Bigger then 72mm turbos? Everyones take?

[driven87]

Moved this over here and i got no responses in the one section. If you did not have to race in a class and just wanted an all out fast car for yourself would you go to like a 74 or 76 trim turbo?? i know people have gone in the 8's with TSM legal turbos but lets say you had no rules and wanted to go faster easier with a big turbo. Thanks for any thoughts.

 

[jasjamz]

There are trade offs you must consider. Added time to spool, looser converter(3800+), boost control, and mounting issues. I'm sure a ball bearing, q or s trim, 76 with a billet wheel would be a monster on the big end. But, you'd have to be at like 30 psi to really see it shine. Now who puts on a turbo that big without all the "other" normal things you see on a car with a turbo that large?
With all the advancements from the early 90's, I think a 70mm is more that enough for any street car simply because it will be capable of making more power than you can put to the ground without blowing the tires off. I see smaller turbo TR's beat ones with larger turbos all the time. (Ain't that right Brer Rabbit) When I grow up :biggrin:thats the biggest I'd buy for a street car. Now a track car....whole different ball game. Going to 28+ psi on the turbo you already have is a real eye opener. Pour in the C16 and arm the alky! Try it if you havent already.

 

[HighPSI]

My opinion, don't go much larger than you need to. You mention doing it "easier" with a larger turbo. This usually means you are compensating for another area that needs to be addressed to get you the results you want.

 

[ijames]

Yes, the bigger turbo will usually be more efficient so you can make the same hp at lower boost but as others said the big price is spoolup. The TSM guys are limited to 3 bolt turbine housings so just changing to a 4 bolt housing will get you a big step up in rated hp and make a state of the art 70 turbo a solid lo-9 turbo without hurting spoolup.