I recently replaced both the clutch and the timing belt on my 325.  If ever there was occasion for a high-revving celebration, this was it.

The 2.7 liter eta version of the M20 is a long-stroke design, with 4 main bearings instead of 7 so as to keep friction low.  This means it doesn’t like revving as high as its non-eta 2.5 liter shorter-stroke, 6-bearing counterpart.

So, for me, high-revving the eta engine means staying on the conservative side of the 4800 redline.  And, normally the rev limiter helps me as such.  Imagine my surprise when I glanced down at the tach and saw the needle descending *towards* the 5000 rpm mark.  I’d revved the engine about where the tach markings even *go*.  Not good.

Seems to me that I have an unhappy ECU.  Darn it. Until I replace it, I need to be very careful as to how high I rev.