997.1 RS slow speed, straight damp road, lost control, why?
Discussion
Lost control in the RS on a straight damp road at 70 mph. very disappointing.
Was driving very normally in middle lane following traffic, was checking the mirrors as car approaching fast in fast lane, felt the car twitch, when I looked up it was pointing right 25 degrees or so, overcorrection spinout results in me crossing all 3 lanes of the motorway, some light damage. but very dangerous!
It felt almost like the car just suddenly lost control, I did nothing to warrant this reaction, was not driving fast, did not see any standing water, did not touch the white line, was not accelerating. It just lost control.
So was chatting to a friend who said that he has heard about this, that the diff is aggressive, more so than the road car and less so than the track car, and when this aggressiveness kicks in, for example if I went over something slick on the road with the right hand rear tyre, that the resulting aggressive torque application on the left rear tyre gives the car a turning moment to the right, contributing to the spinout.
Has anyone come across this? if so I would like to discuss, I now feel that I should not be going over 60mph on a damp and certainly not wet road in this car! fair enough, but I need to get to grips with why this car lost control so it doesn't happen again.
p
Was driving very normally in middle lane following traffic, was checking the mirrors as car approaching fast in fast lane, felt the car twitch, when I looked up it was pointing right 25 degrees or so, overcorrection spinout results in me crossing all 3 lanes of the motorway, some light damage. but very dangerous!
It felt almost like the car just suddenly lost control, I did nothing to warrant this reaction, was not driving fast, did not see any standing water, did not touch the white line, was not accelerating. It just lost control.
So was chatting to a friend who said that he has heard about this, that the diff is aggressive, more so than the road car and less so than the track car, and when this aggressiveness kicks in, for example if I went over something slick on the road with the right hand rear tyre, that the resulting aggressive torque application on the left rear tyre gives the car a turning moment to the right, contributing to the spinout.
Has anyone come across this? if so I would like to discuss, I now feel that I should not be going over 60mph on a damp and certainly not wet road in this car! fair enough, but I need to get to grips with why this car lost control so it doesn't happen again.
p
Thanks for the prompt responses!
The accident happened in January between some of those showers we had, so granted tyres were cold, road was damp to wet, it wasn't raining.
The tyres are Michelin Pilot Sport PS2 N2's all round, tread was good although a bit low in the back, 3mm before illegal. I still have them as replaced the tyres afterwards.
The car had been to a MOT, and large service with Porsche about 1000 miles before. The geometry was setup by Porsche Reading 1 year before that, no bumps or mishaps since then, so assuming it was ok.
Really wanted to investigate the 'Differential Aggressiveness' thought though as my bud, who has also had a GT3 RS, has specifically heard that this has caused crashes almost exactly like this, at slower speeds, sometimes as slow as 60mph, as described in the past.
You have not heard of this?
The accident happened in January between some of those showers we had, so granted tyres were cold, road was damp to wet, it wasn't raining.
The tyres are Michelin Pilot Sport PS2 N2's all round, tread was good although a bit low in the back, 3mm before illegal. I still have them as replaced the tyres afterwards.
The car had been to a MOT, and large service with Porsche about 1000 miles before. The geometry was setup by Porsche Reading 1 year before that, no bumps or mishaps since then, so assuming it was ok.
Really wanted to investigate the 'Differential Aggressiveness' thought though as my bud, who has also had a GT3 RS, has specifically heard that this has caused crashes almost exactly like this, at slower speeds, sometimes as slow as 60mph, as described in the past.
You have not heard of this?
OK, fair enough, I'll keep asking about and investigating the diff angle, but for the time being may have to conclude that one of 2 things happened ..
1- when checking the mirrors, I *must* have hit some standing water (surely, what else?) on the drivers side, (that must have been the twitch I felt,) the car, being lighter than the rest and only doing 70 (so little down-force), must have aquaplaned and pointed slightly right .. the rest is overcorrection/drivers error.
2- when the drivers side tyre lost traction for a second (due to standing water, roadkill, diesel), and I may have been accelerating lightly, the resulting speed differential in the wheels caused the diff to lock, and the resulting jolt forward on the left tyre with traction, further propelled me to the right .. the rest is overcorrection/drivers error.
Whatever happened, better driving skills may have saved me. I never said I was good at handling this car, it seems like a bit of a handful compared to the BMW! When she goes, you've got to be quick and enter the exact right input to save yourself. The BMW would have never aquaplaned there and I do that stretch at 85mph always! I was purposely driving the Porsche 'slow' at 70 to be safe. Not slow enough! .. Oh, and I'll get the geometry checked again ASAP.
So, how fast do you other Porsche guys drive on a (lets say) wet motorway?
Is there anywhere I can go (apart from Silverstone) to learn how to drift this thing safely to improve my handling skills? I'm looking for carparks, flat tarmac'd areas, drift days at venues, lonely wide roads, etc.
1- when checking the mirrors, I *must* have hit some standing water (surely, what else?) on the drivers side, (that must have been the twitch I felt,) the car, being lighter than the rest and only doing 70 (so little down-force), must have aquaplaned and pointed slightly right .. the rest is overcorrection/drivers error.
