bored and stroked 325i engine

[tico481]

From what I've heard, the 2.5l 6 cyl engine has the same block as an M3 engine. So if anyone were to bore and stroke the engine to a 3.2l, would it technically be the same engine as an M3??

[Kevin325i]

False. But true at the same time. The 92 2.5L shares the same block at the NA version of the 95 M3. It can be bored to 3L and use all the 3L parts. The cams are also different. With a 3.2L crank it goes to 3.1L. The later models recieved a different different block/head valve/ train (small valves, single vavle springs)

When the 3.2L came out they used a different bock all together to produce it. I think it may have been derived from the 3.0L block used in Europe but I'm not sure.

Kevin

[wulley1]

I have a 97 328i, with 115K miles. My engine runs amazing, and is still a long, long ways away from needing a rebuild. But I had heard that the M3 crank and CAMs can be swapped in. Do you have to use the M3 pistons and connecting rods as well, or do you have to special order some?


Can an M3 intake manifold bolt on to 2.8 heads? Would there be any significant gains from swapping the two intake manifolds?

[007ben]

96 and later e36 M3 block is the same as the 328 block i belvie.

[Kevin325i]

The crank might bolt up, I think the head would be interchangeable. I thought they were two different blocks between the 3.2L and the 2.8L.

As for intake manifolds all the OBD II manifolds suck. Do the m50 intake manifold swap. You lost a few low end torque but you gain a ton of horsepower in the uppper rpms because the manifold slows better and isn't as restrictive.

[007ben]

328 is a M52 i was think/thought the 96 m3s used the same block just bored out

http://www.racepad.com/BMW/E36M3/96-99/E36M3(96-99).htm
they say its an M52

[Kevin325i]

Good call, I bet the B32 designation means 'bored 3.2L"

Learn something new everyday

[mikester328]

Speaking of bored engines, has anyone attempted boring a 1.9L in the 318's (96+)? What would it go to and would it be cost effective? I'm thinking it's not but I just want to see what you guys think. Thanks

[bigred318]

wow guys that was really good information, i didnt know any of that about the blocks and such!! but anyways say i got a 325 or 328 how much would it be to bore it out to either a 3.0 or 3.2? that would be awesome!

David

Insurance wouldnt know either!

[Kevin325i]

Only the 92 block can be bored to 3.0L the vanos models used a different block with a different valvetrain.

The 2.8L would be better used iwth an OBD I conversion unless you're rebuilding it yourself with high end parts to run high compression or a turbo set up.

[wulley1]

If the OBDI intake increases HP, it seems like the 96+ M3 intake would have even more flow to it. Does anyone know if a OBDII M3 intake will bolt up to a M52 block out of a 96+ 328?

I've been looking around all day, and can't find an answer. Makes me think no, becasue more people would be doing it if you could.

The intake runers on the M3 look like they would flow so much better than the non-M3!

[Kevin325i]

No it's more restrictive because it's OBD II, that's why everyone is doing the m50 intake manifold swap.

[SiGmA_X]

So, with my 93 325is (M50) what would my best power gain options be?

[Kevin325i]

3.2L with OBD I conversion, M50 intake manifold, multi throttle body conversion, euro HFM and Euro airbox...... and you've got a monster. Or just put in the M5 engine.