mattypv50

Driving on the highway tonight...doing probably 60 miles per hour went to shift from 3rd to 4th and for some reason didn't get it into 4th and took my foot of the clutch and RPMs pegged since I was in neutral. As fast I could I clutched in found the gear but it was def right at the red line.

Question - how bad is that? I drove for a while after (20 min) and it was driving find and shifting ok. Is this just as bad as misshifting into another gear?

After a long day I was really looking forward to that drive. Some days are just not the ones.

Thanks guys.

dougrewing

What you describe sounds like redlining the engine in neutral rather than a mechanical over-rev. I wouldn't sweat too much. The rev limiter should have cut fuel at redline and kept you in a safe-ish zone for RPMs.

Vane

Would help if you would tell what year you 911 is.

mattypv50

Sorry. 83 911SC.

I didn't realize that the SC had a rev limiter so fingers crossed it hit 6500 and cut fuel.

Vane

Here something about the SC rev limiter. I have a ’85 and very little knowledge about earlier 911. The new 9xx also store the max rpm and for how long in ECU.
http://forums.pelicanparts.com/porsc...v-limiter.html

If no new noise, I wouldn’t worry too much.

r911

1. an unloaded engine is at much less risk when exceeding the redline than one under load

2. a bit over redline should not harm either engine

3. if it did get harmed you'd likely know it right away

4. Porsche engines should spend a lot of time near redline or they won't be happy

oldskewel

The Porsche 911 Performance Handbook, page 80, says that for the SC, "the rev limiter is a fuel-pump cut-off-type set for 6,850 rpms +/- 150 rpms."

I agree with the other responses. Not to worry. One reason these engines last so long is that they are rev-limited conservatively.

prschmn

Weak link on 3.0s is rod bolts-if it still has normal oil pressure I wouldn't worry-but do try not to repeat!

theiceman

FIFY

and they are not "weak". The lowers are dilivar and corode over years and should be replaced as they cold eventually break. ... its not in the "weak" realm of mag cases or IMS bearings.

theiceman

over reving on the way up is not bad ... over reving on the way down is bad...

Not getting it into gear and reving it up as mentioned the limiter will cut in and you will be fine..

if you had actually " missed a shift " and jammed it into third instead instead of fifth is called the " money shift" and im sure you can guess why . especially if you are being aggressive and immediately hit the gas as you let off the clutch ... this is said mechanical over rev and is usually catastrophic.

I have actually done it and survived but i was very lucky . was out for a cruise and was talking to my passenger and not paying attention. Went down a gear instead of up , but i wasnt hammering it and becasue i always float my foot over the clutch until i am sure, and i NEVER just dump the clutch ( a habit i develped many years ago ) . i was able to punch the clutch as soon as i heard the revs start to spike. ( all happens in a blink of an eye obviously . )
I did manage to throw the fan belt and had to replace it at the side of the road... with my passenger holding the flashlight..

a word to the wise.. learn how to replace your fan belt in the driveway before you have to fiddle with spacers at the side of the road in the dark.