I have a 2006 XK8 and would really like to make it faster. Has anyone done any modifications on their XK8's engine that has increased the horsepower? Something like boring out the cylinders or adding a supercharger? Is this even possiable?

 

Long story short answer,get an XKR or spend more money trying to make an xk go as fast as an XKR. Check out this thread for more discussion.
https://www.jaguarforums.com/forum/s...ad.php?t=44339


"If I agreed with you,we'd both be wrong"

 

Nitrous oxide is the cheapest and easiest solution. Also has quite a bit of risk when not done properly so be careful. Most likely you'll want a "wet" setup, which means that you also increase fuel delivery when the nitrous is used, as opposed to "dry" which just delivers nitrous along with the usual amount of fuel. This risks a lean condition and burning up pistons, etc. I have enough equipment for putting a set-up on my 97 XK8, but have not gotten around to it.

 

From what I have read here there is little you can do to a stock XK8 to make it "go faster" as the way they were built any tinkering will really mess with the computers mind.

 

Someone else was asking a similar question for a 2001 model. The answer in my mind is the same, sell your XK8 and get a XKR. The cost to get more out of your NA 8 is going to be more than just buying the XKR outright. Additionally, with the R you get the sport suspension and the Brembo brakes as a bonus.

 

Strip some weight....same Hp, but it'll be faster now, did u really need that cd changer and passenger seat. That seat weighs a ton, u should lift it up sometime.

 

Hahaha.....My kinda guy......I stripped my track car by 400kg that gives you an extra 70bhp per tonne and you can then sell the parts and probably make a $000

Here's a pic of inside one of my doors.....Ignore the red circles I was showing someone where the glass adjustment was or should I say lack of glass lol

 

The best way to gain up to 20% power is to install new plugs, replace the MAF, clean and flow match the injectors, replace the O2 sensors (no substitute for this one, it's the most important), clean the throttle body, run a diagnostic on the computer to check fuel trims and sensor performances and so on, check fuel pressure, replace the fuel and air filters and change all the lubricants to synthetic. Most older cars (although an 06 is not that old) are down about 20% on power from new due to deterioration of these parts. You can get much of it back. Anything beyond that on this car will affect its reliability.

 

And I was afraid to mention the 'throttle cable adjustment', to make sure its within OEM specs. I gained 20% throttle opening by doing mine. Or should I restate it this way - my throttle cable was stretched so that I had only 80% of my original throttle position before the adjustment.

 

Hey! I heard about this one! This is supposed to be even better than adding nitrous, isn't it?

http://www.youtube.com/watch?v=AV8iF6SMjh8
https://www.jaguarforums.com/forum/s...ad.php?t=38663

 

I'm looking at a Jaguar world magazine article on tunning a 4.0 XK8, remap & Milltek exhaust (non resonated) produced a horsepower gain of 28.5 HP over the stock setup, according to Paramount Performance from the U.K

Jim

 

I guess it depends on how much value you want to put on an 'arm and a leg', that little lot above probably would probably cost $3000.....Thats $105ish per hp, thats almost a kidney

 

With most normally aspirated modern cars, and these in particular, the $-per-horsepower price is pretty steep. Simple bolt-ons that are worth anything are just not out there.


Doug