The rev limiter will catch over revving but not prevent it totally. The engine will have inertia to kick it into over revving in band 1- 3 . Any over revs in bands 4 - 6 I gather need to be caused by an incorrect downshift , ie. 4th to first instead of third. Description: The Cayman's DME (Digital Motor Electronics) records the number of ignition cycles that occur when the engine speed passes 7,300 RPMs. It also records the 'hour' of operation in which the incident took place. These records can be retrieved by using a [link=http://www.planetporsche.net/autolink.php?id=3&forumid=15&script=showthread]PIWIS[/link]. This information can be used by a Porsche dealer to deny a warranty claim when abuse is the cause, or by a potential buyer to identify abuse of a used Cayman. There are six ranges of over-revving that are logged by the DME: Range Rev Speed Comments 1 7,300 - 7,499 RPM Ranges 1-3 can be achieved by bumping into the rev limiter (more likely if a car is driven in [link=http://www.planetporsche.net/autolink.php?id=2&forumid=15&script=showthread]Sport Chrono[/link] Sport Mode). Ignition cycles here are no cause for concern. The Cayman engine is considered mechanically safe beyond 7,900 RPMs, but revving beyond this range is going to result in extra ordinary wear and stress. 2 7,500 - 7,699 RPM 3 7,700 - 7,899 RPM 4 7,900 - 8,399 RPM This ranges (and beyond) can only be achieved by a miss-downshift and these speeds are pushing the range of physical damage. Carefully inspect the number of ignition cycles that have been recorded in this area and get ready to walk. 5 8,400 - 9,499 RPM If the engine is still running, it is very likely that it's been seriously damaged and will likely suffer a premature death. Budget for a new engine. If you have over-revs in this range, don't expect warranty coverage. 6 9,500 - 11,000 RPM If the engine hit this range, it exploded. There is no way this thing is still running. Don't be alarmed if you see 1,000 or more cycles in a range. That sounds like a lot, but keep in mind that a Cayman engine sees 3 ignition cycles per revolution. You can determine how much time was spent in the range by using the following formula: Time at Over Rev = Ignition Cycles / (RPM/20) . So, 1,000 cycles would be less than 3 seconds, or more likely, three 1 second bumps into the rev limiter. It is possible to use aftermarket software to erase over-rev records, so this test should not be used as a definitive or exclusive identifier of abuse. If buying a used Cayman, a pre purchase inspection conducted by an experienced Porsche repair shop or dealership is a very smart move.
