[justpete]

Originally Posted by feuer

E-diff will slow the car down. Absolutely. Not only around the track. When DSC is on the e-diff is on and it will over power the engine, it will cut throttle and the engine will bog. When DTC is on by short press on the button the e-diff is on doing the same as above but is less severe and less abrupt intereference. It will not completely cut throttle but it will cause it to basically flactuate mostly depending how the wheel is gaining traction on the surface. When DSC and DTC are off by long press hold on the button the above intereference no longer happens. Like I said I can spin one wheel endlessly given no traction. Some people say e-diff is on non stop and can't be turned off by the long press hold on the button. I think if that is true then when DSC and DTC are off the brake forse the e-diff is applying is significantly reduced so that it can bog the engine and won't cut throttle. Regarding LSD allowing faster track time I don't know what to say since I'm on open diff and 2-3sec behind cars that have LSD, more power, lighter weight, and etc. so if I pick up 5-6 buy installing a LSD I will be the fastest, heaviest and least powerful car in my group. Now I don't think I'm that good of a driver lol. So probably drivers that gain that much time by going to LSD weren't really comfortable pushing the car in the corners and I know why as I find myself saving the car from a spin out often....

You're right about that, this chassis just isn't as planted as I'd like. It gets better with each mod pass. With the roll bar, defeated stability and ABS, and floating rotors and fixed calipers with Pagid RS29 pads it's a lot more confidence inspiring. Isn't nearly as worrying from what I could tell on the street, cornered much flatter. Expecting it to be much better yet again with a full cage and a better LSD with 30/90 ramps instead of 30/60. Although this time, come to think of it, will have an M3 steering rack so it'll be much different at turn in once I can get it back on the track. Would be nice to not suck at driving so much, he said hopefully.

[Biginboca]

Originally Posted by feuer

E-diff will slow the car down. Absolutely. Not only around the track. When DSC is on the e-diff is on and it will over power the engine, it will cut throttle and the engine will bog. When DTC is on by short press on the button the e-diff is on doing the same as above but is less severe and less abrupt intereference. It will not completely cut throttle but it will cause it to basically flactuate mostly depending how the wheel is gaining traction on the surface. When DSC and DTC are off by long press hold on the button the above intereference no longer happens. Like I said I can spin one wheel endlessly given no traction. Some people say e-diff is on non stop and can't be turned off by the long press hold on the button. I think if that is true then when DSC and DTC are off the brake forse the e-diff is applying is significantly reduced so that it can bog the engine and won't cut throttle. Regarding LSD allowing faster track time I don't know what to say since I'm on open diff and 2-3sec behind cars that have LSD, more power, lighter weight, and etc. so if I pick up 5-6 buy installing a LSD I will be the fastest, heaviest and least powerful car in my group. Now I don't think I'm that good of a driver lol. So probably drivers that gain that much time by going to LSD weren't really comfortable pushing the car in the corners and I know why as I find myself saving the car from a spin out often....

My understanding from researching the E90 traction controls and Ediff is with the long push (5 second) Ediff is now the only electronic nanny still present (well ABS is still on too). That’s the only condition where you can make valid Ediff comparisons because it isolates the Ediff and removes all the traction controls. Ediff doesn’t have settings or variables, it’s always on 100% in our cars it’s the other nannies you can turn on and off with the DTC button.

I have had my traction control cut power many times when I haven’t pressed the DTC button, or even when I have done the short push it still cuts power. A lot of power actually even with the short push. I think when talking about the Ediff we can only speak about the 5 second push (nannies off) because the other 2 settings stability control is what is cutting the power, and it’s not doing it with the brakes only it’s also cutting the throttle so the engine definitely bogs and the car slows. The traction control has much more authority with regards to what it can do to slow the car. (In your example above with DSC and DTC still on it’s not Ediff slowing the car, that’s those separate safety systems of traction controls.)

With the 5 second push I’ve never encountered a condition where the engine cut power or bogged. And I have spun completely out with the rear end power sliding all around behind me due to me using too much throttle input. My first hand experience is telling me the ediff will not slow the car, and that it can actually only make it faster than an open diff.

Since Ediff cannot cut engine power like the other nannies and can only force a wheel with traction to accelerate, this equals more forward movement of the car.

