I have a stage 3 BNR on the way back and before I put it on I want to know if I can remove this flap and the other stuff that goes along with it?

 

What does the factory service manual call that thing?

 

That is your wastegate. It's job is to bring the turbo up to a set boost level and keep it there.

 

I don't think soooooooooooo. As was mentioned......."what does the FREE ONLINE FSM call that thing in the FUEL AND EMISSIONS SECTION of the FSM?"

Just sort of scroll down the pages in the FUEL AND EMISSIONS section of the FSM and of the TWIN TOWERS.

 

I was actually about to post this very same question. The parts you're talking about are the switching actuator and switching valve for the twin-scroll turbo's found on S4's(pg. 4B-53 in FSM). On BNR's website, they say the twin-scroll system is optional at stage 3. And on FC3Spro they say it helps airflow when the twin-scroll is removed on 'highly modified' S4's.

http://www.fc3spro.com/TECH/HOWTO/howto.html

Not trying to jack the thread, but I need to add another question. Can you remove the twin-scroll system on a stock turbo? Or only once you get to the point that Sir.William is at with an upgraded turbo?

 

Yes, it's the twin scroll door and actuator; not the wastegate (although they look very similar).

If at all possible, keeping the twin scroll setup is best for a street car. The turbo will spool much better under 2700 RPM and produce more bottom-end torque. If you're using a big hybrid turbo, it's not going to do much spooling under 2700 RPM either way .

 

you can't keep it with a BNR because brian ports the turbo inlet runners.

 

Thanks for the replies. I knew it was not the wastegate and I figured it was for the twin scroll which I do not have any more. It was removed with the BNR upgrade so it can be removes then?

 

It's not even a question of can you remove it, you should remove it because your **** won't work right it you don't.

 

Thanks all.