How can I get it? I'm going to upgrade my intake and get the K&N air filter, but there has to be other power enhancing mods? Are there any chip upgrades available? Does removing the center muffle really give more power, or does it just make the car noisier? There has to be other ways to get more power out of that V8.

 

Reverend - There are some popular ways -

First one - Jack up the car and drive an XKR under it. That'll get you going faster right away.

Second method - jack up the XKR and drive an Aston Martin DBS under it.

Third method - Jack up the AM and drive a ZR1 under it...Then you'll REALLY have a lot more power in the most cost effective way.

 

Unfortunately, no one manufactures engine modifications for the Jaguars. If you want more power buy the supercharged version because at most with a full exhaust from the manifolds back and a ECU retune you may get 15hp to the wheels. I wish someone manufactures engine parts because even the supercharged Jags just loose efficiency with the pulley upgrades because of the heaton.

 

nope, nope, nope... not alot to gain on the normally aspirated version.

You did find the kickdown switch right? its that big button under the accelerator, I admit not knowing it was there after having my car for a month, then I got ticked off by another vehicle, mashed the pedal, heard a little click as i engaged that button, and I found some hidden power... the V8 is pretty spirited all by its lonesome.

 

I think that gone are the days of being able to do minor tweaks and gaining anything noticeable in terms of real performance. I did a bunch of the popular "bolt-on" tweaks to my 1995 Corvette (which was really OBDI rather than OBDII) such as air intake modification, fuel pressure regulator, throttle body airfoil, lower thermostat, modified MAF, Hypertech programming on PCM, etc. If you added up all of the individual claims for these mods (8-10hp here, another 20hp there) this should have resulted in maybe 100hp increase!! Of course things don't work this way and I really noticed NOTHING significant in terms of seat-of-the-pants improvement. I suppose if you measured 1/4-mile times maybe all of this stuff would have resulted in 1/10th or so off the time but this means nothing in the stop-and-go commuter daily driving that most of us do almost all of the time. As far as exhaust improvements, this turned out to be one of the most consistently overrated and disappointing bang-for-the-buck mods that many were suckered into. I never did this because by almost all reports (at least for the Corvette), gains at the rear wheels were negligible but noise inside the cabin became intolerable.

The ONLY mod I did where I actually noticed an improvement was when I replaced the rockers with higher ratio roller rockers (similar effect to putting in a "hotter" cam). However, this obviously goes beyond the simple "bolt-on" category and requires getting into the engine.

With OBDII and the more advanced computer systems these days, I would think that gaining anything at all without screwing something else up is virtually impossible unless you have sophisticated diagnostic and programming tools handy.

Doug

 

These guys claim to be able to give you some additional power (35 hp). You might want to give them a call. http://www.eurotekdesigns.com/main.html JAGUAR OEM RATINGS OEM RATINGS XK8/XJ8 4.0Liter 290hp@6100RPM 279lbs@4250RPM XJR/XKR 4.0 K 370hp@6150RPM 387lbs@3600RPM XKR 4.2 Liter 390hp@6150RPM 400lbs@3500RPM 4.2 XJR 390hp@6150RPM 400lbs@3500RPM S Type R 400hp@6100RPM 408lbs@3500RPM 5.0 Liters In Development JAGUAR ECU TUNED ECU TUNED XK8/XJ8 4.0Liter 325hp@3200RPM 300lbs@4100RPM XJR/XKR 4.0 K 400hp@6100RPM 429lbs@3500RPM XKR 4.2 Liter 425hp@6100RPM 479lbs@3300RPM 4.2 XJR 425hp@6100RPM 479lbs@3300RPM S Type R 435hp@5900RPM 488lbs@3300RPM

 

Did you read the RPM for the 4.0L NA tune I dont know how that works out

 

I had to assume that that is a typo.

 

What about the Catalyst that Jason is producing? Will that not amount to anything significant?
Brian

 

My guess is that most of these types of bolt-ons will not mean much in everyday driving but there would probably be some "improvement" showing up at the dyno or the dragstrip.

From what I hear/read at other forums, the types of improvements that are most readily "felt" are things like swapping out rear end gears to a higher-number ratio (i.e., going form 3:1 to 3.5:1), adding a supercharger to a normally aspirated car, or boosting pressure for cars that already have turbo or supercharging. Still none of these are cheap and there would also be consequences (gas mileage impact from changing gearing and dealing with heat from increasing boost).

Doug

 

Just kidding around, but in all honesty you would maybe see 10hp at the wheels and that is nothing noticable. The N/A engines are at a loss, but if you want to have a shop produce say custom cams, heads, or intake manifold go for it get some engine mods for the Jaguars going.

 

NOS really but you will be thrashing your engine soon

 

The quickest and cheapest way to gain 10 more HP is shut off the cabin climate control. Far more effective and more measurable than some of the so called aftermarket mods in the $50 to $150 range.

 

Any add-ons will be considered by the ECMs and you will not really gain anything. I would steer away from the oiled filters as they have been known to cause MAF problems.

 

I see another K&N debate coming up

Doug

 

There's a debate about K&N filters?

 

Nope, no debate...nothing to see here...Just move along....

 

I think they are fine and have never had a problem. Others think they can cause damaged MAF sensors and other problems from excess oil coming loose. Gentlemen--start your debate engines

Doug

 

Oh! What!! Where am I?

 

But if the K&N filters are properly treated with the oil, the oil shouldn't come off, should it? I mean, if someone saturated it, I'm sure a little oil would get sucked through, but if it was oiled properly...