Dump Pipe Or Front Pipe

[wolverine]

Most of these guys around here just write off the concept of the split dump though. I can't understand how they refuse to accept the idea of them, yet all agree that an external gate on a bigger turbo is a better idea. The ideas are related.

Been there and done both name brand split and bellmouth back to back. Slightly better result with a bellmouth. The margin is small and could be dyno intraday variation but on 420hp turbo I would save my money and buy the bellmouth.

There has lots of theorising that the bellmouth provides a large low pressure area which might marginally improve low down gas flows with the compromise being felt when the wastegate cracks open. Buggered if I know but unless I see a name brand workshop back to back test and post up results that categorically shows otherwise then I feel comfortable recommending bellmouths (and a slabs of beer with the change).