Throttle body size recommendation
 

I'm building an engine for a customer and the boost arena is something new for me. I'm looking for some recommendations on throttle body size for this combination.
The engine will be a 525" aluminum block, 4.5" stroke, KRE High Port 380 CFM heads, hydraulic roller 255/265 duration, Northwind intake with fuel injection rails added by Wilson manifolds, gooseneck forward to throttle body, 9.25 compression, dual TorqueStorm procharger belt system with two intercoolers
This is a street / show car 79' Trans Am, 6L80E transmission, 3:73 gear 9" rear. I have had recommendations from 90 - 105 MM on the throttle body and I simply don't know. Any thoughts are appreciated

What RPM range and how much boost?

Try this calculator:

Induction CFM

:)

Hey John, since it's a street car probably see 7000 max. Regarding boost, probably on the 12 lbs range

I'd say it would need around 1900/2000 cfm throttle body. (more for racing, but 'street' use probably good enough)

My 'Toilet Bowl' is 4" diameter (around 101mm I think) which supposedly flows 1500 cfm. You would probably need the 105mm at least?
Probably good for street type use. But I'd try for a little bigger?

:confused:

Found this on sizes on Killer Ron's website:

105mm would be smallest I'd go.

Link to the 'Terminator' style throttle body of Flying Toilet:

Terminator

May give some ideas on the size.


:)

105 mm is a very common size for the Accufab and Holley throttle bodies (single blade).

The LS Intakes in this intake system can mount a 105 mm Throttle Body as designed right from Holley for LS Chevy engines,
see photo.

I personally would not use anything smaller than the 105mm TB. So you have a choice on either a 4 BBL 105 MM TB flow
or a single 105 mm TB flow set-up.

Tom V.

We run a 105mm on our 461 cu.in. twin turbo car. seems to like it.

105 or bigger