Airflow over small SSR and low apex height

[Ozonkiller]

http://speedtalk.com/forum/viewtopic.php?t=15340&postdays=0&postorder=asc&start=45

Check out this discussion in Speedtalk.com

Go to Advanced engine discussion and find "discussion on dump vs tumble 4V ports"

I think it will certainly shed some light on this subject.

I know my brain hurts ???

Tom

[jakesportingservice]

Hi just looked at your pictures and noticed that the clay radius is not totally to the edge of the port ?
Was wondering if it was flowed this way because i know that when i was using clay that if it came loose the flow dropped drastically like 20 to 30 cfm at higher lift .
What i would do is take some time and make a radius adaptor for that port and then use a little clay to make the adaptor fit the port if it doesn't fit perfect .
When you use an adaptor it also takes out the error of not having the clay shaped exactly the same everytime. This has helped me alot with looking for very small changes in a port.

Jake

[WPH]

Since taking those pictures I've been gathering more info on this head and how to deal with it. Speedtalk has been a real
eye-opener and I visit their forum every day. If I did this head again I would go wider on the SSR and raise the roof on
the same side as the port floor was tilted. That should lower the SSR speed more to make the air turn easier.
Flow is strongly biased to the right side of the port on these heads.

[WPH]

Dyno run, engine specs:

stock Volvo B21 bottom end, 2128cc
44mm x 35mm valves (stock), 11.8 CR
Cam 270' ish @ 0.050", dual lobe 13.1mm/11.7mm/106 deg
40mm SK Racing dual side draft carbs, 34mm venturis. DIY intake manifold and header.

Very limited build, no bigger carbs available when this engine was put together. Built for a cheap class racing where every cent counts.
Owner/driver was very happy with the results, nearly 40hp more than his previous 2000cc engine.