I understand the reason for gas ports in a race piston, but can they be run on the street? I'm buying a set of CP pistons that have the option of vertical or lateral gas ports, this will be on a twin screw blower motor. Any input appreciated.

 

Not a good idea. Race engines operate under low vacuum and wide open throttle. In a street engine and high vacuum situations, like deceleration, you'll pull oil through the ports and into the combustion chamber.... detonation city.
Gas ports also subject the top ring to alot of heat, shortening ring life. Again, not a big deal for a race engine that gets regular rebuilds.

-Mindgame

 

The reason you use gas ports is primarily to load a ring that has to little radial tension to seal by itself. A normal 1/16 ring has enuff tension it really doesn't need additional tension to seal properly but a dykes, .043, 1.2mm, or back cut rings don't have much tension and require a gas port under most situations. the advantage is you only have the tension on the power stoke and don't have the frictional losses on the other 3 strokes.
If you're using in a street engine or a race engine that goes a while on rebiulds you should use the lateral port as it's alot less likely to carbon the ports shut than a top port.

 

Good post, Taylormade.

http://www.c-zone.net/markm/JimLaBre...s/PB140046.JPG