, he's so fast that he doesn't know where he ended up. Last heard of in Mexico...

 

There are some simple things that can be done but also some that are a waste of money.

The best mod, among many, that I did was fitting an LSD.

The cheapest was cleaning out the soft carbon gunk in my charge coolers and TB and below in the elbow.

All 4.2 XJRs will be losing HP once they reach about 40-50k miles because of this insideous build up. That is why I installed an oil catch can and a water/meth system.

I have no tune for the water/meth however it helps a lot in cooling things down as well as keeping the intake tract clean.

 

Irving,

"...what could I do to get more Hp ? ...

Search "Cambo". He's the XJR tuning guru. Follow his advice and you'll have a 12 second luxury sedan.
As jackra noted above, you'll first need an LSD diff for anything below 30 mph roll on's

(...I'm doing the Valley Hose right now, and the t'body/elbow really do get filthy on these SC cars, as jackra also pointed out. I'm also replacing the SC intercooler pump with a higher flow Bosch 010 - another cheap XJR mod/maintenance item to add to your list)