[ronin951]

Originally Posted by DVC

Yes, good point - I believe the variances are really just in the realm of throttle mapping. (Corrected my terminology above)

+1 for the mapping. On the manual if you hit the sport button the car will accelerate. When going back to Comfort the opposite is true.

[DVC]

I just updated the chart in a few areas... after testing some more over the last couple of days, there are definitely some minor variances in transmission characteristics depending on the mode.
Also, in addition to the obvious throttle mapping differences in Sport mode, I definitely feel like the throttle response is a bit more sensitive in Sport as well.

[utenigma]

Originally Posted by DVC

I just updated the chart in a few areas... after testing some more over the last couple of days, there are definitely some minor variances in transmission characteristics depending on the mode.
Also, in addition to the obvious throttle mapping differences in Sport mode, I definitely feel like the throttle response is a bit more sensitive in Sport as well.

In sport with the drivetrain set to normal? I think you're just feeling the shocks not compressing when the drivetrain winds up - results in a more immediate throttle response, but not a more sensitive throttle pedal.

[DVC]

Originally Posted by utenigma

In sport with the drivetrain set to normal? I think you're just feeling the shocks not compressing when the drivetrain winds up - results in a more immediate throttle response, but not a more sensitive throttle pedal.

No, I'm not saying that the throttle in Sport mode with normal drivetrain is more responsive than Comfort mode... I'm saying that the throttle in Sport driveline configuration (either Sport mode with Sport driveline settings, or in Sport+ mode) is more responsive than Normal driveline configuration (either Comfort mode, or Sport mode with normal driveline configuration).

For the normal vs sport throttle comparison, I evaluated Sport-with-drivetrain-set-to-normal vs Sport+ so the suspension settings were the same.

[ronin951]

I nominate this thread for sticky. DVC you are doing us all a great service.

[DVC]

Originally Posted by ronin951

I nominate this thread for sticky. DVC you are doing us all a great service.

Thanks! utenigma started off a good thread with lots of great info and tests, so I'm happy to add some value to it.

[ronin951]

Originally Posted by DVC

Thanks! utenigma started off a good thread with lots of great info and tests, so I'm happy to add some value to it.

Indeed!

[jetbill]

First AutoX event today with the new car, EB II M-Sport with DHP - handled great.

Seems DSC off with eLSD active is the way to go. Very easy to modulate throttle, as some of you have suggested.
Now I just wish I can set "normal" throttle in Sport mode (firm suspension) but still have the safety nannies on.

DVC I referred to you chart today, very handy to reference on the fly so thanks for creating that. Now that I've got the RE-11's scrubbed in I think I'm ready to get some good times in next weekend.

I think we should all start bugging Dinan for their Shockware software to be released. Now the question is to go H&R, Eibach or stay with stock springs in the interim.

[DVC]

Originally Posted by jetbill

...I just wish I can set "normal" throttle in Sport mode (firm suspension) but still have the safety nannies on.

Hi JB - sorry, but I was just referring back to this thread and re-read your comment above...

If you configure Sport mode to chassis-only, you will have "normal" throttle, and DSC will still be fully active. Is that what you were looking for?

[DVC]

Originally Posted by JMK007

If DSC is off in sport mode, there should be no sport oriented stability control at all. It should be turned off completely, meaning no electronic nanny. Sport + activates dynamic stability control (or sport stability control) allowing the car to oversteer a little before the electronic nanny kicks in. With DSC off while in Sport, there should be no stability control interference whatsoever.

I was playing around in a snow-covered parking lot today, and I was able to validate something that I experienced on the track a couple months ago (but wasn't sure if I had interpreted it correctly).

There's lots of ambiguous information out there about what's actually happening in DTC mode... the consensus seems to be what JMK mentions above: that DTC still incorporates some stability control, but will allow some significant slip angles before cutting in (as DSC would).
Based on my experience, I can pretty confidently say that DTC is purely traction control, and does absolutely nothing in terms of DSC-type stability control. Basically, it allows a bit of wheel slip, and then starts to cut power to the slipping wheel(s).
This is good news for those of us who like to track the car with heavy steering, ultra-responsive throttle, and no DSC. (rev1.2 of my settings chart coming soon ; )

...

For those curious on how I determined this... read on:
On the track back in October (Lightning circuit at NJ Motorsports Park), in my last session of the day, my tires were a bit slick after picking up a bunch of marbles during an off-line pass, and exiting turn 9 at about 100 my back end started to come around. I felt it happening, and started to gently counter-steer and back off the throttle a little... and the back end came back into check nicely without any drama. My instructor smiled and said, aren't you glad you had the stability control on for that? I told him I was pretty sure that it was me that saved it, as I didn't feel the car do anything whatsoever... (I was in Sport+ all day, so DSC was set to only "DTC") But afterwards, I re-thought it and wondered if maybe the car saved it rather than me.

