dump your knowledge here.....

[IanSzgatti]

lets talk air flow and resulting torque.... short runners equals---- and longer runners equal---- etc.

im thinking about all this and wondering... are the small ports the same length as the larger ports on the 3100's or 3400's?

what would happen if you used spacers in between the UIM and the LIM?? is that possible... go ahead and chew this one over... im basically a dry sponge right now..

[bszopi]

The 60V6 store sells 1/2" phenolic spacers for the large port plenum. BUT, they are not to increase the length of the runner, but instead isolate the plenum from the lower manifold to help keep temps in the plenum lower. The longer you can keep the temps cool, the better.

The problem with the spacer is, in order to really get anything out of them, you have to have them pretty big to increase the runner length. On a Beretta, a 1" spacer will cause the plenum to touch the hood (yes, this is from experience). So, the most you can increase the runner length on the 3x00 engine is ~1". From measurements taken awhile back, stock runner length is ~15.75". This results in an increase in length of ~6%. Well it affect the powerband some? Yes. Is it noticeable? Not really. I never tested my setup on a dyno (I was using aluminum spacers), but I'm sure I could have seen a shift in the powerband. But, I think you would see more improvements with the phenolic spacers by creating a cooler air charge into the combustion chamber.

Any more questions?