Track forum general chit chat.

[dogbone]

Originally Posted by kpewpew

dogbone when you turned off MDM at that point, did the car catch you off guard any time during that day? Or was it just smooth sailing because you had already been tracking the car and had lots of seat team?

It was smooth sailing that day because I already had plenty of seat time to feel the car with DSC off. It just took adaptation to work myself and the car up to maximum pace. But, going maximum pace didn't happen instantly. It took several sessions to work up to max pace. My 1:49.0 fast lap was my last hot lap of the day.

When I first turned DSC off in 2014 and started experimenting, the thing that caught me off guard was how much power came on suddenly when you pressed the gas. MDM was very sneaky in how it held the power back and brought it back on smoothly. dparm asked a question related to this today----asking about the gas pedal behavior in the chart. I'll respond to his question. You may find the answer useful.

[dogbone]

Originally Posted by dparm

What jumps out the most in those graphs is how your gas pedal application was much more "binary" when MDM was on. Not sure if that was intentional or not, but the blue lines have a less-steep slope. You're actually at full throttle much sooner with MDM on, though. Could be down to driver confidence? Would be curious to hear your subjective thoughts.

Does AIM let you graph the DSC or TCS activation? In Pi Toolbox, there is a way to do it because the ECU sends a signal when it is actively intervening. Unsure if BMW ECU does it.

Regarding the gas pedal, the answer to your question is not subjective at all-----People who criticize traction control say that it develops bad habits. In my opinion, the least ideal habit I developed with traction control turned on was that I could just mash the gas pedal on corner exit knowing that the computer would bring on the power when it felt safe.

This is why the Red gas pedal lines look so "binary" as you put it. I just mindlessly mashed the pedal to make sure the computer knew I wanted to go. Because I had been experimenting with DSC-off, I knew that the MDM computer controlled the power flow, so I learned over time that I could just mash the gas.

As you noted, the Blue DSC-off gas pedal is much more cautious. Remember, my car is supercharged. There's a lot of power to be had. With DSC off, I had to feather the power on more carefully because the computer wasn't holding any power back. But if you look at the speed lines, I'm not losing any acceleration compared to the red lines because now I control the car's power and I'm bringing the power on sooner with my lesser pedal press. So even though I'm not mashing the gas, the power I call for is coming on straight away and the car is accelerating just fine. In fact, I would argue, it's accelerating better in some cases. And this was only first day of "going for it".

So, it wasn't about driver confidence when MDM was on. It was knowing that the computer controlled the onset of power when MDM was on----that I could just mash the gas and then let the computer bring on the power. And when DSC is off, you gotta work the gas pedal differently. The first time I ever turned DSC off and went through the Bus Stop corner at Buttonwillow, I got a nasty surprise when I hit the gas pedal. With MDM on, I would press the gas fairly aggressively as I hopped over that corner. Yeah.....I did that same thing with DSC off and the power came rushing on immediately and the tail of the car got all squirrelly and I was like, ohhhhhhhhhh hmmmmmm......hahaha! It was these kinds of moments that truly illustrated what MDM was doing quietly without any fanfare.


As far as I know, there is no BMW CAN channel logged by the AIM that tracks DSC activation.

[CorruptCommie]

And that's what builds the bad habits - just getting on WOT with the computer controlling it rather than you.

[dparm]

Originally Posted by ThunderMoose

Have you ever spun in the Vette? Seems like a very sophisticated system that will let you drive fast but not lose control, even in Race mode.

COTA is actually fairly safe as long as you don't try be a hero and save a tank slapper. Plenty of room just to drive straight off if you lose traction. Of course my car is less powerful than yours so I probably have a bit more safety margin.

No spectacular spins, sorry. It has caught me on a few tank slappers when I overheated the tires.


Agree that COTA is pretty safe. The only real place I am worried about a spin is T10. It's a very fast downhill corner that I take flat-out and actually use the inside curbing really aggressively. A spin there would be at ~100mph and would probably send you right across the middle of the track. I did see an ugly one from a Cayman at T2/T3 which is a similar fast downhill corner. He actually transitioned to T3 too quickly, spun the car across the track, and went sideways into the barrier.

