Understeer on a Quattro Help
Discussion
Ok never had a 4x4 car before.
PS4 standards all round newish.
Had understeer going a little fast into a damp greasy corner.
On a normal front wheel drive or rear wheel drive car I can deal with this but on a Quattro, what's the best course of action.
Keep going, let the electronics sort it out or come off the accelerator.
S Tronic box
I know, slow down, but this was a mistake.
Thanks
PS4 standards all round newish.
Had understeer going a little fast into a damp greasy corner.
On a normal front wheel drive or rear wheel drive car I can deal with this but on a Quattro, what's the best course of action.
Keep going, let the electronics sort it out or come off the accelerator.
S Tronic box
I know, slow down, but this was a mistake.
Thanks
I had 2x MK1 TT's, they have excellent grip until they don't like a lot of 4x4 cars, i think it's important to remember they are nearly purely FWD until they slip and aren't actually 4x4.
The worst i had it was a very tight corner that took me by surprise in a forest, it was almost 90 degrees right and i was going 40mph, i turned too hard, back end slipped out but my natural reaction (to turn left and control it like it was RWD) was countered by the traction control systems and i ended up tank slapping left and right several times before i got it straight again.
I don't think anything theoretical would help you your best bet is to find a wide greasy roundabout when it's nice and quiet and deliberately cause it to get a feel for it.
They can do nice 4wd drifts if you're going fast enough, a friend did so once when he was caught out and it was pretty impressive to watch even if somewhat accidental.
The worst i had it was a very tight corner that took me by surprise in a forest, it was almost 90 degrees right and i was going 40mph, i turned too hard, back end slipped out but my natural reaction (to turn left and control it like it was RWD) was countered by the traction control systems and i ended up tank slapping left and right several times before i got it straight again.
I don't think anything theoretical would help you your best bet is to find a wide greasy roundabout when it's nice and quiet and deliberately cause it to get a feel for it.
They can do nice 4wd drifts if you're going fast enough, a friend did so once when he was caught out and it was pretty impressive to watch even if somewhat accidental.
Edited by joropug on Wednesday 25th November 09:04
Assuming it’s a haldex type, it’s a front wheel drive car until wheelspin engages the rears.
If you let off the gas, the front will tuck back in.
If you gas it hard, it will understeer a bit more then the rears will engage. This has one of two effects:
1. The rears spin too and you get an amazing 4 wheel drift and feel like a god.
2. The added thrust just pushes the front even further wide.
2 is more common in my experience. Admittedly with an old and fairly crude haldex 2.
If you let off the gas, the front will tuck back in.
If you gas it hard, it will understeer a bit more then the rears will engage. This has one of two effects:
1. The rears spin too and you get an amazing 4 wheel drift and feel like a god.
2. The added thrust just pushes the front even further wide.
2 is more common in my experience. Admittedly with an old and fairly crude haldex 2.
Thanks so far. It's a proper constant 4 wheel drive A7 3.0 TDI 300+
It was only the front that went., which suprised me.
I'll take the early morning roundabout advice. There are some huge one's on the way to work.
I'm thinking also the temperature has just dropped so my Michelins have stopped working!
I really wasn't sure how to react?
It was only the front that went., which suprised me.
I'll take the early morning roundabout advice. There are some huge one's on the way to work.
I'm thinking also the temperature has just dropped so my Michelins have stopped working!
I really wasn't sure how to react?
mickyh7 said:
I'm thinking also the temperature has just dropped so my Michelins have stopped working!
This is about the only reason I consider Winter Tyres living in the south:- Below 10c Summer UHP starts going iffy; Michelins seem to do a bit better at lower temperatures but even PS4s are far past their best below ~4c. (Ask me how I know! 
)To start with, you’ve already identified the source of your problem here:
4WD improves traction, so almost all the advantage is gained under acceleration.
As with many driving issues, the important thing to remember then, isn’t what the system gives you - it’s what it doesn’t give you that you need to remember, and 4WD doesn’t give you any additional tyre grip under braking, deceleration or when you’re cornering. So if you carry too much speed into a corner & lose speed in the process, the 4WD element of the car is not going to help.
Add to that the typically understeery nature of big Audis (they’re much better these days than they used to be, but still have a tendency to understeer at the limit), and you start to see the problem.
