Understeer Heavy/ Numb Front End?

[FINA]

Hello Everyone,
I just bought the car I have been dreaming of owning for years. I bought a 2015 Audi S4 Prestige. I have had it for about 2 months and I am kind of disappointed with the way it handles. It is extremely heavy in the front end and the understeer is quite noticeable. I did not realize how heavy the car would actually be? I had a B7 A4 previously and it seems that car was much more nimble than this B 8.5 S4. I don't feel like this car handles well around corners. Yes it has strait line power and torque that put's a smile on my face. But, I was looking for a car that would hug the road better at higher speeds. Are there any modifications that can help reduce the understeer? I just added APR stage 1 and I am happy with the overall power. But the car seems kind of numb when it comes to handling? The steering at high speeds, and low speeds feels like there is a notch in the steering wheel? Please provide me with insight and input to improve my experience with my dream car!
THANK YOU IN ADVANCE FOR ANY INPUT!

[o1turbo30v]

Yeah welcome to the world of electric power steering......a rear sway bar upgrade will greatly help the understeer but there’s no cure for lack of steering feel/notchieness.

[SteveYem]

Yeah welcome to the world of electric power steering......a rear sway bar upgrade will greatly help the understeer but there’s no cure for lack of steering feel/notchieness.

If the car is still under factory warranty, a trip to the Audi dealer to report the steering notch sensation could be beneficial. It is a known issue and many have had their steering racks replaced because of it.

[eurotic]

I specifically stayed away from the B8.5 because of the steering feel. My brother has one and I just couldn't come to grips (pardon the pun) with the front end feel. I have a B8 and although it understeers the same, it feels better if that even makes sense.

My dad had an A5 and moved up to an S5 and he too thought that the A5 was more nimble. And I suspect he might be right since there would be less weight over the front wheels as his was the 2.0T.

I know none of that helps you but here are some things you might want to consider doing:
As o1turbo30v suggested you could add a RSB could help some of the understeer. I added both front and rear bars with front soft and rear stiff. It helps.
Install a CR-15. I haven't done this yet but most around here will tell you it's awesome, plus it is one of the cheapest mods you can do.
Install an X-Brace or AK. I have an X-Brace waiting to go in myself but again, people on here generally swear by them. They are pretty pricey though.
And of course tires. Some tires are just terrible at providing feedback. If you are on winters or a crappy (read non-UHP) all season tire that could be a huge contributing factor. I run 225's in winter (Blizzak WS-80) to dig into the snow and steering feel is pretty poor compared to my 265 RE-71-R's.

Food for thought.


Shawn

[tar]

What ^ said

[sliceolator]

Did not see you mention if car is equipped with factory sports diff? Without it, that alone would make it under steer like a pig.

[NAR Mike]

sports diff is everything.

[blackfunk]

I specifically stayed away from the B8.5 because of the steering feel. My brother has one and I just couldn't come to grips (pardon the pun) with the front end feel. I have a B8 and although it understeers the same, it feels better if that even makes sense.

My dad had an A5 and moved up to an S5 and he too thought that the A5 was more nimble. And I suspect he might be right since there would be less weight over the front wheels as his was the 2.0T.

I know none of that helps you but here are some things you might want to consider doing:
As o1turbo30v suggested you could add a RSB could help some of the understeer. I added both front and rear bars with front soft and rear stiff. It helps.
Install a CR-15. I haven't done this yet but most around here will tell you it's awesome, plus it is one of the cheapest mods you can do.
Install an X-Brace or AK. I have an X-Brace waiting to go in myself but again, people on here generally swear by them. They are pretty pricey though.
And of course tires. Some tires are just terrible at providing feedback. If you are on winters or a crappy (read non-UHP) all season tire that could be a huge contributing factor. I run 225's in winter (Blizzak WS-80) to dig into the snow and steering feel is pretty poor compared to my 265 RE-71-R's.

Food for thought.


Shawn

Ding, ding, ding. For the win.

Let just be honest here. This car understeers - period. I have all the suspension bars - front and rear. Endlinks. AK. SD etc. Michelin PSS, light weight wheels etc etc etc. Even a BBK thats lighter than stock. I only use the steering in comfort mode too but its still a lifeless understeering pig. I'm convinced that there's nothing that can be done to alleviate that.

[dillysd]

Strange, I feel the understeer as very minimal, I have CR15, coilovers with adjustable upper control arms and a rear sway. I think that if you have the adaptive steering, this would be where the issue lies. I don’t and coming through a corner is a rear end job every time. Once I stiffened it up, the electronic feel is minimal as well.