Originally Posted by dogbone

Regarding the gas pedal, the answer to your question is not subjective at all-----People who criticize traction control say that it develops bad habits. In my opinion, the least ideal habit I developed with traction control turned on was that I could just mash the gas pedal on corner exit knowing that the computer would bring on the power when it felt safe.

This is why the Red gas pedal lines look so "binary" as you put it. I just mindlessly mashed the pedal to make sure the computer knew I wanted to go. Because I had been experimenting with DSC-off, I knew that the MDM computer controlled the power flow, so I learned over time that I could just mash the gas.

As you noted, the Blue DSC-off gas pedal is much more cautious. Remember, my car is supercharged. There's a lot of power to be had. With DSC off, I had to feather the power on more carefully because the computer wasn't holding any power back. But if you look at the speed lines, I'm not losing any acceleration compared to the red lines because now I control the car's power and I'm bringing the power on sooner with my lesser pedal press. So even though I'm not mashing the gas, the power I call for is coming on straight away and the car is accelerating just fine. In fact, I would argue, it's accelerating better in some cases. And this was only first day of "going for it".

So, it wasn't about driver confidence when MDM was on. It was knowing that the computer controlled the onset of power when MDM was on----that I could just mash the gas and then let the computer bring on the power. And when DSC is off, you gotta work the gas pedal differently. The first time I ever turned DSC off and went through the Bus Stop corner at Buttonwillow, I got a nasty surprise when I hit the gas pedal. With MDM on, I would press the gas fairly aggressively as I hopped over that corner. Yeah.....I did that same thing with DSC off and the power came rushing on immediately and the tail of the car got all squirrelly and I was like, ohhhhhhhhhh hmmmmmm......hahaha! It was these kinds of moments that truly illustrated what MDM was doing quietly without any fanfare.


As far as I know, there is no BMW CAN channel logged by the AIM that tracks DSC activation.

Thanks, this is good context for the data. Have you ever thought about doing a math channel to calculate yaw rate or similar data?

[Richbot]

True race traction control systems do not let you get away with mash and crash you want a little bit of slip to get the most forward bite from any tire. Drivers still have to feed in throttle to get the car’s attitude right for best exit and screwing up will still spin the car The mash and steer habit does not translate to those systems and you’re back to square one

So looking at what the pros are doing and saying hey me too i also can has tc just like the pros is not how any of this works

You would need line pressure at each caliper to know what it’s really doing imo

[Ximian]

Originally Posted by Richbot

So looking at what the pros are doing and saying hey me too is dumb

I didn't expect to be personally attacked this early in the morning.

[Richbot]

Originally Posted by Ximian

I didn't expect to be personally attacked this early in the morning.

I edited for less personal aggression

[Ximian]

Originally Posted by Richbot

I edited for less personal aggression

[roastbeef]

Another random post from me- but a while back I posted a video from gale banks where he was researching diff covers and how they work to reduce temperature and churning.
If you watched the vid, you saw that those huge square diff covers that add a few quarts of capacity don't really do much and some actually raise the fluid temps because they are less efficient in cooling.
They just posted a pic of what they came up with and they look very similar to bmw M diffs with built in cooling channels and "scoops" at the bottom to direct air up and through the cooling fins directly behind the diff, which was a dead spot for airflow. Just thought I would mention it because it's cool, and some dudes have tow rigs on here.

[dogbone]

Comparison analysis between my fastest possible MDM lap and a DSC-off lap during the same track day.



Here are some of my thoughts when I look at the AIM data of the MDM lap versus the DSC-off lap. (Again, Blue is DSC-off and Red is MDM.)

-Most of the DSC-off time gains happened in two sections of the track. From 2000-5000ft, and from 9000-14000. The beginning up to 2000ft was pretty even. And the middle from 5000-9000ft was also even. I'm not a pro driver, so I'm not consistent each lap at every moment on the track. But there are some pretty significant differences between those two speed profiles considering I knew the track. It's not like I was faster later in the day because I simply had the layout down better in my head. There was power immediately at my disposal and I was using it.

