B34 Bottom End with B35 Head

[QBANG]

Well I just picked up a B35 head from a guy on the E28 forums, I know should for done more research before hand.... but it was a impulse buy. Are there anythings to watch out for when mixing it with a B34 bottom end? It will drop my C/R a little, but one can always add a few more psi to make up for that. Pistons will be replaced down the road. Is there anyone running this?

[yert315]

3 second search from mye28:

Does any e34 head constitute as a B35 head swap? Meaning, do I need to find a e34 535i head over finding a 525i head for maximum performance gains?

No, you can only use the head off of the 535i. I recommend you do a bit more searching on the differences between a b34 and b35 head. The 525i engine isn't even the same family of engine.

With which ever head it is, does this swap turn my b34 into a b35 motor? Theoretically? What are the differences?

No, the head alone does not make it a b35. The pistons are different in the b35 and you will actually drop the compression ratio of your engine from 8:1 to 7.45:1 (the b35 is 9:1)which is not going to help performance at all.

Upon choosing to go this swap route what all b35 parts do I need to install as well? Intake manifold, wiring, intake all together, throttle body, ecu, etc?

If you did the head you would want to install at least the intake manifold as it's runners are different. The wiring and electronics would help, but since you lowered the compression by swapping only the head, I don't know how worth it it would be. IMO, you are better off swapping the whole engine to a b35.

Also, I'm interested in millerperformance's MAF conver w/ WAR chip. Now with the swap do I need to install an e34 ecu with miller's e34 WAR chip/MAF conversion? Or, does all this stay e28 stock and I look into ordering the the package for my e28 ecu/intake?

If you did the electronics swap you would use the e34 parts, if not use the e28 one. I don't know how well it would run with only the head, but since it's tunable it would probably work ok with some tweaking.

I'm looking to build up an entire b35 and put it in down the road. If all this b35 head swap looks to price'y, I should save the $$ for the build up hunh? But I want some good power in the mean time.

Like I said, just wait and drop in a used b35.

Now, if I decide forego the swap and stay with the b34 head and the mechanic has the valve cover off. What could I do to get a little more boost outta her? I heard I can just throw a b35/e34 Cam in there. Is that true? What other b35 parts need be installed? Is there an adjustable cam gear out there to match up to? Will that statisfy my mild hunger for now?

You could upgrade the cam but that's about it. It will still need some tuning to take advantage of it and then you are back to deciding what electronics you want to run.