Recently went to Minna Gallery for performance upgrades for my ' 01 XKR.Selected two for further evaluation: air intake system with heat shield and supercharger pulley upgrade. Understand the rewards but it's the unknown risks and unintended consequences that worry me ie transmission, rear end, computer problems, etc.

Would appreciate all advice in order not to make wrong or poor decisions.

Many thanks in advance.

St8teman

 

The supercharger pulley will make the system run a little hotter. You may get a slight increase in pull off line, but will be hard pressed to feel much difference in any other range. Opening the front end will help some with the cold air intake, but you would need to also open up the exhaust to feel much difference again. I added the cold air system to my XJ8 and it kept setting off the CEL, so I had to remove it. It also makes a little more under hood noise. The drive train can handle some increase in torque, but before I would put a lot of money into performance mods, I would be sure that the timing chains are in good order and the plastic tensioners were replaced with the improved metal ones. Just my $.02 worth.

 

By changing the upper supercharger pulley you will notice an increase as you will get more boost sooner. If you change the lower you will be very surprised. The faster you turn the blower the more heat you will generate so you will need to increase the cooling system as well, there are larger supercharger radiators to address this. If you are looking into changing the intake make sure you are not drawing in air from the engine bay as all you are doing is drawing in hot air. You may be better off sticking with a stock intake & installing a K&N air filter. I can tell you the changes will be amazing, I am running these upgrades & a few others as well, my 0-60 times are 4 seconds that is with 20.5 psi max boost. It all comes down to money as it does get expensive. You may also want to lookminto water methanol injection it will lower your charge temp. Just my two cents

 

I've heard thay K&N's are a bad idea with Jags because they screw up the MAFS.

Anybody know if this is really true? I run K&N in my truck but never had a problem.

 

Thanks for the good advice. I believe I will stay the course on this one as I don't test the car's capability very often. Would have been a nice to " know you got it if you need or want it " thing.

St8teman

 

I think the thing about K&N filters is that they are just fine as long as you follow the oiling instructions. Not enough oil and the filter will not filter well; too much oil and the residue could end up on the MAF and screw with readings. I have used a K&N on my 95 Vette for 13 years and have had no ill consequences and intake breathing is somewhat improved.

Doug

 

I don't know if I have ever 'needed' any more power. Just remember that the tranny is a 5 speed Mercedes unit. If sport mode is not on, it is in the fuel saving mode and starts off in 2nd gear and shifts smoothly. This is how I drive the car in normal everyday traffic. If you want it to go faster, quicker, put it in the sport mode. This allows it to start off in first gear and hold on the the gears a little longer. If you floorboard it in regular driving mode, a switch under the pedel will force it into first gear.

 

Sadly, I didn't discover this 'switch' until I had the car for about a month and a half. Pleasantly surprised I was.

 

I recall one guy from the other XK forum stating that he put his XK on a dyno with K&N and showed that it does not increase HSP at all, so he vehemently recommends staying with a high quality paper filter. My truck is more impervious to such things but I have no preformance issues with the Jag, so I'm not going to put K&N in it.

Better safe than sorry, especially since these cars can be finicky!

 

I recall one guy from the other XK forum stating that he put his XK on a dyno with K&N and showed that it does not increase HSP at all, so he vehemently recommends staying with a high quality paper filter. My truck is more impervious to such things but I have no preformance issues with the Jag, so I'm not going to put K&N in it.

Better safe than sorry, especially since these cars can be finicky!

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What is the "other" XK forum? I think I recall that new clean stock filters work about as well as a K&N. The thing about the K&N though is that they flow better as they get dirty versus the stock filter. The arguments regarding benefits from these types of minor modifications seem to go on and on. There always seems to be a dyno run somewhere that shows some gain from doing "x" and there are just as many that show no gain. But as long as no harm is done I always get a psychological gain in horsepower when tinkering.

Doug

 

The "other' site is here.

http://forums.roadfly.com/forums/jaguar/jaguar_xk8/

Great site for tech info. as there are numerous gearheads there.

 

Before spending the money on a K&N in-engine-compartment air filter, read the following:

http://www.kennebell.net/techinfo/ge...AirWARNING.pdf

Although it is directed to those with superchargers the induction of hotter air to a naturally aspirated engine decreases hp, and it quite possibly will also mess up the MAF and throttle body, requiring, at the least, frequent cleaning.