SimonH

Have a MY00 PPP with decatted d/p. Love the sound the exhaust makes but has anybody else noticed the whooshing noise the exhaust makes at high(er) revs? When accelerating hard the exhaust makes the usual rorty noise however the sound then changes to a whooshing/rushing-of-air type noise.

Any of you boffins know what causes this?

AndrewC

This is a characteristic of the PPP backbox, it's fairly restrictive compared to some of the aftermarket 'boxes (good bottom end torque, not so good for top end), at higher revs pressure builds up at the backbox and the gas flow accelerates causing the whoosh sound.

Personally I quite like the sound but not at the expense of top end power

Andrew...

TonyBurns

iTrader: (3)

Never noticed loss of top end power in my MY00 PPP'd turbo (with downpipe of course )

Tony

john banks

That's because you haven't tried a freer flowing backbox on it Tony I suspect - I did and was converted.

raybotha

I suspect you may be hearing the woosh from the dp as well , also evident in the twindump variety . John have experimented at length with restriction / bottom end torque and flow / topend power , cant decide myself wich is better so am going to see on road behaviour with another car as test .

Ray

TonyBurns

iTrader: (3)

Hmmmmm may have to try that then John ill see how much those scoobymania ones are

Tony

AndyMc

have a look at this thread I started a while back

http://www.scoobynet.co.uk/bbs/thread.asp?ThreadID=29842

Andy