Gas ported pistons

[didk-e]

Is there anyway tech can catch me with these? We have 11:1 rule and they will pull a head but that's as far as they will go so I was going to go with the kind that are done on the side of the piston instead of the top. But just want to make sure they cant find it any other way before I spent the money! Thanks

[RACEMAN]

Gas porting won't change CR. CR is a function of total cylinder volume (including head) with piston at bottom dead center versus total volume at top dead center. Do the math.

Do you really understand what gas porting is supposed to do? The function is to allow easier access for gas pressure to get behind the ring so that it pushes the piston ring tighter against the cylinder wall thereby creating a tighter seal and reducing the amount of gas that would escape to the crankcase (blowby).

Which also brings up the topic of Total Seal piston rings. If I remember correctly you would use gas porting with std. piston rings or use TS rings but not together.

Not sure where you got your info but I think I'd start looking for another source for tech help.

[didk-e]

So if we build a motor that shows 10.8 on the whistle box with gas ported pistons it wont have more CR when the motor is running?

[Krooser]

no difference….

[LM14]

You have the potential for more actual compression (not static) but only by gaining ring seal. There are so many good rings out there, I don't feel gas porting is needed anymore for circle track engines.

I also don't believe in Total Seal rings anymore. Give me a quality moly faced ring and the correct bore finish. I think Total Seal rings wear cylinders faster, much like gas ported pistons do.

I'm not an engine builder but this has been my observations, your mileage may vary.

SPark

[RACEMAN]

Typically, when we mention CR, we're talking about static CR. Meaning it's a measure of the 2 volumes.

A dynamic measurement (cranking the engine) could yield a measurement different from the static measurement but I've never really had experience in that area.

[didk-e]

Thanks for the info guys