It is commonly held on this forum that the grind on the GSC S1 cams is turbo spool friendly compared to other manufacturer's cams available for the Evo VIII. I am not sure whether any definitive testing has been done or the conclusion is from seat of the pants driving impressions or studying the spec card on the cams.

At any rate, I am just wondering whether in comparison strictly to the GSC S2 Grind for the VIII, the S1 will get a turbo to spool more quickly than the S2 grind. I know that a lot of peeps upgrade from the S1, to the S2 cams somewhere along the line. Have the people making this swap noticed a loss with regards to turbo spool between the S1, and the S2's?

Aaron (ER) has found that powerwise the S2 grind loses no power anywhere in comparison to the S1. But, what about strictly spoolwise? Is there any noticeable difference between the two just in terms of turbo spool? A couple hundred RPM? Any comparative boost plots on an otherwise same setup?

 

Their is a back to back on here somewhere. The s2 cams gained power everywhere over the s1 cams. Same or faster spool also. IMO the only reason to run s1 cams is you don't wanna change valve springs.

 

S2's all the way! theyll make your ***** bigger too

 

Makes sense.