Aftermarket DSC upgrade for track use?

[iPhoneEngineer]

Hey all,

One reason I have hesitated to track my Z4MC is that the DSC can't be used on-track. I can drive the car dramatically more effectively with the DSC off, in ways that do not at all apply to the stability control system on the Porsche Turbo S. I spun the car once during a track weekend, at a track I intentionally chose for generous run-off room, and have been a bit wary since then. I was able to hold onto it for several oscillations, but couldn't get ahead of the cycle and eventually lost it (fortunately 0 damage to the car, barely stayed on-track).

Though the car is for sale, I'm thinking about keeping it if I can fit an aftermarket stability control system that can be set with very generous, track-appropriate configuration without a tremendous amount of work. Has anyone done this? The main thing I'm interested in is a little extra help bringing a spin back under control.

[pokeybritches]

I had wondered about this as well several years ago. I think it would take too much R&D. Maybe there's a way to lessen the inputs of the accelerometers.

[ga41]

If i remember correctly the E46 M3 CSL and CS have an intermediate DSC mode called M-Track which allows for a bit more slip before reigning it in. With some re-programming it could be retrofitted to the regular E46 M3's but as our ECU's are different doubt it can be retrofitted on our cars... Don't know of any other options...

[The HACK]

Originally Posted by ga41

If i remember correctly the E46 M3 CSL and CS have an intermediate DSC mode called M-Track which allows for a bit more slip before reigning it in. With some re-programming it could be retrofitted to the regular E46 M3's but as our ECU's are different doubt it can be retrofitted on our cars... Don't know of any other options...

I've driven multiple versions of the E46 M3 with and without competition package on track, and with DSC on, DSC off, and DSC in M mode. Compared to the E46 M3, the DSC "on" mode on the MZ4 is almost like the M mode in the E46 M3 with competition package.

I'm going to try and keep this short, since my views on DSC has been well documented here and elsewhere. IMO, Yoda's philosophy can be applied to DSC too.

Originally Posted by Yoda

DSC on or off. There's no "advanced" DSC mode.

If you want a "safety blanket" to keep you from wadding up your car, leave DSC on and learn to operate within its parameters (i.e. smooth inputs, smooth arcs, late with the apex rather than early...etc, you know, all the true fundamentals of going fast). You can be DAMN fast with DSC on, you just won't be, you know, HAVING FUN. Or you drive with DSC off and learn to really drive a car and use all the advance skills you have at your disposal (and if you have a car that has more power than traction, all the power you have too). There really is no middle ground until you get to the really advanced stuff like F1 type traction control (which isn't much different in principle, but MUCH different in application).

But as far as THIS particular chassis is concerned, once you started the oscillation it's already TOO LATE. The relatively short chassis coupled with RWD means the force needed to slap the tank is far less than say, a 3 series or a late model Porsche (Porsche has its own set of problems, since there are more mass concentrated behind the rear axle, and it generates far more force and momentum to create the pendulum effect, i.e. tank slapper, but they seem to have overcome the laws of physics in the last 3 generations). If you haven't reduced the oscillation by the 2nd movement, it'll become increasingly difficult to recover.

[gmd2003]

Originally Posted by The HACK

I've driven multiple versions of the E46 M3 with and without competition package on track, and with DSC on, DSC off, and DSC in M mode. Compared to the E46 M3, the DSC "on" mode on the MZ4 is almost like the M mode in the E46 M3 with competition package.

I'm going to try and keep this short, since my views on DSC has been well documented here and elsewhere. IMO, Yoda's philosophy can be applied to DSC too.

If you want a "safety blanket" to keep you from wadding up your car, leave DSC on and learn to operate within its parameters (i.e. smooth inputs, smooth arcs, late with the apex rather than early...etc, you know, all the true fundamentals of going fast). You can be DAMN fast with DSC on, you just won't be, you know, HAVING FUN. Or you drive with DSC off and learn to really drive a car and use all the advance skills you have at your disposal (and if you have a car that has more power than traction, all the power you have too). There really is no middle ground until you get to the really advanced stuff like F1 type traction control (which isn't much different in principle, but MUCH different in application).

But as far as THIS particular chassis is concerned, once you started the oscillation it's already TOO LATE. The relatively short chassis coupled with RWD means the force needed to slap the tank is far less than say, a 3 series or a late model Porsche (Porsche has its own set of problems, since there are more mass concentrated behind the rear axle, and it generates far more force and momentum to create the pendulum effect, i.e. tank slapper, but they seem to have overcome the laws of physics in the last 3 generations). If you haven't reduced the oscillation by the 2nd movement, it'll become increasingly difficult to recover.