-Let's look at the 2000-5000ft section. This is the exit of OffRamp to the approach of Bus Stop. My Blue gas press at 2000ft was more cautious than the Red press, but the blue acceleration leaps away and gains a bit of time. Then the Blue gas hesitates slightly and Red catches up. But, at 3500 ft, going through the series of turns of Cotton Corners, Grapevine and Club Corner, it's not even close. DSC-off allows you to go through there much faster because the power isn't being held back. In the Red lap, I'm pressing the gas plenty from 3500ft to 6000ft, but the speeds are nowhere near the Blue lap. That's because MDM is holding the power back in all those turns. And there are other examples in the rest of the lap where the Red lap is hammering the gas, but the Blue lap is achieving higher speeds. These are simply more examples of MDM holding the power back until it feels it is safe.

-On the Blue lap, the accelerations at 9000ft and 11000ft were able to happen earlier and rose more sharply than the MDM Red lap which allowed higher top speeds. I also was being more aggressive later in the day in those braking zones, braking later and carrying more speed to the apex. If you look at the final two brake presses, the Blue brake presses are quite a bit heavier than the Red presses and they're later than the Red lap. So I was staying on the gas longer, coming in with more speed, pressing the brake later, carrying more speed while braking. You're watching someone's learning process here---learning what the R1S are capable of. (This was my first day trying R1S tires.)

-The MDM front brake caliper activations happen ridiculously often. On the chart labeled "Front Caliper Activations", look in the gaps where I am not pressing the brake pedal (the chart above). There are a zillion little grabs of the brake on the Red lap. This is MDM worrying that a spin might be imminent. These little nudges happening constantly is why brake pads can get trashed very quickly with MDM. MDM doing dozens of brake nudges per lap, lap after lap builds extra heat and wears pads and rotors out prematurely

-Gas Pedal behavior. We touched on this in my response to dparm. On the Red lap with MDM, I mashed the gas early and hard. I did this because I learned over time that MDM would bring on the power smoothly when it felt it was safe to do so. So, basically, I could press the gas whenever I wanted and just waited for the computer to bring on the power. I pressed early so the computer would know that I was looking for max acceleration. I wasn't happy about this gas pedal response/behavior, but that's how the M3's DSC works. You can't tune it in any way. On the Blue DSC-off lap, I was much more cautious and smoother with the gas pedal and it still resulted in higher speeds in most sections of the track. Having access to all the power whenever you call for it appears to be much better for lap times.

-The final acceleration at 13,500ft is interesting. On the Blue lap, I slowed more than the Red lap going into the final turn. You can see I got on the gas far later than the Red lap, but started accelerating immediately and much more sharply than the MDM lap and ended up with a higher finishing speed than the MDM lap. Yet another example of mashing the gas while using MDM and letting the computer handle how the car accelerates.

-Brake pedal presses--it's a bit hard to see in this particular chart's screen capture, but I appeared to be braking a bit later in just about every braking zone during the Blue lap. I would chalk this up to being more aggressive and exploring the limits of a higher grip tire later in the day. Braking later--as long as you can keep the car together--generally leads to better lap times.

There's other tidbits you could look at, but I've tried to touch on the major things mostly relating to MDM.


In my opinion, if a person wants to drive a car without any computer traction control aids, they need to learn about the dynamics of weight balance of an automobile. Knowing the feel of the current state of a vehicle's weight balance/weight shift, and what that means, is the key to understanding what you can do with a car in any given moment. Getting on a skid pad or autocross course can start to give you that experience. For example, I hear people complain that their car understeers EVERYWHERE. Well, I would argue that that person doesn't understand weight balance. If you get on the gas hard and shift the weight of the car to the rear and then turn the steering wheel a ton, there's very little weight on the front tires. How are the tires supposed to grip without any weight on them? You have to adapt your driving to not be mashing the gas too early (shifting the weight rearward) and trying to turn at the same time.

