991 TT Aerodynamic Data
#16
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I understand that everything is about balance but I don't have the funds to do all the aero at once. Where do you feel I should focus on? Rear downforce or front end downforce? I feel now with my GT3 bumper that I may be too front end biased and oversteer on certain corner where i never used to.
#17
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I understand that everything is about balance but I don't have the funds to do all the aero at once. Where do you feel I should focus on? Rear downforce or front end downforce? I feel now with my GT3 bumper that I may be too front end biased and oversteer on certain corner where i never used to.
991.1GT3 Downforce@200 kph: Front 14Kg, Rear 29 KG--
991.2 GT3 @ 200KPh: Front 19Kgs, Rear 42Kg with wing at 5 degrees position
991.2 GT3 @ 200KPh: Front 16Kgs, Rear 53Kg with wing at 9 degrees position
991TT @ 200KPh: Front 20Kgs, Rear 40Kg in performance mode
GT3 has better drag coefficients however.
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#19
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Jean,
your a madman!! Love this data.
Do you know what the 991.2 Cup front bumper with Porsche Motorsport canards generates in downforce. Are you modeling these or you have the data?
been looking all over. Trying to figure out delta between this setup and 2RS setup with the two small canards.
your a madman!! Love this data.
Do you know what the 991.2 Cup front bumper with Porsche Motorsport canards generates in downforce. Are you modeling these or you have the data?
been looking all over. Trying to figure out delta between this setup and 2RS setup with the two small canards.
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It is mainly the louvers, according to Porsche they double the front downforce. The dive plains are mostly used to balance the front, they do increase downforce somewhat but also drag, not as efficient as the louvers or the diffuser.
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Jean,
your a madman!! Love this data.
Do you know what the 991.2 Cup front bumper with Porsche Motorsport canards generates in downforce. Are you modeling these or you have the data?
been looking all over. Trying to figure out delta between this setup and 2RS setup with the two small canards.
your a madman!! Love this data.
Do you know what the 991.2 Cup front bumper with Porsche Motorsport canards generates in downforce. Are you modeling these or you have the data?
been looking all over. Trying to figure out delta between this setup and 2RS setup with the two small canards.
It is difficult to dissociate elements, on the GT3R, the mix of front fender louvers, large splitter, canards, air exit through front trunk and addition of a guerney in the front wheel well nearly doubles the front downforce vs. the Cup car from what I have been told by a very trusted source.
The rear diffuser and flat bottom are the most efficient aerodynamic parts, i.e. maximizing downforce with very limited impact on drag.
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#22
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I had always been curious as to what the impact of the aero was. Thanks Jean, very informative.
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Some additional data that could be of interest to some..
So I mentioned that the GT2RS has a total Cl of ~ -0.35 which gives a total downforce of 49/93 KGs= 140Kgs ( ~310lbs) at 200kph.
The Manthey high downforce kit has increased the downforce to 70/200 Kgs= 270KGs (594 lbs) at 200 kph reaching a coefficient of Cl = -0.68
At max speed that's a downforce of 1700lbs for the GT2RS MR vs 900lbs for the GT2RS
Downforce GT2RS MR vs. GT2RS = +93%
Changes were a different front splitter with Cup car flat floor, 2 small front canards each side, the rear uprights were modified 2" higher and seems they did a subtle change to them to be further leaning rearward. The rear wing span was increased slightly (I suspect to 300mm instead of 280mm), end plates larger, and they fitted a larger diffuser ( I read somewhere it was the 911R diffuser modified). I am not 100% sure about how precise this info is, but pretty close.
I am moving in that direction, GT2RS front bumper and rear decklid being fittedbut I am changing the GT2RS wing for a larger one and customizing the uprights to my requested sizes. The new rear wing provides a downforce up to 200Kgs @ 200kph depending on its setup, also adding a custom sized rear CF diffuser. Upfront, a front splitter extending about 4" ahead of the GT2RS front lip and a pair of 991.2 Cup canards. It should all be fitted and tested in time attack mid February. Hoping it will not be a fiasco!
So I mentioned that the GT2RS has a total Cl of ~ -0.35 which gives a total downforce of 49/93 KGs= 140Kgs ( ~310lbs) at 200kph.
