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Originally Posted by 94SolGrl
Ummmm (DOHC) VTEC engines are usually running a 16:1 compression... 12:1 can handle 4-5lbs, and the magic number for high boost is 9.1:1. The LS blocks have 9:1, and the B20 blocks have 8.6:1.
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Don't get offended....Veryone makes mistakes and I am not trying to be rude, but more make sure that people who read this know the correct information.
16:1, That is dead wrong. Even a race car on race gas would have issues with a c/r that high. The most you can run on street gas if tuned well is 12:1 or so.
the USDM B18B1 has a 9.2:1 compersiion ratio. A B20 has a 8.8:1 c/r (but can handle less boost due to weaker sleeves. A B20 is essentially a bored out LS block). A B18C1 has a 10.0:1 c/r. A USDM B16A has a 10.2:1 c/r. A jdm B16A has a 10.4:1 c/r. Both types of JDM B18C's (the Type-R and the SiR) have a 10.6:1 c/r, the B16B has a 10.6:1 c/r also...that is the HIGHEST compression ratio that ANY B-SERIES MOTOR HAS.
Now most stock turbo'd cars (like the WRX for example, and SR20Det, etc) hang around a 8.5:1 or 8.8:1 compression ratio.
The B20 DOES have a lower c/r than the B18B1, true. However, a B20 block is basicaly a bored out B18B1 block. It has thinner cylinder sleeves.
Anyways, as I said, not trying to be an ass, just trying to make sure the correct info is out there. If someone had read that, and went out and turbo'd a motor built to 12:1 c/r, they'd have a massive engine failure to put it mildly.