2015 S4 DSG - CTS Intake, APR Stage 1 ECU, APR TCU, APR CPS, AWE Touring, AWE Res Pipes, 034 Trans/Diff/Subframe Mounts, RS Grille, RS Fog Grilles, ECS Boost Gauge, TSW Nurburgring 19x9.5

[CollecTTor]

Ding, ding, ding. For the win.

Let just be honest here. This car understeers - period. I have all the suspension bars - front and rear. Endlinks. AK. SD etc. Michelin PSS, light weight wheels etc etc etc. Even a BBK thats lighter than stock. I only use the steering in comfort mode too but its still a lifeless understeering pig. I'm convinced that there's nothing that can be done to alleviate that.

Endlinks, braces, wheel weight, and tires (assuming same size and model front and rear) aren't going to change understeer. Understeer is defined by the understeer gradient. Understeer gradient is a relationship between half of front axle weight divided by front wheel rate and half of rear axle weight divided by rear wheel rate. If the front is greater than the rear, it's going to understeer. If the rear is a greater value, it's going to oversteer. Without addressing spring rates relative to weight distribution, then no, the understeer isn't going to change. The casual enthusiast thinks that installing some lowering springs, better tires, and roll bars is going to magically transform their car into a neutral cornering beast. In reality, none of those modifications change wheel rates relative to cornering except the swaybars. That said, if the spring rates aren't high enough, and the common mantra of biggest swaybar possible is installed, you could be HURTING your understeer gradient as you are removing independence of the axle in question by possibly lifting the inside tire while cornering, thereby removing half of the available grip at that axle.


Cliff's: you didn't change anything that would improve understeer. These cars are ~55% front nose heavy. They're also AWD. Adjust your driving style or learn to modify suspension for specific handling characteristics.

[jonwoods]

The only good solution is to buy a RWD BMW.... Then you need to deal with owning a modern BMW though. Similarity, I don’t fully trust the S4 at the limit nearly as much as I’d like to. It “wallows” for lack of a better word. All that power and the sport diff keeps it fun, but it always feels like the electronics are compensating for a less-than-ideal design.

[blackfunk]

Endlinks, braces, wheel weight, and tires (assuming same size and model front and rear) aren't going to change understeer. Understeer is defined by the understeer gradient. Understeer gradient is a relationship between half of front axle weight divided by front wheel rate and half of rear axle weight divided by rear wheel rate. If the front is greater than the rear, it's going to understeer. If the rear is a greater value, it's going to oversteer. Without addressing spring rates relative to weight distribution, then no, the understeer isn't going to change. The casual enthusiast thinks that installing some lowering springs, better tires, and roll bars is going to magically transform their car into a neutral cornering beast. In reality, none of those modifications change wheel rates relative to cornering except the swaybars. That said, if the spring rates aren't high enough, and the common mantra of biggest swaybar possible is installed, you could be HURTING your understeer gradient as you are removing independence of the axle in question by possibly lifting the inside tire while cornering, thereby removing half of the available grip at that axle.


Cliff's: you didn't change anything that would improve understeer. These cars are ~55% front nose heavy. They're also AWD. Adjust your driving style or learn to modify suspension for specific handling characteristics.

We are in 100% agreement. I mentioned all that because it was an intentional effort to remove mass from the front of the car. Sway bars are set to allow max 'oversteer' as per the manufacture. My basic point was to say that there's just about no amount of bolt on's that will turn this car into a tail out handler - I blame quattro. IMHO this platform is relatively benign, not a bad thing it just is what it is. I've had front wheel drive cars that were more fun. I've had rear wheel drive cars that were less fun.

[blackfunk]

The only good solution is to buy a RWD BMW.... Then you need to deal with owning a modern BMW though. Similarity, I don’t fully trust the S4 at the limit nearly as much as I’d like to. It “wallows” for lack of a better word. All that power and the sport diff keeps it fun, but it always feels like the electronics are compensating for a less-than-ideal design.

Exactly. Driving at the limit your senses tell you the back end should start stepping out but the reality is that it never ever does. FOR ME, its a bit disconcerting.

[SDV325]

Initially last summer I felt the same as you, loved the car but the handling is in desperate need of improvement, especially the initial turn in (due to the heavy nose)

In order I installed the following with a month or more in between each one
CR-15
Rear Sway /Moog
Front Sway /Moog
AK.

The rear sway definitely helped the turn-in factor around corners but did nothing for transitional turns (S bends, traffic circles etc) or hard initial turn ins, thats where the front sway really made a difference. You will read a lot of people recommending a rear sway only, i feel thats a big mistake. The bigger front bar helps keep the front more planted and doesn't allow the car to nose dive as violently.

