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Discussion Starter #1
I was thinking about doing a complete rebuild of my 325's engine. Based off of what I've researched I have the M54 model engine. Being all about power I was wanting to bore and stroke the engine just a wee bit to see if I can get a tad more juice.

However there are no purpose built kits for the non-M3 e46. Given that even the S54 is based on the M54 block and such would it be possible to use the kit here (a stroker kit from VAC for the S54) if I had the engine itself bored to 87mm.

I have a feeling this isn't possible, so my plan was to grab new pistons and do a .5 mm bore and try to scoop up the crankshaft from a 330i which has a longer stroke. Would the crank from the 330 be compatible with the 325?
Or even more to the point, would there be a god awful amount of work involved to make the crank compatible?

Thanks for any info!
 

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First, the S54 is not "based on" the M54 block. The S54 is iron and the M54 is aluminum.

Second, there simply isn't enough material to bore the M54 from 84 to 87 mm. IIRC, the max possible bore is 84.5.

While the 330 crank would be a direct swap, the remaining differences in intake manifold, etc would complicate tuning (ie, you would need an expensive custom tune). In the long run, it would be a lot less hassle and more cost effective to simply trade your 325 for a 330, swap in a complete b30, or add FI. Although a bit more involved, an S54 swap could also be a lot of fun.
 

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Swap in a B30 and add cams+headwork, that's the easist route. Otherwise, leave the displacement stock and again, cams+headwork. Tuning can be handled from many places, but make sure you have one in mind before you tear into your car.
 

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Either find a B30 or use the rotating assembly from one.

There are also guys using the 3.2 block from the E36 M3 with the dual vanos head from the M54. I'm fascinated by this and want to try it some day.
 

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Discussion Starter #6
Thanks

Ok thanks so much for the info! I think that I'll just see if I can find a b30 variant to bore .5 and then swap the whole rebuilt shebang into the car. Once again thanks!
 
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