I don’t see how slowing a tire with no traction, which isn’t contributing to forward movement, accelerating a tire with traction, and not cutting engine power can “slow the car”. It makes no sense!

What I just described is exactly the same way a LSD that reduced Pete’s track time by 6 seconds does. The LSD is better than Ediff but they are working towards the same goals and the end result is the same just Ediff isn’t as effective as LSD. But the ediff car cannot be slowed by the ediff it still has to be faster then a open diff car. Ediff is not “slowing the car”.

I propose a hypothetical example to show my train of thinking...

Let’s that in Pete’s example his car had an open diff the lap time might have been 100 seconds. He had Ediff added his lap time is now 96 seconds. Now he adds LSD his lap time is 90 seconds. The Ediff is serving a function and not slowing him down! It’s just not as good as a LSD but no ones saying it is.

[bbnks2]

Originally Posted by Biginboca

Let’s that in Pete’s example his car had an open diff the lap time might have been 100 seconds. He had Ediff added his lap time is now 96 seconds. Now he adds LSD his lap time is 90 seconds. The Ediff is serving a function and not slowing him down! It’s just not as good as a LSD but no ones saying it is.

I'm sorry but the thing that you, and the others who try to defend the e-diff, continue to want to ignore is that the e-diff doesn't always work the way it's programmed to like in a perfect world. E-diff can absolutely be slower around a corner than an open diff. I am not qualified, and neither are you by the looks of it, to try to explain it. There are cars that lap faster than a e8x/e9x that have open diffs. I've ran my 135i with an open diff. My lap times were actually pretty much dead on consistent with the e-diff lap times and possibly 1s faster at LimeRock (hard to tell such a small difference). The car felt different for sure (more predictable/smooth I dare say?). Running an open diff is not a problem if you've got the mechanical grip and you know how to use your right foot properly (I also have linear throttle mapping instead of BMWs 80% throttle at 20% input).

The e-diff programming is designed to keep the rear-end in check... it's not designed for taking sharp turns on-power. E-diff is trail braking through turns due to wheel speed differences even in situations where both tires are still providing adequate Mechanical grip. A mechanical LSD operates as an open-diff while cornering until resistance changes (NOT wheel speed like the e-diff)... Just because two wheels are spinning at different speeds does not mean you need to slow one of them down. Also, the e-diff begins applying the brakes before the slip ever happens. That's an example of unwarranted loss that slows the cars acceleration and/or robs power.

Also, any differential adds drivetrain loss vs an open diff. If you don't have traction loss all this lsd babble is a moot point (again, even a mechanical diff operates as an "open-diff" while cornering). You keep bringing up 200rpm in/2 rotations out... But then ignoring that the frictional loss of ANY lsd means you won't be getting 200rpm in anymore since there is more drive-train loss. The motor can only provide a finite amount of torque.

Another consideration is that the e-diff might actually measure ALL 4 WHEEL SPEEDS. Meaning, the e-diff can, and will, influence full-on drifts by reducing power output (if what I am saying is true). I say this because of what I've experienced at dyno sessions... Ever taken an e-diff equipped car to a dyno? Even if you disable all traction control, the car will not run on a dyno properly. It takes a few minutes for the car (e-diff) to FREAK OUT enough about the rear wheels spinning faster than the fronts before the car THROWS A MECHANICAL FAULT and completely disables ABS/E-diff (Trifecta lights on the dash). So yes, based on this theory, the e-diff slows down full-on drifts to "keep them in check" to a certain degree before it fails altogether. After leaving a dyno session you need to clear abs faults to get your e-diff/abs back (you will have the trifecta lights on the dash). Also, my 135i has massive torque that SHOULD be adequate enough for doing burnouts, yet when trying to do a full-on drift the car BOGS. The only time people seem to get these cars to drift is in the rain and yet even at 450wtq the car seems to barely be able to sustain that drift (all that braking being applied).

The e-diff is also most likely tied into the yaw sensor. It uses the cars yaw rate to apply it's preemptive brake force. However, a tuned car can easily see a greater yaw rate than a factory car without losing mechanical grip. Again, another example of how e-diff slows the car down (it's predictive braking).