2- when the drivers side tyre lost traction for a second (due to standing water, roadkill, diesel), and I may have been accelerating lightly, the resulting speed differential in the wheels caused the diff to lock, and the resulting jolt forward on the left tyre with traction, further propelled me to the right .. the rest is overcorrection/drivers error.
Whatever happened, better driving skills may have saved me. I never said I was good at handling this car, it seems like a bit of a handful compared to the BMW! When she goes, you've got to be quick and enter the exact right input to save yourself. The BMW would have never aquaplaned there and I do that stretch at 85mph always! I was purposely driving the Porsche 'slow' at 70 to be safe. Not slow enough! .. Oh, and I'll get the geometry checked again ASAP.
So, how fast do you other Porsche guys drive on a (lets say) wet motorway?
Is there anywhere I can go (apart from Silverstone) to learn how to drift this thing safely to improve my handling skills? I'm looking for carparks, flat tarmac'd areas, drift days at venues, lonely wide roads, etc.
Edited by Posh868 on Wednesday 16th April 10:56
Edited by Posh868 on Wednesday 16th April 11:20
mikem7709 said:
I've just replaced the PS2s on mine with a fresh set as they were 5yrs old. The rears were on 4mm and the fronts still on 6mm, I've put the fronts onto my daily driver and can't believe how little grip they have - they squeal in the dry and light up the ESP in the wet.
Haven't driven the GT3 on its fresh rubber yet but I'm expecting a marked improvement.
This is a good point! The tyres were over 3 years old ..Haven't driven the GT3 on its fresh rubber yet but I'm expecting a marked improvement.
Rockster said:
Even with new tires on my Porsches I slow down on damp roads. The tires do not play well with water on the road. And if it is cool, cold, you are just asking for trouble.
3mm tread depth is not worn out by the legal definition but I know from experience tires worn down to this point are slippery on damp roads like would not believe.
Alignment, aka geo, is probably not a contributing factor though bad geo can result in uneven tire wear. Then what you have is are tires that are half good, half no good, if the wear is uneven across the rear tread faces, which is a good sign the geo is bad.
When you replace the tires have the car treated to a proper geo to be sure you and the new tires start out right
The 3mm comment is also a good point, reducing traction even further .. 3mm tread depth is not worn out by the legal definition but I know from experience tires worn down to this point are slippery on damp roads like would not believe.
Alignment, aka geo, is probably not a contributing factor though bad geo can result in uneven tire wear. Then what you have is are tires that are half good, half no good, if the wear is uneven across the rear tread faces, which is a good sign the geo is bad.
When you replace the tires have the car treated to a proper geo to be sure you and the new tires start out right
The tyres that it spun with are evenly worn, probably implying no geometry issue ..
Steve Rance said:
It probably won't be the diff. That only locks under hard braking or acceleration. If you weren't pushing and you were on sports it's unlikely it's your geo unless the car is pretty much undrivable everywhere. More likely to be a pack of oil or Diesil on the road ie something external.
I'd get your geo checked as a matter or course though.
yes id agree, diesel is a distinct possibility, thought that at the time..I'd get your geo checked as a matter or course though.
I welcome all opinions; Mr Demon, post the links for the other straight line legal spins, I cant seem to find them and want to have a read of that. And when you're in an RS with your foot planted, you'll realise why the car is so addictive.. nothing compares! But yes, she's sometimes a scary monster.
gfreeman said:
Once upon a time I stupidly drove to Spa on very worn cups when the heavens opened just south of Folkstone - and continued for most of the rest of the trip.
Fingertip control, a tight sphincter and large cahunas were swung into action.
By the time I got to Stavelot my underpants had been sucked into the old starfish and I couldn't see over the steering wheel thingy...
My, how we larfed....
;o)Fingertip control, a tight sphincter and large cahunas were swung into action.
By the time I got to Stavelot my underpants had been sucked into the old starfish and I couldn't see over the steering wheel thingy...
My, how we larfed....
Holy crap, you guys do talk a load of junk. I got to laugh. lol
Yea, you might be right, the old girl is a bit hard to handle, but back in the day the turbo was not an easy machine either!, the '73 Carrera RS used to spin out as well, they all do .. its that whole 'engine out over the back' thing .. you either love a 911 or you don't.
Let me tell you again, put yourself in one of these, with your foot planted, and you'll understand why there's nothing like it.. crazy fast, and it howls!, 100mph in 2nd gear.
In the dry this beast sticks like glue, but in the wet I'm going to be going really slow .. haha
Please someone find the thread with the other Porsches spinning out and post the links. I got to read that.
Edited by Posh868 on Friday 18th April 02:01
OK, I found some straight line and other interesting threads on Rennlist ..
I suppose it would be ok to post some links?
991 Written off at 50 mph while responsibly driving
http://forums.rennlist.com/rennforums/991-gt3/8010...
