Thread: RS4 & E90 M3
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      10-25-2006, 09:29 PM   #28
JK42
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Drives: E70 BMW X5 4.8i
Join Date: Oct 2006
Location: Northern Europe

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Quote:
Originally Posted by Smoltz View Post
I took a look at that website. Very interesting, lots of good information. However, with that being said. You're misinterpreting the data. Your statement is that the 335 has a drivetrain loss of 4% tq and 6% power. That is incorrect. On that website it is properly stated that 4% and 6% represent the discrepancy between stated engine performance and measured powertrain performance. The correct interpretation of the data is that the 335's hp & tq are underrated by BMW.

-Adam

edit: Here's what I'm talking about...
Sometimes it is, sometimes it's not. I've seen engine dynos of many BMW's, and they are not as over-powered as people usually think. The old 330Ci for example had 240hp instead of 231hp about 95% of the time, and about 305Nm instead of 300Nm on the engine. Seeing my own 130i on the dyno, it's engine had 272hp and 323Nm instead of the factory values of 265 hp and 315Nm, so the powertrain loss is still now very, very low.

This is because BMW has specifically stated that they have had huge success in decreasing the powertrain loss, and that RWD is the best technology to decrease it. BMW has added double-chain drives to the driveshaft on all N-series engines (such as N52B30) like they had on the S54B32 E46 M3 straight six, which is one of the biggest single areas of power loss of the whole transmission "chain". Also the driveshaft power distribution parts have been strenghtened with a totally new rear axle design beginning on the E90/E87.

Best regards,

Jussi