I am getting a twin turbo setup and right now i have a 230/236 cam on a 112 lsa, would it benefit me greatly to get a turbocharger cam with less split? Also, how do GT28 turbochargers compare to other turbos out there? They rate them at 350 max hp each, is this at the flywheel or rear wheels?

 

A tighter LSA will benefit you because you won't lose so much boost. Also a cam with less duration wouldn't hurt because there is more overlap with a bigger cam.

 

check out Combination Motorsports

 

Cutting down the duration will help so you don't have as much overlap. I believe the equation goes ((Intake + Exhaust)/4 - LSA) *2 = overlap @ 0.050

So you've got 9* of overlap. The way that it was explained to me is that the pressure in the exhaust headers is usally greater than the boost created so when you have overlap you get exhaust blowing back into the chamber and slowing the incomming air down.

 

Your typical turbo cam has 114 LSA... Less overlap is better for any boost vehicle. The primary difference between the turbo and blower cam is that the blower cam needs longer exhaust duration.

MN_Vette said it correctly, overlap is bad for boost.

 

Is 8* of overlap too much for hi performance superhcharger setup (D1 Procharger). I was looking at some of C Motorsport's S/C cams and a lot of them had around 8* of overlap with that fomula.

 

I can't really say... define "too much". If you live in Cali, yes too much would make you fail smog.

Also, most Dynamic Compression Ratio calculators use the Advanced Duration. With that in mind, about 50-52* of overlap is about the limit. The problem is that Advertised Duration may vary 0.003 between manufacturers. The reason for AD is that the compression bleeds and builds the moment the valve lifts from the seat.

Measurement of 0.050 are more consistant for an industry standard, however are too sloppy for any DCR calculator I've ever used.