9:1+
It should have a minimum of 70 psi.
One of the harder swaps I've seen done in a Prelude. Much custom work that has to be done, should not be your first experience with building a car.
A diesel engine requires at least a 20:1 compression ratio, or about double a gasoline engine. The PSI this translates to depends on the size of the cylinder. You will need to consult the manufacturer's service manual.
10:1 - 12:1 through that range is fine
14:1 compression
120psi
94 prelude being the 4th GEN it depends on the model s-133HP si-158HP VTIR-190-200 ish
possibly a lot of carbon build up in the combustion chamber but in a lifetime I have never had a small engine with to much compression.
60 p.s.i.
Alot.
An engine compression test on a 99 Grand Prix GTP can cost $180
Low compression will not cause an engine to not run. It may not run efficiently but it will run. Low compression on all cylinders is caused by wear, and can only be fixed by overhauling the engine. Low compression on just one cylinder can be a blown head gasket, burnt valve, or a broken ring on that cylinder. I also depends on what you mean by "below average". An engine with lots of miles may very well have a compression reading that is below the factory specifications and not be cause for alarm. It depends on how much below specs that compression is. In any case, the only fix is to open the engine up.