I have a 2007 XKR and I am unable to find any performance modifications. What have you guys done and what do you recommend. I am looking for about 25-30 horse power for under $1k.

Thanks for your help!
Stan

 

to give you an idea of what can be done. click on the following links for some ideas,


There are a number of different upgrades you can do to your cat for under 1000 that will yield you 25 horse power. I believe the most common is the upper supercharger pulley which can be had for under $300. I personally plan to go with full exhaust, pulley, ECU tune, Filter and intercooler cooling. I would love to get my HP up near the 2010s

Jaguar XKR 2007 Modified by Paramount Performance MASSIVE POWER!!!! - YouTube

Paramount Performance Ltd - Jaguar XK and XKR MY 2006 Engine Upgrades

Paramount Performance Ltd - Jaguar XK and XKR MY 2006 Exhaust Systems

Jaguar XK8 & XKR Performance Parts, Exhaust Intake Systems, K&N, Borla, Remus, Arden, for Jaguar XK8 & XKR

 

I wonder how PP got such high number with those mods. They must have dynoed after a cool down period, with ice packs on the SC, ice water through the system, other mods not listed or just a strong motor from factory.

I have all the mods above plus more and I got no where close to those numbers but my "rough" estimate gains are 84RWHP and 77RWTQ. Unfortunately, I did not do a baseline on my car but these estimate gaines are based on Gn4hir's stock dyno run. Heat soak was the major problem and robbed power. I might have gained more if not for the dyno shop being an hour away. Next mod will be Water/Meth or Killer Chiller.

I would say the best bang for the buck with my SOTP would be the pulleys and hiflo cats.

 

Thank you both for your suggestions. I saw the pulley upgrade on line and wondered if it was worth it. I will definitely check it out.
Thank you for your help!

My friend has a 2009 BMW M3 and wants to race me in the 1/4 mile. Who do you think would win?

Thanks,
Stan

 

I'll leave it to the owners of the XKR to give you definitive information, but a quick look at the numbers puts the stack in BMWs favor looking at power to weight.

Vince

 

BTW...I got all my performance mods from Eurotoys except for the hiflo cats (Nameless Performance). If you want to checkout Eurotoys...definitely give Mike a call....he does all my mods install and service.

I'd say the M3 will probably be quicker against the 4.2L XKR. As for the 5.0L XKR, it should start pulling away from the M3 from the vid below although the M3 Coupe should be quicker than the 4dr.

 

I think heat soak is a huge issue with increased boost. Actually, it is an issue with the stock OEM.
I haven't seen any comments on aftermarket intercoolers. I have seen some which have separate cooling fans that attempt to address heat soak in a stationary vehicle.
As for aftermarket Cats, I checked the Painless site and they do not list any products for the post '07 XK/XKR: Jaguar - 2007+ XK/XKR - Nameless Performance. Wonder if their cats do in fact fit a post '07, and what kind of hp gain is experienced?

 

Can you discuss under what circumstances heat soak is an issue, and why? Is there a need for concern with stock OEM? Thanks

Bruce

 

Heat is a particular issue with supercharged motors because as air is compressed it gains heat. Air intake heat gain causes power losses. Basically, anything you can do to reduce intake air temperature increases power. Conversely, heat reduces power.

If an auto is sitting or in slow traffic little air passes across the intercooler making the intercooler at least temporarily inefficient. Charge air is not cooled as much and power is lost.

Intercooling the charge air revolutionized supercharging/turbocharging. I can speak from the experience of having supercharged autos without intercoolers (Paxton supercharged Shelby GT350 and '61 Corvair). Both of my applications suffered large power loss on heat soak conditions, which also caused detonation problems. On very hot days I would disconnect the supercharger drive belts to relieve detonation.

I think Saab was the first mfg. to utilize intercooling; and this made turbocharging a practical power source.

I invite you to read "Forced Induction Performance Tuning" by A. Graham Bell, an Australian. It is very readable. Also read the technical papers on the Kenne Bell supercharger site.

 

What I was actually questioning is why you think "heat soak is a huge issue with increased boost" from a pulley (which is generally only 1.5 psi I think), and "an issue with the stock OEM". I'm quite familiar with heat soak, and recognize that it is a normal operating condition for both super-charged and turbo'd engines, with sensors and engine management used to operate the engine safely under this condition.

Are you saying that this vintage of XKR has a problem that you are aware of in stock form, or with a pulley in normal use? I have a stock 5L XKR that I track quite aggressively, and know that it hasn't exhibited any signs of heat soak even after 30 minute lapping sessions. I'd be quite comfortable in the intercooler's capacity with putting a pulley on it for street use that's much less demanding than the track, but wonder about track use. For that I would consider using water-injection to supplement the intercooler's efforts.

Should owners of the 4.2 be worried about heat soak?

Bruce

 

I put on a new custom muffler from solo performance and the car sounds like
a washed up **** star with a head cold......lost all class and there is no difference in power that i could feel....only up side is the larger dual pipes look great.....but the sound has to go.

do you think that using the performance cats (200 cel) and mid pipes with the stock muffler would be any good?

 

That's the set up I have and its perfect b/c you can maintain the dynamic exhaust function if you want. Although currently I have pulled fuse 19 to deactivate the dynamic exhaust.

I have a thread up here someplace with before and after sound clips.

 

My mid pipes and rear muffler are stock, only cats are changed.

 

I put the stock muffler back on kept the x over mid pipe and 200 cel x
After market cats and it sounds killer.
I'll post clips shortly

 

I pulled fuse 19 and the sound was louder but it lost power in the mid and
high RPM range.... .?

 

What's the deal with cold air intake mods.... I read that it doesn't work
then I read that it does.... So what's the tech?
I have an 09 xkr with 200 cel cats cross over and free flow mid pipe. Stock rear muffler
Would love to get 500-550hp not sure how..... It was very easy on my pushrod American v8
caddie ctsv in fact a supercharger pulley gave me over 600 HP ....500 should be easy on a fine tuned jag..... Should it not?

 

Hi Bfarrell!

Happy Holidays! Just curious how you found the performance difference w/the 200 cell cats? Was thinking of doing that myself.

Regards,
Zack

 

Hi Zack, The cats added a noticeable improvement and better sound.
my favourite up grade is the upper pulley.

Best
Barry

 

hi barry,,
would you please tell me where to buy those cats?

 

Not sure this is useful to anyone regarding the underhood heat issues.. the mechanic at my Jaguar dealer told me that with the GT version of the XKR (I think its called GT.. they only made a few of them) Jaguar removed the engine cover that goes over the supercharger and it has higher flow hood vents and he also said that the under engine cover was removed as well. All this to reduce heat.
When you look under the car there is a black sheet that pretty much seals off the engine from the road.
Lawrence.