Single Dump V Twin Dump

[bai6tmk11]

Looking to do a dump & cat change on my ba, car is tuned to 250 RWKW at presant.

There are various brands and configurations of dump pipes around and this is where I would like to hear from what people have used and what gains were found, my car is a daily driver so I am more interested in low to mid improvement than top end and will be keeping the factory cat back exhaust on

[riptide]

I would go the single dump every time for an internal wastegate. There are loads of threads where people are having trouble controlling boost with the twin dump, not even realising half the time what the cause is.

I think initially exhaust suppliers started making twin dumps for internally wastegated turbos because they are easier to manufacture and twin dumps are the norm for external wastegates.

The reason I have revived this old thread is because we are having a real problem getting the boost down over 4,000rpm with an Xforce twin dump on a BA when we have checked everything else and never had any trouble with the standard or single 4" dump.

Wastegate is ported and tested on the bench.

Just my opinion but any comments would be appreciated.

Chris