Hello,

I completed my build of a 357 for my 1991 GTA. I have AFR 180's with Accel high flow intake and runners. Cam is the Lingenfelter 74216. Static compression is about 10.5:1 and dynamic compression is about 8.34:1. TCI Streetfighter 700R$ with 2,600 stall.

I have a stock 48mm throttle body on the car now that is sticking. So, time to replace. I have been looking at Summit at their brand of throttle body as well as BBK.

So, my questions?

1. Based on my motor, will I gain anything by going to a larger throttle body?
2. If so, what size 52mm or 58mm?
3. Is the Summit throttle body a quality piece or should I go with BBK?

Thanks for the help!

 

Have you dynoed your car yet?
Did it fall off more than you thought it should?

I say if ya gotta replace it anyway, at least upgrade!!!!

Seeing as you don't have a big cubic inch engine..... but have certainly improved the amount of air your engine should be using..... I say go with the 52mm.

On a very lean tune.....I hit 330 Hp and 349 Ft/Lbs @ the Rear Wheels with the original 48mm TB with much the same combo as yours(357",LPE Cam, AFR Elim 180's.) So 48mm can do the trick

58mm is probably overkill in this situation.
As for the Summit Brand, like most things these days it's made by one of the other big companies with the Summit stamp on it.

Go for it......... Buy the Summit Throttle Body and save yourself $100.oo and spend it elsewhere!!!!

By the way Professional Products has a 52mm throttle body for like $200.00 which is another $50-60 cheaper than the Summit stuff....... and $150.oo cheaper than Holley stuff!
http://www.summitracing.com/parts/PFS-69705/

When you think about what the throttle body does, there's really no reason to spend a ton of cash.....

my

 

Thank you for your very thorough response. It is greatly appreciated!

I have heard a lot of negative things about Professional Products but like you mentioned, the design is relatively simple. So, it should be fine.

The car has not been on the dyno yet because as soon as I got it running it went to the body shop. Wow, sounds like your car does well!!! 330 at the rear wheels is about my goal. I was hoping for 350 but 330 is good enough!