A lot of what I just said is speculation (none of us know how e-diff programming looks), but the e-diff does cause the car to feel funky at times. I've seen the car burn up the left tire and then 2 seconds later the opposite tire is lighting up. That's the e-diff trying to balance the torque through the application of the brakes. It's doesn't work right sometimes plain and simple... Rcomps need a bit of slip at times and produced mechanical grip at significantly greater slip angles than a street tire... track pads have significantly different friction coefficients depending on temperature... These are variables that the e-diffs programming were not designed around.

If you still don't understand what we are trying to say, read this:http://www.houseofthud.com/differentials.htm

The "EDL (often referred to as Electronic Traction Control)" and the "So why use EDL if it's so bad?" sections explain the issues pretty well (the same issues many people are trying to point out here).

[justpete]

Originally Posted by bbnks2

I'm sorry but the thing that you, and the others who try to defend the e-diff, continue to want to ignore is that the e-diff doesn't always work the way it's programmed to like in a perfect world. E-diff can absolutely be slower around a corner than an open diff. I am not qualified, and neither are you by the looks of it, to try to explain it. There are cars that lap faster than a e8x/e9x that have open diffs. I've ran my 135i with an open diff. My lap times were actually pretty much dead on consistent with the e-diff lap times and possibly 1s faster at LimeRock (hard to tell such a small difference). The car felt different for sure (more predictable/smooth I dare say?). Running an open diff is not a problem if you've got the mechanical grip and you know how to use your right foot properly (I also have linear throttle mapping instead of BMWs 80% throttle at 20% input).

The e-diff programming is designed to keep the rear-end in check... it's not designed for taking sharp turns on-power. E-diff is trail braking through turns due to wheel speed differences even in situations where both tires are still providing adequate Mechanical grip. A mechanical LSD operates as an open-diff while cornering until resistance changes (NOT wheel speed like the e-diff)... Just because two wheels are spinning at different speeds does not mean you need to slow one of them down. Also, the e-diff begins applying the brakes before the slip ever happens. That's an example of unwarranted loss that slows the cars acceleration and/or robs power.

Also, any differential adds drivetrain loss vs an open diff. If you don't have traction loss all this lsd babble is a moot point (again, even a mechanical diff operates as an "open-diff" while cornering). You keep bringing up 200rpm in/2 rotations out... But then ignoring that the frictional loss of ANY lsd means you won't be getting 200rpm in anymore since there is more drive-train loss. The motor can only provide a finite amount of torque.

Another consideration is that the e-diff might actually measure ALL 4 WHEEL SPEEDS. Meaning, the e-diff can, and will, influence full-on drifts by reducing power output (if what I am saying is true). I say this because of what I've experienced at dyno sessions... Ever taken an e-diff equipped car to a dyno? Even if you disable all traction control, the car will not run on a dyno properly. It takes a few minutes for the car (e-diff) to FREAK OUT enough about the rear wheels spinning faster than the fronts before the car THROWS A MECHANICAL FAULT and completely disables ABS/E-diff (Trifecta lights on the dash). So yes, based on this theory, the e-diff slows down full-on drifts to "keep them in check" to a certain degree before it fails altogether. After leaving a dyno session you need to clear abs faults to get your e-diff/abs back (you will have the trifecta lights on the dash). Also, my 135i has massive torque that SHOULD be adequate enough for doing burnouts, yet when trying to do a full-on drift the car BOGS. The only time people seem to get these cars to drift is in the rain and yet even at 450wtq the car seems to barely be able to sustain that drift (all that braking being applied).

The e-diff is also most likely tied into the yaw sensor. It uses the cars yaw rate to apply it's preemptive brake force. However, a tuned car can easily see a greater yaw rate than a factory car without losing mechanical grip. Again, another example of how e-diff slows the car down (it's predictive braking).

A lot of what I just said is speculation (none of us know how e-diff programming looks), but the e-diff does cause the car to feel funky at times. I've seen the car burn up the left tire and then 2 seconds later the opposite tire is lighting up. That's the e-diff trying to balance the torque through the application of the brakes. It's doesn't work right sometimes plain and simple... Rcomps need a bit of slip at times and produced mechanical grip at significantly greater slip angles than a street tire... track pads have significantly different friction coefficients depending on temperature... These are variables that the e-diffs programming were not designed around.

