Stock turbo/downpipe flow question

[FerociousP]

Hopefully the turbo experts can help me out here. I was wondering why I haven't seen this type of collected downpipe/wastegate design for Rx-7s. The ones below are from random cars on google, but my point is that the wastegate gases seem have a much smoother transition than trying to get around the backing plate and that this could potentially reduce boost creep in stock configuration AND help out overall flow from the turbine and the wastegate. I know the ports on the turbo themselves are an issue, but could this help?

Am I on track with this? :o11:

flange
http://himni-racing.com/images/SUBARU%20downpipe%20flange.jpg

Collected transistion:
http://www.racingworks.com/images/greddy_sr20det_turbo_outlet.jpg

[RETed]

It's because those things are more difficult to make and thus drive up the cost of the finished product...

Why don't you start making them and see how well it sells?


-Ted

[FerociousP]

because I don't have a welder or welding skills for that matter. I also wasn't asking why noone makes them, but why they are uncommon. Similar but different.

My questions were:

Why don't we see this design more often?
Is this design more beneficial to the car?
Would it reduce boost creep?
Would it provide overall a better design?

I understand cost and demand, especially in regards to FC owners. If someone has tried this and found that it doesn't help common turbo issues found in stock setups then that is what I am looking for.

A more direct question:

With a stock turbo, would it be more beneficial to bolt up a typical downpipe or one with this design with cost still being reasonable?