Alpine Exhaust port fixes

[spmdr]

Just about everything I try to do with getting more performance out of

an Alpine engine points BACK to the bottle neck exhaust port.


The hard 90 degree bend coming off the exhaust seat is the killer.


There are several ways of looking at the problem.

Conventional wisdom would suggest FLOW and MORE flow.

Shape and size would dictate FLOW.

In the ALPINE, BOTH of these are, as Ken Miles may say, "IN THE SEWER"!


So what is left?

At this point, I'm going with TURBULENCE.

Here is an interesting quote:

"Having little to no turbulence is just as important as the air flow and the air speed."

This coming from a guy who tests exhaust ports at 45" (as well as the usual 25 and 28).


My current thinking is to fill in the long side, "bowl" area to make the long side shorter.


Has anyone "been there, done that"?


Another thought is thinking about the exhaust from a PULSE point of view.

I'm thinking there is a standing wave starting at 4000 RPM....

Hmmmmm.

DW

 

[jdoclogan]

This is why I created the 4 into 1 header with 1 1/4" outside diameter/1" inside diameter tubing and all four tubes at 20" in length. This mathematically creates a better scavenging effect that provides better flow. My "seat of the pants" test indicated I was getting better torque. Jerry Titus and Doanne Spencer also concluded staying with the 1 1/2" exhaust pipe was best.