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Discussion Starter · #1 ·
I was just looking at specs on bmwusa.com to check out curb weight differences between my 325i 5sp and a 330i auto. it's 3219 v 3362.

but i noticed the bore on both engines is the same 3.31 inches.
The stroke on hte 330 is 3.53 in vs the 2.95 onthe 325i.

I'm fairly new to the real guts of the engines so can someone help me out. Does that mean the 3.0L engine is "bigger" in usable height alone. Or do they use the same engine core/block and allow more power out of the 330?

is it possible/worthwhile to increase the stroke on the 325i engine?
 

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increasing the stroke on a 325i engine will simply increase your torque, BUT the increase will be proportional to the loss in hp because the con riods would be longer it'd take longer for the big end to make it all the way round the crank, this is jst basic physics. now the reason why the 330i has a wider stroke... maybe because they found the engine was pushing out too much hp compared to torque (NA petrol engines have a torque problem) so they exntended the con rods a bit i dunno this is jst a pure guess
 

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I know nothing about the physics of internal combustion engines. Even after reading "howstuffworks" I still walk away as dumb as when I went in:tsk:
 
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