GT3 Near Crash! (at 35MPH)
03-02-2020, 02:02 PM
#16
SJW, a Carin' kinda guy
Rennlist Member
Rennlist Member
This is why my stock wheels and Cup2 hold up my table and I run winter wheels with Bridgestone RE980AS tires year round. I also never turn off the nannies.
Cup2 I am sure are great when hot, but cold and wet forget it. They are hockey pucks.
Cup2 I am sure are great when hot, but cold and wet forget it. They are hockey pucks.
Last edited by evilfij; 03-02-2020 at 02:21 PM.
03-02-2020, 04:15 PM
#18
Instructor
Hi Guys/Girls, I recently purchased a 2018 911 GT3 (4L 991.2) which I’ve had for around 3-4 weeks, so I’m still taking things steady while I’m still sussing the car out. Whilst I was out on Sunday I approached a roundabout, stopped to let traffic go then pulled out and went round the roundabout increased ( very gradually) the speed to around 35 MPH as I exited. The back end immediately kicked out to the right, I quickly turned to the right to catch the car, I overdid that so the car went the other way and I managed to turn the other way and steady the car. Conditions on the road were dry with various wet patches (including my pants now!!!) which I had probably hit when the rear end went, to be honest I was totally shocked and shaken at how poorly the car performed (had it not been a dual carriageway and really quiet I would have gone into someone at the side of me, if it been a normal road I would have probably had a head on collision) I could have gone through the same route in my wife’s Santa Fe or any Ford Fiesta etc at 45-50 MPH with no problems.
Am I missing something! The tyres are massive at the rear, the suspension set-up is supposed to be world class ( most GT3 owners must have watched Chris Harris going round a circuit at incredible speeds) there are various electronic safety features built into the car ( I was just in basic mode i.e, nothing sporty and no esp switched off)
It’s now made me worried about driving it, I previously had a BMW M2 and this could be twitchy when things got wet/damp (all rearwheel drive cars a prone to this) but I’ve never lost a car like that, and I’ve been driving for 35 years. Is this something other GT3 drivers are aware of or is this something that makes you think somethings not correct with my car,
I would appreciate some feedback please, this is my first 911 but like I mentioned I have had rear wheel drive cars, I’m aware that in general with the 911 it’s slow into corners and fast out. Thanks in advance!
Am I missing something! The tyres are massive at the rear, the suspension set-up is supposed to be world class ( most GT3 owners must have watched Chris Harris going round a circuit at incredible speeds) there are various electronic safety features built into the car ( I was just in basic mode i.e, nothing sporty and no esp switched off)
It’s now made me worried about driving it, I previously had a BMW M2 and this could be twitchy when things got wet/damp (all rearwheel drive cars a prone to this) but I’ve never lost a car like that, and I’ve been driving for 35 years. Is this something other GT3 drivers are aware of or is this something that makes you think somethings not correct with my car,
I would appreciate some feedback please, this is my first 911 but like I mentioned I have had rear wheel drive cars, I’m aware that in general with the 911 it’s slow into corners and fast out. Thanks in advance!
, and terrifying when its a surprise 
Actually the Dunlop Sport Maxx which came OEM on my GT3RS are much better in the cold and wet than the Michelins which breakaway with little warning when cold
03-02-2020, 04:27 PM
#19
Burning Brakes
Step 1: Install Michelin Pilot Sport 4S (awesome dry and wet grip)
Step 2: Align the car. Do not assume that the alignment is good, because even brand new cars are out of spec.
Step 3: Have the sway bar settings checked. Your rear bar should be at full soft, and the front one in the middle for mostly street driving and easy track use.
Be aware that a full tread Cup2 tire might be heat cycled out, and its dry grip will be highly compromised. There are plenty of treads about tires with too many heat cycles.
There is an easy test: reset the g-force meter, drive to a test road where you can run a skidpad of about 200ft in diameter, just set 4 markers (cans, hocky pucks, traffic cones). Run the car counter-clockwise and clockwise, check the highest g-force readings left and right. Do this on cold tires and hot tires. Cold Cup2 on good conditions will give you close to 1.1g (at ground/air temperatures above 60 degrees). Hot Cup2 should exceed 1.3g. If your readings are nowhere near these values, those tires are shot. The counter-clockwise and clockwise values should be very similar, if they are a little far apart, there are alignment corrections to be made.
Also...do not use the Suspension Sport (PASM-Sport) button for any street driving, the stock calibration is too stiff and you're reducing grip levels just to feel a stiffer ride. The car sticks better in Comfort (except on certain racetracks, Sport performs better).
Nice first post, better than a Value Thread.
Step 2: Align the car. Do not assume that the alignment is good, because even brand new cars are out of spec.
Step 3: Have the sway bar settings checked. Your rear bar should be at full soft, and the front one in the middle for mostly street driving and easy track use.
