Hey... This is a simple question. Will one of you gents post the links to any exhaust, pulley, inter cooler sprayers, etc to increase hp on the 2007 - 2009 XKR?

I have a buddy in DFW area that's looking into buying a slightly modded XKR 07' with 75k miles, great condition with custom stainless exhaust and upper pulley and thinks the car now has over 500 hp with these mods!

I'm knowledgeable about the x100 with these mods only plus Hiflo cats would bring maybe 25 - 30 hp at best! Maybe I'm wrong if so educate me... Any links would be appreciated good or bad.

I'd say your (modest) figures are realistic. For 500HP it needs a TS (twin screw blower).

Take a look at the XKR GT3 prep post on this form and then do some more research on what was done to gain their HP on a 4.2

Your assumptions are accurate. Highflow cats, exhaust, and a pulley would bring this car to around 400 whp, 470 crank from what I have seen on a Dynojet.

Engines lose power with age, so at 75'000 miles, no way it was still making the "as new" power anyhow.

Anyone claiming 500hp at the crank with an Eaton blower is kidding themselves.

The guy claimed he spent $7000 on performance mods including an engine tuning....

As I tried to stress to my friend ecu tuning is like finding an unicorn behind a rainbow for the Jaguar.

I suggested that he walk away because of potential of the car being experimented on by novice tuners that do not know Jaguars. There's plenty of XKR's on the market to settle for a car with questions.

Powered by magic pixie dust, I expect...

People claim all sorts of fantastical figures for the output of their tuned cars. My response: "Show me the dyno, before & after".

I think the biggest reason cars lose power at 75,000 miles is clogged cats. Rings don't wear out that fast with modern injected cars. That issue was mostly related to washing cylinders with fuel in the bad old carburetor days.


Having said that, I would not by a modded jaguar.

Agreed guy! "Show me the dyno, before & after"

People often have money to spend on mods but not on dynos. Weird or what.

Yeah; how do you know you got your money's worth without some sort of objective measurement?

Any OEM Jaguar mesh grill is a must. Comes in black or chrome. I don't feel the lower is as necessary, but maybe you'll want to do that one too? Remove the fuse for the antenna. Dremel and powder coat the calipers. Larini exhaust.

500hp is achievable , See me signature. Although without a proper tune, these car are very specific and most generic of the shelf tunes not properly developed will gain minimal and might even loose power , speaking from experience. With the mods he's got I doubt if car has more than 440 crank hp without a "properly developed tune"

Dyno , track numbers to back up the claims?

Infinite scroll strikes again, random bump on a 4 year old thread.