991 RS ON TRACK
Discussion
Isaldiri,
I wanted to follow back up on your balance comment. I am not sure that this holds for all situations tbh.
Thinking to the change between 997 Cup and 996 Cup (and over to my project Cup) the impact of aero is significant but doesn't hold with this concept.
The 997.1 Cup (as shown from the graph posted earlier) has some decent aero going on (relatively speaking) but its far more rear biased than the weight split of the car at ~38/62.
It works quite effectively though for reasons that are quite clear when understood.
The issue with the 996 and 997 based platforms (and all 911s I assume) is that the rear engine wants to push round while cornering. The faster you are going, the greater the effect becomes. If one wants to be fast and safe the car requires to be set up as neutral as possible for high speed situations by pushing grip to the rear.
The drawback however is that in slower speed stuff the rear engine effect isn't as pronounced. The basic setup that you put on the car to keep it neutral now causes the car to understeer.
The driver learns techniques to deal with this and work with it, and on the 996 Cup - despite the large rear wing - this approach is still very much a feature of setup and driving just as it is with the street GT3 cars on 996 and 997 platforms.
The extra oomph from the 997 Cup wing is enough to change approach somewhat IMV. The rear wing configuration creates more DF and corresponding grip. This increases as speed increases and the increasing grip helps counteract the tendency of the rear to push round when cornering. As a result, in my experience one doesn't have to send as much grip to the rear to achieve the same neutral high speed balance. The knock on effect is that there is less understeer in the slower stuff simply because the grip balance is now less rearwards. The aero drops off with speed keeping the car more neutral across a range of corners. One can then drive the car quite differently than one does with a typical 996 Cup or street GT3. I always found myself driving them from the rear end rather than on the nose after setting them up this way. Others may feel differently.
The later 997 Cups increased rear DF further and also added more front DF. This allowed not only the above benefit but an overall increase in total overall grip.
On my project 996, I am using a larger 997 wing and mounting position to bring some of this to the car. I also like the rear end stability it gives under braking but that is a different topic. People see the large wing and assume that its heavy on push, but this isn't quite what happens when set up appropriately.
I wanted to follow back up on your balance comment. I am not sure that this holds for all situations tbh.
Thinking to the change between 997 Cup and 996 Cup (and over to my project Cup) the impact of aero is significant but doesn't hold with this concept.
The 997.1 Cup (as shown from the graph posted earlier) has some decent aero going on (relatively speaking) but its far more rear biased than the weight split of the car at ~38/62.
It works quite effectively though for reasons that are quite clear when understood.
The issue with the 996 and 997 based platforms (and all 911s I assume) is that the rear engine wants to push round while cornering. The faster you are going, the greater the effect becomes. If one wants to be fast and safe the car requires to be set up as neutral as possible for high speed situations by pushing grip to the rear.
The drawback however is that in slower speed stuff the rear engine effect isn't as pronounced. The basic setup that you put on the car to keep it neutral now causes the car to understeer.
The driver learns techniques to deal with this and work with it, and on the 996 Cup - despite the large rear wing - this approach is still very much a feature of setup and driving just as it is with the street GT3 cars on 996 and 997 platforms.
The extra oomph from the 997 Cup wing is enough to change approach somewhat IMV. The rear wing configuration creates more DF and corresponding grip. This increases as speed increases and the increasing grip helps counteract the tendency of the rear to push round when cornering. As a result, in my experience one doesn't have to send as much grip to the rear to achieve the same neutral high speed balance. The knock on effect is that there is less understeer in the slower stuff simply because the grip balance is now less rearwards. The aero drops off with speed keeping the car more neutral across a range of corners. One can then drive the car quite differently than one does with a typical 996 Cup or street GT3. I always found myself driving them from the rear end rather than on the nose after setting them up this way. Others may feel differently.
The later 997 Cups increased rear DF further and also added more front DF. This allowed not only the above benefit but an overall increase in total overall grip.
On my project 996, I am using a larger 997 wing and mounting position to bring some of this to the car. I also like the rear end stability it gives under braking but that is a different topic. People see the large wing and assume that its heavy on push, but this isn't quite what happens when set up appropriately.
mollytherocker said:
Ok, I get that, its about subtle redirection, maximising flow etc.
But what about that great big sloping bonnet and windscreen? These must have a colossal effect?
It is not always subtle, but it often about something local that then feeds into the bigger picture.But what about that great big sloping bonnet and windscreen? These must have a colossal effect?
I am not sure what you are getting at ref the bonnet and windscreen? Are you suggesting that the area of these must make more difference than a wing with a smaller area?
Here are my own CFD plots for my project 996 when I was looking at wing mounting options. This is at 40m/s so ~89.5 mph. Maybe these will help you with whatever you are asking.
The first is velocity vectors and streamlines, the second is pressure. Red high, blue low on both. Remember velocity is inversely proportional to pressure.
Edited by fioran0 on Tuesday 13th October 23:30
fioran0 said:
Isaldiri,
I wanted to follow back up on your balance comment. I am not sure that this holds for all situations tbh.
