Originally Posted by
dj apolaro
With the testing we have done, you need to add a .1 shim to run 25%. It gives good power but can be sensitive to tune. Your temps will be lower than you are used to also. If you add .15, it will be safer and easier to tune and temps will be about the same as when you ran your 16%.
DJ Apolaro
How about the head clearance for .21 engine?
I've found out the 2 x 0.1mm and the under sleeve shim, the total head clearance around 0.58~0.62, there is lack of low end power.