Detailed M4 HPDE track day review - Update - June 13/15

[jphughan]

Originally Posted by MaynardZed

Higher pressures in front will increase understeer but improve steering response. Turn in might feel better but car will push worse midturn.

Originally Posted by pikcachu

No, higher pressure in the front will decrease understeer

http://www.tirerack.com/tires/tirete....jsp?techid=58

Originally Posted by MaynardZed

Far be it from me to disagree with "the rack", but there's a few things on that chart that I would protest

MaynardZed is more right than pikachu, but it's not as simple as "higher/lower will increase/decrease understeer" because higher and lower are both relative, not absolute. If you go too high on pressure, you won't be using the edges of the tread, which will increase understeer because your contact patch will be smaller. If on the other hand you go too low, the center of the tread will cup upward and lose contact with the road, which will ALSO increase understeer because again, your contact patch will be smaller. But if manufacturer-recommended pressures are the starting point, typically reducing tire pressure will reduce understeer. The only TRUE way to determine whether your tire pressures are appropriate is to use a pyrometer to measure the edges and center of the tire immediately after a track session. If they're nice and even, you're spot on. If the center is hotter, lower your pressure. If the edges are hotter, increase your pressure.

All that said, I usually shoot for 38-39 hot after coming in from a cooldown lap (which usually means 30-31 cold) and find that I like how my car feels and how the tread wears. I don't own a pyrometer because I don't really care about a tiny bit of extra speed I may be able to gain from setting pressures perfectly. Nobody is paying me to set lap times, and frankly I'm not sure I'm good enough of a driver to be able to tell the difference from a tiny pressure adjustment.

Originally Posted by MaynardZed

There are basically 3 levels of traction control intervention:
1) safest / most intrusive = DSC and MDM on
2) mild intervention = DSC off, but MDM on
3) no intervention = both DSC and MDM off

I believe MDM and DSC are really different levels of the same system, it's just that MDM is less intrusive. I could be wrong though and MDM is entirely separate system? Anyone know for sure?

MDM is a special mode of DSC, not a completely separate system -- which is why your breakdown is a little confusing. Most people think of MDM as DSC still being on, just with more leniency due to a higher threshold for intervention. It's easier to classify the three mods as just, "DSC full on, MDM, and DSC full off."

[CanAutM3]

Originally Posted by M4isKing

so its different from e92m? i thought mdm was a setting within dsc. mdm is just like a half dsc on mode where it allows some slippage but will still autocorrect.

it used to be:

-dsc on (standard mode)
-mdm on (half mode, dsc is still on)
-full dsc off

It is the same as on the E9X. See post #63

[M4isKing]

Originally Posted by CanAutM3

It is the same as on the E9X. See post #63

yep exactly how i put it. found it a little weird. i remember there was this same confusion on f30post when the cars first came out.

[M3 Adjuster]

Originally Posted by dkhm3

amazing- good to know the m did not overheat.

It's an M car... duh...

There are no overheating issues with the 1M either....

[nonagon]

Originally Posted by M3 Adjuster

It's an M car... duh...

There are no overheating issues with the 1M either....

M cars aren't immune; I believe the F10 M5 had limp mode issues related to heat when it first came out.

[karussell]

Originally Posted by M4isKing

so its different from e92m? i thought mdm was a setting within dsc. mdm is just like a half dsc on mode where it allows some slippage but will still autocorrect.

it used to be:

-dsc on (standard mode)
-mdm on (half mode, dsc is still on)
-full dsc off

you are correct. mdm still has stability control activated. just it allows for slightly larger slip angle before working. after instructing this weekend at road atlanta with an F10 M5 and a F80 M3 I can say that mdm has its place in the learning curve however it does intervene still too aggresively. I wonder if the US MDM mode is more restrictive than the european MDM. that was the case in the E9x.

I prefer to teach old school with DSC off however most students nowadays prefer to keep DSC on and that's completely fine but i think it elongates the learning curve quite a bit. DSC now is entirely too conservative and even a typical novice first time on the track would have issues with it after a session.

[M3 Adjuster]

Originally Posted by karussell

you are correct. mdm still has stability control activated. just it allows for slightly larger slip angle before working. after instructing this weekend at road atlanta with an F10 M5 and a F80 M3 I can say that mdm has its place in the learning curve however it does intervene still too aggresively. I wonder if the US MDM mode is more restrictive than the european MDM. that was the case in the E9x.

