[Thomas590]

Originally Posted by ChristosD

have a read through this thread here(page 118-119) i been trying to find out why it makes a different noise for a while now, its killing me lol

https://www.e90post.com/forums/showt...18714&page=118

Check out this thread, it might help you to find the answer.
https://f80.bimmerpost.com/forums/sh....php?t=1211456

Originally Posted by nioh_lbbm2

Are you talking about the fart in between shifts? That's the wastegate releasing boost between shifts...

How can you be sure of this that it's a wastegate?

Originally Posted by CanAutM3

When abruptly lifting the throttle on the S55, "farting" noises can be heard. There is some wizardry happening in the engine system to keep the turbos spooled. It is most probably a combination of the waste-gates, Vanos and fuel injection that come into play to maintain high energy gases in the exhaust.

Originally Posted by Boss330

As far as I know, very few production turbo engines employ anti lag by using an open throttle and injecting fuel. The S55 and Porsche 991 Turbo S has at least "cold blowing". That is, keeping the throttle/valvetronic open on the overrun so that the engine continues to pump air and spool the turbo. The 991 Turbo S only introduced this technology on the facelifted version going on the market this year.