If you still don't understand what we are trying to say, read this:http://www.houseofthud.com/differentials.htm

The "EDL (often referred to as Electronic Traction Control)" and the "So why use EDL if it's so bad?" sections explain the issues pretty well (the same issues many people are trying to point out here).

Definitely tied into the yaw sensor but more importantly, the steering angle sensor so it can compute the ideal rear wheel speed difference and pulse the brakes should the measured speeds deviate beyond bounds. There is latency in the computation and it appears from observation on the track that the system is pretty much only capable of dealing with normal aggressive street driving but track driving at anything other than novice levels is beyond its programming. The stability system certainly exhibits this behavior and the e-diff no doubt deviates from ideal LSD-approximation just as easily which in turn leads to a net slowing rather than a net acceleration as inner wheel slip starts to occur under heavy track driving conditions. Otherwise it has to act very much like a limited slip, and does, the theory is quite clear (and I did minor in ME) but the reality of this implementation under what would be abnormal conditions is quite a bit different and wouldn't be experienced unless tracking the car. It'll be interesting to see how the MDM software works in the M6, from what I've read it's actually not bad at all but then it would have to be given the cars it's found on.

[vasillalov]

e-Diff is designed to prevent grandma/grandpa from tail spinning on an icy road by cutting the power from the driveline and by playing with the DSC and the ABS.

It is total garbage for the track! The end. Full stop!

If you have any serious aspirations for track driving, get a mechanical diff and then code out all of the other systems to stop interfering with the car. Those revolve around coding the DSC (DXC), ABS and the traction control.

[justpete]

Originally Posted by vasillalov

e-Diff is designed to prevent grandma/grandpa from tail spinning on an icy road by cutting the power from the driveline and by playing with the DSC and the ABS.

It is total garbage for the track! The end. Full stop!

If you have any serious aspirations for track driving, get a mechanical diff and then code out all of the other systems to stop interfering with the car. Those revolve around coding the DSC (DXC), ABS and the traction control.

Disconnect your steering angle sensor, easy peasy.

[feuer]

Originally Posted by justpete

Disconnect your steering angle sensor, easy peasy.

Are you certain that this disables the ABS completely?

[justpete]

Originally Posted by feuer

Are you certain that this disables the ABS completely?

Yes, I can easily lock up the brakes at will.

[aaddam2]

think a Head to Head battle between eDiff and LSD is needed to sort this out, someone needs to commission randy pobst for this test.

I too want a LSD but dont really want to spend 2k...stupid welded ring gear adding cost!

[feuer]

Originally Posted by aaddam2

think a Head to Head battle between eDiff and LSD is needed to sort this out, someone needs to commission randy pobst for this test.
I too want a LSD but dont really want to spend 2k...stupid welded ring gear adding cost!

For this to be accurate it will have to be the same car that will undergo diff swap. I think with a race car driver driving the difference would be insignificant because armatures won't be as comfortable to drive as aggressively without LSD. You can have Wavetrac LSD for about $1800.

[aaddam2]

To OP, to one Intermediate (more on the novice end) to another, I drove with full Traction on last year and really didnt feel the car being held back too much unless i hit the rumble strip, or had the rear slip out slightly. a few times i was glad I had it on. I plan on single pressing it this year. my car is way more powerful this year than last so ill probably wait until later sessions until I do that haha. but if you autocross the single press method is trash! turn it all the way off! instantly made up like 2+ secs on <60sec course. think traction is all dependent on confidence and skill. when I feel that the nanny is really holding me back then ill turn them off. that way the confidence isnt greater than the skill, bc thats when bad things happen.

I do find it interesting/funny that the eDiff wears the rears down faster than fronts especially if you are tracking the car (rears are lower than fronts and i changed rears 2 track days after the fronts along with normal driving). good thing i work for a brake company lol

[feuer]

aaddam2 hook us up with brake pads! My front to rear pad wear ratio is almost 3 to 1. While just starting the 3rd front set I need to replace the rear. Or sometimes toward the end of the 2nd front set. I have the F-series big brake kit. I go through few sets per track season.

[aaddam2]

Originally Posted by feuer

aaddam2 hook us up with brake pads! My front to rear pad wear ratio is almost 3 to 1. While just starting the 3rd front set I need to replace the rear. Or sometimes toward the end of the 2nd front set. I have the F-series big brake kit. I go through few sets per track season.

