Is it possible to bump up the compression ratio slightly on the 20VT is you have the head skimmed a bit? Or is the clearence between the valves and pistons so small that this is a bad idea?

Just wonderd if you could run a an engine like this and use a bit less boost, but make it more responsive...

You would be better to skim the block, than the head to raise the compression

yeah, but this means an engine out job.
Thinner gasket as well will help, I did block, head and thin gasket and I'm rather impressed with the way the car picks up (mind you 16vts have 8:1 compared to the 8,5:1 for the 20vts)
(estimated comp at the moment at 8.7-8:1)
V.

The other alternative is forged high compression pistons or a thinner gasket (which is available). I think the thinner gasket bumps it up to 9.5:1 but also gives better squish properties

Higher CR makes a big difference to off-boost performance, and the engine responds well to it. I run a higher than std compression ratio.

But don't expect to run the same boost if you go over 9:1 and also to ensure ECU compliance you will have to run SUL. The SUL this isn't a problem as it will also make the engine more efficient/economical which will probably totally offset the cost of the fuel

Does that mean run less boost for the same power, but with a better curve, or run more boost for the same power, or something else?

Thanks John.
I run a FMIC, use SUL and run less than one bar most of the time, so sounds ideal. Do you know who makes that head gasket, and what are better squish proiperties? Does that mean the head gasket is less likely to fail in the future?

Same power for slightly less boost generally. The VAG 1.8T engine uses higher comp and lower boost.

Squish is all about forcing the combustion gasses into the centre of the combustion chamber to improve combustion. Because the head gasket 'hole' is wider in diameter than the cylinder it slightly impacts the overall mixture. The smaller height of the higher comp head gasket means that less gasses can be diverted in the direction of the gasket section.

The head gasket is more likely to fail actually to be honest but still v unlikely as it is still a metal gasket with integral fire rings.

John, Any idea who makes these, or suplies them. Some time google has been fruitless

YHPM