Be aware that a full tread Cup2 tire might be heat cycled out, and its dry grip will be highly compromised. There are plenty of treads about tires with too many heat cycles.
There is an easy test: reset the g-force meter, drive to a test road where you can run a skidpad of about 200ft in diameter, just set 4 markers (cans, hocky pucks, traffic cones). Run the car counter-clockwise and clockwise, check the highest g-force readings left and right. Do this on cold tires and hot tires. Cold Cup2 on good conditions will give you close to 1.1g (at ground/air temperatures above 60 degrees). Hot Cup2 should exceed 1.3g. If your readings are nowhere near these values, those tires are shot. The counter-clockwise and clockwise values should be very similar, if they are a little far apart, there are alignment corrections to be made.
Also...do not use the Suspension Sport (PASM-Sport) button for any street driving, the stock calibration is too stiff and you're reducing grip levels just to feel a stiffer ride. The car sticks better in Comfort (except on certain racetracks, Sport performs better).
Nice first post, better than a Value Thread.
The following 5 users liked this post by A/S:
AlexCeres (03-04-2020),
bogey1 (03-04-2020),
I am the Walrus (03-05-2020),
NevB (03-02-2020),
TxnBluDvl (03-05-2020)
03-02-2020, 04:28 PM
#20
Rennlist Member
It's always the second skid that gets you.
You are new to the car and not tuned into what it is telling you.
As others have said, sign up for a local autocross, get an instructor, and you will quickly learn your car in ways you can never do by yourself on the street.
It's not only cold tires that are causing you some despair, it's also upsetting the balance of the car. Again, you will learn about that at autocross.
Good luck and enjoy your new car. You got a great one!
You are new to the car and not tuned into what it is telling you.
As others have said, sign up for a local autocross, get an instructor, and you will quickly learn your car in ways you can never do by yourself on the street.
It's not only cold tires that are causing you some despair, it's also upsetting the balance of the car. Again, you will learn about that at autocross.
Good luck and enjoy your new car. You got a great one!
The following users liked this post:
AlexCeres (03-04-2020)
03-02-2020, 04:55 PM
#22
Addict
Rennlist Member
Rennlist Member
Yes. Softening (outer hole) gives more relative grip at that axle and stiffening (inner hole) gives more relative grip to the other axle. You can also maintain the same balance but change how much the car rolls in the corners by stiffening both axles the same amount (or soften for more leaning).
Generally, the front bar is more effective for controlling balance on turn-in and rear bar more effective for corner exit.
I currently have my bars set for maximum oversteer (soft front, stiff rear). It's a lot of fun, but I'm considering returning to my previous setting of middle front and stiff rear (a bit more stable).
Generally, the front bar is more effective for controlling balance on turn-in and rear bar more effective for corner exit.
I currently have my bars set for maximum oversteer (soft front, stiff rear). It's a lot of fun, but I'm considering returning to my previous setting of middle front and stiff rear (a bit more stable).
03-02-2020, 05:17 PM
#23
Thanks everyone for replying, it is looking like temp in the tyres which has played the significant role, I had only done about 4-5 miles before this happened, it was also a chilly day . As I mentioned it was the speed that (literally) threw me 30-35 MPH, but like a lot of you that have had experience with these tyres are aware of their cold shortcomings.
I will look into the PS4S tyres, thanks! Fsts2k- Traction was switched on. I agree with people that have suggested pushing the car in large space/car park/parking lot, just to get a feel for both the tyres and the weight of the car. I will look into checking out the alignment and sway bar, thanks for the kind words. Like I said it's my first Porsche so I've got to learn and adapt.
I will look into the PS4S tyres, thanks! Fsts2k- Traction was switched on. I agree with people that have suggested pushing the car in large space/car park/parking lot, just to get a feel for both the tyres and the weight of the car. I will look into checking out the alignment and sway bar, thanks for the kind words. Like I said it's my first Porsche so I've got to learn and adapt.
The following 3 users liked this post by ST1040:
03-02-2020, 06:36 PM
#24
Traction control should have made it a non-event unless it was extremely cold (below 40F) or unless you’re tires are totally hard / heat cycled out. Are you sure you didn’t over react to a little computer controlled tail out situation? Otherwise, summer tires have no business on the street below 45-50F. Have fun with your new P Car!
03-02-2020, 07:16 PM
#25
Rennlist Member
similar situation happened to me in my .1 GT3
got delivered in the middle of winter and I was itching to drive it , so we had a bit of weather break and took it out and I think the temp outside was like 40 degrees and took a sharp turn at 30-35 miles per hr and the car drifted and almost hit a curb.
It was all tires
learned my lesson and never looked back
another situation to be careful and drive slow even in warm temps , if driving under heavy rain, the cup2 tires can hydro-plane easier than other tires
got delivered in the middle of winter and I was itching to drive it , so we had a bit of weather break and took it out and I think the temp outside was like 40 degrees and took a sharp turn at 30-35 miles per hr and the car drifted and almost hit a curb.