Oh wow! what pads are you running currently? and did you have to swap in the M3 Master Cylinder? but was running what is now called Raybestos SP918XPH front, Raybestos SP1170XPH rear last year. testing a new pad formula this year. did like a total of 5 track days and like 3-4 AutoX. and pads are at like 1/2 life. they are very stable over a broad temp range, bit dusty but not squeaky.

maybe I my slow diesel doesnt stress my brakes as much haha.

I also wonder if we have crossed paths since i see you are in Chicago. we should link up at some track days this year.

[feuer]

Originally Posted by aaddam2

Oh wow! what pads are you running currently? and did you have to swap in the M3 Master Cylinder? but was running what is now called Raybestos SP918XPH front, Raybestos SP1170XPH rear last year. testing a new pad formula this year. did like a total of 5 track days and like 3-4 AutoX. and pads are at like 1/2 life. they are very stable over a broad temp range, bit dusty but not squeaky.

maybe I my slow diesel doesnt stress my brakes as much haha.

I also wonder if we have crossed paths since i see you are in Chicago. we should link up at some track days this year.

I use the BMW OEM pads. The front370/rear345mm F-series rotors are expansive so rotor friendly pads is what I prefer. The brakes are huge so BMW OEM are Ok. I change the master cylinder too. I do 10 to 12 track days. Blackhawk, Autobahn and Gingerman. Basically every other weekend or so during track season. BMW OEM pads are very dusty and I hate washing the Apex wheels. Check with your people about F-series pads. The 335d make more than sufficient power. Seat time will make you go faster.

[bbnks2]

Originally Posted by feuer

I use the BMW OEM pads. The front370/rear345mm F-series rotors are expansive so rotor friendly pads is what I prefer. The brakes are huge so BMW OEM are Ok. I change the master cylinder too. I do 10 to 12 track days. Blackhawk, Autobahn and Gingerman. Basically every other weekend or so during track season. BMW OEM pads are very dusty and I hate washing the Apex wheels. Check with your people about F-series pads. The 335d make more than sufficient power. Seat time will make you go faster.

Dust = stopping power

[feuer]

Originally Posted by bbnks2

Dust = stopping power

True but some dust less than others. I think, at least from what I have seen on track, Hawk, Stop Tech, CoolCarbon, Performance Friction and Porterfield all dust less than BMW OEM pads. I has been 4 seasons on the F-series brakes and I would like to try other pads.

[aaddam2]

Originally Posted by feuer

True but some dust less than others. I think, at least from what I have seen on track, Hawk, Stop Tech, CoolCarbon, Performance Friction and Porterfield all dust less than BMW OEM pads. I has been 4 seasons on the F-series brakes and I would like to try other pads.

Originally Posted by feuer

True but some dust less than others. I think, at least from what I have seen on track, Hawk, Stop Tech, CoolCarbon, Performance Friction and Porterfield all dust less than BMW OEM pads. I has been 4 seasons on the F-series brakes and I would like to try other pads.

We dont have any performance pads for the F3x calipers yet. ill put in the good word to the guys that are in charge of that

we do offer a EU pad for you tough a more robust pad for higher energy cars (heavy euro cars with power and need to withstand stuff like autobahn) might be better as an OE substitute. but also porterfield is raybestos ST pad line.

did you know brake dust is actually mostly from rotors not pads? are you using drilled/slotted rotors? i would say go cheaper with blanks, and splurge more on pads.

btw Gridelife midwest signed up, and debating which GPSTracktime's im going to do this year, maybe the WindyCityBMW track day at ABCC South.

[feuer]

Originally Posted by aaddam2

We dont have any performance pads for the F3x calipers yet. ill put in the good word to the guys that are in charge of that

we do offer a EU pad for you tough a more robust pad for higher energy cars (heavy euro cars with power and need to withstand stuff like autobahn) might be better as an OE substitute. but also porterfield is raybestos ST pad line.

did you know brake dust is actually mostly from rotors not pads? are you using drilled/slotted rotors? i would say go cheaper with blanks, and splurge more on pads.

btw Gridelife midwest signed up, and debating which GPSTracktime's im going to do this year, maybe the WindyCityBMW track day at ABCC South.

