Semi-PP thought/question

[vex]

Originally Posted by My5ABaby

Would it be feasible or possible to create a semi-pp engine where the peripheral ports opened and closed similar to the stock 5/6th ports on S4/S5 N/As? Basically the car would still have decent street drivability with the top end advantages of a semi-pp.

Yes. It can be done. The port however wouldn't be that advantageous because it would only be as big as the 6PI sleeve itself. Any bigger and you don't have control of the port like you want, any smaller and you're not getting the benefit of the port.

If however you kept the bridge port and extended it down on the iron to the lower portion of the secondary port you can feasibly increase the single port size based on RPM and the 6PI system. The benefit of that? Hard to say. I'd be concerned about intake velocity, unknown reliability issues (water jacket leakage, etc).

To have a specific bridgeport open or close based on RPM value, that would take some engineering and some ingenious development of technology. I would think a simple flapper door attached to a solenoid or linear actuator would work well. Perhaps even a plumber would be better used. The benefits however would be far less for the gains they merit.