M52 2.8 rebore to 3.2L

[PeterJ]

Hi Zroadster.org,
I have a 98 2.8 Z3 with AFE cold air intake, M50 inlet manifold conversion (including widened throttle bodies) & Schrick cams, Eisenmann exhaust + remap. I was wondering if it was feasible & worth while to bore the engine out to 3.2L & what would I need...I am looking for maximum power from normal asperation. Apart from new pistons/rings...what else should I be looking at? Upgrade Crank/con rods, valves etc...have not decided yet...just thinking...any views? I don't want to put in a different engine or change the car. Just maximize the power from the existing engine.

 

[HornelZ3M]

You could add nitros gas and a supercharger and watch it blow up.. Seriously, if you are going to spend that money on a 2.8 you just as well drop a 3.2 m engine in, now thats fast. :-o

 

[r37]

stroking to 3.0 would be a massive amount easier and cheaper. couple that with: forged pistons, bigger valves, full port+polish, blueprinted intake/exhaust, s50 intake manfold, free flowing exhaust manifold, 2.5 inch port back exhaust with either dual race cats or a sport cat, m3 injectors+fuel pump and a re-map. should be good to go. As a preventative measure an alloy radiator (i think the m3 ones fit) would be a nice addition to keep things cool.

edit: if you add in some titanium valve springs and keep the tolerances close you might be able to add 500rpm to the redline.

 

[HornelZ3M]

Exactly what i said :ymblushing:

 

[PeterJ]

my M52B28 2.8 (single vanos)has bore 84mm stroke 84mm whereas the S50B32 has bore 86.4mm and stoke 91mm & I think they use the same cylinder block (am I correct?), so altering the bore & stroke to S50B32 should be feasible. Then would need to think about an S50B32 crank if it would fit(?).
Why would stopping at 3.0 be massively cheaper?

For the exhaust manifold, I am told the S50 will not fit the M52 in a Z3 (is that correct??), so I am trying to get one from Australia & they seem almost impossible to get for RHD Z3's

The idea is that the only changes you can see around the car (apart from the quad exhuast!) are the AFE cold air intake (essentially an airfilter), the M50 inlet manfold (but that is a OEM BMW part - I have ordered an M50 fuel line cover as the M52 cover does not sit well on the M50 inlet manifold). Almost everything else is internal to the engine.

I think I would work with CA Technology(UK) and get their advice on the details & get the parts shipped over & put togther over here for assembly...anyway, still 'just thinking' at present...

Thanks for the tips guys...

Peter