patrick4588

So I am looking to put a manual car into the 7s this year. the plan for this car at the start, was a lightweight manual in the 8s, but still streetable. but that changed quickly as the project went along. ended up with a chromoly tube chassis car. originally I built a 5.3, stroked to a 6.2 and was going to put a t4 (1.10/96mm) billet s480 to it. But after blowing the motor in my m3, I will putting this setup into that car instead. So now, since im full blown race car, I am going to build an LSX and shoot for a bit more hp. With the goal of say 1300hp, what displacement and size turbo would any of you guys suggest. I'm leaning towards the same turbo or switch over to something like a precision Gen2 PT7675. Precision will spool faster, and claims to be rated for just as high of hp by being more efficient. alternatively there are the cheaper older and proven version like the PT88. Precision has a new its a straight line drag car, and nitrous equipped as well. will likely do compression around 10-10.5:1 and keep stroke a little shorter, with intent to rev higher.

Alternatively, I can keep the same turbo for the lsx, and get a smaller precision turbo for the m3 since goal for it will be around 750-800whp vs 12-1300whp on race car. Or buy all new turbos for both. The m3 is also a manual car but will be more a fun street car and run at no prep events.

**Edit

while thinking, I will keep the billet s480 for race car, and go with a 376 LSX. With the nitrous, can handle any spool issue. so then that leaves what turbo to get for the M3.

Iron 5.3 bored to 3.903 with 4" stroke.(6.2L) Wiseco/K1 rotating assembly at 10.5:1
ported 317 heads with btr springs/retainers, manley valves, ls7 lifters and trays, hardened pushrods
Tick stage 2 T56 trans - McLeod RXT clutch and flywheel

Aiming for 800whp with relatively quick spool. I'm thinking be better off grabbing a little smaller turbo, maybe a 70-75mm. With the increased displacement and stroke, spool should be decent even with a journal bearing