Cliff's: you didn't change anything that would improve understeer. These cars are ~55% front nose heavy. They're also AWD. Adjust your driving style or learn to modify suspension for specific handling characteristics.

Agreed. More i read your post more holds true about most if not all the suspension mods available for this platform. Even with the few bits i've changed out i still feel the understeer hasn't changed that much if at all. The slower cornering/weight transfer (<30mph) where the nose of the car used to dive horribly has been reduced, not eliminated. I still have to brace myself the same around long sweepers the same at the same speeds basically, you cannot hide the weight of this car no matter how much you mod it.

[eurotic]

Endlinks, braces, wheel weight, and tires (assuming same size and model front and rear) aren't going to change understeer. Understeer is defined by the understeer gradient. Understeer gradient is a relationship between half of front axle weight divided by front wheel rate and half of rear axle weight divided by rear wheel rate. If the front is greater than the rear, it's going to understeer. If the rear is a greater value, it's going to oversteer. Without addressing spring rates relative to weight distribution, then no, the understeer isn't going to change. The casual enthusiast thinks that installing some lowering springs, better tires, and roll bars is going to magically transform their car into a neutral cornering beast. In reality, none of those modifications change wheel rates relative to cornering except the swaybars. That said, if the spring rates aren't high enough, and the common mantra of biggest swaybar possible is installed, you could be HURTING your understeer gradient as you are removing independence of the axle in question by possibly lifting the inside tire while cornering, thereby removing half of the available grip at that axle.


Cliff's: you didn't change anything that would improve understeer. These cars are ~55% front nose heavy. They're also AWD. Adjust your driving style or learn to modify suspension for specific handling characteristics.

I like this!

[CollecTTor]

We are in 100% agreement. I mentioned all that because it was an intentional effort to remove mass from the front of the car.

It's not just weight removal, it's weight distribution relative to axle rates. What you changed was tenths of a % with no change in wheel rates.

[SteveYem]

Funny, what resonated the most with me about the original post was the complaint about the notchy steering. I have been living with it on my 2015 S4 as well, and the dealer said they cannot do anything for me because of my aftermarket suspension (lowered on coilovers), which they claim could contribute to the problem, if not cause it altogether. Of course I don't buy it, but that's their position and the only way I can get them to look at it is if I go back to the stock suspension.

That being said, I would be way more concerned about getting that problem eliminated before diving into all of these understeer-reducing modifications. If you are still under the factory warranty and on stock suspension, take it to the dealer and get this taken care of first.

[SDBolts]

I agree with much of what's been posted here, but figured I'd add my personal experience.

I came to my S4 from a heavily modified Subaru Legacy GT Spec.B. My wife and I took the S4 on a road trip about a month after getting it - it was the first real opportunity to drive backroads and push the car. I felt much the same - the car understeers like a pig and you could really feel all the weight out front. Steering, especially turn in, felt pretty numb as well. Overall, I was bummed - the car goes well, is very comfortable, but was a big step down for me in the handling department.

My first change was a CR-15. While that didn't make the understeer go anywhere, it did make the steering numbness, especially on turn in, almost vanish. Definite step in the right direction.

The next change was KW Variant 1's along with a RSB and endlinks, followed very shortly by adjustable links for alignment purposes. Huge change in how the car felt. Sure, if I go into a corner too hot, I'm going to push still, but the feedback I get from the car is much more useful now. Ride is much firmer, although not overly harsh for me (ride quality is a really subjective measure though). Understeer is much reduced from it's original form.

The final bit for me so far was Michelin PS4S tires. The grip is phenomenal and the feedback is even better (Had Dunlop Sport Maxx prior) with these tires.

Assuming you have the sports differential, the joy of practicing a 'slow in, fast out' driving style with this setup is awesome. There's grip for days and you can really get on it pretty hard early apex on most corners and shoot out of the corner like a bolt of lightning. That said, quick transitions simply aren't the strong suit of the car in just about any setup, owing to a pretty portly curb weight and the balance.

[NAR Mike]

My previous car was 2010 BMW 335 xDrive and now I have a 2011 Audi S4 with sport diff and the Audi handles light years better than 335, stock for stock. I think its the differential, car just feels a lot more confident around the twisties

[Jay@JXB]

Stiffen rear bar
Stiffen rear springs
Stiffen rear dampening

Those are the main 3 that will help understeer. Beside that, you could get bigger/stickier front tires or worse/smaller rear tires.

Camber adjustments can help quite a lot. The S4 rolls over quite a bit. I run almost 4° up front and although she doesn’t oversteer too often, she sure has a nice contact patch in the corners.



If NONE of those work for you, give yourself a 1/8” total toe out in the back and HOLD THE FUCK ON.


