GT3's and over-revs..... What's all the fuss about??
Discussion
Ok, so I keep reading on numerous threads about over rev this and that and rev range 1 and 2, etc. I understand that the ECU can give these reading and of course understand what an over-revving is.
Question is though, what evidence is there out there that a history of over-revs means impending doom for future use of that engine? And what rev ranges are reflected by ranges 1 & 2? My Mk1 996 GT3 has a K400 Manthey conversion, which raises the rev limit from 7600 to 8400. Would I therefore be in either RR1 or 2 if using all the revs? FYI this conversion was done at about 40k miles ago and is now on 80k and is still running perfectly. And it's had a decent amount of ack use in this time too.
I just get the feeling that too much importance is placed on over-revs and wonder if people walk away from potential purchases because of it, when maybe there is no need to, as in the case of my car.
Am interested to hear fact and real experiences rather than opinion and theory
Cheers
Terry
Question is though, what evidence is there out there that a history of over-revs means impending doom for future use of that engine? And what rev ranges are reflected by ranges 1 & 2? My Mk1 996 GT3 has a K400 Manthey conversion, which raises the rev limit from 7600 to 8400. Would I therefore be in either RR1 or 2 if using all the revs? FYI this conversion was done at about 40k miles ago and is now on 80k and is still running perfectly. And it's had a decent amount of ack use in this time too.
I just get the feeling that too much importance is placed on over-revs and wonder if people walk away from potential purchases because of it, when maybe there is no need to, as in the case of my car.
Am interested to hear fact and real experiences rather than opinion and theory
Cheers
Terry
I'm with you terry. It all seems like a storm in a teacup to me.
I didn't have mine read when I bought it. I assessed it as I would any other car that doesn't have access to that data.
On the other hand I knew the car and some would say these cars cost a lot of money so why not carry out every check you can.
It boils down to what camp you fall into.
Either view and judge a car for what it is, test drive it, check the panels, history etc, then buy it and enjoy it, or spend 2 years fannying about expecting a "brand new" 12 year old car and look for any single reason to reject everything you look at.
I'm the former. There are do-ers and there are dreamers.
The do-ers are currently enjoying their cars having realised a dream. The dreamers are still scouring the classifieds and emailing sellers questions like "has anyone ever broken wind in the nomex recaros?" or "Have you ever closed the door a bit too hard, so the car shook a tiny bit? It wears the shockers out that does."
Anyway, I know you asked for facts but there aren't many about are there regarding over-rev ecu history resulting in a failure. I know Henry from 911V said he once rejected an over-revved car where the over-rev was quite far back in terms of hours use. I can't remember if it later failed or something but that's all I've heard of.
I admit it's handy info when buying a car you don't know, but it bores me to tears.
I didn't have mine read when I bought it. I assessed it as I would any other car that doesn't have access to that data.
On the other hand I knew the car and some would say these cars cost a lot of money so why not carry out every check you can.
It boils down to what camp you fall into.
Either view and judge a car for what it is, test drive it, check the panels, history etc, then buy it and enjoy it, or spend 2 years fannying about expecting a "brand new" 12 year old car and look for any single reason to reject everything you look at.
I'm the former. There are do-ers and there are dreamers.
The do-ers are currently enjoying their cars having realised a dream. The dreamers are still scouring the classifieds and emailing sellers questions like "has anyone ever broken wind in the nomex recaros?" or "Have you ever closed the door a bit too hard, so the car shook a tiny bit? It wears the shockers out that does."
Anyway, I know you asked for facts but there aren't many about are there regarding over-rev ecu history resulting in a failure. I know Henry from 911V said he once rejected an over-revved car where the over-rev was quite far back in terms of hours use. I can't remember if it later failed or something but that's all I've heard of.
I admit it's handy info when buying a car you don't know, but it bores me to tears.
terryb said:
Ok, so I keep reading on numerous threads about over rev this and that and rev range 1 and 2, etc. I understand that the ECU can give these reading and of course understand what an over-revving is.
Question is though, what evidence is there out there that a history of over-revs means impending doom for future use of that engine? And what rev ranges are reflected by ranges 1 & 2? My Mk1 996 GT3 has a K400 Manthey conversion, which raises the rev limit from 7600 to 8400. Would I therefore be in either RR1 or 2 if using all the revs? FYI this conversion was done at about 40k miles ago and is now on 80k and is still running perfectly. And it's had a decent amount of ack use in this time too.
I just get the feeling that too much importance is placed on over-revs and wonder if people walk away from potential purchases because of it, when maybe there is no need to, as in the case of my car.
Am interested to hear fact and real experiences rather than opinion and theory
Cheers
Terry
Whilst the Manthey K400 Motronic ECU is reconfigured to run without the MAF and allow a higher rev limit, they didn't bother to reconfigure the logging facility. Your ecu will therefore most likely display large amounts of type 1 and 2 overrevs activity if interrogated. Ignore them.Question is though, what evidence is there out there that a history of over-revs means impending doom for future use of that engine? And what rev ranges are reflected by ranges 1 & 2? My Mk1 996 GT3 has a K400 Manthey conversion, which raises the rev limit from 7600 to 8400. Would I therefore be in either RR1 or 2 if using all the revs? FYI this conversion was done at about 40k miles ago and is now on 80k and is still running perfectly. And it's had a decent amount of ack use in this time too.
