Originally Posted by Maxwell
I understand that the larger 80TB flows more air but I have my doubts about it's relevance, because the intake ports in the heads are really the restriction not the 75MM TB.
I can't find any dyno graphs from VRS, I will have to email him and see what he found. It could be he dosen't have the computer tuned to adjust for the extra incoming air.
Thanks for getting me into this air flow issue... I discovered a valuable bit of information that I will explain and follow-up with photos... Please don't diss me for my photos these days... I'm using my iphone as my camera... I'm lazy !!!
So we'll work backwards from the head upward and bare in mind i've had my Dremel Tool on some of this stuff... The intake at the head (block) is 50mm x 30mm and this meets the bottom of the flow through ports that are forged into the sides of the SC... The lower dimensions of these are 50mm x 30mm and the upper dimensions are 60mm x 32mm... These upper ports meet the intake plenum ports which are 58mm x 33mm... Then it moves up to the neck of the plenum box which squeezes to a 62mm x 40mm oval and into a 50mm round inlet... That inlet matches up to the 52mm outlet of the Y pipe that turns into a 85mm x 63mm oval... This mates-up with the outlet of the charge air cooler which is a 83mm x 64mm oval...
The intake of the Charge Air Cooler mates with the base of the SC which is basically a 140mm x 70mm rectangle.... The SC inlet is 75mm, exactly the same diameter of the TB...