People say traction control teaches you bad habits. Here are the two worst habits I think you can get from using traction control in an E9x M3:

-As I've shown here, with DSC on, you can sort of mash the gas whenever you want when exiting a corner. The computer will decide when it's safe to actually bring on the power. So you're not really learning proper gas pedal behavior. (In fairness to me, I knew this was DSC's behavior, and I was trying to accelerate as quickly as possible within the bounds of MDM. I had practiced quite a bit learning proper gas pedal behavior without traction control. I wasn't struggling once DSC was off later in the day.)

-With DSC on, people will come into high speed corners/rounders and completely let off the gas----no maintenance throttle. Without DSC or rear aero, this would shift the weight of a car forward and lighten the rear quite a bit, which would greatly increase the chance of a spin when you get on the gas again---no weight/grip back there, especially if the steering wheel is still turned. DSC can nudge the front brakes to eliminate that situation. If you don't know that DSC is doing that, you can be surprised by a spin when you turn DSC off.

But these things don't make traction control evil. You just need to learn about it.

In my particular case, I started participating in motorsport in 2012 at 42 years-old with absolutely no prior experience. And I showed up with a supercharged car, so there was even more trouble to be had. Believe me when I tell you I was SOOO nervous when I would get on track. I would barely sleep the night before an event (which just made things even worse). Back then, I felt like I benefitted from MDM because I felt that it allowed me to approach the edge without getting myself into any major trouble. It was a safety net for my mind as much as my novice driving. And there wasn't an instructor in the car very often. I was learning on my own most of the time. MDM gave me an indication of where [it thought] the limits were. And over time, I learned how to drive within them. (I didn't get super aggressive with the gas like you see in this Red lap until much later.) To this day, I do not think that was a bad thing. Later on, could I have benefitted from being able to tune the traction control settings more?----like being able to tune the throttle response? Yeah. Does it mean DSC was worthless? Definitely not.

When I look back on my start into motorsport, the one thing I wish I did was hire a quality instructor. My learning curve would have moved MUUUCH faster.

There's no universal answer when it comes to traction control. Everybody is out there for different reasons. Some people like to mod their car and then hard park it in a paddock. Some people want to mash the gas pedal on the straights, brake 800 feet too early and lightly cruise the corners. Some guys want to race and trade paint going three-wide into a corner. Other guys get off on passing cars on track like they're in a race. Some people want to drift every fricking corner. Some dudes are just out to have fun and don't run any kind of timer. Others focus on lap times and noodle the data trying to find the last 0.1 sec. You need to do what makes you comfortable and still keeps you safe. Everybody comes from a different background and has a different skill set. When some guy shows up who drove kart tracks, rally cars and dirt bikes his whole life.....yeah that guy might not be feeling the need to have a computer backing him up. But when another dude has tons of tech money and shows up to a track for the first time ever with a 700hp McLaren and has never laid eyes on a berm......yeah.....maybe he should leave those aids on.

In the end----What's faster?....What's slower?.....Would a 2019 traction control system be faster than a pro driver in a car with gobs of hp and torque? Maybe. Who knows.....it might really be something that you need to analyze on a case by case basis. And.....does it even matter? I drove traction control while it was still fun. When it wasn't fun anymore, I turned it off. But I did spend the time to learn before doing that.

[M eyedoc]

dogbone
Gotta say, that was an incredible post with one of the most levelheaded explanations l have read lately (on about any topic actually...).

I will tell you, I probably learned more about driving the weekend I turned everything off while tracking an M5. I Realized I would not make it through the 3 day weekend with rear brakes with MDM helping. Spent Saturday afternoon questioning my sanity, but by the end of Sunday, not only was I over a second faster, I found the car completely transformed into something special. The right pedal was no longer an on-off switch, but successfully learning to throttle steer with 560hp was an experience like no other. I agree, this is not something that should be taken lightly, because off mean off and there is no safety net. But the education that it provided was priceless.

My recommendation to others is to grab an instructor to ride along, even if you run in a solo group, if you are questioning turning everything off. He or she will be able to pick up many little hints on how much the car is helping. Then work together on a plan to safely start the new learning process.

