[xsboost]

There are actually a lot of things wrong with the SR20 Head. I have a highport head on the flowbench at the shop right now. The short side radius of the exhaust is one of the worst I have ever seen. For one there is a ledge right after the valve seat that needs to be addressed. The Short side is almost a 90* angle.

I have a whole write up I will dig up on the flaws of the SR20 head. I am getting a low port head soon to cut on as well as a KA24DE head. We have already seen promising gains on the High port even before we did the valve job. We now have oversized SS valves in the head and we are going to start some more porting and get some more numbers from the flowbench. This head is going on a customers car, but we are doing mine next.

I am waiting on the flow numbers from the low port head to see if we can get a little better cfm out of it without loosing too much velocity. I like the port angle on the High port head (S13) except that the lifter galley dips so far down into he port it spreads the valves apart too much. We are working on converting a Sunny GTiR Solid lifter head to fit on the S13 Block. As long as we can get the oil drain backs to work we will be fine. The solid lifter head does not have as deep of lifter galleys so it does not dip as far into the port as on the hydro motor.

I will have some more numbers later

Danny

Polk Performance

501-847-7223