Joined
·
3,939 Posts
There appear to be at least two distinct failures that people are experiencing. One is a failure of the main bearing; this appears to be an engineering (either design or assembly) flaw unrelated to over-revving the engine. The other is valvetrain damage related to over-revving the engine, similar to that seen in E36 M3s. This seems to be related to driver error.
However, as Nick points out, a number of cars with SMGs have experienced over-revs, and have also experienced engine failure. Also as Nick points out, it *should* be impossible to over-rev an SMG car. The engine computer has a fuel cutoff that theoretically prevents going much past the redline, and unlike manual tranny cars, the shift computer is not supposed to allow you to engage a gear that is too low for the speed you are traveling.
So, while driver error may explain some or all of the manual transmission over-revs, it does not explain the bearing problems or the apparent flaw in the SMG program. What is unclear is how common either of these latter two flaws are.
However, as Nick points out, a number of cars with SMGs have experienced over-revs, and have also experienced engine failure. Also as Nick points out, it *should* be impossible to over-rev an SMG car. The engine computer has a fuel cutoff that theoretically prevents going much past the redline, and unlike manual tranny cars, the shift computer is not supposed to allow you to engage a gear that is too low for the speed you are traveling.
So, while driver error may explain some or all of the manual transmission over-revs, it does not explain the bearing problems or the apparent flaw in the SMG program. What is unclear is how common either of these latter two flaws are.
