TB question
 

what is the biggest size throttle body i can go on a stock ls1 intake for my 98 z28. and would it make a difference without upgrading the intake?

im pretty sure the biggest is an 85mm tb and it should give you a bump in hp

Anything larger than the 75mm stock intake opening is a waste of Money and wont perform any better than a Ported stock throttle body that you could do for free..

The larger throttle bodies come with reducer plates that adapt the the larger throttle body opening to the smaller intake opening so you are not really changing anything..

I would go with a ported stock TB as well. I got one for my SS and it made a big difference in the driveability of the car. It might not be a big hp increase but the throttle response is a lot better.

-

ok guys thanks for the tips

by the way how can i port my own tb? i never tired it before so im not to sure

I didn't want to risk the downtime or chance of doing damage so I bought a ported one from somebody that's been doing them for a while. I think it was $60 and my TB exchanged. If you don't want to try it yourself, search around on LS1tech.

-

New Era Performance in N.Y. does them for $75 but you have to send them your throttle body..

Doing it yourself isnt hard if you have access to a Dremel and a few bits..
To be safe just dont mess with the I.a.c. ports