What is the Maximum Effective Compression Ratio, for B18A motor??

[IndianStig]

HaHa! A healthy b18a/b can handle around 230whp not any more than that. Focus on the power not the psi. Turbo's flow differently. What turbo are you refering to?
A garrett t3/t4 57 trim ar.63 would be ideal.

True!

[Vteckidd]

you are missing the point completely.

There is DYNAMIC Compression and STATIC COmpression.

your LS motor is around 9.5:1 STOCK. If you were to boost it, on STOCK internals, you can run up to around 15psi with good tuning and the motor should be pretty reliable. The problem with stock pistons is the ringlands, they collapse and are the weak link.

If you decide to do forged internals, youll want around 9.5 or 10.0:1. At that point the pistons and rods are good for 1000whp, but your sleeves are not. The stock sleeves become the weak link at this point and will break past the 400whp mark.

Effective compression ratio is kind of pointless unless you are all motor. SInce turbo cars dont run big cams, your static and dynamic compression is pretty close to the same number.

WIth an NA engine, you can get away with a HIGH compression ratio (12.5 or 13.0+:1 if you run a very big camshaft,. like a PRO3. And all that means is you can push the limits of pump gas on the higher compression motor because the overlap from the cams "bleeds" compression off. so your 13.0:1 STATIC motor is more around 11.5: Dynamic or while the engine is running.

On a turbo car, in most cases, the difference in your compression is so small between static and dynamic, that its not really taken into account. Youll want to look at WHP and PSI more than compression