So I've been checking out the bolt on performance mods such as those available at the Mina Gallery - Supercharger pulley, dual intake, exhaust. I have not searched out any others.

The claims of 12 - 15 HP throughout the RPM range for the pulley, 10 - 12 HP increase for the dual intake, and about the same for the exhaust would represent (conservatively) 34 HP increase from these three. And these increases are supposed to be at the wheels.

For those of you who have done these mods, do you "see" these HP increases? Have you dyno'd your machine since the upgrades to see if they have actually given the advertised increases in HP?

And an important question - aside from lowering gas mileage, none of these present any long term negative side effects - correct?

TIA

 

Yes they do work, you will notice an slight increase in performance, Intake and Exhaust will help, you can tell the difference, but don't expect and incredible difference, but will notice a small change. The Pully thing I can't comment on, regular underdrive Pulleys, will cause acc. to run slower, like altinators, this can be bad. But I'll let someone else comment on that.

 

Can't speak with much authority on how Jaguar's respond to bolt-on's but as a long time Corvette owner and Corvette Forum member the rule of thumb is that "if there were easy ponies in the barn" the manufacture would have found them.

Bolt on intake's/exhaust may show a 10 to 20 RWHP increase over stock, is that noticeable or the noise factor in dyno results, or different conditions that cause the change???

The only way to really know is track time. For decades the rule has been 10 RWHP = .1 reduction at the track. Is .1 noticeable??? On the street I doubt it.

Tom

 

As a long time track racer and tuner, I can say that no gains come free of some trade offs. You can generally get good power gains from cold air intakes and by opening the exhaust track but, they came at the price of noise.

The 07+ XKs already have fairly noisy exhaust. I would not want to open it any more, given the nature of the car as a luxury sports cruiser.

I used to race rotary engined Mazdas in various SCCA classes and know a fair amount about modifications. My "classic" 1993, third generation twin turbo RX-7 packs about 500 HP, depending on the boost setings. With 2600 lbs to move around it is a beast. Great car to take out once in a while and enjoy the race-car-like performance but the ride and the noise in the car would make any long distance drive a real chore.

My recommendation is to leave your XK stock. If you need more power get the supercharged one. If you want a race car, get a real race car. No street car will ever match the track performance of a $25,000 race car.

Also, remember that in the Jag category of cars, aftermarket equipment tend to be frowned upon at resale time.

Albert

 

confuse what is bolt on.kn filter? header? exhaust? cam? how if i add turbo to my mustang? is turbo bolt on? how pcm tuen?* why so different power change in tune for different cars?

 

As other's have already said - don't bother.
My 285HP 1997 Porsche is tuned from the factory to go far faster than legal speed limits in 3rd gear. If 500HP on an XKR is not enough for you, go get a dedicated track car - and stay on the track, drag-strip, or dyno.

 

Anything that did not come on the car "Stock" is considred a "Bolt-On", and that includes "Turbo". If you put another Intake filter that is not the stock filter then it's aonsidered a Bolt -On.