I realize that there's going to be a lot of subjectivity here, but how much noise should my supercharger be making at slow speeds? There is a pronounced whine pretty much from start up, and I don't know if that's normal, as I've never had a supercharged car before.

 

Hi Craig. I don't really notice the whine, unless I hop on it. Except for after shut off. I can hear it spooling down after shut off. Are you referring to an audible whine from inside the car, with the windows up, at idle for instance? Or, standing outside the car, in front of it, at idle?

Certainly very subjective. Could also fall in the "within tolerances" category. Some may make more noise than others, all within tolerable operational limits.

 

Thanks, SuperTrav. I hear the whine pretty much at all speeds, including idle. I suspect that something is going wrong, since most of what I've read talks about the whine being evident only when stepping on it. Any insight into what the problem is would be appreciated.

 

Same here,my XJR has done 120k and i only hear the lovely wine when pushing hard on the loud pedal.
So i presume something is going wrong with your sc

 

Hmm, I wonder if this might be covered under my dealer's full power train warranty. I've got about 800 miles to go before that expires.

 

So, it turns out this noise has something to with the blend doors. I'm not sure I want to take the dash out to sort it out. I need a few months to recover from last week's wallet-lightening visit.

 

If you think the noise is coming from the blend doors, have you tried turning the A/C off but leave the rest of the climate control running? If the noise goes away, it is likely that your system is low on gas.

Myself and a few others have experienced this and evacuating and re-gasing the system seems to be the cure. I thought my gearbox or engine was causing the whine and one day turned the climate control off to have a better listen then realised the noise stopped when I did it.

I also experienced a whistling noise more recently and eventually realised that my wife had closed the face vent on her side but left it open just enough to cause a whistle!

 

I had something similar in my car and earlier this week I got it into my head that it may have been something to do with the power steering. Topping up made no difference, so then I decided to remove all the fluid from the reservoir with a syringe and replace it with new Mobil ATF fluid.

That solved the problem and my car no longer sounds like a washing machine on spin cycle.

 

I'm missing something here. Turbochargers "spool down" after shutoff because they are spun by exhaust gasses and freewheel when the exhaust stops. Superchargers are spun by a belt attached to the crank and stop when the crank stops. It must be something else causing the whine.

 

I hear the "spooling down" sound in my XKR. It is the cooling fans slowing down after shutdown.