Forced induction vs. high compression pistons?

Question

What is the major difference between forced induction and high compression pistons? In the end, it seems like they both accomplish the same thing. My only guess would be extra power from running leaner and hotter, but that must have a downside as well. Reason I ask...I'll be building a new engine here soon and would like to keep my options open for possible forced induction later on. If I can get the same effect (or close to it) from just high compression pistons, I'll forget about supercharging all together.

Answer 1

I'd steer clear of high comp pistons.
You'd first have to know if the heads needed to be machined to accept them. You might end up with an interference engine which means a valve would be hit by the piston if something like the timing chain or gear was off time or skipped time from wear and tear later on.

The other thing would be having to run on high octane gasoline all of the time to prevent knocking or run on when you turn the key off.

Turbo chargers and super chargers are better options for street cars. They add cost and maintenance headaches but give you the equivalent of many more cubic inches without having to move up to a bigger block motor.

If you have a 300 cubic inch engine and a super charger you would have to equivalent of a 600 cubic inch engine as far as the total volume of fuel air mix in the combustion chambers. This means lots more power from a significantly smaller/lighter engine than a V-8 or V-10 big block bored to 600 cubic inches without a super charger.

Most engines function like a vacuum cleaner by sucking in the air and fuel mix. If you increase the air pressure/volume artificially you allow the piston to suck in more fuel/air mix on the intake stroke.

Good Luck!

Answer 2

I've never heard of a high-compression ring before. Generally in boosted applications, you'd use a low-compression piston, in which case, the compression ratio is how much the volume of air/fuel mixture will be compressed in the combustion chamber. I don't believe it has anything to do with TDC or the rings.

Answer 3

I understand where your coming from. The difference is the total air/fuel mixture is much greater with super/turbo charging. High compression alone has far less mixture to work with. Lower compression supercharged engines still have very high compression (with the pressurized induction) and a lot bigger charge in the cylinder. Don't confused compression ratio and total charge available under high pressure.

Answer 4

Generally speaking it is better for the longevity or dependability of the engine to turbo charge it. The trouble with high compression ratios it that it is more wear and tear on the engine, you are more likely to blow a head gasket or a piston, not to mention that a turbo is using exhaust to create boost, your just dumping the exhaust anyway, why not put it to a little more use first.