Carrying too much speed into a corner in any car can become messy. Going in quick & then sorting it out introduces too many different weight transfer movements & can quickly unsettle the tyres at speeds where, using a better technique, they will still be gripping well. Remember that with weight transfer, it isn’t where you’re increasing the weight that really matters - it’s where you’re decreasing the weight, because that is where your tyre grip is going to decrease.
In simple terms, it is much easier to put speed on through a corner than it is to take it off. Especially in a 4WD car.
So, best technique (on the road - track driving is different in this respect), is to take a little more speed off on approach, and then start accelerating right at the very moment you start to turn the steering wheel. Just a little acceleration at first, just to maintain your entry speed & start the rearward weight transfer, and then increase the acceleration through & out of the corner. This is where 4WD cars are at their absolute best & the first time you get a corner “right” they will absolutely reveal themselves to you.
Going back to your original question - what to do if things have already gone wrong?
Modern stability control systems are designed to sort out understeer & as long as you leave the systems on (you really should leave them on all the time!), they will step in to help you. Just make sure you keep steering in the direction you want to go, hold a neautral throttle (don’t lift off fully) and the systems will do their utmost to point the car in the direction you want to go.
I made a video about cornering balance a couple of years ago. This principle is relevent in any-wheel drive cars, so ignore the fact I’m in an RWD car in the video:
I’ll also be making a video very soon about skid control & stability/traction control.
mickyh7 said:
Had understeer going a little fast into a damp greasy corner.
But to add a little detail, it’s important to remember what advantage 4 wheel drive (either full-time or part-time) gives you, and more importantly, what it does not give you.4WD improves traction, so almost all the advantage is gained under acceleration.
As with many driving issues, the important thing to remember then, isn’t what the system gives you - it’s what it doesn’t give you that you need to remember, and 4WD doesn’t give you any additional tyre grip under braking, deceleration or when you’re cornering. So if you carry too much speed into a corner & lose speed in the process, the 4WD element of the car is not going to help.
Add to that the typically understeery nature of big Audis (they’re much better these days than they used to be, but still have a tendency to understeer at the limit), and you start to see the problem.
Carrying too much speed into a corner in any car can become messy. Going in quick & then sorting it out introduces too many different weight transfer movements & can quickly unsettle the tyres at speeds where, using a better technique, they will still be gripping well. Remember that with weight transfer, it isn’t where you’re increasing the weight that really matters - it’s where you’re decreasing the weight, because that is where your tyre grip is going to decrease.
In simple terms, it is much easier to put speed on through a corner than it is to take it off. Especially in a 4WD car.
So, best technique (on the road - track driving is different in this respect), is to take a little more speed off on approach, and then start accelerating right at the very moment you start to turn the steering wheel. Just a little acceleration at first, just to maintain your entry speed & start the rearward weight transfer, and then increase the acceleration through & out of the corner. This is where 4WD cars are at their absolute best & the first time you get a corner “right” they will absolutely reveal themselves to you.
Going back to your original question - what to do if things have already gone wrong?
Modern stability control systems are designed to sort out understeer & as long as you leave the systems on (you really should leave them on all the time!), they will step in to help you. Just make sure you keep steering in the direction you want to go, hold a neautral throttle (don’t lift off fully) and the systems will do their utmost to point the car in the direction you want to go.
I made a video about cornering balance a couple of years ago. This principle is relevent in any-wheel drive cars, so ignore the fact I’m in an RWD car in the video:
I’ll also be making a video very soon about skid control & stability/traction control.
But Reg....
All the stability systems in the world are not going judge how much road is left before you understeer into the ditch... so we shouldn't rely on them.
If your understeering into a corner due to too much speed, you still need to get rid of the speed... so your back to the same old Understeer situation.
Cars understeer because it's engineered into them as the natural reaction of understeer is to back off the gas. Which is how to remove understeer. The stability systems will help you do this through the corner if the car becomes un-balanced but you still need to remove the speed.
If you gently remove the forward 'push' then the front wheels will slow and the grip will come back naturally.
It's the same as it's always been. Too much speed and skid equals brown trousers
My Evo would understeer at silly speeds until you flicked into overtseer or drifted even with AYC.
