As the subject says, my plenum will be coming off again and I figure it wouldn't hurt to do a little porting.

My question is what the original purpose was of casting the "walls" behind the TB and in front of the EGR passages. My guess is it was to prevent reversion of the EGR gas to in front of the throttle blades and cause irratic idle and incorrect readings. Has anyone who has kept their EGR operational noted any such issues when removing the "walls"? I have to keep the smog ****'s at bay and this is a daily driver as well.

Thanks as always!

 

Well, since EGR is not active at idle it would not matter anyhow. EGR only functions at cruise, not idle or WOT. With the rush of incoming air there would not be any reversion into the throttle blades. I removed the "wall" and have not seen any problems. I can't see where there would be any negative effects. I have people tell me all the time to remove it but it only costs weight and what 3/4 lbs total for the system no big deal. No HP losses.

 

Yeah sorry, I should have said light throttle cruising. But either way, it seems ok.

Thanks!

 

When I ported my plenum I started working on my EGR wall, got pissed and siamesed the walls between the throttle blade holes on the plenum. And I dont regret it at all horsepower wise, but I did notice a slight loss of torque and throttle responce. But a $30 airfoil later it was all back. I just smoothed everything out as much as I could. Tried to take 90 degree walls and roll them over and so on and so forth. She will pull to 4800 almost 5000, from 4400-4600 before.

Bottom line, for free it aint bad.