XF SV8 full throttle noise

[carlpea]

I purchased an SV8 yesterday (85000 miles) and so far I'm loving it! I have, however, noticed a noise when on full throttle. It occurs when at motorway speeds and putting your foot to the floor. It sounds like squealing / super charger noise, the revs don't jump, as if the clutch is slipping, but I've read about the 6 speed auto and adding an additive to cure it? The car drives really well and the gear changes are silky smooth.

It feels like you can push the accelerator... and then there is a bit of resistance... then you push harder and the noise occurs. It doesn't happen all the time on kick down, only on full throttle.

Any advise? I just want to make sure I'm not in for big bills!

Generic picture below as I haven't had time to take pics yet (Bonnet not closed properly!).

[carlpea]

I've had chance in investigate further and it appears to be coming from the rear of the car rather than the front!

I think it's the exhaust. I've noticed that normally the cars have two pipes, but mine has four, so the previous owner must have had something none OE fitted.

[Benbay001]

carlpea said:

I purchased an SV8 yesterday (85000 miles) and so far I'm loving it! I have, however, noticed a noise when on full throttle. It occurs when at motorway speeds and putting your foot to the floor. It sounds like squealing / super charger noise, the revs don't jump, as if the clutch is slipping, but I've read about the 6 speed auto and adding an additive to cure it? The car drives really well and the gear changes are silky smooth.

It feels like you can push the accelerator... and then there is a bit of resistance... then you push harder and the noise occurs. It doesn't happen all the time on kick down, only on full throttle.

Any advise? I just want to make sure I'm not in for big bills!

Generic picture below as I haven't had time to take pics yet (Bonnet not closed properly!).

As you are surely aware, the SV8 is supercharged.
That will be the whining noise you can hear.
The supercharger on my S Type R (same engine) was very noisy when under load. As far as im aware they are all like that.
If it is honestly coming from the rear, then it could be a diff issue.
The clutch wont slips, because its a conventional torque converter auto, not a twin clutch jobby.

But im sure someone with more knowledge will be along shortly to tell me im wrong.

[carlpea]

I've done a little more investigation and it has an exhaust made by Longlife:

http://www.longlife.co.uk/

Not sure if that's a good thing or not but explains why my car sounds different to other SV8's!

[carlpea]

I've had the back boxes replaced with OEM and no more noise... I can hear the super charger now!