The DSC is close to the one in the E46 M3 competition package , id say its right in the middle between the reg M3 and the CP M3 . As you improve in ability however it greatly hampers further improvement and car control . The Z4M even with optimal setup has a tendency to understeer . You can minimize this with setup , but to be truly fast in this car you must have some slip angle in every corner . The DSC does not allow you to do this in the Z4M . So its always off for me . At my skill level the difference between. , on and off is over 2 seconds a lap ( 1:20 lap ) . It totally kills the throttle when i try adjust the car with the gas , or trail brake . Way to complex to retrofit though , but damn is it getting really good in newer cars . In my 2014 CP M6 it is so good I may actually be faster with it on !
My two cents
George

[iPhoneEngineer]

Initially I was convinced that if I could not drive without interference from the DSC, I was not driving well enough and was being sloppy. Unfortunately I'm pretty confident not only from my own experience, but quite a few other people that the very normal / almost necessary levels of understeer that this car demonstrates on a track is enough to trip the DSC and massively reduce engine power, with delayed restoration of that power even when the slippage has stopped. It is somewhat more generous with oversteer and so I have never had a problem with it interfering then.

In the case I spun, it was an off-camber sweeping turn and I applied slightly too much power, too early. Then in attempting to recover I did not properly account for the rear being light due to the camber and some descent.

I am by no means an expert driver on the track, probably moderate (lots of experience with tactical, deserted mountain roads — only 5-6 track days). So in order to learn I definitely want some degree of safety net when I screw up, yet with the DSC on for a full track day, I was neither learning nor having fun, just being frustrated by it unpredictably deciding to cut power with very minor slippage.

It is surprising to me how much the systems have improved, judging by the 2012 Turbo S not having literally any of these negative characteristics, but I'd be willing to spend $3-5k to get a better stability control system in the car and start converting it to a safe track practice vehicle.

[Blind32]

Originally Posted by The HACK

If you want a "safety blanket" to keep you from wadding up your car, leave DSC on and learn to operate within its parameters (i.e. smooth inputs, smooth arcs, late with the apex rather than early...etc, you know, all the true fundamentals of going fast). You can be DAMN fast with DSC on, you just won't be, you know, HAVING FUN. Or you drive with DSC off and learn to really drive a car and use all the advance skills you have at your disposal (and if you have a car that has more power than traction, all the power you have too).

+1

I leave it on for the first session. Feel out the track and conditions. Also go to a track day when it rains. Work on your car control in the wet. We have a track around here that is sealed and when it rains, it is like ice. Can barely go over 30 in some parts. Not extremely fun but you learn your car quickly and how much countersteer to give.

[gmd2003]

Originally Posted by iPhoneEngineer

Initially I was convinced that if I could not drive without interference from the DSC, I was not driving well enough and was being sloppy. Unfortunately I'm pretty confident not only from my own experience, but quite a few other people that the very normal / almost necessary levels of understeer that this car demonstrates on a track is enough to trip the DSC and massively reduce engine power, with delayed restoration of that power even when the slippage has stopped. It is somewhat more generous with oversteer and so I have never had a problem with it interfering then.

In the case I spun, it was an off-camber sweeping turn and I applied slightly too much power, too early. Then in attempting to recover I did not properly account for the rear being light due to the camber and some descent.

I am by no means an expert driver on the track, probably moderate (lots of experience with tactical, deserted mountain roads — only 5-6 track days). So in order to learn I definitely want some degree of safety net when I screw up, yet with the DSC on for a full track day, I was neither learning nor having fun, just being frustrated by it unpredictably deciding to cut power with very minor slippage.

It is surprising to me how much the systems have improved, judging by the 2012 Turbo S not having literally any of these negative characteristics, but I'd be willing to spend $3-5k to get a better stability control system in the car and start converting it to a safe track practice vehicle.

You will hands down be a better driver learning car control with everything off. Just focus on improving you're smoothness, apex points etc and don't worry how "fast" you are. The advanced systems in newer cars are creating a bunch of very shitty drivers in my opinion. People think they are hot shit and when they do exceed the laws of physics and the cars electronics ability to correct have severe offs and crashes at really high speeds. I saw a totaled GTR at my last track day because the driver had no idea where the limits of traction and grip were. He was totally flooring it in every corner and relying on the car to sort things out. So don't get the impression that electronic safeties make you safe on track. They tend to cover up bad habits, and push track offs you would have had at lower speeds to much higher speeds.
My two cents.
George

[tikamak]

Originally Posted by gmd2003

You will hands down be a better driver learning car control with everything off. Just focus on improving you're smoothness, apex points etc and don't worry how "fast" you are. The advanced systems in newer cars are creating a bunch of very shitty drivers in my opinion. People think they are hot shit and when they do exceed the laws of physics and the cars electronics ability to correct have severe offs and crashes at really high speeds. I saw a totaled GTR at my last track day because the driver had no idea where the limits of traction and grip were. He was totally flooring it in every corner and relying on the car to sort things out. So don't get the impression that electronic safeties make you safe on track. They tend to cover up bad habits, and push track offs you would have had at lower speeds to much higher speeds.
My two cents.
George

When you drive a car with no traction control for a few years, you get a driver like this dude right here:

Proud to be lebanese

[z4msteve]

If you're afraid of taking your car off track or spinning, you probably can't afford to track the car. You shouldn't track a car you can't afford to leave at the track or at least repair in the event of a catastrophe. Some companies like lockton motorsports now offer HPDE insurance, so if you really want to spend $3000 for a safety net just pay them to cover your weekends.