Yes, I have the dimpled/slotted. However, on same rotors Lamumba is using front pads D1609 and rear pads D1656. They are called Porterfield RS4 I think and brake better than BMW OEM with lot less dust. But they are twice as much than BMW OEM so I never got them. Is this Raybestos ST similar to RS4? Gridelife is expensive. I go with GPS, Autonation, MVP and Gingerman track dirrectly.

[The HACK]

This is the problem I have with you E9x guys.

NONE of this stuff you guys are arguing matters if the OP isn't even capable of extracting more than 60% of what the car is capable of. You guys focus WAY too much on the equipment, when the REAL equipment y'all need to focus on is the hardware between the seat and the steering wheel.

2 pages of arguing about e-Diff? Really, a good driver learn to extract performance out of the limitations of the car. Traction control and DSC holding you back? Unless you're time-trialing or wheel-to-wheel racing, what you (OP) should be concentrating on is figuring out IF the DSC is kicking in all the time, why it's kicking in. Is it kicking in to save you from the wall @ Auto Club Speedway at 130mph, or is it kicking in because you've extracted all the performance beyond the parameters set by BMW?

And if your answer is "I don't know?" Leave it on. And even if your answer is "I've extracted all the performance I can as limited by BMW's DSC programming?" Leave it on and drive and see if you can pick up another 1/2 second per lap with it on. Trust me. You can.

Before I was made an instructor more than a decade ago, I was SURE I was extracting all I could from my car and the first gen DSC on the E46 was holding me back. I had an instructor with me in one of the B group runs, I kept pestering him about turning off my DSC. He says he trusts my skills enough, he'll allow me to turn off DSC on one condition. That I get a ride with him in his E46 after a session with the DSC off. Keep in mind this is all before Harry's Lap Timer, and all I had was a first gen GoPro HD. So I recorded my session without DSC with the GoPro, then hopped into his car (same model E46 as mine) with the same GoPro. He insist that for 2 laps that I keep an eye on his dash, then he proceeds to drive 5 hot laps with DSC ON.

So all this time, I figure he just wanted to get a few hot laps in (BMW CCA at the time discourage instructors from driving without a passenger, so the only way instructors get to drive is to take a student or fellow instructor out) Once his warm-up lap was over I noticed that his DSC wasn't kicking in, despite the fact that it was on (light off on dash). In 5 laps it maybe kicked in once at one of the slowest corner of the track. When we came back into the pits, he drops me off with a big grin and told me to review and watch my video.

This being the first gen GoPro HD, I couldn't review anything unless I had a computer to download the footage from the SD card. So I got home after the weekend, and watched and reviewed my own driving vs. the laps I caught in the instructor's car. To my chagrin, the instructor's lap time with DSC on was nearly 2.5 seconds faster than mine with DSC off on a 2 minute and change lap. Granted, it wasn't the same exact car, nor the same equipment on the car (his was far more "stock" than mine at the time), nor likely the same tires (I didn't check, my ego tells me that he was on better tires, but in all reality, given how much noise it was making, it's unlikely it was THAT much better than the Extreme Summer Bridgestone S-03s I had at the time).

Don't get me wrong. I wasn't a slouch by any stretch of imagination. It was a track that I had driven at least a dozen days. I probably have had about 30 track days at that time, and was one of the faster drivers in the "B" group. Yet with DSC "holding him back" he was easily 2.5 seconds faster than I was with DSC off.

So why am I telling you all this?

Even if you FEEL that DSC is holding you back, there are always ways you can use it as a tool to "learn" more. And yes, ultimately you WILL have to turn all the driver's aid you can turn off off to become a better driver. But there's NO point where you absolutely can't learn from having some aid turned on to see when and where it's interfering, and to figure out WHY it's interfering to make you a better driver.

If you're still reading, here's my standard disclaimer. You're a freaking glutton for punishment. I would PERSONALLY never read more than 2 sentences I have to write (or say). But if you want to skip all that, here's what you should do as a progression for learning how and when to turn off your driver's aid.

Leave it on. Start taking skid pad, car control, and autocross lessons. Leave it on for the track, turn it off for skid pad/car control/ax where if you do f**k up, and you WILL, nothing bad happens except for a bruised ego and a huge headache fro the rush of adrenaline (ask me how I know). Keep it on for track until you've done enough skid pad/car control/AX to a point where you're absolute confident with your car control skills, knowing you can and will catch mistakes before driver's aid intervene. At this point you should have done at least a dozen track days. Maybe more. You know how to push it and you can FEEL when the car intervenes, and even predict when the car WILL intervene.