Thinking to the change between 997 Cup and 996 Cup (and over to my project Cup) the impact of aero is significant but doesn't hold with this concept.
The 997.1 Cup (as shown from the graph posted earlier) has some decent aero going on (relatively speaking) but its far more rear biased than the weight split of the car at ~38/62.
It works quite effectively though for reasons that are quite clear when understood.
The issue with the 996 and 997 based platforms (and all 911s I assume) is that the rear engine wants to push round while cornering. The faster you are going, the greater the effect becomes. If one wants to be fast and safe the car requires to be set up as neutral as possible for high speed situations by pushing grip to the rear.
The drawback however is that in slower speed stuff the rear engine effect isn't as pronounced. The basic setup that you put on the car to keep it neutral now causes the car to understeer.
The driver learns techniques to deal with this and work with it, and on the 996 Cup - despite the large rear wing - this approach is still very much a feature of setup and driving just as it is with the street GT3 cars on 996 and 997 platforms.
The extra oomph from the 997 Cup wing is enough to change approach somewhat IMV. The rear wing configuration creates more DF and corresponding grip. This increases as speed increases and the increasing grip helps counteract the tendency of the rear to push round when cornering. As a result, in my experience one doesn't have to send as much grip to the rear to achieve the same neutral high speed balance. The knock on effect is that there is less understeer in the slower stuff simply because the grip balance is now less rearwards. The aero drops off with speed keeping the car more neutral across a range of corners. One can then drive the car quite differently than one does with a typical 996 Cup or street GT3. I always found myself driving them from the rear end rather than on the nose after setting them up this way. Others may feel differently.
The later 997 Cups increased rear DF further and also added more front DF. This allowed not only the above benefit but an overall increase in total overall grip.
On my project 996, I am using a larger 997 wing and mounting position to bring some of this to the car. I also like the rear end stability it gives under braking but that is a different topic. People see the large wing and assume that its heavy on push, but this isn't quite what happens when set up appropriately.
That was very interesting thanks. So assuming I haven't horribly misunderstood you, very simplistically, the extra rear biased downforce helps with the 997 Cup as you can setup the car to be more neutral at non aero speeds and the rear downforce helps you out at high speeds when you really don't want oversteer and the rear engine configuration stops you from understeering horribly with all the extra rear aero? That would also perhaps not be at complete odds with what I was told given that was I think with regards to a mid engine racing car rather than a rear engine Cup/911.I wanted to follow back up on your balance comment. I am not sure that this holds for all situations tbh.
Thinking to the change between 997 Cup and 996 Cup (and over to my project Cup) the impact of aero is significant but doesn't hold with this concept.
The 997.1 Cup (as shown from the graph posted earlier) has some decent aero going on (relatively speaking) but its far more rear biased than the weight split of the car at ~38/62.
It works quite effectively though for reasons that are quite clear when understood.
The issue with the 996 and 997 based platforms (and all 911s I assume) is that the rear engine wants to push round while cornering. The faster you are going, the greater the effect becomes. If one wants to be fast and safe the car requires to be set up as neutral as possible for high speed situations by pushing grip to the rear.
The drawback however is that in slower speed stuff the rear engine effect isn't as pronounced. The basic setup that you put on the car to keep it neutral now causes the car to understeer.
The driver learns techniques to deal with this and work with it, and on the 996 Cup - despite the large rear wing - this approach is still very much a feature of setup and driving just as it is with the street GT3 cars on 996 and 997 platforms.
The extra oomph from the 997 Cup wing is enough to change approach somewhat IMV. The rear wing configuration creates more DF and corresponding grip. This increases as speed increases and the increasing grip helps counteract the tendency of the rear to push round when cornering. As a result, in my experience one doesn't have to send as much grip to the rear to achieve the same neutral high speed balance. The knock on effect is that there is less understeer in the slower stuff simply because the grip balance is now less rearwards. The aero drops off with speed keeping the car more neutral across a range of corners. One can then drive the car quite differently than one does with a typical 996 Cup or street GT3. I always found myself driving them from the rear end rather than on the nose after setting them up this way. Others may feel differently.
The later 997 Cups increased rear DF further and also added more front DF. This allowed not only the above benefit but an overall increase in total overall grip.
On my project 996, I am using a larger 997 wing and mounting position to bring some of this to the car. I also like the rear end stability it gives under braking but that is a different topic. People see the large wing and assume that its heavy on push, but this isn't quite what happens when set up appropriately.
Edited by isaldiri on Wednesday 14th October 00:03
More or less.
You still set the car up to be neutral on high speed corners where you definitely don't want it to be loose. However the extra rear aero produces additional grip in this situation to help things out. You don't have to move quite as much grip backwards as you normally would.
As a consequence, the car also tends to have less push than it did before in slower corners. The car naturally has more grip up front because less balance was sent to the back to try and keep the engine in line when going faster.
All IMHO of course.
The shift in aero balance with the 991 models is interesting. I assume its a result of the RWS system and torque vectoring etc. These all help to keep things in line anyways so the DF can be adjusted accordingly. The 991 Cup still runs an aero balance more in line with previous models and the GT3R just has the usual.....loads of it.