I personally find myself having to manhandle the Z4M to be effective on track, and if I forget to turn of DSC I immediately notice the first hot-lap.

[ZStig]

I'm thinking racelogic traction control has a solution, but might screw with our electronics and throw it into limp mode

[iPhoneEngineer]

z4mSteve, I can definitely afford to leave the car at the track. I've considered instead tracking my 2012 911 Turbo S (hasn't turned 4k miles yet), and have had fun modding up a Cayenne Turbo to 600HP.

I don't think this has anything to do with money. I'd like to have a greater degree of freedom to improve my driving skills without going entirely without stability control as an aid if a situation exceeds my ability. Far more of a concern than wrecking the car is being injured in the process.

[iPhoneEngineer]

gmd2003, I think you are absolutely right. A lot of modern stability control systems can actually enhance the limits of handling by routinely doing single-wheel braking (without visibly activating the DSC warning light). That is definitely not what I'm looking for here.

My only interest is a system that is very tolerant, to allow me to drive the car entirely manually, except if normal limits are significantly exceeded and it's pretty obvious the car is entering a spin. In such a situation, I will be making inputs to attempt to resolve it, but for additional reassurance as I gain experience it would be much better to have a stability system to assist in the process. As has been mentioned, the short wheelbase of this car means that there is some degree of finesse in breaking out of an early spin, and while I'm very interested to master this by my own merits, if I get it wrong once or twice I don't want that to be game over for the car (or a long term injury for myself).

I don't expect this situation to happen even once per track day. But even once every 10 track days, if it happens near a wall and I fail to contain it (even by a small margin), that is my concern.

[Shipkiller]

Originally Posted by z4msteve

if I forget to turn of DSC I immediately notice the first hot-lap.

I see this also. It's like "what is wrong with my car", then I look down and see the DSC flashing at me and then I turn it off...

[gmd2003]

Originally Posted by iPhoneEngineer

gmd2003, I think you are absolutely right. A lot of modern stability control systems can actually enhance the limits of handling by routinely doing single-wheel braking (without visibly activating the DSC warning light). That is definitely not what I'm looking for here.

My only interest is a system that is very tolerant, to allow me to drive the car entirely manually, except if normal limits are significantly exceeded and it's pretty obvious the car is entering a spin. In such a situation, I will be making inputs to attempt to resolve it, but for additional reassurance as I gain experience it would be much better to have a stability system to assist in the process. As has been mentioned, the short wheelbase of this car means that there is some degree of finesse in breaking out of an early spin, and while I'm very interested to master this by my own merits, if I get it wrong once or twice I don't want that to be game over for the car (or a long term injury for myself).

I don't expect this situation to happen even once per track day. But even once every 10 track days, if it happens near a wall and I fail to contain it (even by a small margin), that is my concern.

The newer systems that allow slip angle like the M- mode in the F13 M6 would not bail you out of that situation . If you don't counter steer appropriately you're gone . What they do is allow you to put the maximum amount of power down coming out of the apex , which is nice .

[abashoe]

I came from a Z3MCoupe where the ASC was no where nearly as invasive. After my first track day with my Z4 MCoupe I was almost ready to sell. The DSC was so intrusive it ruined my day.

I realize now it likely has to deal with my driving style. Its really only a certain condition for me: turns where the apex is part of decreasing elevation changes (1 and 5 and NJMP-L)

DSC off cured it, but I did have a minor off track excursion on my next HPDE. So until I get better I don't want to turn it off.

Does a decent suspension setup reduce the DSC invasiveness dramatically? Other than PFC pads I'm stock. Im hoping coilovers and camber plates will reduce it immensely. Is this a realistic expectation?

[gmd2003]

Originally Posted by abashoe

I came from a Z3MCoupe where the ASC was no where nearly as invasive. After my first track day with my Z4 MCoupe I was almost ready to sell. The DSC was so intrusive it ruined my day.

I realize now it likely has to deal with my driving style. Its really only a certain condition for me: turns where the apex is part of decreasing elevation changes (1 and 5 and NJMP-L)

DSC off cured it, but I did have a minor off track excursion on my next HPDE. So until I get better I don't want to turn it off.

Does a decent suspension setup reduce the DSC invasiveness dramatically? Other than PFC pads I'm stock. Im hoping coilovers and camber plates will reduce it immensely. Is this a realistic expectation?

No actually doing suspension mods will make it kick in more . Less body roll and faster weight transfer make for a better setup but it can and does make the system intervene more in my experience. I went DSC off full tine early on in my career with this car , you can not drive it effectively on track in the dry with it on .
George