When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
The over rev occurs before the gear is even engaged, and if it is, it just gets worse.
Most of the time, if the driver catches it, the over rev stays below 9600.
Are you sure this is not just a special case that occurred when you had a broken gearbox? I just don't think Porsche's rev-matching software would intentionally rev to nearly 9600 rpm - this would be a gross software programming error and I don't think they would be this incompetent. The rev limiter should not allow the engine to exceed 9000 rpm (maybe they allow a slight excess). The actual over-rev should never occur without engaging the gear and releasing the clutch pedal.
I think the likely explanation is that you had a defective car - did you ever experience this in another car (or hear of another driver experiencing this in his car)?
Are you sure this is not just a special case that occurred when you had a broken gearbox? I just don't think Porsche's rev-matching software would intentionally rev to nearly 9600 rpm - this would be a gross software programming error and I don't think they would be this incompetent. The rev limiter should not allow the engine to exceed 9000 rpm (maybe they allow a slight excess). The actual over-rev should never occur without engaging the gear and releasing the clutch pedal.
I think the likely explanation is that you had a defective car - did you ever experience this in another car (or hear of another driver experiencing this in his car)?
Well, the gear was never fully engaged, so it wasn’t a mechanical over rev - it would have been via the software blip. But it would be the software that did it, right?
I think a lot of the 992.1 manual cars will show R1-3. Let me clarify; the ones which actually get driven will show it. This engine with the ITB is very rev happy and Porsche over engineered it. If you get a scope and an oil analysis and have 100 more hours on it post incident, you should be fine.
Well, the gear was never fully engaged, so it wasn’t a mechanical over rev - it would have been via the software blip. But it would be the software that did it, right?
I really can't comment on your particular case, but I have seen people choose the wrong gear (for which a gross over-rev would have occurred), the Rev-Matching software revved the car to 9000rpm (but no higher), so the driver moved the shifter out of that gear before ever releasing the clutch and no harm (nor excessive revs) ever occurred. My friend pulled a DME report and it was clean. This is how it's meant to work...
We have now turned Three 992 GT3 manual over rev cars into 4.5L. They all did the money shift and had various degrees of damage ranging from snapped timing chains to broken bolts out of the cam adjusters. All warranty denials and all facing an $80K replacement at the dealer.
Below is the latest Dyno graph from a 992 GT3 DeMan 4.5L (non over-rev car) Running 98 octane. We also mapped it for 93 Octane and it did 600.7HP
992 GT3 DeMan 4.5l conversion
We have done Nine 992 GT3 4.5L conversions as of today as well as Eleven 991.2 GT3/RS cars all with very similar results.
Doesn’t matter if clutch is disengaged or not. The normal auto blip operation juices the engine while the clutch is disengaged and before the shifter is even in gear. Can the software be improved? Probably, but it can definitely cause a massive overrev when the clutch is disengaged and the transmission is not in gear.
One of the reasons PCNA repurchased my car…
My 718 doesn’t behave that way. The car waits until the gear is selected before blipping, because it doesn’t know if I’m going to shift up or down. Once the gear is selected, it will blip before the clutch is fully is fully engaged though.. As others have stated, the autoblip shouldn’t rev match to an incorrect shift. If it has time to calculate the proper match it surely has time to calculate a NO and not blip past redline. If it behaved that way it might if you’re trying to shift down too early, but it still probably wouldn’t have helped with the OP’s shift.
Maybe I’m not understanding the bolded text above.
My 718 doesn’t behave that way. The car waits until the gear is selected before blipping, because it doesn’t know if I’m going to shift up or down. Once the gear is selected, it will blip before the clutch is fully is fully engaged though.. As others have stated, the autoblip shouldn’t rev match to an incorrect shift. If it has time to calculate the proper match it surely has time to calculate a NO and not blip past redline. If it behaved that way it might if you’re trying to shift down too early, but it still probably wouldn’t have helped with the OP’s shift.
Maybe I’m not understanding the bolded text above.
Even if it tried to blip past redline, the ECU would cut it out.
A mechanical over rev is different. There’s not much that be done. It would have to be a manual clutch override via hydraulics or explosive detonation, like the rollover protection in a cab, and those would add unnecessary nannies to try to stop a money shift.
Last edited by Mike Murphy; 10-24-2023 at 11:30 PM.
Even if it tried to blip past redline, the ECU would cut it out.
A mechanical over rev is different. There’s not much that be done. It would have to be a manual clutch override via hydraulics or explosive detonation, like the rollover protection in a cab, and those would add unnecessary nannies to try to stop a money shift.
I understand the difference. What I’m trying to determine is did the OP’s car over rev (via blip) before he fully let the clutch out. I’d like to know the answer to this for my own purposes. You’d think the blip would hit the rev limiter. Have tried the bolded part above, if so what car?
I understand the difference. What I’m trying to determine is did the OP’s car over rev (via blip) before he fully let the clutch out. I’d like to know the answer to this for my own purposes. You’d think the blip would hit the rev limiter. Have tried the bolded part above, if so what car?
If the car is not broken, the engine won’t over-rev without a mechanical over-rev (which doesn’t happen unless you let out the clutch pedal). The blip function will not exceed redline.
If the car is not broken, the engine won’t over-rev without a mechanical over-rev (which doesn’t happen unless you let out the clutch pedal). The blip function will not exceed redline.
Exactly. Rev-limiter and auto blip are completely unrelated to OPs mechanical over-rev as seen in the video.
I have over revved a race car (996 cup) in similar fashion (3-> 2 missed upshift). Result was predictable.
I have been told that some race clutches will ‘detonate’ under load and ‘save’ the engine. A race mechanic can chime in on that.
But I bet if you ask next year, you might get a different answer...
Makes no sense for anybody to offer fixes/upgrades right now while the 10 year factory engine warranty still applies to the 991.1 engines. I imagine next year when those start to dry up, DeMan, Dundon and potentially others will step into the marketplace.
But I bet if you ask next year, you might get a different answer...
Makes no sense for anybody to offer fixes/upgrades right now while the 10 year factory engine warranty still applies to the 991.1 engines. I imagine next year when those start to dry up, DeMan, Dundon and potentially others will step into the marketplace.
That is correct, but was just curious to see if anything is being planned. A 4.2L rebuild putting out 550hp would be pretty sweet.
10-24-2023, 12:41 PM
