|
The whole idea of a twin scroll manifold with the ewg housing and one wastegate, etc. is no good.
First off, I have never seen one twin scroll manifold that didn't already have a provision for a wastegate so using the ewg housing would make zero sense.
Second, I could be wrong, but I don't think they make the ewg housing in t3.
Third, there are plenty of twin scroll manifolds that have both wastegate reliefs converge so that you only need to use one wastegate.
Using a twin scroll mani with a regular housing is a no go. Absolutely no gain is going to come from that.
As far as AR's you are right about the smaller it is the quicker the spool but top end falls off sooner.
For your RB25 you are most likely going to want a .63 housing on most medium sized turbos. You obviously want the quicker spool so I would pick a .63 housing on a t3 Precision 6266. You would be at full boost (if we say full boost is 20psi) around 4k rpm and you have more top end than you could use. That turbo is rated for 680whp I believe and it's billet. If your really worried about spool then go for the 5858. I use it on my 2 liter sr and it spools just as quick as my 2871 did and it is rated for up to 580whp so it has plenty of top end.
The gtx28 is just too small of a turbo for the rb25 in my opinion. You can rev 8500 rpm with that motor bone stock. Any gt28 sized turbo is just out of breath when it's spinning that high.
|