Originally Posted by
RayJ
For those not in the know. Shimming the liner effectively increases exhaust timing, and port timing. What you will gain is more rpm in the motor and a shift in the torque curve to higher rpms. It will also help smooth out the bottom end abit. I'm not sure on the evo3 tuned version if they changed the crank timing. It's pretty aggressive already. Shimming is alot cheaper than actually re machining the liner.....or carving up the piston. Those that do add shims to a liner MUST reshim the head. Raising the liner will reduce compression of the motor if all the standard shim are left in place.
Raising the liner does increase timing...but it raises the boost and transfer timing much more then it lists the exhuast timing... lifting the liner may raise the boost timing lets say 10 degrees but its only going to add 2 degrees to exhaust, which is going to affect blowdown timing ..... I guess its a cheap and easy way to add a little punch to a motor, but its not the same as actually cutting the ports manually