OK, here it goes. I drive an XK8 almost daily. It is pretty stock, with the exception of an after-market air filter. Stock exhaust beginning to end. When I accelerate (from a speed of 70MpH so the transmission is locked), all I hear is (wonderful) V8 noises. Sounds like a nice symphony of the expected mechanical noises from the intake of a Jaguar V8. Definitely a more noticeable since the air filter was updated. Love it.

I had a chance to check out and test drive an XKR, and the noise emitted under the same circumstances was entirely different. No "V8" noises at all, just the continuous sound of the supercharger and belt, a semi-loud whine more akin to a turbine or an "industrial" hair dryer. The car was (poorly) fitted with an Aluminum intake (no resonators) that likely contributed to the noise level. Not sure how I feel about it. I was hoping for more of a mix between "V8" and supercharger noises.

I was hoping to get input from folks that drive these XKRs regularly. Is this a hint this particular supercharger bearings are going (car has 120K miles)? Is it in need of maintenance, or even a full rebuilt? Thanks for any input.

 

I've been driving the XKR for 13 years and it has a nice sound. The supercharger does whine, but only when using heavy throttle at high RPMs.

The whine is hard to describe, but industrial hair dryer might cover it. The exhaust sound is there, but not pronounced. I cant say that I can hear any belts, just the supercharger whine.

The whine starts when the vacuum operated bypass closes and the engine is getting boost. I don't monitor carefully, but it seems that boost is coming on strong in the 4000-4500 rpm area.

 

My 4.0 Xkr has also got an aluminium intake air tube and an aftermarket air filter which give some nice intake sound. It also got a stainless steel exhaust system (Milltek) full cat back with only small silencers behind the rear axle, the rest just piping. So there are lots of wonderful v8 exhaust sound together with a bit of intake sound, all very delightful to my ears. The super charger only is heard when at above 3000 rpm and at least 50% throttle

When I bought the car 3 years ago it was completely stock. I could barely tell it had a v8 engine. Boring. But now it is anything but boring! 😀

 

9 years here; completely stock car. Exactly all of this. VERY quiet, but fits the character of the car, and easily addressable if you want to make it louder. Belt and internal-to-supercharger odd noises on a stock car should not exist. May need a coupler (I prefer the original spring loaded as they can hide noise better as the SC ages) if internal, or a full rebuild (have had to do a full rebuild due to former owner lack of maintenance on my XJR, at 110k in my X100 XKR it's perfect with oil changes every 30k since new).

 

Look at your XK8 exhaust. I bet it has some straight through pipes.

If you want more of a Growler sound when you change your XKR Cats put 200 cell instead of 400 cell ones on. It makes a big difference. Not only that you get a performance increase too.