I just get the feeling that too much importance is placed on over-revs and wonder if people walk away from potential purchases because of it, when maybe there is no need to, as in the case of my car.
Am interested to hear fact and real experiences rather than opinion and theory
Cheers
Terry
The 996 GT3 type 1-2 overrev scenario is more applicable to dealers buying cars for stock, and OPC warranty issues.
marky911 said:
I'm the former. There are do-ers and there are dreamers.
The do-ers are currently enjoying their cars having realised a dream. The dreamers are still scouring the classifieds and emailing sellers questions like "has anyone ever broken wind in the nomex recaros?" or "Have you ever closed the door a bit too hard, so the car shook a tiny bit? It wears the shockers out that does."
I don't agree with your analysis. Yes of course obsessive attention to detail will stop you buying when "normal" people would just get on with it. And just the same, a complete laissez-fair attitude to the condition of the car is equally daft. It's each person's choice of what they are happy with and what they are not. To ignore the max revs on a car with quite an expensive engine when the manufacturer has a/ put in the instrumentation to read it and b/ has some view on what is good and what is bad is foolhardy. Up to you though.The do-ers are currently enjoying their cars having realised a dream. The dreamers are still scouring the classifieds and emailing sellers questions like "has anyone ever broken wind in the nomex recaros?" or "Have you ever closed the door a bit too hard, so the car shook a tiny bit? It wears the shockers out that does."
mrdemon said:
We all know porsche built the engine to take 10k revs.
Really? I never knew that. Guesswork or irony?Bert
These engines regularly get buzzed well into rev range 2 in Carrera cup and Super Cup. The only ones I've ever seen fail are due to overheating due to rad damage. My 996 Cup engine had 90 hours on it when it started the season in it and I blew the clutch 4 times through range 2 over revs whilst learning to flat shift in it. If I remember correctly one registered 10900 on the motec. We had no budget for a rebuild so we leak tested it and it was fine so we ran it on for the rest of the season. 70 hours later it still pulled like a train. I sold the car to a team in Hong Kong who have the engine a full rebuild as part of the beginning of season refresh. Apparently there was no sign of any real wear at all!
These engines are very robust.its the drivetrain a that can suffer more with abuse and that doesn't show up on the ECU. I would have no problem buying a car with rev range 2 activity providing a leak test was fine.
These engines are very robust.its the drivetrain a that can suffer more with abuse and that doesn't show up on the ECU. I would have no problem buying a car with rev range 2 activity providing a leak test was fine.
mrdemon said:
We all know porsche built the engine to take 10k revs.
this is not true for the road engines. variocam cannot take much more than factory rev limit without crapping out and causing a valvetrain problem. the race engines have no variocam and thus can rev higher without valve train problems.ill reply in more detail on the tech side later, but suffice to say that being revved higher through normal operation (ie increased red line) and being revved higher by being twisted through the arse involve two very different sets of loadings.
BertBert said:
I don't agree with your analysis. Yes of course obsessive attention to detail will stop you buying when "normal" people would just get on with it. And just the same, a complete laissez-fair attitude to the condition of the car is equally daft. It's each person's choice of what they are happy with and what they are not. To ignore the max revs on a car with quite an expensive engine when the manufacturer has a/ put in the instrumentation to read it and b/ has some view on what is good and what is bad is foolhardy. Up to you though.
Bert
Yep, as you say, up to me. My car is fine and dandy, hence why I probably get bored by the rev-range obsessives. Bert
terryb said:
Ok, so I keep reading on numerous threads about over rev this and that and rev range 1 and 2, etc. I understand that the ECU can give these reading and of course understand what an over-revving is.
Question is though, what evidence is there out there that a history of over-revs means impending doom for future use of that engine? And what rev ranges are reflected by ranges 1 & 2? My Mk1 996 GT3 has a K400 Manthey conversion, which raises the rev limit from 7600 to 8400. Would I therefore be in either RR1 or 2 if using all the revs? FYI this conversion was done at about 40k miles ago and is now on 80k and is still running perfectly. And it's had a decent amount of ack use in this time too.
I just get the feeling that too much importance is placed on over-revs and wonder if people walk away from potential purchases because of it, when maybe there is no need to, as in the case of my car.
Am interested to hear fact and real experiences rather than opinion and theory
Cheers
Terry
Well, I have hit the rev limiter of the engines of my Porsches so I guess that qualifies as real experience. Question is though, what evidence is there out there that a history of over-revs means impending doom for future use of that engine? And what rev ranges are reflected by ranges 1 & 2? My Mk1 996 GT3 has a K400 Manthey conversion, which raises the rev limit from 7600 to 8400. Would I therefore be in either RR1 or 2 if using all the revs? FYI this conversion was done at about 40k miles ago and is now on 80k and is still running perfectly. And it's had a decent amount of ack use in this time too.