All the stability systems in the world are not going judge how much road is left before you understeer into the ditch... so we shouldn't rely on them.
If your understeering into a corner due to too much speed, you still need to get rid of the speed... so your back to the same old Understeer situation.
Cars understeer because it's engineered into them as the natural reaction of understeer is to back off the gas. Which is how to remove understeer. The stability systems will help you do this through the corner if the car becomes un-balanced but you still need to remove the speed.
If you gently remove the forward 'push' then the front wheels will slow and the grip will come back naturally.
It's the same as it's always been. Too much speed and skid equals brown trousers
My Evo would understeer at silly speeds until you flicked into overtseer or drifted even with AYC.
super7 said:
But Reg....
All the stability systems in the world are not going judge how much road is left before you understeer into the ditch... so we shouldn't rely on them.
If your understeering into a corner due to too much speed, you still need to get rid of the speed... so your back to the same old Understeer situation.
Cars understeer because it's engineered into them as the natural reaction of understeer is to back off the gas. Which is how to remove understeer. The stability systems will help you do this through the corner if the car becomes un-balanced but you still need to remove the speed.
If you gently remove the forward 'push' then the front wheels will slow and the grip will come back naturally.
It's the same as it's always been. Too much speed and skid equals brown trousers
My Evo would understeer at silly speeds until you flicked into overtseer or drifted even with AYC.
I am not sure your evo is typical. I suspect it has a much more neutral and less intrusive stability control system than your average audi All the stability systems in the world are not going judge how much road is left before you understeer into the ditch... so we shouldn't rely on them.
If your understeering into a corner due to too much speed, you still need to get rid of the speed... so your back to the same old Understeer situation.
Cars understeer because it's engineered into them as the natural reaction of understeer is to back off the gas. Which is how to remove understeer. The stability systems will help you do this through the corner if the car becomes un-balanced but you still need to remove the speed.
If you gently remove the forward 'push' then the front wheels will slow and the grip will come back naturally.
It's the same as it's always been. Too much speed and skid equals brown trousers
My Evo would understeer at silly speeds until you flicked into overtseer or drifted even with AYC.
I agree, lifting off is the natural reaction and so cars are designed to cope with this but I think what Reg is saying is that you don't need to, as the car will do this for you. Plus, as I am sure you are aware, lifting too much can be as bad as not lifting enough. So again, unless you are a driving god then maybe it is best left to the car?
I am old school, I learnt where the limits were when traction control and ABS were not a thing so I would instinctively lift slightly and try and control the balance myself. However I found to my cost that this can cause problems with modern systems. My first car with decent stabilty control was my 320d. First time I pushed it out of a corner I expecting mild oversteer so instinctively lifted slightly and unwound the steering just as the DSC took over and straighten the car out. The result being me fishtailing up the road, fighting the DSC! I learnt then that it was much better to keep things neutral and let the car sort it out. Either than or turn off the DSC! Not on the road of course.....
Some good information on here, thanks.
My problem started when 'I found myself in the middle of it all's
I'd already made the error.
It is a stiff car, and I did let off and it did fix itself.
However last night I went back to the roundabout and behaved very badly.
I learned this.
When the understeer happens, floor the Gas.
It immediately found grip, and control came straight back. I managed to steer it around with out any fuss, just a bit too fast for normal traffic !
After half a dozen goes I think I'm in charge of it now.
My problem started when 'I found myself in the middle of it all's
I'd already made the error.
It is a stiff car, and I did let off and it did fix itself.
However last night I went back to the roundabout and behaved very badly.
I learned this.
When the understeer happens, floor the Gas.
It immediately found grip, and control came straight back. I managed to steer it around with out any fuss, just a bit too fast for normal traffic !
After half a dozen goes I think I'm in charge of it now.
mickyh7 said:
Thanks so far. It's a proper constant 4 wheel drive A7 3.0 TDI 300+
It was only the front that went., which suprised me.
I'll take the early morning roundabout advice. There are some huge one's on the way to work.
I'm thinking also the temperature has just dropped so my Michelins have stopped working!
I really wasn't sure how to react?
its an audi, its setup for monumental understeerIt was only the front that went., which suprised me.
I'll take the early morning roundabout advice. There are some huge one's on the way to work.
