chriscool888

I am doing a turbo build with a b18b block and i want to get a set of je b16 pistons and b16 manley turbo turff connecting rods plus a micro polished b16 crank with a b18a1 head on 15psi. the compression calculator shows that i will have a 5.46 compression ratio without turbo, why does that sound so low? and is that good or bad?....with the 15 psi turbo it reads 11.03, is that good or bad?....how much power do you think this setup will run? thanks

MPR

The b16 and b18 blocks share the same bore, but the b16 has a shorter stroke. So now you've but shorter stroke rods and crank in block meant for longer stroke rods/crank. That's why your compression is lower. Why do you want to run a b16 crank in a b18 block?

5.46:1 CR is way too low. You generally want 9:1+ if you want even some power/response when not under boost.

Don't pick a random boost number to base your build on. Set a power goal. That will determine how much boost is required, what turbo would be best suited and if there will be anyother necessary modifications required.

intenseneal

Swing and a miss. B16 piston is a B18a/b motor with a/b rods in a good increase in compression. Should be over 10.5:1. Yes you can turbo it and run high boost but I would use forged pistons running that much boost and the high a compression. You will need a very good tune to make a high compression boosted motor run right and last. Most got for under 10:1 when boosting. The up side to higher compression is you can spool the turbo a lot faster.