Juicedz28

Do the throttle bodies differ in size from 98-02? i have a throttle body i ported myself off of a 98 z28 that l would like to swap with the throttle body off my 02 ws6. If the core of the 02 is bigger i will just port that one. But i put alot of time into the one off my 98 so i was wondering if theres a difference in size? Thank you

nemss1

stockwise, the bore is the same. only difference is 98's have a smaller TB cam. u would need a TB cable off of a 98 to make a 98 TB work on a 99-02

jimmyblue

iTrader: (11)

I have played with both and the difference in
cable draw for full-open appears to be zero;
the difference is in the cam profile, late ones
open slowly initially and faster at the big end;
probably just a CAFE drive cycle trick.

You can swap the shaft & cam between models
no prob. Casting # is identical for the body.
Slight difference in the PCV fittings (can be
removed w/ a little twist & pull) and the
coolant nipples (hacksaw).

If you have the traction control, that has the
potential to bind up the cable draw. The early
TB will probably care less about that since the
late, does most of its angular business at the
very end of the draw.

01ssreda4

iTrader: (96)

^^^^agreed with above.

Juicedz28

Thanks for the great responses. Also, whats the bore on a stock tb? And how much would you gain on a really good port job? thanks guys

Z28/2002

iTrader: (27)

Correct me if I'm wrong but the stock size is 75mm. People have saw around 10 hp by porting the stocker

01ssreda4

iTrader: (96)

yep 75mm, and i could see 5 to maybe 10 hp. but throttle response is what most people notice.

Juicedz28

Cool. How bout mm wise. How much do you gain?

01ssreda4

iTrader: (96)

^^^^the way it was explained to me is that it is ported to the full 75mm bc when it is factory/unported it cant flow 75mm very well at all bc of the way it is designed.

69_YENKO

iTrader: (16)

+Juan

even though it only gives 5-10hp you will definatly be able to feel the added throttle response in the SOTP right away

nightmare23

iTrader: (5)

i have a 98 throttle body on my 02 works fine...well kinda ..its a quicker respons but id rather have the 02 ..its a smoother ride

Juicedz28

Did you leave it as is. Or did you change the shaft?

nightmare23

iTrader: (5)

i just left it as is.... works good...