I just get the feeling that too much importance is placed on over-revs and wonder if people walk away from potential purchases because of it, when maybe there is no need to, as in the case of my car.
Am interested to hear fact and real experiences rather than opinion and theory
Cheers
Terry
Range 1 or range 2 or range N over revs matter not or they matter some or they matter a lot.
When they matter a lot is for instance when someone brings a car in with a sick engine and wants it repaired (replaced) under warranty. Over revs in the higher ranges or too many in the lower ranges -- I do not know what the criteria are -- the warranty claim is denied.
When they matter some is one is looking at a car. If there are an above average (whatever that is) number of range one over revs or over revs in the higher ranges even if the last over rev event occurred a goodly time in the past (> one hour is what the techs tell me they like) and even if the engine passes an extended test ride/drive test with flying colors the over revs matter because they provide one with a clue as to how the car was used, treated.
Now if you are *not* a member of the set of people who believe these engines are so much over designed (sure they are, every engine is, but there are limits of course) and can take over revs with aplomb and believe the best way to treat an engine is to drive the car like it was stolen then these over revs count for something and that is whatever you want to them to count for.
Or if you are a member of the set of people who believe these engines are over designed to the point of indestructibility and can take over revs like they were raindrops on a duck's back and at every opportunity drive your car like it was stolen then these over revs count for nothing.
By way of some example... Some time ago at the intro of the C-GT a test driver (from a car mag) blew the engine in a C-GT. Missed shift. Postmortem found the engine revs reached 14K and something beyond before something in the engine let go. But this is not enough for me to if I owned one of these cars to raise its redline to 13,999 rpms or being more serious to anything above whatever Porsche set the redline too. The same applies for lesser cars and engines.
Anyhow, I spoke to some Porsche techs about over revs business some months ago. I started out above with what they told me: to repeat over revs matter a great deal if the engine is sick and a warranty claim is being made. One of the first things done will be a dump of the DME for over revs and I believe based on what I've picked up over the years other data that is used by Porsche to determine if abuse/misuse possibly even neglect is in evidence and can thus provide Porsche justification for denying the claim.
They also told me the over revs don't matter if the last event occurred in the past (the 1 hour figure was given) and the engine passes an extended test ride/drive test. The techs indicated they believe a one hour test ride/drive is appropriate. While over revs are important and one wants to be sure the engine is not or soon will not exhibit any symptoms from being over rev'd there are more things to be worried about than over revs and any after effects and a test that has the engine running running one hour is a reasonable amount of engine run time to bring these other things to light.
Yep. In my experience from sitting next to drivers in GT3's at track days I would say that (repeat again) it is not the engine of a GT3 that suffers through driver abuse/misuse or whatever. It is the gearbox and transmission. I think in the case of the GT3, there is perhaps to much emphasis of rev range incidents and not enough on gearbox and transmission abuse.
A replacement GT3 motor is what, 20k?
The Mezger is a very strong unit but no engine can take a serious buzz on a missed downshift without damage.
There happens to be a way of checking if this damage may have been done.
Its up to you whether you can be arsed to check. You can just risk it if you want. Do you feel lucky? Well, do ya punk?!
The Mezger is a very strong unit but no engine can take a serious buzz on a missed downshift without damage.
There happens to be a way of checking if this damage may have been done.
Its up to you whether you can be arsed to check. You can just risk it if you want. Do you feel lucky? Well, do ya punk?!
mollytherocker said:
A replacement GT3 motor is what, 20k?
The Mezger is a very strong unit but no engine can take a serious buzz on a missed downshift without damage.
There happens to be a way of checking if this damage may have been done.
Its up to you whether you can be arsed to check. You can just risk it if you want. Do you feel lucky? Well, do ya punk?!
The only GT3 engine that I've ever had personal experience of having a catastrophic failure was a 3.8 that ingested a faulty sub component. Compare that to the literally 100's of track days and races that I've attended and you can get a realistic perspective. You really do have to abuse this unit to break itThe Mezger is a very strong unit but no engine can take a serious buzz on a missed downshift without damage.
There happens to be a way of checking if this damage may have been done.
Its up to you whether you can be arsed to check. You can just risk it if you want. Do you feel lucky? Well, do ya punk?!
Steve Rance said:
mollytherocker said:
A replacement GT3 motor is what, 20k?
The Mezger is a very strong unit but no engine can take a serious buzz on a missed downshift without damage.
There happens to be a way of checking if this damage may have been done.
Its up to you whether you can be arsed to check. You can just risk it if you want. Do you feel lucky? Well, do ya punk?!
The only GT3 engine that I've ever had personal experience of having a catastrophic failure was a 3.8 that ingested a faulty sub component. Compare that to the literally 100's of track days and races that I've attended and you can get a realistic perspective. You really do have to abuse this unit to break itThe Mezger is a very strong unit but no engine can take a serious buzz on a missed downshift without damage.
There happens to be a way of checking if this damage may have been done.
Its up to you whether you can be arsed to check. You can just risk it if you want. Do you feel lucky? Well, do ya punk?!
If it sounds good and runs well, its fine?
Gassing Station | Porsche General | Top of Page | What's New | My Stuff