I ported mine to 70mm. I don't think you can go much more than that w/o adding some extra material.

 

We ported mine out to 75MM, we had to weld one of the IA holes shut because the machine cut into it. Which was fine because my new TB only had one IA hole

 

What kind of HP gain is expected by porting it to 68mm? My TB is also much wider, but as I changed it with some other things I don't know if the effect is as positive as I would have also ported my intake manifold.

Can someone clarify?

Maybe also show a pic of his ported manifold intake?


TIA,

Andreas

 

Unless your intake pipe is larger then the stock TB (most arn't) you'll gain nothing.

 

Hmmm... What if we have a 70mm throttle body , can we expect 10-15whp ?

 

Again, unless your intake pipe is the same mm as your TB no gains will be seen, and even if it was...unless your HIGH hp I would doubt you would see any gains aside from dyno error.

 

Thanks for the info

 

I'm porting mine now, here are the stock measurements:
-throttle body bore: 62mm
-diameter of face of intake manifold: 63.70mm
(the back face of the throttle body tapers out and is also 63.70)
-diameter that will break into the IAC passage: 69.80mm

Without welding, it looks like 68mm would be the max. I'm porting the throttle body and manifold to 70mm though, 27% area increase over the stock 62mm. Aside from re-building the IAC wall, you may want to consider rebuilding the MAP sensor channel wall at the backside of the throttle body. If you bore away the inner channel wall, the path for crud to reach the sensor will be much shorter. Boring to 70mm and fixing the IAC & sensor channel look do-able though.

 

As long as you are at it go ahead and take some weight off it. I was able to remove 4 lbs dropping the weight to 8 lbs.

 

I think you mean ~12.5% not 27%