Gas Porting....
Drag racers generally go vertically. That being said, some Nitrous guys won't run them because it's the first place a crack will start in the top land.....some do successfully though. I've seen anywhere from 8 to 16 of different diameters even on equally good engines. Because the verticals can become plugged with carbon, the roadrace and circle track guys generally go laterally, which is hard to spot...it basically bisects the top of the top ring groove and runs a channel to the back of the groove. People have run them on the street successfully too-even for extended periods. Yes it does apply pressure to the backside of the ring, but mostly on the first 30% of the powerstroke.
The thinner, lighter, more conformable, and flatter surface of the ring/ring groove, the less it's necessary (per x piston speed)...but if you're looking for the last little bit...it never seems to hurt. We've dyno'd some very high quality .7mm ring combinations that it didn't seem to help either....but I'd say that's the exception. If you're turning quite a bit of piston speed w/ a "off the shelf" 1/16 ring...I'd say gas ports would help more. Also, at the Engine Masters challenge this year, we ran .043 rings without gas ports (because it wasn't legal. Some people tried dykes, but the winners were running anywhere from .8mm to .043 conventional rings according to the finalist I worked with.. He also said his sealed up great....no issues running thin rings without gas ports..at least on our pistons
hope this helps. -Brian Nutter-Wiseco Automotive.
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Will a 1200 HP turbo or nitrous combination with more than twice the cylinder pressure see a gain due to gas porting, absolutley. It's a very practical method of helping the rings seal against high pressure combustion gases.
I believe Reher Morrison uses a 1000 HP bogey in their recomendation on when to use gas ports. I'm sure that in a smaller ci engine that # could be brought down a bit.