I prefer to teach old school with DSC off however most students nowadays prefer to keep DSC on and that's completely fine but i think it elongates the learning curve quite a bit. DSC now is entirely too conservative and even a typical novice first time on the track would have issues with it after a session.

I have been a proponent of using MDM as a tool for quite some time. Indeed it is a step in the process.


I an sure that the euro MDM is less restrictive on the f8x just as in it is on the e9x and e8x. The same attorneys are still working at BMW NA. :-).

While the US Version I agree is a bit too restrictive, it is certainly possible for a driver that is smooth to drive these cars at roughly 85-90 percent of full pace even with the MDM on. I know that I can!


With novice and intermediate students, I let my students determine if they are more comfortable with DSC fully ON or MDM. I do not let normally let these D and C level students run with DSC fully off.. The ones that I have given some reign to, generally don't even know how badly they are lighting up the rear tires. I had one intermediate student (who felt he was advanced) that was adamant that he wanted to " drive the car". I let him spin the wheels for a session on his E90 M3 and then the next session I demanded that he put MDM back on to literally show him that he was SLOWER around the track with DSC off. Acceleration felt faster to him, and he had (just) enough skill to catch the rear end as it really stepped out... but the simple fact is that he gained speed at the end of the straights with MDM on, which finally proved to him that I was correct.

I make sure that my novice and intermediate students know that that the blinking dsc will slow them down if they aren't smooth. I also let them know that if they can't negotiate the course moderately quickly without the DSC light flashing at them, then they are not ready to take the " training wheels" off yet. Advanced (B group) and Upper level advanced ( A group) students of course typically of course are familiar with their vehicle and the course enough that they can prefer to roll with DSC off. However... even advanced level students with a BMW turbo vehicle will find it is difficult to control wheelspin without going to larger wheels and tires than what comes stock on the vehicle from the factory.

Originally Posted by karussell

M4 just needs way more tire. I think 295's if they fit on the rear. up to 275's in front. mpss's get greasy if they are over inflated. what hot pressure were you using? i experimented with the M4 on SPA and Ring and found they prefer lower pressures than the e90 on the track.

Correct. 1M came with 245/35 front and 265/35 rear on 19s. While I have switched to 18s... it was only when I went with a 285/30/18 rear that I realized that I had been spinning the tires still on full acceleration with 275/35 Hoosiers. I prefer 285 square for rotating, however I have also fit 285/30/18 Front and 315/30/18 rear on my 1M and found this to be a pretty good combo. With the F8X having even more torque than the 1M... I am sure that it needs tires this size or wider.

There is actually enough clearance on the 1M to go bigger than 315s on the rear...... but not much more can be done up front. Whatever size is max available up front.. Camber plates are still a neccessory.

[M3 Esq]

Originally Posted by M3 Adjuster

I have been a proponent of using MDM as a tool for quite some time. Indeed it is a step in the process.


I an sure that the euro MDM is less restrictive on the f8x just as in it is on the e9x and e8x. The same attorneys are still working at BMW NA. :-).

While the US Version I agree is a bit too restrictive, it is certainly possibly for a driver that is smooth to drive these cars at roughly 85-90 percent of full pace even with the MDM on. I know that I can!


I make sure that my students know that that the blinking dsc will slow them down if they aren't smooth.

I agree with this, not to mention that leaving it on might save the car is you really F up.

[M4isKing]

Originally Posted by M3 Adjuster

I have been a proponent of using MDM as a tool for quite some time. Indeed it is a step in the process.


I an sure that the euro MDM is less restrictive on the f8x just as in it is on the e9x and e8x. The same attorneys are still working at BMW NA. :-).

While the US Version I agree is a bit too restrictive, it is certainly possible for a driver that is smooth to drive these cars at roughly 85-90 percent of full pace even with the MDM on. I know that I can!


