The B16 has a 59mm throttle body (what the CAI connects to ) but if you check out a millimeter to inch conversion table you will see that 59mm is 2.32 inches. Why would you want cai tubing that could completely fit around your throttle body?
The ITR TB is 62mm which is 2.44 inches.. that means that a 2.5 inch CAI should be more than big enough for the TB's of both the b16 and ITR and bottlenecking shouldn't even be an issue?

I could be so so lost and not even know it.. am I missing something? someone please explain, this is driving me nuts!

 

the intake piping must be larger than the tb dia in order to get maximum power.

Throttle bodies work on the principle tht their dia is not constant. If you measure the intake side, and the intake manifold side, you'll see there is a noticable difference in dia. The Tb takes the air in at a larger dia, and compresses it as it flows through and exits at a smaller dia.

 

So the actual TB is say 59mm but the part that the intake connects to is 3inches?

 

Ignore that last comment..

 

I've got a 3" ITR AEM CAI on my b16 with a 68mm trottle body from holley

 

That sounds like a little bit of hot air...and makes sense. Never woulda thunk it. If the engine can't suck it in, why have it just sittin' there in the cold air (relative) intake? So a 2.5 inch intake is the best one? Now for the controversy. This is for my own selfish interest (I hope this is of interest for you too, Colin). Which brand or design?
Stevie B