Compression Ratio

[jtiet87]

So i asked my machine guy where my compression ratio is at. Originally mine was at 8.5:1 now it is at 9:1. My compression went up .5 and its suppose to be built for turbo. Now my question is can my motor even handle turbo? how much am i going to be able to boost? I thought usually when you rebuild your motor for turbo the compression goes down and it went up wtf?

[evildky]

qwhat are you building? I mean specifically, the stock n/a for 76 was a dished top N42 block with an N42 or N47 head yielding about 8.3:1, lets assume your "rebuild is just rings and bearings, the compression ratio won't cange, you can go to a lwoer vilue head such as the E31 along with a 1 mm headgasket and this gets you to about 8.7:1, mill about .020 off the block ro head and you'll be right at 9.0:1, so maybe you decide to build an F54 flat top block? with the P90 head, this gives you about 8.5:1, so as you can see there are any number of variables taht will rails or lower your CR, what variables are you using? and yes you can run higher CR with turbo, mine will be 8.5:1, the stock turbo setup is 7.3:1, tuning is key, you can't stock a big fatty turbo on stock injection with a high compression block with stock cast pistons, they will melt! which si why I spent a knot on my forged Wiesco's, so what does your "engine build" consist of? what block? pistons? crank? head? HG? bore? you should have specified what you're desired CR was and the machine shop should have helped you to achieve it