T66 .96 a/r p-trim 20-26psi. comments/suggestions on what type or how big I should go on the intake side.

chuck

another pic

Don't forget to bevel the edge to 2mm to protect your apex seals from smashing into the closing edge of the port. Other wise they are nice and huge and will flow some serious exhaust. I tend to go a little smaller for street cars to help out with apex seal longevity. Nice job with porting to match your diffuser. Keep us updated with your results..

Put the 2mm bevel on them today. That took more effort then the porting.

Pic below is what my primary ports are, 90% done.

chuck

I wonder if there is any pro or con to leaving a sharp edge on the opening side of the exhaust port; where the apex seal "drops" over the side.



And what differences are noticed with a slightly elliptical (curved) closing edge versus a flat closing edge?

1: A sharp edge will "trip" the flow over the port, creating turbulence. You want a gradual opening on the edge, so the flow doesnt seperate from the runner wall.



2: Rounded exhaust ports have a broader torque curve, with the torque peak occuring at a lower rpm than squared off ports. Squared off porks make the engine more peaky, but have a stronger top end than rounded off ports.

Pic of secondary ports. Went up 5mm and out 2.5mm. S5 front and rear plate.

chuck

Another photo from the out side

chuck

Nature and the flow bench do not favor a sharp edge anywhere. You can nearly double the flow of a radiused edged hole over a sharp edged hole. At least a slight radius all around to protect the apex seal but the largest radius on the lower ramp.



Lynn E. Hanover

Nice work, Sleeper7. I'd love to see the results of this!



B