I am running a BBK 52mm TB and want to know if it will be a ristriction when I put on my Vortech S trim (6-7psi)?

 

I'm using a 52mm and it seems to be working fine... actually it seems to be working good. The consensus is that anything bigger than 52 will be overkill unless you are making serious power. For a mild blower app, IMO, a 52mm is fine. If you had aftermarket heads, big cam, big cubes, I'd say 52 would pose a slight restriction. I doubt any more than 10 rwhp on the dyno and that's peak not average. Maybe an AS&M 54 if you like to pay a lot of money.

 

I doubt you would see much gain with a bigger TB. Put the money you would spend on one into eliminating intake resticiton upstream of the blower (on the "suck"rather than the "blow" side).

Rich Krause

 

I did a search before and read what the same responses, is there a calculation though? Does VE increase, if so how do you determine it? Can it go above 100% VE.

I currently am making 383rwhp N/A, and expect to see 450-470rwhp with 5-6psi (assuming my cam bleeds off a little cylinder pressure). I have my XE230/236 ground on a 114LSA.

 

The only thing a larger throttle body will do in a blower application is decrease the amount of pressure that builds up in the intake tract.

THATS IT

so you might have 12psi with a stock TB and end up with 10psi with the larger one with similar power