Exhaust Port relocation ideas.

[NoDOHC]

Originally Posted by GorillaRE

This will have a very negative effect on engine performance and consistency. The extreme amounts of exhaust reversion this port timing change will cause is something that we are trying to ovoid.

I like your attitude and thinking, but its not applied to the right issue.

-J

I agree that exhaust reversion is not our friend, but I don't see how this modification would be anywhere near as bad as a bridgeport. The significant overlap is minimal (about 10 eccentric shaft degrees). Most modern cars have significantly more overlap than that.

If you can explain why this will give terrible inconsistency, please do, as this will save me the trouble of building it.

I am curious myself as to what this mod will behave like. That is why I want to try it.

It really should act a lot more like a factory-cammed piston engine after moving the port than it does now. This should provide for better fuel economy too.

Please read my above post about the cusp on the housing shielding the exhaust port. Even at 1,000 rpm, it will be hard for air to move through a 0.050" slit. The overlap on a bridgeport occurs with the dish clearing the cusp, allowing free air flow.