header efficency

how important is flow before the turbo.
thanks guys

you guys have some awesome cars:bow:

You would be surprised at how unimportant it would be. You can easily make 200hp per cylinder with 1 5/8 ID header tubing. I know of one 4 cylinder SVO motor making 800hp with 1 1/2 ID tubing. For midsize V8s wanting to make up to 1000hp, we usually use 1 5/8 ID headers into 2 1/4" crossover pipes and merge those pipes into a collector at the turbine flange. You can decrease spool up time by building a true merge collector at the turbine housing also.

Do you have any pics of what a merge collector at the turbine inlet flange would look like?

Thanks!

I think Burns Stainless makes a true merge collector that the turbo mounts to, I think I saw their ad in Turbo magazine.

I'll try and post a picture of the Y pipe I made for the last turbo system I built which had two 2.5" crossover pipes merging into the collector. Burns stuff is sweet, but WAAAAYYYYYY expensive. Actually, they make merge header collectors with a V band attachment. You still have to make pipes to join the collector into the turbo and that's where I build another merge.