Fullybuilt h22a, max power around 9000rpm dyno was 8800, would a 70mm be enough or go straight for a 75mm which is the optimial size of the piping (ITR 3 inch) since a 70mm would be a bit less that the induction pipe so it would loose some velocity ?

or am i understanding this wrong ?

 

70mm would perfect but 75mm would folw so much batter. if it was me I would go with the 75mm. you will not loose velocity. you will gain velocity B/C the throttle body is bigger so it will
suck more air in. this only helps 75mm if you good cams high compression pistons a good N/A car

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vadim &raquo;</TD></TR><TR><TD CLASS="quote">70mm would perfect but 75mm would folw so much batter. if it was me I would go with the 75mm. you will not loose velocity. you will gain velocity B/C the throttle body is bigger so it will
suck more air in. this only helps 75mm if you good cams high compression pistons a good N/A car</TD></TR></TABLE>

Er no, the bigger you go you lose velocity in return for more volume flowed.

Throttle body size is determined by your IM.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">http://www.team-integra.net/sections...?ArticleID=471
The best way to find out if your TB is too small for your IM plenum is to determine what the intake manifold absolute pressure (MAP) sensor is reading (in the plenum) when you are at full throttle ( or wide open throttle (WOT) ) while the car is accelerating using a datalogger. The MAP should be equal to, or close to, atmospheric pressure. If it isn't or there is a MAP drop at WOT, then your TB is still too small.

A 70mm (at the intake side or TB opening) to 65mm bore (at the plate side) ITR taper bore TB: More than enough for most big N/A Teg engines.
</TD></TR></TABLE>

 

The ITR intake piping is 3.0" (76.2mm). If you got either TB, your air velocity will increase. larger diameter to smaller diameter will increase velocity, but reduce quantity. I think the 70mm TB would be sufficient. Perhaps if you have the money/time, you could get the 70mm TB and have the front end enlarged so it would taper down to 70mm and increase velocity efficiently.

 

ok that cool i did not know that I thinking the bigger the batter. for a N/A thanks for tell me that

 

yeah but you can always port your intake manifold..

so for a 3inch pipe with stage 3 cam and some high compression.. most people run 70 but curious to see what a 72 or 74 would do.. you can get custom sizes now with the large selection of billet throttlebodys available...