Compression - How much is too much?

[tolisspi]

ZDoman Wrote:I always used to resurface the cyl head and the block top. Especially the block top used to have some small "rust" points, it used to be -0,1-0,2mm off the top to get it OK. With this I wasn't able to use thin metal headgasket on any of my engine (i tried 0,8mm) 1because the piston was knocking on the cyl head at the first engine start. So be careful!

I know an AW11 guy who has 12:1 CR with stock everything and he rallycross race the car. 2He told its not revving over 7000 but has a great torque I wouldn't try it, but it is working for a long time for him...maybe 99+ octane petrol, I don't know.

1. How is the sound exactly? Every time you start the engine knocking? For 1-2 sec?
2.- Why not revving more that 7000rpm? Which is the problem?

About CR maybe is depending from the country and the car for example
Official Greek brochure for AE86 CR 9,4:1
Official French brochure for AE82 GT CR 10:1
and
Haynes service book(English edition) for AE82 GT 10:1
All the cars not cat.