[MaximusB]

Tons of good points made by everyone in regards to DSC/MDM. Really enjoyed reading all the comments, especially how dogbone broken it down. Much appreciated.

For my next track day I'm just going to keep DSC on and focus on being smooth at entry and exit. The track I am going to have 16 corners. 4 of them I am quite consistent with and about 6 corners I had trouble with. So just going to focus on those 6 corners, goal is to be more consistent and maintain momentum through them.

[Richbot]

I think part of this discussion is because most people come at this all backwards and sideways and on fire. They finally get a really awesome car and are like MAN THIS THING IS WASTED ON THE STREET I SHOULD REALLY TRACK IT

when they should have been tracking/autocrossing whatever shitpile they happened to have before to get ready for said awesomeness so that they don’t have to learn limit handling on a car that can carry 10mph through a given corner than their old shitpile could

[dparm]

dogbone can you calculate the total amount of time on the gas and brake for a given lap or session (or percentage)? I often find that to be very useful when trying to figure out if my setup or technique helped me. Pi Toolbox/Cosworth Toolbox does it automatically.

[slicer]

Originally Posted by Richbot

I think part of this discussion is because most people come at this all backwards and sideways and on fire. They finally get a really awesome car and are like MAN THIS THING IS WASTED ON THE STREET I SHOULD REALLY TRACK IT

when they should have been tracking/autocrossing whatever shitpile they happened to have before to get ready for said awesomeness so that they don't have to learn limit handling on a car that can carry 10mph through a given corner than their old shitpile could

This is true. I'm by no means the best driver but I can say I learned a lot driving garbage manual transmission cars in slippery conditions starting at age 16. I performed my initial skid-pad exercises on neighborhood streets. Complete jackass at 16. Mowed over a mailbox drifting around a corner.


Thankfully I'm now in a climate where snow and ice are a thing of the past .

[dogbone]

Originally Posted by M eyedoc

dogbone
Gotta say, that was an incredible post with one of the most levelheaded explanations l have read lately (on about any topic actually...).

I will tell you, I probably learned more about driving the weekend I turned everything off while tracking an M5. I Realized I would not make it through the 3 day weekend with rear brakes with MDM helping. Spent Saturday afternoon questioning my sanity, but by the end of Sunday, not only was I over a second faster, I found the car completely transformed into something special. The right pedal was no longer an on-off switch, but successfully learning to throttle steer with 560hp was an experience like no other. I agree, this is not something that should be taken lightly, because off mean off and there is no safety net. But the education that it provided was priceless.

My recommendation to others is to grab an instructor to ride along, even if you run in a solo group, if you are questioning turning everything off. He or she will be able to pick up many little hints on how much the car is helping. Then work together on a plan to safely start the new learning process.

Thanks!

Glad to hear that you had a good time pushing an M5 around a track!

[dogbone]

Originally Posted by Richbot

I think part of this discussion is because most people come at this all backwards and sideways and on fire.

This is how I come into every apex now that DSC is off.

[dogbone]

Originally Posted by dparm

dogbone can you calculate the total amount of time on the gas and brake for a given lap or session (or percentage)? I often find that to be very useful when trying to figure out if my setup or technique helped me. Pi Toolbox/Cosworth Toolbox does it automatically.

ummm I don't know if it's possible in the AIM software. I'm not aware of any standard screen or page you could look at to see something like that.

Perhaps a custom formula could calculate it? I don't know.....

[ThunderMoose]

Originally Posted by dogbone

ummm I don't know if it's possible in the AIM software. I'm not aware of any standard screen or page you could look at to see something like that.

Perhaps a custom formula could calculate it? I don't know.....

Here's the formula that I use Lap_integr(throttle)/lap_integr(100).

I have it but never use it quite honestly because it's not particularly helpful.

Most of what it takes to going really fast comes down to braking and positioning through the corners.