The Manthey high downforce kit has increased the downforce to 70/200 Kgs= 270KGs (594 lbs) at 200 kph reaching a coefficient of Cl = -0.68
At max speed that's a downforce of 1700lbs for the GT2RS MR vs 900lbs for the GT2RS
Downforce GT2RS MR vs. GT2RS = +93%
Changes were a different front splitter with Cup car flat floor, 2 small front canards each side, the rear uprights were modified 2" higher and seems they did a subtle change to them to be further leaning rearward. The rear wing span was increased slightly (I suspect to 300mm instead of 280mm), end plates larger, and they fitted a larger diffuser ( I read somewhere it was the 911R diffuser modified). I am not 100% sure about how precise this info is, but pretty close.
I am moving in that direction, GT2RS front bumper and rear decklid being fittedbut I am changing the GT2RS wing for a larger one and customizing the uprights to my requested sizes. The new rear wing provides a downforce up to 200Kgs @ 200kph depending on its setup, also adding a custom sized rear CF diffuser. Upfront, a front splitter extending about 4" ahead of the GT2RS front lip and a pair of 991.2 Cup canards. It should all be fitted and tested in time attack mid February. Hoping it will not be a fiasco!
#27
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Some additional data that could be of interest to some..
So I mentioned that the GT2RS has a total Cl of ~ -0.35 which gives a total downforce of 49/93 KGs= 140Kgs ( ~310lbs) at 200kph.
The Manthey high downforce kit has increased the downforce to 70/200 Kgs= 270KGs (594 lbs) at 200 kph reaching a coefficient of Cl = -0.68
At max speed that's a downforce of 1700lbs for the GT2RS MR vs 900lbs for the GT2RS
Downforce GT2RS MR vs. GT2RS = +93%
Changes were a different front splitter with Cup car flat floor, 2 small front canards each side, the rear uprights were modified 2" higher and seems they did a subtle change to them to be further leaning rearward. The rear wing span was increased slightly (I suspect to 300mm instead of 280mm), end plates larger, and they fitted a larger diffuser ( I read somewhere it was the 911R diffuser modified). I am not 100% sure about how precise this info is, but pretty close.
I am moving in that direction, GT2RS front bumper and rear decklid being fittedbut I am changing the GT2RS wing for a larger one and customizing the uprights to my requested sizes. The new rear wing provides a downforce up to 200Kgs @ 200kph depending on its setup, also adding a custom sized rear CF diffuser. Upfront, a front splitter extending about 4" ahead of the GT2RS front lip and a pair of 991.2 Cup canards. It should all be fitted and tested in time attack mid February. Hoping it will not be a fiasco!
So I mentioned that the GT2RS has a total Cl of ~ -0.35 which gives a total downforce of 49/93 KGs= 140Kgs ( ~310lbs) at 200kph.
The Manthey high downforce kit has increased the downforce to 70/200 Kgs= 270KGs (594 lbs) at 200 kph reaching a coefficient of Cl = -0.68
At max speed that's a downforce of 1700lbs for the GT2RS MR vs 900lbs for the GT2RS
Downforce GT2RS MR vs. GT2RS = +93%
Changes were a different front splitter with Cup car flat floor, 2 small front canards each side, the rear uprights were modified 2" higher and seems they did a subtle change to them to be further leaning rearward. The rear wing span was increased slightly (I suspect to 300mm instead of 280mm), end plates larger, and they fitted a larger diffuser ( I read somewhere it was the 911R diffuser modified). I am not 100% sure about how precise this info is, but pretty close.
I am moving in that direction, GT2RS front bumper and rear decklid being fittedbut I am changing the GT2RS wing for a larger one and customizing the uprights to my requested sizes. The new rear wing provides a downforce up to 200Kgs @ 200kph depending on its setup, also adding a custom sized rear CF diffuser. Upfront, a front splitter extending about 4" ahead of the GT2RS front lip and a pair of 991.2 Cup canards. It should all be fitted and tested in time attack mid February. Hoping it will not be a fiasco!
#29
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For comparison, the 2019 ZR1 Corvette Big Wing Model was rated at 900-1000 lbs of down force at top speed. 200ish mph.
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Hopefully Jean, when this is all built and sorted, you can post a couple of pics of it. Very impressive, thank you.