With novice and intermediate students, I let my students determine if they are more comfortable with DSC fully ON or MDM. I do not let normally let these D and C level students run with DSC fully off.. The ones that I have give some reign to, generally don't even know how badly they are lighting up the rear tires. So instead.. I make sure that my novice and intermediate students know that that the blinking dsc will slow them down if they aren't smooth. If they can't negotiate the course moderately quickly without the DSC light flashing at them, then they are not ready to take the " training wheels" off yet.

i used to use mdm but i am now fully dsc off.

i think a student shouldn't be driving fast at all with mdm on because 99% of the time its guaranteed the fist lap he goes dsc off will result in a spin. im in the camp of turn it off and go slow and gradually work up to speed. and keep in mind that anything abrupt will cause a spin (hence slow in te beginning)

i know i got slower after i turned it off no matter how good i was doing with mdm on.

[MaynardZed]

Originally Posted by M4isKing

i used to use mdm but i am now fully dsc off.

i think a student shouldn't be driving fast at all with mdm on because 99% of the time its guaranteed the fist lap he goes dsc off will result in a spin. im in the camp of turn it off and go slow and gradually work up to speed. and keep in mind that anything abrupt will cause a spin (hence slow in te beginning)

i know i got slower after i turned it off no matter how good i was doing with mdm on.

But you eventually were quicker with it fully off? I'm with you, maybe thinking the MDM might give one a false sense of security?

Not sure what I'll do on my next track day with day with the M4. I used to track my E60 M5 with everything off. Had to be careful in 2nd gear coming out of turns but overall not too difficult. S85 had a lot less torque than S55 and more linear power curve though. Inclined to leave MDM on for the M4.

M3 Adjuster:
FYI, with DSC fully on, the light flashes in 3rd gear on the straights with the PSS. Might be too much to ask students to not allow it to come on at all before progressing?

[M4isKing]

Originally Posted by MaynardZed

But you eventually were quicker with it fully off? I'm with you, maybe thinking the MDM might give one a false sense of security?

of course! on both points.

I definitely learned much faster in terms of reaction/prediction with DSC off even though I started much slower. Helped to intentionally lose traction to practice too.

With MDM I never really fully understood what a car did when the light flickered/sometimes did not flicker.

Im sure with your experience you'll be ok.

[FTS]

Same with me as M4isKing. I don't think DSC, PSM and all other nannies are learning tools, I believe they tend to prevent the learning process actually.

[CanAutM3]

Originally Posted by FTS

Same with me as M4isKing. I don't think DSC, PSM and all other nannies are learning tools, I believe they tend to prevent the learning process actually.

+3 (or whatever the count is)

I have to agree with all the ones advocating DSC Off.

DSC/MDM can be used as a safety net in adverse conditions, when learning a new track or for the first couple of laps of the day (to explore track condition). But to become a good and safe driver, there is no way around this, one needs to learn how to drive without the aids.

Even if the light is not flashing in the cluster, even with Euro MDM, DSC is doing minute adjustments (see Ti-Jean's excellent video on the topic). I have seen way too many intermediate/advanced students overdrive their cars and relying on the electronic nannies to keep them on the track. Keep in mind the longer one waits to turn off the nannies, the more dangerous it is once one does.

[Black Gold]

Originally Posted by CanAutM3

+3 (or whatever the count is)

I have to agree with all the ones advocating DSC Off.

DSC/MDM can be used as a safety net in adverse conditions, when learning a new track or for the first couple of laps of the day (to explore track condition). But to become a good and safe driver, there is no way around this, one needs to learn how to drive without the aids.

Even if the light is not flashing in the cluster, even with Euro MDM, DSC is doing minute adjustments (see Ti-Jean's excellent video on the topic). I have seen way too many intermediate/advanced students overdrive their cars and relying on the electronic nannies to keep them on the track. Keep in mind the longer one waits to turn off the nannies, the more dangerous it is once one does.

so true.

I should have learned with DSC off on a slower car like an s2000 or Miata

but I was late to turn DSC off on my m3, and am better for it now. ill probably use MDM for the first few sesisons on my m3 just to get used to it and then turn it off and slowly build speed.

im an intermediate level driver with average skills, so nothing special here

ive actually signed up for some car control clinics with pcd and bmw cca and autocross for the first time, to learn better car control in event of a slide. I think most newish drivers would benefit from this

[FTS]

I really like that approach too Kenny; I will start with couple of autoxes to learn the basic handling, most likely be very cautious my first day/event on the track with MDM and once I feel I have the basic understanding of the chassis I'll turn it [all of off boys]

[M4isKing]

Originally Posted by KennyPowers

so true.

