Difference in TB Size

[ezrollin]

Is there a difference in cfm of rwd 2.8 / 3.4 throttle bodies.

[bszopi]

You need to multiply it by the VE than divide it by 1.5hg's. Per the Holley book, a single barrel TB has a VE of 1. (this is assuming a round faced single barrel TB. An oval faced TB could have a higher VE by design and then would have higher CFM rating)
So as an example we'll use the stock Fiero TB.
52mm is 2.05" throttle plate has 3.3sq/in which is 462, X VE (which is 1) is 462. Divided by 1.5 = 308 CFM.


65mm=2.56" = 5.15sq/in = 480cfm
62mm=2.44" = 4.67sq/in = 435cfm
58mm=2.28" = 4.08sq/in = 381cfm
56mm=2.20" = 3.8sq/in = 354cfm
52mm=2.05" = 3.3sq/in = 308cfm

http://60degreev6.com/forum/f65/intake-upgades-t24998

Figure out the TB sizes and do the math. It will at least give you a basic idea.

[ezrollin]

Thanks for the info but I don't have either in my possesion to measure,thought someone might happen to know.I'm refering to 2.8 and 3.4 camaro tb's.

[IsaacHayes]

3.4 IIRC is 52mm. I don't think it was 56mm. 3400 ones are, but I think the 3.4l RWD was 52mm. Can't tell you about the 2.8 rwd at all! lol