Originally Posted by TomB
it reduces the compression of the engine. when i added the .10mm shim i noticed it needed to be re tuned a bit, just keep this in mind. the extra shims will (i think, mark can correct me if i am wrong) will make it idle a little better, and tun a bit cooler as well.
the extra shims also assist in the break in process, as the go's are too tight when new otherwise, i found.
With my 7 port I wanted to reduce the power abit. I'll add some shims for this one.
I am getting my first 5 port 2morrow. I am contemplating should I mod it or not. I really dont think its needed, these engine are so fast you take yourself out the racing game as you struggle to get proper setup for good laptimes. Meanwhile you overpowered and throwing the car all over the place.
I think I will leave this one stock.