GT3 Over revs - AGAIN!
Discussion
When buying mine from OPC I was stupid enough not to look at the RR report and took verbal statement that it was clear in all ranges. Once I came back down to earth from the euthoria of buying my dream car I started to chase my report from OPC Reading. It took a while but eventually got an email with part of a screen print showing all RR clear.
Being the synic that I am I'm thinking it could have been from any car, how easy is it to get the report and what does it look like? Should I maybe go to an indy and get a report from them?
On another matter Steve Rance if you read this how did you get on with your diff and any update on your braking and suspension matters. Maybe an update on your thread?
Being the synic that I am I'm thinking it could have been from any car, how easy is it to get the report and what does it look like? Should I maybe go to an indy and get a report from them?
On another matter Steve Rance if you read this how did you get on with your diff and any update on your braking and suspension matters. Maybe an update on your thread?
When buying mine from OPC I was stupid enough not to look at the RR report and took verbal statement that it was clear in all ranges. Once I came back down to earth from the euthoria of buying my dream car I started to chase my report from OPC Reading. It took a while but eventually got an email with part of a screen print showing all RR clear.
Being the synic that I am I'm thinking it could have been from any car, how easy is it to get the report and what does it look like? Should I maybe go to an indy and get a report from them?
On another matter Steve Rance if you read this how did you get on with your diff and any update on your braking and suspension matters. Maybe an update on your thread?
Being the synic that I am I'm thinking it could have been from any car, how easy is it to get the report and what does it look like? Should I maybe go to an indy and get a report from them?
On another matter Steve Rance if you read this how did you get on with your diff and any update on your braking and suspension matters. Maybe an update on your thread?
mollytherocker said:
ro51ter said:
Rev range 6 would take some doing!
Easy as pie. 5th to 2nd instead of 4th should do it?The way I buzzed (to use the racing term) the engine in my first race car (911 SC) was by accelerating flat out in third and then hitting 2nd instead of 4th i.e. I mis-shifted on the up shift. I think doing so when you've just red-lined it is likely to be far more damaging than when on a downshift, when you're probably braking anyway (hence bringing the road speed closer to what's appropriate for the gear you've mistakenly selected).
The Wolf said:
m33ufo said:
I'm guessing this info is quite old? You've needed further investigation for range 3 hits for a few years.
Yes correct.Their attitude towards the over revs has changed a few times over the years.
mollytherocker said:
It certainly can be reset. But that cannot be hidden.
Sure? I got advice conflicting to this (but I was asking about 996 specifically, mind)Only if you can find earlier readouts will you you learn the truth, and I don't think you can go in to any OPC and they will magic up every read out, so you would have to do a fair bit of detective work.
Certainly I wouldn't just look at the latest readout and think "Great! no over revs!", but you would want to see periodic readouts over the cars life.
If you care more of number on a piece of paper over what you can actually see in front of you that is....
fredt said:
mollytherocker said:
It certainly can be reset. But that cannot be hidden.
Sure? I got advice conflicting to this (but I was asking about 996 specifically, mind)Only if you can find earlier readouts will you you learn the truth, and I don't think you can go in to any OPC and they will magic up every read out, so you would have to do a fair bit of detective work.
Certainly I wouldn't just look at the latest readout and think "Great! no over revs!", but you would want to see periodic readouts over the cars life.
If you care more of number on a piece of paper over what you can actually see in front of you that is....
fioran0 said:
Steve,
Be wary drawing comparisons in that way. The street engines are not the race engines when it comes to high rpms. The extra stuff that's added and/or changed on to the street engines reduces the headroom and very much forms weak points.
Motorsport reckon anything over 10k rpm should be opened and looked over to make sure but the reality is that they tend to be robust; and the clutch pressure plates break first saving the engine in practice (on the 996 anyways). The rivets pop on the restraining straps.
The variocam stuff very specifically alters the landscape with the street units (though is not the only factor or component change).
These parts cannot take the over-revs in the way the race units can.
Sadly there is not the data from street units to properly quantify precisely where limits are, and the variocam in particular responds in a complex way to dynamic events. Since not all over-revs are created equal its very difficult to set guidelines on what's ok and what's not.
I suspect this is some of the reason for the rev limit quagmire in the first place; and the shifting sand responses from Porsche over the years when it comes to the road cars is a response to a situation in which they know there's potential for problems but its impossible to neatly quantify it.
Don't get me wrong. I hate the over-rev situation and how messy it is. It's also disappointing that every mention of it turns into a blockbuster thread when stuff about cars withers quickly.