Pilot Sport tyres 'very cold weather sensitive' compared to others
http://forums.rennlist.com/rennforums/porsche-supe...
997 Loss of control blamed on the PSM
http://forums.rennlist.com/rennforums/997-turbo-fo...
3 More GT3's aquaplane at around 50mph in these posts
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
This car (first in thread) aquaplaned at 70 .. http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Aquaplane at 40 mph
http://forums.rennlist.com/rennforums/997-gt2-gt3-...
Lots of track accidents, but all reinforce that in the wet these cars are very hard to handle and will spin on you unpredictably, many experienced drivers left scratching their head ..
http://forums.rennlist.com/rennforums/997-gt2-gt3-...
Seems like fairly slow speed aquaplaning is a huge issue! no matter what tyres you have ..
Its very easy to say 'I don't believe he was going that slow', or 'oh that guy was going too fast' or 'should be going slower in the wet', or 'that man cant drive'. But how slow is slow enough? 60mph on the motorway in the wet without rain? 50? 40?
I feel that I have done enough research now to determine that:
1. most if not all of these stories are in fact true, it has happened to me, and like me these guys have nothing to loose by sharing factual accounts of what happened
2. the GT3 should be driven exceptionally slowly and carefully in the wet, there are just too many accounts of loss of control in wet conditions at legal speeds
3. standing water is extremely hazardous to these cars due to the light front-end
4. unpredictable spins can occur in the wet with no warning which require a large amount of skill (much more so than for any other car) to overcome
In closing, one comment that stuck is when asked "what tyres do you put on your GT3 in the wet?" one experienced driver said "slicks! because she goes right up onto the trailer" - haha - no wet driving at all for him!
So when you pass a 997.1 GT3 RS going 50mph in the slow lane in the wet, that'll be me! .. and I'll be laughing at how ridiculous it is as well!
I suppose it would be ok to post some links?
991 Written off at 50 mph while responsibly driving
http://forums.rennlist.com/rennforums/991-gt3/8010...
Pilot Sport tyres 'very cold weather sensitive' compared to others
http://forums.rennlist.com/rennforums/porsche-supe...
997 Loss of control blamed on the PSM
http://forums.rennlist.com/rennforums/997-turbo-fo...
3 More GT3's aquaplane at around 50mph in these posts
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
This car (first in thread) aquaplaned at 70 .. http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Aquaplane at 40 mph
http://forums.rennlist.com/rennforums/997-gt2-gt3-...
Lots of track accidents, but all reinforce that in the wet these cars are very hard to handle and will spin on you unpredictably, many experienced drivers left scratching their head ..
http://forums.rennlist.com/rennforums/997-gt2-gt3-...
Seems like fairly slow speed aquaplaning is a huge issue! no matter what tyres you have ..
Its very easy to say 'I don't believe he was going that slow', or 'oh that guy was going too fast' or 'should be going slower in the wet', or 'that man cant drive'. But how slow is slow enough? 60mph on the motorway in the wet without rain? 50? 40?
I feel that I have done enough research now to determine that:
1. most if not all of these stories are in fact true, it has happened to me, and like me these guys have nothing to loose by sharing factual accounts of what happened
2. the GT3 should be driven exceptionally slowly and carefully in the wet, there are just too many accounts of loss of control in wet conditions at legal speeds
3. standing water is extremely hazardous to these cars due to the light front-end
4. unpredictable spins can occur in the wet with no warning which require a large amount of skill (much more so than for any other car) to overcome
In closing, one comment that stuck is when asked "what tyres do you put on your GT3 in the wet?" one experienced driver said "slicks! because she goes right up onto the trailer" - haha - no wet driving at all for him!
So when you pass a 997.1 GT3 RS going 50mph in the slow lane in the wet, that'll be me! .. and I'll be laughing at how ridiculous it is as well!
Edited by Posh868 on Tuesday 22 April 21:06
Yes, based on the feedback and research, I've all but ruled out the diff as the issue.
I do believe that in summary all those links conclude that the car (911 in general, possibly GT3 especially) can be unpredictable, and if this thread serves for others to be overly careful with theirs, then great. I for one am totally surprised by the findings and totally didn't expect this behaviour from the car.
And yes again, if you were a terrifically experienced driver, with much drifting and car control under your belt, and lightening fast reflexes; you may stand a chance when she decides to go.
But .. if you're like me with only 8 trackdays, no racing experience, and a moderate knowledge of car control, you've a high risk of crashing. So be careful.
I do believe that in summary all those links conclude that the car (911 in general, possibly GT3 especially) can be unpredictable, and if this thread serves for others to be overly careful with theirs, then great. I for one am totally surprised by the findings and totally didn't expect this behaviour from the car.
And yes again, if you were a terrifically experienced driver, with much drifting and car control under your belt, and lightening fast reflexes; you may stand a chance when she decides to go.
But .. if you're like me with only 8 trackdays, no racing experience, and a moderate knowledge of car control, you've a high risk of crashing. So be careful.
Gassing Station | 911/Carrera GT | Top of Page | What's New | My Stuff