turboputz
Well-Known Member
Here it goes......If I'm thinkin about runnin 12+ lbs of boost whats the best CR for the block build? How do I achieve that compression?
I'm an engine noob......
Lower compression is usually achieved through the design of a new cast piston that you buy. It may be slightly dished like a bowl in some cases. This will increase the combustion chamber size and lower compression.
Compression can also be lowered through the use of a thicker than stock metal or copper head gasket. When the piston is at it highest point it will now be further from the roof of the combuston chamber. Again combustion chamber size increases while bore and stroke stay the same and compression lowers.
Changing of the headgasket thickness should only be used to achieve a small level of compression lowering. Meaning going from a 26mm gasket to a 75mm headgasket is a poor substitute for getting lower comp pistons.
8.3:1 to 8.5:1 compression is ideal for turbocharging above 15 psi on the F23. What that means is that with a good tune at this comp level you will be able to eliminate detonation and protect the longevity of the engine. Detonation is when the gas and air mixture explodes before the spark plug fires. This can cause knock and ping, which are both very bad things. Before this goes way over your head I will just mention three ways to combat detonation.
1: Adequately cooling the intake charge
2: Lowering compression
3: Tuning, tuning, tuning
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