just wondering what size throttle bodies would be best suited to an a15 with alot of work?
engine specs

12:1 comp
port work and 5 angle valve job
extractors
wolf 3d ecu and indivdual coils
balanced and a few other bits

i have a set of 36mm itbs ,and my old carb setup had 34mm chokes ,so does thast mean the itbs will flow more than the 34mm choked carbs? and the itbs dont have an inner venturi like carbs

also my runners are 38mm od and taper into the oval gx port

dont really want to make the manifold up then find the setup i have is too restrictive and will need to be changed

aiming at 130rwhp

cheers

Yes, 35 bores will flow more air than 34 mm bores. A15 ports are 28x34.

head has been matched to gx ports :)

ok sweet well the 36mm itbs should be about right then

now to finish the mani and do abit of wiring to make it all run!

Doesnt itb size get determined by revs and cc's? Or is that just carbys because of velocity? Sorry just learning about all this

If you ever want to step up I have some 50mm :)

You can get 55s from TWM

But pipes larger than the ports will only slow it down.

Going from what Steve Newing ran on his race 1200 coupe with 1580cc A15, you should go for Neils 50mm units as the A15 rod stroke ratio, revvs and double the capacity of a bike engine would mean 48-50s would be right on for 1.6L with that high comp and short TDC event especially when using fuels like e85.

Yea I hear what your saying but if the port is smaller than what the throat of the throttle body is then its not going to flow any more

Being said, bigger means less restriced intake and unlike carbs I dont need to worry bout low down air speed

Interested to see it running, had A play with the ecu and I have got it to fire inkectors and stuff so need some coils and to finish the mani and I can try start it!

tapered manifold will make a difference, sounds like a ripper motor!

Don't suppose you'd know the brand of those itb's? Sounds like a heap of fun