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[steampunkjunker]

The H&R front anti-roll bar set on soft tightened up the front end steering significantly since the front doesn’t need to roll over and load up before firming up. Much better dynamics. Even if there is possibly more steady-state mid corner push (which I haven’t noticed at all btw) the F and R feel so balance without that tricycle stiff rear end with a floppy front end feeling. I’ll take the improved corner entry and overall stability any day. If you’re goal is rotation for Auto-X I’d understand just the rear but F and R IMO for street and road track.


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[audigsr]

I didn't notice too much of understeer (could be because I have sport differential), but the numbness was a little bothersome. Although, I do appreciate the electronic steering when just cruising around-makes driving smooth easy. Coming from a e90 335i though, I really miss the direct feel of the hydraulic steering. I recently installed the cr15 and Alu Kreuz drivetrain stabilizer to try to combat this a bit. I definitely noticed a difference in turn in feel with the cr15. It helped reduce that second delay I was feeling from initial steering inputs. The Alu Kreuz helped a lot with hard corning, I felt as it got rid of the sloppiness in hard corning over stock. Car just overall feels more planted and stable. All this is highly subjective though and opinions on these mods are varied. I did do sway bars in my past cars and noticed that they do help with understeer, but road harshness seemed to increase as a result.

[4DOORFUN]

Assuming you have the sports differential, the joy of practicing a 'slow in, fast out' driving style with this setup is awesome. There's grip for days and you can really get on it pretty hard early apex on most corners and shoot out of the corner like a bolt of lightning. That said, quick transitions simply aren't the strong suit of the car in just about any setup, owing to a pretty portly curb weight and the balance.

I could not agree more with this. This was the biggest adjustment for me after previously owning a balanced RWD car. You absolutely have to enter the turn slower in the S4, but with the sports diff., you can hammer the throttle after the the front wheels are finished with the initial turn in. The car pulls out of the turn like it's on raiis. Once in a while I can even get the rear end to kick out a bit which is really just when my tires are not fully warmed up.

[1ronin]

Previously had a 135i and it was a blast to drive with 50/50 weight distribution. Also missing my 2016 STI which was right before this S4 since the wife said I needed a more mature car (I'm 35).

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[brs2c]

Several others have mentioned it, but the CR-15 is the best bang for the buck. It is really a no-brainer, so why not go ahead and buy and install it, and then decide what you want next?

[cspcrx]

Stiffen rear bar
Stiffen rear springs
Stiffen rear dampening

Those are the main 3 that will help understeer. Beside that, you could get bigger/stickier front tires or worse/smaller rear tires.

Camber adjustments can help quite a lot. The S4 rolls over quite a bit. I run almost 4° up front and although she doesn’t oversteer too often, she sure has a nice contact patch in the corners.



If NONE of those work for you, give yourself a 1/8” total toe out in the back and HOLD THE FUCK ON.


Sent from my iPhone using Tapatalk

This is how you get ride of it! but you do so at the sacrifice of road comfort, that is always the trade off.
My front wheel driver CRX has very little issues with under steer, in fact I fight over steer more than under steer. The suspension has been setup to allow this condition.

[wooster]

Endlinks, braces, wheel weight, and tires (assuming same size and model front and rear) aren't going to change understeer. Understeer is defined by the understeer gradient. Understeer gradient is a relationship between half of front axle weight divided by front wheel rate and half of rear axle weight divided by rear wheel rate. If the front is greater than the rear, it's going to understeer. If the rear is a greater value, it's going to oversteer. Without addressing spring rates relative to weight distribution, then no, the understeer isn't going to change. The casual enthusiast thinks that installing some lowering springs, better tires, and roll bars is going to magically transform their car into a neutral cornering beast. In reality, none of those modifications change wheel rates relative to cornering except the swaybars. That said, if the spring rates aren't high enough, and the common mantra of biggest swaybar possible is installed, you could be HURTING your understeer gradient as you are removing independence of the axle in question by possibly lifting the inside tire while cornering, thereby removing half of the available grip at that axle.


Cliff's: you didn't change anything that would improve understeer. These cars are ~55% front nose heavy. They're also AWD. Adjust your driving style or learn to modify suspension for specific handling characteristics.

All correct. There is no way to reduce understeer ( I have a 2019 B9 S4 with H&R HAS springs just to firm things up) in car that has the engine so far forward. Compared to my E90 M3 my S4 is just a sloppy cruiser. But great torque.

[ThoseRings]

All correct. There is no way to reduce understeer ( I have a 2019 B9 S4 with H&R HAS springs just to firm things up) in car that has the engine so far forward. Compared to my E90 M3 my S4 is just a sloppy cruiser. But great torque.

Holy 7 year old thread bump!!!