Compression - How much is too much?

[XJS]

jondee86 Wrote:The factory ECU doesn't know what compression you are running, so
it doesn't care Problem is that the fuel and igntion maps are not
optimised for the higher compression, so you can't really take advantage
of the potential. That will have to wait until you get your cams and new
management installed.

I believe that you need to be careful to avoid detonation at some high
load low rpm situations ?? Maybe someone who has done this can give
you an idea if it is a problem or not ?? I have a fully worked bigport
head sitting in the shed, and have been wondering if it would be worth
putting it on a bog stock bigport engine

Cheers... jondee86

The factory ECU does care. The main input for the ECU is some form of air measurement (pressure (MAP) or flow volume(AFM) ). If you pump up your compression ratio, the engine will consume more air, so the ECU will inject more petrol, simple is that. Of course there are limitations, but with moderate lift and timing there won't be any problem.