As an example when comparing my data with pro race driver Scott Heckert's data in my same car, there were times when I was able to go to full throttle sooner exiting a corner, but since he had braked softer and positioned the car better at entry he carried 5-10 mph more. There's much more to learn by zooming on the corners and focusing on brake pressure (or variant).

In most short double apex type corners, you want to enter so fast that it's nearly impossible to get to throttle until you get to second apex (big bend at LRP, 2 and carousel at MO, 11 at VIR). So in those cases higher Time on Throttle indicates that you over slowed on entry - bad thing.

I was looking at our two fastest laps at VIR and I was on throttle 71% to his 70% but he got me by 0.4 seconds.

When we work together, we spend 75% of our time on braking and positioning and the other 25% on throttle- being patient through low speed corners, committing sooner in high speed corners, and eliminating transition from throttle to brakes in braking zones.

YMMV.

[M eyedoc]

Originally Posted by dogbone

Thanks!

Glad to hear that you had a good time pushing an M5 around a track!

Yep, it was the gateway drug to get me back to the track after many years away. Have since moved to an e46 M and an e90 M. Much less torque, but more fun with lots less weight.

[dogbone]

Originally Posted by ThunderMoose

Here's the formula that I use Lap_integr(throttle)/lap_integr(100).

I have it but never use it quite honestly because it's not particularly helpful.

Most of what it takes to going really fast comes down to braking and positioning through the corners.

As an example when comparing my data with pro race driver Scott Heckert's data in my same car, there were times when I was able to go to full throttle sooner exiting a corner, but since he had braked softer and positioned the car better at entry he carried 5-10 mph more. There's much more to learn by zooming on the corners and focusing on brake pressure (or variant).

In most short double apex type corners, you want to enter so fast that it's nearly impossible to get to throttle until you get to second apex (big bend at LRP, 2 and carousel at MO, 11 at VIR). So in those cases higher Time on Throttle indicates that you over slowed on entry - bad thing.

I was looking at our two fastest laps at VIR and I was on throttle 71% to his 70% but he got me by 0.4 seconds.

When we work together, we spend 75% of our time on braking and positioning and the other 25% on throttle- being patient through low speed corners, committing sooner in high speed corners, and eliminating transition from throttle to brakes in braking zones.

YMMV.

Your stories about your instructor are exactly what I’m talking about when I say that instruction shortens the learning curve. Given enough time, it is possible to learn things on your own, but good instruction shortens that time dramatically.

I struck out on my own and learned slowly. I have always said I’m not in a hurry to be fast, but looking back, I think I would have enjoyed getting past the novice mistakes more quickly with good instruction.

Thanks for the formula. I’ll give it a try.

[ThunderMoose]

Originally Posted by dogbone

Your stories about your instructor are exactly what I’m talking about when I say that instruction shortens the learning curve. Given enough time, it is possible to learn things on your own, but good instruction shortens that time dramatically.

I struck out on my own and learned slowly. I have always said I’m not in a hurry to be fast, but looking back, I think I would have enjoyed getting past the novice mistakes more quickly with good instruction.

Thanks for the formula. I’ll give it a try.

Actually my route is probably similar to yours.

I started in 2010. Switched from E92 to E46 in 2012. Started to do TT in 2013. Finished runner up from 2014-2016 in Texas Region. Won it all in 2017. By the end of 2017, I had 5 track records in 3 states in NASA TX. All of this was kind of on my own, using AIM DL and SmartyCam, sharing data with friends and watching other videos but no real formal coaching (other than then early DE instruction I got in 2010 - 2012).

In 2018, I had the great fortune to meet up with Scott at a Chin event and officially hired him a month or so later at WGI and LRP where we went on to set 2 more official track records in 2018.

I hired Scott again at Mid Ohio in May and we unofficially broke that track record. Scott helped me shave off 4 seconds in 2 days.

I am sure others are smarter than me at improving their own skills, but there is no way I could have made the step change in improvement in 2018 (my 9th year driving) without Scott. It was amazing at how little I really know even though I thought I was fair competent.

I guess there is no place in your driving journey where a great coach isn't going to help you. May be tenths vs seconds, though Scott is still helping me find chunks.