M20b27 turbo

[b12rlw]

Hi all, I've been collecting a load of parts for my turbo build. I've got a 2.5HC, 2.5LC 2.0 rods and an eta crank. My question is, when using the low comp block with eta crank and 2.0 rods, which pistons (low comp or high comp) should I use to obtain the best compression ratio for turbocharging with an 885 head? Also what machining will be required ie, block and piston skirts? Thanks

[b12rlw]

any advice?

[ross2009]

eta crank ,130mm rods, low comp pistons, which will give you silly low cr
so then really the block needs to be decked to raise the comp a alittle and bring it bk in to the 8s
but how much is a matter of what cr you want and some calculations in to how much to take off

[E30coupwes]

[quote="ross2009"]eta crank ,130mm rods, low comp pistons, which will give you silly low cr
so then really the block needs to be decked to raise the comp a alittle and bring it bk in to the 8s
but how much is a matter of what cr you want and some calculations in to how much to take off[/quote]

So what sort of compression ratio should you be aiming for to supercharge this engine as I'm looking at doing the same conversion along with a 288 cam

[ross2009]

Holy thread revival lol

Best comp for high boost is about 8- 8.5-1 cr