some questions for reducing the compression ratio.

[KIMI]

I need to reduce the compression ratio of CBR600RR because i want to use a turbo on it. I think adding a proper CylinderHeadGasket may be a good way.The thickness of the adding metal gasket is 0.86mm.And does anyone know where i can process it ? A website or a adress is both ok.And do you have any good ideas in reducing the ratio? Thank you.
cole

[Adambomb]

Using a thicker head gasket is the easiest, but least desirable method of the reducing compression ratio. Thicker head gaskets blow easier, which is a bad combination with boost. Also, effective quench is reduced since the gap between the top of the piston and the quench area on the head is increased. This may actually make it more likely to detonate, effectively throwing away any detonation resistance you're trying to gain with lower compression ratio.

The "best" way to do it is with custom pistons. I don't have a ton of experience ordering custom pistons, but if you plan for it wayyy in advance you might be able to work something out at a reasonable price.

[Canuck Racing]

Take out the piston rings. Any excessive pressure will blow by, meaning that you're always at the maximum pressure of the combustion chamber!

[kapps]

How about use a smaller restrictor http://fsae.com/groupee_common/emoticons/icon_eek.gif . Seriously, pick an rpm (say 7k) and design for restricted flow above that engine speed. Then have orders to all drivers to never be in gear on the throttle below that rpm. When idling and free-revving, you shouldn't have to worry that much.

It worked for Winston Cup...

[KIMI]

[QUOTE]Originally posted by Adambomb:
Using a thicker head gasket is the easiest, but least desirable method of the reducing compression ratio. Thicker head gaskets blow easier, which is a bad combination with boost. Also, effective quench is reduced since the gap between the top of the piston and the quench area on the head is increased. This may actually make it more likely to detonate, effectively throwing away any detonation resistance you're trying to gain with lower compression ratio.

what is the meaning of quench area ?

[Macros]

http://lmgtfy.com/?q=cylinder+head+quench

[Adambomb]

Just google it, that will give you a much better explanation than I can come up with, pretty pictures and all.

[Wesley]

The problem with the RR is that there isn't much material you can remove from the piston dome, they're already pretty thin. The pentroof combustion chambers don't have any good area for material removal either, so you're pretty limited in terms of material removal.

If you are really careful you might get a little bit of volume, but the most robust way to do it is custom pistons with a slightly lower compression height (either by dropping the piston face or raising the wrist pin)