12APPT

Ok guys, I am in the midst of a S4 semi-PP engine build. The bridgeports will not be into the waterseal, but the housings will be notched. The PP's will be 1 1/4 inch large and will be between the opening and closings of the side ports. I have a guy making the manifold already.



Here are the questions:



I will have a GT40 on it with a 1.08 hot side. Is that enough or should I move up to a 1.19?



I will be running RA Super Seals and will stud the engine. I do not want to have extra dowels put in, will this be sufficient for 15-18lbs of boost? I hear the rear iron tends to crack around the dowel area. Hopefully with the studs (and possibly going with an S5 rear plate) it will have enough clamp force on it.

j9fd3s

imo i wouldn't do turbo, bridgeport AND PP, pick two....



if you have the gt40 turbo, start with that, i think it'll end up being too small, but you're going to have enough things to sort out that it wont matter right away, and its still enough to do 500hp...



the rear iron breaking doesnt have anything to do with clamping, its a tuning problem. one of the things about your setup that i wouldnt do in mine, is the BP. WHEN you break the iron, there is a lot of porting work to put it back together, id much rather have a street port and run a couple more psi of boost...



in fact if it was MY turbo engine i'm not sure id even port it at all, that IS what the turbo is for. theres a fellow, JRAT who is making over 500hp on a street port, with 2.5" catback.



unless you're actually competatively drag racing, i dont even know what you'd do with that kinda of power... i do live in an area where you can pass people like they are standing still with 100hp....

1Revvin7

Move up on the hotside and make sure your exhaust is bigger than 3" and you will be good to go..