Interesting stuff. I wasn't aware the difference between the two was quite so great. Appreciating a sample size of one is statistically worthless, my road-engined car raced for 2.5 seasons (and for many years before that in sprints) before requiring a rebuild. In retrospect, it should probably have been opened up at the end of each season, but time will tell.Be wary drawing comparisons in that way. The street engines are not the race engines when it comes to high rpms. The extra stuff that's added and/or changed on to the street engines reduces the headroom and very much forms weak points.
Motorsport reckon anything over 10k rpm should be opened and looked over to make sure but the reality is that they tend to be robust; and the clutch pressure plates break first saving the engine in practice (on the 996 anyways). The rivets pop on the restraining straps.
The variocam stuff very specifically alters the landscape with the street units (though is not the only factor or component change).
These parts cannot take the over-revs in the way the race units can.
Sadly there is not the data from street units to properly quantify precisely where limits are, and the variocam in particular responds in a complex way to dynamic events. Since not all over-revs are created equal its very difficult to set guidelines on what's ok and what's not.
I suspect this is some of the reason for the rev limit quagmire in the first place; and the shifting sand responses from Porsche over the years when it comes to the road cars is a response to a situation in which they know there's potential for problems but its impossible to neatly quantify it.
Don't get me wrong. I hate the over-rev situation and how messy it is. It's also disappointing that every mention of it turns into a blockbuster thread when stuff about cars withers quickly.
I will update this thread in 5 years time to let you know how it's doing...
berty37 said:
Pretty sure MTR is right there Fred. Its the same as people who try to chip or flash the car's ECU and then return it to factory settings before the OPC see it. Ken at 9e told me that when you tamper with things like this it creates a count on the car's brain that cannot be erased.
I was told by a tuner that he could make rr's go away on my car (996 GT2), invisibly. Makes sense to me as its just a chip with noughts and ones on them, and if you access the right areas of the coding I don't understand why you couldn't put whatever values you wanted? (I have no idea how these things work 
)If a cars rr's have been tampered with, would this be immediately obvious on a read out?
I don't know for definite fred only what this chap at 9e told me and maybe the 996 is different but they have tuned tons of cars. I would say knowing Porsche, it isn't as simple as just erasing over revs by decoding I would hazard a guess at you try to do that it leaves a digital hand print somewhere else. People must chip and flash the car's ECU and think when the car goes in for service or potential warranty work they can just switch it back and its all done. I would doubt that personally.
Cunno said:
Also which figures are correct the ones you posted or the table on page 2 of this thread? As per page 2 I believe a RR1 in a 997 starts at 9000rpm and not 8400rpm. This is the fundamental difference between a 996 and 997 when it comes to logging RR1s, the 997 doesn't log anything until you exceed the limited by 600rpm while the 996 logs RR1s as sone as you hit the limiter, which explains why cars like mine show no RRs recorded although it lives on track.
The info I got comes from 2 independent sources, though I still won't vouch for it.I'd say it is somewhat contradictory that a stage 1 occurs often whilst I find 600rpm above already a quite serious overrev?
This is how the Yanks deal with RRs
You lot need to hold your heads in shame;)
http://rennlist.com/forums/997-gt2-gt3-forum/86289...
You lot need to hold your heads in shame;)
http://rennlist.com/forums/997-gt2-gt3-forum/86289...
Cunno said:
This is how the Yanks deal with RRs
You lot need to hold your heads in shame;)
http://rennlist.com/forums/997-gt2-gt3-forum/86289...
3 Clutches You lot need to hold your heads in shame;)
http://rennlist.com/forums/997-gt2-gt3-forum/86289...
Impressive rodgering of an engine. Those are skid marks that will never wash out. I must confess to the walk of shame back to the pits after blowing the odd 996 cup clutch ( gearbox Rodgering ) but my hat goes off to anyone feckless enough to blow 3 chaps on a road car.
See me after class Stupid Boy.
See me after class Stupid Boy.
That's some doing on the clutches. My grandma only managed 2 in 10k miles and she used to use about 6,000 rpm before finding the bite point. Regarding the over Rev I assume these are from engine breaking ie slowing down or missing gears. An dynamics engineer once told me that over reving going down the box does not put as much load on the engine as pushing it hard near to the red line under load in say 3 rs gear. These engines and cars are designed for hard work from time to time hence why we buy them. Look on YouTube on engine testing some are ram for hours well above the Rev range we could achieve for a few seconds. If it sounds right offers the correct pressures and tenperatures it would not stop me buying a car that was revved hard 4 years prior.
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