Rick in Colorado

From time-to-time there is talk about how the car keeps track of over-revs via its electronics. To the best of my knowledge I've hit the rev-limiter twice - both times because the 1st to 2nd shift comes up sooo fast when you get on it hard. While I obviously try to avoid it (as witnessed by my 'only twice' confession), doesn't the rev-limiter prevent damage due to over-reving? [At least for people that don't hit it everytime they go through the gears]

Or...are people talking about botched downshifts - hitting 2nd rather than 4th - where the rev-limiter can't be of any help?

tstafford

I think the botched downshifts are much more significant.

fast1

Yes, the rev limiter will protect your engine from dangerous over revs on upshifts, but as you state will not protect it on downshifts. BTW the ECU records all over revs in total ignitions. So even if you bounce off the rev limiter for a fraction of a second, the ECU will record a substantial number of ignitions. When you bounce off the rev limiter, the ECU will record a level 1 overshift which is no big deal. My recollection is that there are 6 levels, and levels 4 and higher are considered dangerous.

Dave07997S

Yea no protection against a money shift...only on the way up not down.

Dave

MartyB

As has already been said, the money shifts with the concomitant mechanical overrevs are what you don't want to see, but a BUNCH of range 1 and 2 overrevs could also tend to show that the car has been driven hard and bounced off the limiter regularly. Although the car is designed to rev to the limiter, I don't think I would seek out a pre-owned one that saw almost exclusively red line shifts. There are a bunch of threads on this topic and the rev ranges should be pretty easy to turn up with a search.

cvazquez

Frissen a 6speed forum member experienced a catastrophic event (blown engine) produced by a shift error from 5th to 2nd. According to him a new replacement flat6 in Mexico will cost him around twenty thousand pesos. Ouch!

Driveby

Money Shift = Mechanical Over-rev caused by down shifting too many gears for a given speed. The rev limiter is electronic and can not overcome the mechanical engagement of gears.

JFScheck

Good question although we have discussed this before.

Just remember - going up is electronic - coming down is mechanical.

MichaelL

My car has been into the rev limiter twice, once when I ran it over 100 mph in 3rd and once when a friend put it into the limiter in 1st. Unless there is a mechanical over-rev, there will be no damage.

JW911

That's about $1,800 US dollars. what a deal...

wross996tt

You guys need to read this:

Type II over revs

fuenfer

This link you present is applicable to the 996, but not the 997.

The 997 now has six different levels of "overrev." I've seen a document (on Renntech.org, IIRC), that outlines the revs for each range. My Porsche dealership tells me 1-4 can happen from hitting the rev limiter, whilst 5-6 is a problem.

Stephenkng

Are those apply to our 997 as well. I have heard something different. 6,750+ is type II????

Loren

Type 2 over range on a 996 mean something different that type 2 over range on a 997.

fast1

There's no need to guess. Next time you take your car in for service, ask them to run a DME over rev report for you. It only takes a couple of minutes. I had a report run about a year ago, and I do remember that there were six ranges, but I can't recall the RPMs per range. The mechanic wrote over rev next to range 4 and up.

Keep in mind that the report indicates the number of ignitions in the range. If for example range 1 is 7800 RPM, that would equate to 130 revs per second or 195 ignitions per second for a six cylinder car. So if you hit 7800 RPM for a half of a second, the report would show the number 98 for each occurance and the number is cumulative.