You still set the car up to be neutral on high speed corners where you definitely don't want it to be loose. However the extra rear aero produces additional grip in this situation to help things out. You don't have to move quite as much grip backwards as you normally would.
As a consequence, the car also tends to have less push than it did before in slower corners. The car naturally has more grip up front because less balance was sent to the back to try and keep the engine in line when going faster.
All IMHO of course.
The shift in aero balance with the 991 models is interesting. I assume its a result of the RWS system and torque vectoring etc. These all help to keep things in line anyways so the DF can be adjusted accordingly. The 991 Cup still runs an aero balance more in line with previous models and the GT3R just has the usual.....loads of it.
Fiorano - many thanks for taking the time on all the above. A last question if you could say, what would the 430 challenge aero numbers look like compared to the 997 cup as I believe you have mentioned running the challenge before so am quite interested given you had posted on the differences in driving the 2 cars previously how the downforce balance would look to compare the different engine configurations.
APOLO1 said:
Scooty100 said:
Hello David yours I trust ? Looks awesome
Hi S, Yes from Monday, most exciting car to drive I have ever owned.....
We should try and rent Spa for ourselves next season, we could probably put 25 - 30 of us up for a day, what an epic day that could be
The aero thing is lost on me. I get it on a racing car but on a road car that's on road tyres and carrying over 100kg of fat already, it's bonkers. Re visit Neil's lovely 996 build. He's stripped the car right down to bear weight and got every other aspect of the build right first before he added the Aero. On that car it makes sense but to put it on a car that would benefit far more from a diet first, it does not.
I had an Escort Cosworth in the early 90's, Ford claimed it was the first production car to generate positive downforce.
It was VERY stable at close to 100 mph speeds, so I guess they were right.
I have no doubt the latest RS is the same, indeed a lot better, I doubt it works much below 80 ish though.
Anyway, can someone tell me what flying lap time it has done around Goodwood ????? I am interested to know.
cheers.
It was VERY stable at close to 100 mph speeds, so I guess they were right.
I have no doubt the latest RS is the same, indeed a lot better, I doubt it works much below 80 ish though.
Anyway, can someone tell me what flying lap time it has done around Goodwood ????? I am interested to know.
cheers.
Well car agree with apollo,it just won their performance car and is 'the best 911 they have driven' or something along those lines.
THe ferrari 488 came 2nd followed by the mclaren 675lt,the gt4 came an honourable 4th with a mention that had value been taken into account it would be the winner.
THe ferrari 488 came 2nd followed by the mclaren 675lt,the gt4 came an honourable 4th with a mention that had value been taken into account it would be the winner.
franki68 said:
Well car agree with apollo,it just won their performance car and is 'the best 911 they have driven' or something along those lines.
THe ferrari 488 came 2nd followed by the mclaren 675lt,the gt4 came an honourable 4th with a mention that had value been taken into account it would be the winner.
I was just about to read that bloody article. Please administer yourself a Chinese burn.THe ferrari 488 came 2nd followed by the mclaren 675lt,the gt4 came an honourable 4th with a mention that had value been taken into account it would be the winner.
franki68 said:
Well car agree with apollo,it just won their performance car and is 'the best 911 they have driven' or something along those lines.
THe ferrari 488 came 2nd followed by the mclaren 675lt,the gt4 came an honourable 4th with a mention that had value been taken into account it would be the winner.
Since I have had the RS, not picked the keys up for the 918......THe ferrari 488 came 2nd followed by the mclaren 675lt,the gt4 came an honourable 4th with a mention that had value been taken into account it would be the winner.
Its that good.......
APOLO1 said:
Since I have had the RS, not picked the keys up for the 918......
Its that good.......
It is interesting to me that it seems as if every owner has had a strikingly similar experience, including multiple car owners. It is more that the usual "my new car is the best ' stuff. For me personally the new car just blew me away compared to anything I had previously driven, but I thought it might have been because there are many cars i did not have the opportunity to drive, so it is very good to hear that I was not deluding myself as to how bloody great this cars really is.....Its that good.......
911Viking said:
Somewhat funny, not only here, with everybody having an opinion without even haven driven the car.
Trust me, it would silence every single one of you, the car is just shockingly good. There is nothing out there coming anywhere close.
I don't think anyone (unless they are an idiot) would argue it's a great car and a step forward, but some of the hyperbole on here is horse sTrust me, it would silence every single one of you, the car is just shockingly good. There is nothing out there coming anywhere close.
t. I don't need to drive one to know that, there is plenty of evidence out there when you start to compare lap times that it's a bit quicker, but not 918 quick or any quicker than a 997 GT2 for example (yea I know that as many more horses) and not massively quicker than a 991 GT3 or Turbo, or any quicker in some instances. It's a 911 a few percent better than the last 911 version. Same as it ever was, same bks as there ever was with the 997 and 996 before them arriving, just after they arrived, and so then the world turns. Gassing Station | Porsche General | Top of Page | What's New | My Stuff