Hi
I have an issue, that only occurs when I drive 120-130 km/h in my XK8 from 98...no vibrations, no loose tires or faulty bearings...but a lot of resonnans...sounds like a roar from underneath the car, but can't determine if it's front or rear...actually very strange...any ideas. Anybody?

 

Is your air filter box connected to the silencer (plastic tube extension that goes into the firewall/fender) in engine compartment? Gets loud if not. John

 

Are you feeding it the proper premium fuel? They growl a lot of they don't get feed the right diet.

 

Is it still a stock exhaust? Maybe the PO played with it and you have the "drone" common to some aftermarket exhaust systems.

 

Will check asap...:-)

 

We only have 92 and 95 in DK - so not much of a choice here. And I don't think noise is coming from engine.

 

I guess exhaust is original...what do you mean by "drone"..?


Thanks in advance

 

Upon switching to aftermarket exhausts and/or removing sections of the OEM system, many guys experience a "droning" hum-like noise at certain RPMs. Search the forum and you will find many links.

Remember the exhaust system has functions over and above just the expulsion of air from the engine. It also baffles or quiets the exhaust to acceptable levels and impacts engine performance. This is especially true with Jags, due to their target buyer. Look at how many mufflers are underneath and you will get the idea. Remove part of that system without planning and you change the airflow and noise level. Sometimes that's good, sometimes it's not.

 

I am all stock and the drive train has no issues or parts out of balance.The exact same sound appear at these speeds. I can actually change the tone of it by releasing throttle when cruising downhill. It is not a drone, but rather a resonance in the system, kind of a sweet-spot. It is most pronounced when holding speed constant in the very narrow range where it occurs. It disappears completely with minor changes in speed. All designs, no matter how good have expected and unexpected compromises. This is one of them. It would be really fun if somehow this was planned to occur at what is an almost ideal cruising speed for this car. Kind of reminds you of the heritage. Enjoy it, nothing is broken or about to break. It was investigated on my end thoroughly.