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3.0 stroker theory
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i would use a piston (stock, aftermarket or other) that preserves the combustion chamber dynamics of the OEM pistons. a taller comp height piston with thick crown would probably suit better though more material would need to be removed but could be shaped better. or use a shorter rod, b25 piston and M/C crank. or shell out 800 for forged babies. lots of options89 E30 325is Lachs Silber - currently M20B31, M20B33 in the works, stroked to the hilt...
new build thread http://www.r3vlimited.com/board/showthread.php?t=317505
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Originally posted by E46Twist View PostThe purpose is to explore and see if the M54 pistons will work, and there is a decent chance they will. If they do you can build a 2.9 pretty cheap
"Fast is Sexy"
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Originally posted by E46Twist View PostThe purpose is to explore and see if the M54 pistons will work, and there is a decent chance they will. If they do you can build a 2.9 pretty cheap
"Fast is Sexy"
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As soon as someone can show me a case of using this setup and it not working or getting to be $$$ I'll stop it. I know the M54 pistons are not optimal in stock form but if they work with a stick or slightly thicker HG then I count it as a success. The 2.7i stroker is not perfect but runs on the principle of cheap yet effective and worth while. I am not doing this to get a the most power I can, I am doing it to justify not doing a turbo or swap. If it fails I can shave the pistons myself but would not consider a successful budget stroker.
"Fast is Sexy"
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A flat top style piston still works with an 885 head, infact many aftermarket pistons aren’t the OEM shape so it is not a show stopper by any means.
It’s not what I’d do as less squish and subsequently less mixture motion is not good for an efficient burn. The M20 can make as much if not more torque per litre as the 24V versions when done correctly it just has a harder time breathing.....
As for how important piston shape is, well BMW designed atleast 4 different piston crown variations to be used with the 885 with all being basically the same offset dish-dome and angled squish. Three were for the b25 in varying CR and one for the SETA so they thought it was important.
from what i have noticed over the last decade those with good CR using OEM shape piston and the 885 make better bottom end and midrange which IMO is down to combustion efficiency. i dont have scientific proof but it seems to be the trend. those with flat tops often tend to be trickier to tune due to knock if CR is up there and cam duration is relatively small.
flat top suits a 200 or 731 headLast edited by digger; 05-26-2014, 03:43 PM.89 E30 325is Lachs Silber - currently M20B31, M20B33 in the works, stroked to the hilt...
new build thread http://www.r3vlimited.com/board/showthread.php?t=317505
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