997.2 GT3 has 2x downforce over 997.1?
08-05-2014, 03:07 AM
#17
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Last edited by Fisher; 08-05-2014 at 05:05 AM.
08-05-2014, 08:51 AM
#18
Race Car
08-05-2014, 09:34 AM
#19
Pro
Thread Starter
Looks like Cup lip and, canards and the rear wing at max would help on the .1. It states it not buoyant (lift), so its borderline... at that fine line a little down force helps, especially at the front where under steer is relatively common.
08-05-2014, 10:40 AM
#20
On the .2RS, increasing the rear wing was like finding a new car. It made a very big difference at COTA. I could drive "flat out" from T1 Exit to braking into T4. T16-T18 was also much improved, at least 5mph through there. Even on rapidly cycling-out tires, I was able to keep my lap times respectable.
08-05-2014, 10:54 AM
#21
08-05-2014, 11:03 AM
#22
Tough to say how accurate those tests are. I used to work with an ex-chief engineer at Ford, who told me Sport Auto is pretty good at their testing methodology, and that test results captured are generally treat as a strong source. The aero stuff is performed by a team that uses the mercedes wind tunnel. It's not a rolling tunnel - the car tires are placed on load cells.
08-05-2014, 11:27 AM
#23
Rennlist Member
On the .2RS, increasing the rear wing was like finding a new car. It made a very big difference at COTA. I could drive "flat out" from T1 Exit to braking into T4. T16-T18 was also much improved, at least 5mph through there. Even on rapidly cycling-out tires, I was able to keep my lap times respectable.
08-05-2014, 11:53 AM
#24
Interesting, maybe the variances between Porsche and Sport-Auto data are due to wing attack angles and/or ride height/rake, instead of testing procedures(which Porsche is historically pretty conservation with)?
Tough to say how accurate those tests are. I used to work with an ex-chief engineer at Ford, who told me Sport Auto is pretty good at their testing methodology, and that test results captured are generally treat as a strong source. The aero stuff is performed by a team that uses the mercedes wind tunnel. It's not a rolling tunnel - the car tires are placed on load cells.
08-05-2014, 01:47 PM
#25
The .1 RS had the wing in the OE as delivered position with ZERO angle of attack - the downforce numbers quoted are correct, in my opinion, but the significant testing differences comparing .1 to .2 numbers are because the .2 GT3 and .2RS had significant and more significant (GT3/RS) 'zeroed' angles compared to the .1RS wing. The minimal rear downforce .1RS numbers is from the shape of the wing alone - start to crank the wing up and you immediately begin to feel the back end drag/downforce.
Trust me when I say this, if you crank up the .1RS wing to 13-15 degrees (similar to the .2 cars) there is a substantial different feeling and downforce numbers produced - substantial; so much so, that at Mosport on the back straight if you running the .1 RS wing at 15degress the car starts to cavitate 2/3rds the way down the back straight as it gets completely aero unbalanced - the Cup front lip perfectly balances the car and corrects this.
In my .1gt3 with the RS wing at 15 degrees and with a 4.0 R&P I can take turn #4 at Mosport on the rev limiter in 4th gear at 125mph / 200kph and there is NO rear end rotation (the 4.0RS at this speed is producing 60kg of rear end downforce with the wing in stock position - my guess equivalent to the .1RS wing at 15 degrees). In a 996 turbo or 997mk1gt3 with rear wing in OE flat position (producing no downforce) the rear end will come around every time at this speed - you can make the turn but it is more than a bit frightening with the rear end out coming down #4.
Trust me when I say this, if you crank up the .1RS wing to 13-15 degrees (similar to the .2 cars) there is a substantial different feeling and downforce numbers produced - substantial; so much so, that at Mosport on the back straight if you running the .1 RS wing at 15degress the car starts to cavitate 2/3rds the way down the back straight as it gets completely aero unbalanced - the Cup front lip perfectly balances the car and corrects this.
In my .1gt3 with the RS wing at 15 degrees and with a 4.0 R&P I can take turn #4 at Mosport on the rev limiter in 4th gear at 125mph / 200kph and there is NO rear end rotation (the 4.0RS at this speed is producing 60kg of rear end downforce with the wing in stock position - my guess equivalent to the .1RS wing at 15 degrees). In a 996 turbo or 997mk1gt3 with rear wing in OE flat position (producing no downforce) the rear end will come around every time at this speed - you can make the turn but it is more than a bit frightening with the rear end out coming down #4.
Last edited by 997gt3north; 08-07-2014 at 06:00 PM.
08-05-2014, 03:11 PM
#26
On the .2RS, increasing the rear wing was like finding a new car. It made a very big difference at COTA. I could drive "flat out" from T1 Exit to braking into T4. T16-T18 was also much improved, at least 5mph through there. Even on rapidly cycling-out tires, I was able to keep my lap times respectable.
08-05-2014, 03:22 PM
#27
What I've been told is that cup wing is the way to go, though I don't know what it takes to make it work with the current uprights. $2K for news seems like highway robbery compared to a 5K wing.
08-05-2014, 03:41 PM
#28
It doesn't work with the OEM uprights, you have to buy the cup wing and cup uprights. Mooty recently sold his wing/uprights. I think I have enough downforce with my higher aftermarket uprights and fully tilted wing, I'm just a DE guy after all.
08-05-2014, 06:30 PM
#29
Rennlist Member
I buy it. When we drove the .2 GT3 in Germany in Spring 2009 on the press long-lead we had it at an indicated 312km/h (193 mph) and it was NAILED to the road. I mean an uncanny feeling of directional stability. Very nice. Wish I could drive mine in Germany...