I'm thinking also the temperature has just dropped so my Michelins have stopped working!
I really wasn't sure how to react?
slow in fast out, the good thing with quattro is you can nuke it on the apex and it fires the car out of the corner in a straight line (you hope lol)
mickyh7 said:
Some good information on here, thanks.
My problem started when 'I found myself in the middle of it all's
I'd already made the error.
It is a stiff car, and I did let off and it did fix itself.
However last night I went back to the roundabout and behaved very badly.
I learned this.
When the understeer happens, floor the Gas.
It immediately found grip, and control came straight back. I managed to steer it around with out any fuss, just a bit too fast for normal traffic !
After half a dozen goes I think I'm in charge of it now.
Flooring the gas is not a standard reaction though and in a real emergency will you remember, because it's not natural My problem started when 'I found myself in the middle of it all's
I'd already made the error.
It is a stiff car, and I did let off and it did fix itself.
However last night I went back to the roundabout and behaved very badly.
I learned this.
When the understeer happens, floor the Gas.
It immediately found grip, and control came straight back. I managed to steer it around with out any fuss, just a bit too fast for normal traffic !
After half a dozen goes I think I'm in charge of it now.
I guess with an active 4x4 system, flooring it spins the front wheels up and the car reacts by cutting the power to front and transferring it to the back. Hence doing the same as coming of the gas, but in your case, you'll end up going faster!!
[quote=super7]
Flooring the gas is not a standard reaction though and in a real emergency will you remember, because it's not natural
I guess with an active 4x4 system, flooring it spins the front wheels up and the car reacts by cutting the power to front and transferring it to the back. Hence doing the same as coming of the gas, but in your case, you'll end up going faster!!
[/quoter]
A very good in fact massive point.
When the s
t Hits the Fan, its remembering to do what's NOT natural!
Ha Ha Fingers crossed.
I guess Winter will be a good Teacher!
Flooring the gas is not a standard reaction though and in a real emergency will you remember, because it's not natural
I guess with an active 4x4 system, flooring it spins the front wheels up and the car reacts by cutting the power to front and transferring it to the back. Hence doing the same as coming of the gas, but in your case, you'll end up going faster!!
[/quoter]
A very good in fact massive point.
When the s
t Hits the Fan, its remembering to do what's NOT natural!Ha Ha Fingers crossed.
I guess Winter will be a good Teacher!
mickyh7 said:
super7 said:
Flooring the gas is not a standard reaction though and in a real emergency will you remember, because it's not natural
I guess with an active 4x4 system, flooring it spins the front wheels up and the car reacts by cutting the power to front and transferring it to the back. Hence doing the same as coming of the gas, but in your case, you'll end up going faster!!
A very good in fact massive point.I guess with an active 4x4 system, flooring it spins the front wheels up and the car reacts by cutting the power to front and transferring it to the back. Hence doing the same as coming of the gas, but in your case, you'll end up going faster!!
When the s
t Hits the Fan, its remembering to do what's NOT natural!Ha Ha Fingers crossed.
I guess Winter will be a good Teacher!
One of the reasons a lot of 4x4s and Awd cars come to grief in snow and ice is because they do have a lot more traction when accelerating but can’t achieve miracles on corners where the car’s tendency is to go straight on. Made worse when the driver has been lulled into a false sense of security and is going a bit too fast.
Slow in, fast out is definitely the way forward (or sideways).
Slow in, fast out is definitely the way forward (or sideways).
During spring 2018 (beast from the east) I met a q7 in a lane.
The q7 wasn't able to slow down..the look of horror on her face when she realised 2.2 tons plus summer tyres (adding 4wd doesn't change anything)=difficult to slow down on snow.
Thankfully I was in a fwd car with winter tyres and was able to stop, select reverse and back up to a place wide enough for her to pass as the q7 kept on it's titanic course.
No, I am not exaggerating.
The q7 wasn't able to slow down..the look of horror on her face when she realised 2.2 tons plus summer tyres (adding 4wd doesn't change anything)=difficult to slow down on snow.
Thankfully I was in a fwd car with winter tyres and was able to stop, select reverse and back up to a place wide enough for her to pass as the q7 kept on it's titanic course.
No, I am not exaggerating.
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