Compression ratio increase. Learn me.

[Sagaris]

Here I am, the typical forum butt asking questions about things that will more than likely never happen. Here it goes.
I see that the M20B25 has a relatively low compression ratio (8.8:1 if my memory serves me). I was anticipating replacing the pistons with lightweight units and figured it would be a good time to purchase a domed piston that would increase the compression ratio. Between 9.5-10:1 or so
I am worried that I would have to fight of pre-ignition issues.

Has anyone increased their compression ratio? Did you experience knocking/pinging problems? Were the gains worth it?

[digger]

if you adjust the timing to suit and use premium there should be no issues (there are factory M20b25 with 9.7:1 CR in Europe and 9.4:1 in SA), however i hope if you are going for a lighter higher compression pistons that that is not the only mods you do internally. Compression ratio alone won't do a whole lot but with new pistons the options for longer stroke become available.

[StereoInstaller1]

MM makes those bitchin' 11 to 1 that also make your motor non-interference...

[nando]

actually the 11:1 pistons are still interference, it's the 10:1 pistons that aren't.

depending on what fuel you are using, 9.5:1 or 10:1 are fine. if you're in california don't push it too hard..