von

Grinding out that bridge in the lower manifold that seperates the secodary runners and then knife edging the block side where the lower manifold bridge usualy connects to. If anyone has ported their manifold they will know what im talking about...

Project84

You mean like this write up in the archive?

https://www.rx7club.com/forum/showth...threadid=79511

niner

i've messed around w/ my manifolds plenty, and I'm not really following you.

all the port runners need to be left separated. do you mean connect the secondary runners w/ primaries? bad idea. and the knife edge thing sounds like overkill.
can you explain yourself a little better?

mazdaspeed7

I dont know why you would do that. Youre only moving the divider between the 2 ports on the end housings about 1/2" closer to the intake ports. And by removing the original divider, youre makign the runner volume bigger at that one point, and its only going to hurt airflow. All in all, its not worth any HP. And its more work. Why not just knife edge the part in the manifold? Thats what I always do.

von

Thnx mazdaspee7. thats the ansewer I was looking for. Yes I have knife edged the manifold part but was ready to take my manifold off again so was just wondering. I did not know that the extra 1/4 inch was going to hurt flow because of the runners being to large at that point....? But yeah I do kinda understand. Thnx