What would you rebuild and turbo?

[shad325es]

I have an 86es motor but can get a 88is motor for really cheap.
I know that once you put a b25 head with the b27 block that u get a lower CR, witch is what your looking for when you turbo right?
But the b27 has a lower rev limit than the b25. Im looking to get about 350 to 450 hp and want some opinions on what yall would choose the b27 with b25 head or just straight the b25, and y?
Suggestions and feed back please!! Thanks

[Gunni]

Either way you´ll be able to reach your goal.
the 2.7 should provide a little better spool and low down torque with the 2.5head

Get a turbo with 60mm inducer on the compressor for 450hp.

[jaistanley]

The compression may be lower but you should consider the shape of the combustion chamber.. I certainly dont know for sure but I seem to recall that using the 2.5 head on the ETA bottom end not only lowers the compression but introduces a less than ideal combustion chamber.. This can actually make detonation worse. It might be better (if that IS the case) to have the pistons domed on a lathe to lower the compression.

Someone will be able to confirm. I'm just playing devils advocate, I dont know much about M20 engines.

Jai

[Gunni]

Alot of people on the e30tech forum run ETA´s with 885head and 325i intake .
Plenty power using a turbo.