At this point, turn off driver's aid, dial your speed back 2 notches, then ease yourself up to speed over several sessions. On an average 4 session track day, I would recommend leaving driver's aid on for the first session while you and the car get used to the surroundings, turn it off for the next 3 sessions, drive 2 notches slower in session 2, 1 notch slower in session 3, then up to speed in the first half of session 4 until you're comfortable driving with DSC off all the time.

Then turn DSC back on and see if you can match your lap time with DSC on and off. IF you can still drive faster with DSC off than on, continue to turn DSC on for a session or two to see if you can get the two speeds to normalize. When you can drive with DSC on as fast as you can drive with it OFF, what you'll find is the next session you turn DSC off, your lap time will likely IMPROVE.

Even at this stage, I occasionally will drive with DSC on for a session or two to assess, just to see if I'm actually better than the car's computer.

All bets are off in inclimate weather though. I once caught a car going sideways hydroplaning @ 90 mph. Let's just say it left a little more than a brown streak in my underpants.

[bbnks2]

Originally Posted by The HACK

This is the problem I have with you E9x guys.

NONE of this stuff you guys are arguing matters if the OP isn't even capable of extracting more than 60% of what the car is capable of. You guys focus WAY too much on the equipment, when the REAL equipment y'all need to focus on is the hardware between the seat and the steering wheel.

Everything you just ranted about is exactly what was said in the argument. E-diff and DSC are great for people who still need to build confidence and skill, but as you progress as a driver you will want to learn to drive with them turned them off. Even beginner level drivers in BMW CCA would use traction control (single click) because DSC just intervenes too much.

The argument was purely abotu whether E-DIFF slowed the car down, which I think no one will ever prove definitively either way with actual data, but I think I presented the bulk of the argument for why e-diff absolutely can be slower than an open diff in situations. I didn't really get any solid rebuttal.

[The HACK]

Originally Posted by bbnks2

Even beginner level drivers in BMW CCA would use traction control (single click) because DSC just intervenes too much.

No. That's not the point I'm trying to make. DSC intervenes too much because you don't know what you're doing. Even as an advanced intermediate driver in the CCA, with DSC off, I was SLOWER than an instructor driving a fairly similar car with DSC ON.

Read my post again. What I am saying, is if your DSC is kicking in all the time, and you're a beginner or intermediate driver, there's a reason why it's kicking in. It's not kicking in to intervene and slow you down. It's kicking in to save your @ss. Turn DSC off when you know what you're doing, and even then, turning it back on sometimes can lead to great learning opportunities.

What I've come to realize, having driven all manners of BMWs on track at speed, is that you can get sh*t balls FAST with DSC on and it won't intervene if you know what you're doing. An ADVANCED driver (A group or A solo type) can drive with it ON if they're being smooth up to about 8/10th, or about a second to 1.5 seconds off fast pace on a 2 minute lap*.

And again, after more than a decade instructing with a variety of track organizations out west, I'll say this. Those that complain the most about DSC holding them back are typically the types that will benefit MOST from having DSC on. That's just experience speaking. Those that benefit from turning DSC off are typically those that already understand the limitations of DSC and won't have to ask whether they need to "turn DSC off."

Let that sink in y'all.

* Above example implies a fairly average, technical track like Buttonwillow CW 13 or Chuckwallah Valley Raceway. For tracks like WSIR and Auto Club Speedway (to some extent), DSC plays by a different rule. Auto Club Speedway's high bank confuses the crap out of DSC, because on the oval portion the outside is turning much faster than the inside. On cars with track pads and big brakes, you can feel the "thump thump" every 3/10th of a second on the big oval when you're at speed** because the bank trips out the yaw sensor...Car thinks you're not turning as much as you are based on the steering angle, but the wheel sensors are telling it another thing. WSIR on the other hand, DSC on or off makes little difference because it's mostly high speed turns and sweepers. DSC rarely intervenes (for me, at least) at WSIR big track unless you screw up.