It was all tires
learned my lesson and never looked back
another situation to be careful and drive slow even in warm temps , if driving under heavy rain, the cup2 tires can hydro-plane easier than other tires
03-02-2020, 08:15 PM
#26
Burning Brakes
In the 991 series, the front bar has 3 holes on each side, and the rear one has 2 holes. Normally, you would use the same hole per axle, but there is such a sizeable gap between adjustments (especially with the front bar) that we can use one corner adjustment only.
I have had the GT3RS being loose (tendency to oversteer at the limit), then adjusted the front bar one hole towards stiffer on each side, and the car changes to pushy (tight or tendency to understeer). In these cases, only one hole in the front bar is needed to be adjusted and the car gets closed to balanced. Fine tune with tire pressures (or fine tune with multiple DSC Sport maps, playing with the voltage range applied to the axle shocks).
I miss the resolution available in the 996 GT3 sway bars: 5 holes in the front, 4 holes in the rear, those cars are so adjustable, and no e-diff, torque vectoring, RWS or other ABD stuff modifying the dynamics, just pure feedback, if they were not so ugly inside and out I would jump back.
I have had the GT3RS being loose (tendency to oversteer at the limit), then adjusted the front bar one hole towards stiffer on each side, and the car changes to pushy (tight or tendency to understeer). In these cases, only one hole in the front bar is needed to be adjusted and the car gets closed to balanced. Fine tune with tire pressures (or fine tune with multiple DSC Sport maps, playing with the voltage range applied to the axle shocks).
I miss the resolution available in the 996 GT3 sway bars: 5 holes in the front, 4 holes in the rear, those cars are so adjustable, and no e-diff, torque vectoring, RWS or other ABD stuff modifying the dynamics, just pure feedback, if they were not so ugly inside and out I would jump back.
03-02-2020, 09:45 PM
#27
Addict
Rennlist Member
Rennlist Member
03-02-2020, 10:09 PM
#28
Burning Brakes
Step 1: Install Michelin Pilot Sport 4S (awesome dry and wet grip)
Step 2: Align the car. Do not assume that the alignment is good, because even brand new cars are out of spec.
Step 3: Have the sway bar settings checked. Your rear bar should be at full soft, and the front one in the middle for mostly street driving and easy track use.
Be aware that a full tread Cup2 tire might be heat cycled out, and its dry grip will be highly compromised. There are plenty of treads about tires with too many heat cycles.
There is an easy test: reset the g-force meter, drive to a test road where you can run a skidpad of about 200ft in diameter, just set 4 markers (cans, hocky pucks, traffic cones). Run the car counter-clockwise and clockwise, check the highest g-force readings left and right. Do this on cold tires and hot tires. Cold Cup2 on good conditions will give you close to 1.1g (at ground/air temperatures above 60 degrees). Hot Cup2 should exceed 1.3g. If your readings are nowhere near these values, those tires are shot. The counter-clockwise and clockwise values should be very similar, if they are a little far apart, there are alignment corrections to be made.
Also...do not use the Suspension Sport (PASM-Sport) button for any street driving, the stock calibration is too stiff and you're reducing grip levels just to feel a stiffer ride. The car sticks better in Comfort (except on certain racetracks, Sport performs better).
Nice first post, better than a Value Thread.
Step 2: Align the car. Do not assume that the alignment is good, because even brand new cars are out of spec.
Step 3: Have the sway bar settings checked. Your rear bar should be at full soft, and the front one in the middle for mostly street driving and easy track use.
Be aware that a full tread Cup2 tire might be heat cycled out, and its dry grip will be highly compromised. There are plenty of treads about tires with too many heat cycles.
There is an easy test: reset the g-force meter, drive to a test road where you can run a skidpad of about 200ft in diameter, just set 4 markers (cans, hocky pucks, traffic cones). Run the car counter-clockwise and clockwise, check the highest g-force readings left and right. Do this on cold tires and hot tires. Cold Cup2 on good conditions will give you close to 1.1g (at ground/air temperatures above 60 degrees). Hot Cup2 should exceed 1.3g. If your readings are nowhere near these values, those tires are shot. The counter-clockwise and clockwise values should be very similar, if they are a little far apart, there are alignment corrections to be made.
Also...do not use the Suspension Sport (PASM-Sport) button for any street driving, the stock calibration is too stiff and you're reducing grip levels just to feel a stiffer ride. The car sticks better in Comfort (except on certain racetracks, Sport performs better).
Nice first post, better than a Value Thread.
The following users liked this post:
bogey1 (03-04-2020)
03-02-2020, 10:36 PM
#29
Rennlist Member
Lots of great stuff here, but just be sure it was not spilled diesel on that roundabout.....
Had 3 very bad instances of that in my time there.
Good luck with the new car!!
Had 3 very bad instances of that in my time there.
Good luck with the new car!!
