SuperEta to 2.7i?

[Chapel]

Looking at an 88 528e... looks fantastic... how do I get it to be a 2.7i? I know SuperEta to i swaps are much easier.

[jlevie]

Swap in an an M20B25 head (or rework the head on the car with M20B25 parts), intake, throttle body, AFM, engine harness, and DME. It is really just about like turning an M20B27 into a 2.7i, but the result has slightly higher compression.

[Chapel]

how different are the heads? I thought they were the same heads as the 325i but with eta cams, valvesprings, lifters and rocker arms?
I know the intake manifold is different and the TB and AFM.
Do I need the engine harness? I thought I could just swap ECUs.

[SpecM]

You don't need a harness, a s-eta uses motronic 1.1 already

And yes the head is the same except the cam and springs. The rockers are the same, and m20s don't have lifters.

Sent from my Vortex

[TheTacoMan]

You also can use the throttle body but it is 2.5in vs 2.7in I. It works fine just kills a bit of top end.

[Chapel]

Oh yeah. Forgot no lifters in these.
So the simplest way to do it would be doing a cam and valve spring swap. Intake manifold with throttle and afm. And then finding a 173 ecu?
Any fueling differences?
Would the 173 ecu work in an e28?

[lateracer]

So the simplest way to do it would be doing a cam and valve spring swap. Intake manifold with throttle and afm. And then finding a 173 ecu?
Any fueling differences?
Would the 173 ecu work in an e28?

173 should drop right in. Fueling differences are negligible if any, not even sure they're different injectors.

Simplest way gets to be a matter of opinion for the head/cam. Pulling out a cam and valve springs with the head still attached is way more of a PITA than with the head pulled IMHO. It can be done though.

Because the i has slightly larger valves than the eta and it's easier than an in car cam swap, a recently freshened i head swap gets my vote for this job. Also gives you a chance to blow a few hundred extra on things that probably don't (but might) need attention like head gasket, timing belt, rusty exhaust studs, etc.:curse:

[phenryiv1]

Read this:

http://www.r3vlimited.com/board/showthread.php?t=150051

[Chapel]

danke

[e30trooper]

find a head with intake,tb and injectors with fpr. You will need the b25 afm and also a 173dme. DONE

[Robotin]

go m30.