I should have learned with DSC off on a slower car like an s2000 or Miata

but I was late to turn DSC off on my m3, and am better for it now. ill probably use MDM for the first few sesisons on my m3 just to get used to it and then turn it off and slowly build speed.

im an intermediate level driver with average skills, so nothing special here

ive actually signed up for some car control clinics with pcd and bmw cca and autocross for the first time, to learn better car control in event of a slide. I think most newish drivers would benefit from this

Hey its a step forward! That's all you can ask for: to get better each time out.

Good call on the car control/autox: just hammer it on the gas and get the car to lose traction on purpose.

[gthal]

I'm not going to suggest running DSC off isn't nerve wracking. I'm very cautious with DSC completely off and very careful with the car. Ego completely goes out the window as does a need to be too fast (i.e. testosterone induced stupidity). It is all about consistency, repeatability and smoothness without traction assistance... I suppose that's why it is the best way to learn. Regardless, running without any electronic assistance in a $90,000 car can be a somewhat scary feeling

[Trakrzy]

Excellent writeup gthal! Track days are a god sent on this part of the universe so glad to see you are enjoying it! It will be interesting to see how the C7 Z06 is once it's out and available! If you ever come down to CMP my way, give me a shout...we have a good M group running during the summer, would be nice to have an F8X to see how it runs with us hooligans.

[M3 Adjuster]

Originally Posted by gthal

I'm not going to suggest running DSC off isn't nerve wracking. I'm very cautious with DSC completely off and very careful with the car. Ego completely goes out the window as does a need to be too fast (i.e. testosterone induced stupidity). It is all about consistency, repeatability and smoothness without traction assistance... I suppose that's why it is the best way to learn. Regardless, running without any electronic assistance in a $90,000 car can be a somewhat scary feeling

It appears the last several people are lining up to say drive with dsc off as if the idea was to drive with dsc on all the time. I Simply said it can be used as a tool for a period of time in the development of a driver. I never suggested that advanced students should drive around with it on the rest of their lives.

And indeed, I do plenty of driving with dsc off. However I will often go out the first session or perhaps two of the day to check out conditions or especially at a new track.

It's easy to say drive with dsc off all the time when it's not your 90k or your car isn't one of 740 and you are driving a relatively disposable e36 or e46. As you mentioned it can be a bit nerve racking with it off. So no shame in leaving it on if you are just out lapping with no ego. Want to go fast and catch someone or time laps then go dsc off.

Interesting how dsc is ok for F1 drivers... But the common man.. No way. ! Lol.

At any rate...Didn't really mean to hijack ....

[SakhirM4]

Originally Posted by M3 Adjuster

Didn't really mean to hijack ....

Sure you did

[vladberca]

MDM on is ok for beginners. DSC off is too much if you jump straight into such a powerful car

[Sapper_M3]

Originally Posted by M3 Adjuster

It appears the last several people are lining up to say drive with dsc off as if the idea was to drive with dsc on all the time. I Simply said it can be used as a tool for a period of time in the development of a driver. I never suggested that advanced students should drive around with it on the rest of their lives.

And indeed, I do plenty of driving with dsc off. However I will often go out the first session or perhaps two of the day to check out conditions or especially at a new track.

It's easy to say drive with dsc off all the time when it's not your 90k or your car isn't one of 740 and you are driving a relatively disposable e36 or e46. As you mentioned it can be a bit nerve racking with it off. So no shame in leaving it on if you are just out lapping with no ego. Want to go fast and catch someone or time laps then go dsc off.

Interesting how dsc is ok for F1 drivers... But the common man.. No way. ! Lol.

At any rate...Didn't really mean to hijack ....

Traction control, stability control, and ABS are all banned in F1.

With that said, every F1 team would use the technology--racing designed systems, not the stuff we have in our road cars--if they were allowed to (and hell, many teams do attempt to use it even when they AREN'T allowed to!). The stuff we have in our cars is very intrusive, even at the most relaxed settings, and waiting until a student is very fast before "letting them" (as you put it) turn off the electronic aids is a sure fire way to deeply ingrain bad habits. But hey, everyone has their teaching methods.