which idle near stock an good for stock turbo i cant make up my mine???? still thinking which is better. will which is better.

 

You need to do a search. The S1 is the newer version. Greg @ GSC says they're superior to the 272's.

 

he ever going to prove that though?

 

He proved that the S1's were superior to the GSC 272/280's for the IX, not sure about back-to-back testing on an VIII, though...

 

I can't give you any numbers, but my seat of the pants tells me there is definitely more down low with the S1's. Unfortunately, I never got the 272's dynoed, so there will be no back-to-back.

 

what is the difference between S1 and 272's?

what grind are the S1's?

im upgrading to an EVOgreen, and im sticking with my year old 272/272... unless there is a huge difference.

 

THE S1's have 10.5mm of lift onboth cams with slightly less duration (like 268 and 266 IIRC). However, I think the ramp rates are significantly different. It's best to call Greg @ GSC. I think the specs are on their site too.