** Auto Club Speedway is one of those tracks that will bring most of your modern BMW to its knees. Because of the banking, and the fact that the e-Diff function can not be turned off, it eats up the rear brakes like few other tracks and causes limp mode due to brakes overheating rather than engine oil. I was in a particularly fast student's E92 328i once, and by the 2nd session he can only do about 2 laps at speed, then the car would go into limp mode. When we plugged in the ODBII, the oil and coolant temps were within range and should not have caused limp mode. Further investigation reveal that even with DSC turned off (yes I let him turn it off) the car was overheating the rear brakes due to the nature of the beast...ACS has a LONG banked turn, which causes the eDiff to activate on the long oval, and a bunch of 180º sweepers, hairpins, decreasing radius turns, combined with a tight, almost autocross like section near the end before you get back on the bank...The eDiff was screaming for mercy as his speed picked up in the 2nd session.

But clearly you guys are all advance drivers who know that DSC can only hold you back. So I'll shut up now and leave you all alone.

[bbnks2]

Originally Posted by The HACK

No. That's not the point I'm trying to make. DSC intervenes too much because you don't know what you're doing. Even as an advanced intermediate driver in the CCA, with DSC off, I was SLOWER than an instructor driving a fairly similar car with DSC ON.

Read my post again. What I am saying, is if your DSC is kicking in all the time, and you're a beginner or intermediate driver, there's a reason why it's kicking in. It's not kicking in to intervene and slow you down. It's kicking in to save your @ss. Turn DSC off when you know what you're doing, and even then, turning it back on sometimes can lead to great learning opportunities.

What I've come to realize, having driven all manners of BMWs on track at speed, is that you can get sh*t balls FAST with DSC on and it won't intervene if you know what you're doing. An ADVANCED driver (A group or A solo type) can drive with it ON if they're being smooth up to about 8/10th, or about a second to 1.5 seconds off fast pace on a 2 minute lap*.

And again, after more than a decade instructing with a variety of track organizations out west, I'll say this. Those that complain the most about DSC holding them back are typically the types that will benefit MOST from having DSC on. That's just experience speaking. Those that benefit from turning DSC off are typically those that already understand the limitations of DSC and won't have to ask whether they need to "turn DSC off."

Let that sink in y'all.

* Above example implies a fairly average, technical track like Buttonwillow CW 13 or Chuckwallah Valley Raceway. For tracks like WSIR and Auto Club Speedway (to some extent), DSC plays by a different rule. Auto Club Speedway's high bank confuses the crap out of DSC, because on the oval portion the outside is turning much faster than the inside. On cars with track pads and big brakes, you can feel the "thump thump" every 3/10th of a second on the big oval when you're at speed** because the bank trips out the yaw sensor...Car thinks you're not turning as much as you are based on the steering angle, but the wheel sensors are telling it another thing. WSIR on the other hand, DSC on or off makes little difference because it's mostly high speed turns and sweepers. DSC rarely intervenes (for me, at least) at WSIR big track unless you screw up.

** Auto Club Speedway is one of those tracks that will bring most of your modern BMW to its knees. Because of the banking, and the fact that the e-Diff function can not be turned off, it eats up the rear brakes like few other tracks and causes limp mode due to brakes overheating rather than engine oil. I was in a particularly fast student's E92 328i once, and by the 2nd session he can only do about 2 laps at speed, then the car would go into limp mode. When we plugged in the ODBII, the oil and coolant temps were within range and should not have caused limp mode. Further investigation reveal that even with DSC turned off (yes I let him turn it off) the car was overheating the rear brakes due to the nature of the beast...ACS has a LONG banked turn, which causes the eDiff to activate on the long oval, and a bunch of 180º sweepers, hairpins, decreasing radius turns, combined with a tight, almost autocross like section near the end before you get back on the bank...The eDiff was screaming for mercy as his speed picked up in the 2nd session.

But clearly you guys are all advance drivers who know that DSC can only hold you back. So I'll shut up now and leave you all alone.

Maybe you just suck? I speak from my personal experience and my lap times aren't too far off "advanced" drivers even if my technique and confidence is not up to par... You make a lot of assumptions and you miss the point because of your own personal experiences... You admit yourself that DSC is slower and then you assume the people who began a discussion within this thread can't drive at level where DSC makes you slower LOL Everyone stressed to OP to leave the nannies on for now...