Turbo Mani: HMT-style 4-2-1 Top Mount
Wastegate: Tial V38/MVS 38mm

Just wondering how/where to place the wastegate merge, back into the exhaust stream. I will be running a cat, so it'll have to dump back in before that. I realize a smooth merge (kind of like a 2-1 collector) is ideal, but how far from the turbo should the merge be? I've read some reports of moving it away from the turbine outlet will decrease turbulence and somewhat reduce spool time/increase power. But how far downstream of the turbo should it be placed? Can to merge be too far downstream?

What about the size of the wastegate merge? Should it be the same or slightly larger than the outlet port of the wastegate? Is this one of those things where you want to have it taper or slightly on the small side to keep gas velocity up, or?

Thanks.

 

You've really answered your own question. Smooth merge, close to the downpipe itself, etc. I'll simply add that the size of the tube you're using for the wastegate is fine (about 1.75" IIRC), and have it merge as close to the end of the downpipe before it goes to the Cat as possible. The important factor is a smooth transition into the downpipe.