frenchyoliver

Hie there.

Here in europe, we are using thick cylinder head gasket to decompress the engine and lower the compression ratio. We a friend, we have been able to output 350 hp from a 2 liter VW engine last summer , lowering from 11 to 9.5.

Do you know what would be my best bet in this direction and what would I end with in compression ? His there any reference in the market for such ?

1991 L98 corvette.50K miles. for a blowerworks + air/air exchanger

BrianCunningham

Not sure the thicker gasket will hold under boost

Even if it does, it doesn't fix the cast piston issue.

gerardvg

It all depends on the fuel you have available.
I am running 8psi boost at around 5,600 rpm and use 98 octane fuel,
however it will ping with the standard 91 octane unleaded. the engine is standard and has an air to air intercooler, my vette has been supercharged for around six years now without a problem.
We have 91,95 and 98 octane available here in Australia

dizwiz24

If you had to take your heads off, then couldnt you do some porting / bowl work to increase the combustion chamber cc's which would in turn lower your CR.

I dont know if it would lower enough. Perhaps someone with experience (contact Lloyd Elliot) may know.

jsiddall

Careful with octane ratings. Australia and Europe typically use RON for octane rating whereas NA uses (R+M)/2 (average of RON and MON). That reduces the NA numbers by 4-5 points compared to what you see in most of the rest of the world. So your 91, 95 and 98 gas probably maps to the exact same stuff people in NA buy as 87, 91 and 94.