Now flash forward to today... Out in the snow-covered parking lot, I was kicking the back end around under acceleration in DSC, DTC, and DSC-off to evaluate how things reacted in each scenario:

• DSC - as expected, electronics were working hard to cut power and wheel spin, and apply brakes to individual wheels to kill the over steer. Even when I kicked off a spin, and then immediately lifted off the throttle, DSC stayed active and was pretty effective at keeping the car from spinning much at all.
• DTC - Traction control kicked in after a little wheel slip to fight spinning wheel(s), but nothing to mitigate spin. I tried a couple times kicking off a spin and just lifting off the throttle (so there was no wheel spin, and no traction control action happening) and the car would just spin freely without any lights coming on... I could easily spin through a full 360 without any DTC activity of any sort.
• DSC-off - No DSC-type intervention, but lots of e-LSD activity in effort to mitigate wheel slip. Once spinning, the car continued to spin freely similar to as in DTC mode.

So Sport+ mode seems pretty well-suited for the track after all... Just the effect of cutting excessive wheel spin under acceleration shouldn't be too invasive (wasn't problematic for me at any point), and may be just enough to help avoid a spin that isn't easily corrected if the driver severely overcooks it.

[SergioK]

So at the end of the day, for track days, just throw it into Sport+ and be done with it?

[DVC]

Originally Posted by SergioK

So at the end of the day, for track days, just throw it into Sport+ and be done with it?

Yep

[momo3605]

Originally Posted by DVC

Yep

Wait no. I thought sport+dsc/dtc off was best. That way you get e-LSD

[DVC]

Originally Posted by momo3605

Wait no. I thought sport+dsc/dtc off was best. That way you get e-LSD

Not much difference between the effect of eLSD and DTC from what I could tell... in the snow at least. But Sport+ retains the sharper throttle mapping/response.

[utenigma]

Sport+ pulls your throttle when the rear slips

If you're at the tractive limit of the tires mid corner and apply throttle coming out of the apex, you don't want the ecu pulling throttle when the rear tires lose traction (which they should a little), nor do you want a touchy throttle

IMO I still think DSC OFF is the best way to go

[momo3605]

I'm going to say that if you're tracking with large wide turns, then sport+ might be the better option, but for autocrossing (which I've done) sport+ pulls the throttle too much and DSC OFF/Sport is the better option.

[DVC]

Originally Posted by utenigma

Sport+ pulls your throttle when the rear slips

If you're at the tractive limit of the tires mid corner and apply throttle coming out of the apex, you don't want the ecu pulling throttle when the rear tires lose traction (which they should a little), nor do you want a touchy throttle

DTC does allow some wheel spin before steps in and cuts power. eLSD applies ABS to a slipping wheel to mitigate spin. Definitely a different approach to maintaining traction, but neither is ideal.
But if you're at the limit of grip mid-corner, and you apply power, then either eLSD or DTC would intervene to mitigate excessive wheel spin. I'd be curious to hear feedback from others on how well (or poorly) each function in this regard. As I indicated above, I had no issues with DTC on the track... even as my back end started to come around, it didn't intervene. Maybe in other situations or for others, it has been more invasive (?)
I haven't spent much time in eLSD mode on dry pavement... but prior to the snow testing, I did also test it out on a slicked-up figure 8 skid pad at the track...I found it to be pretty invasive, and all the rear ABS activity was a little freaky.

I personally don't mind the sharp throttle mapping, and find it to be a fair trade for the improved responsiveness that comes along with it. It requires a more nuanced touch, but the slightly increased lag in comfort throttle bugs me.

Originally Posted by momo3605

I'm going to say that if you're tracking with large wide turns, then sport+ might be the better option, but for autocrossing (which I've done) sport+ pulls the throttle too much and DSC OFF/Sport is the better option.

Maybe this is the rule of thumb...
Can you share some details on your experience with the effects of DTC vs. eLSD on dry asphalt? (On snow, the effect felt pretty much the same)

[momo3605]

Originally Posted by DVC

Depending on how well the eLSD actually works on asphalt, then I could see that making sense...
Can you share some details on your experience with the effects of DTC vs. eLSD on dry asphalt? (On snow, the effect felt pretty much the same)

So the thing is, this thread wasn't created until after I had autocrossed, so I didn't even know the car had e-LSD, hence I wasn't paying attention or feeling for it, but I will say with DTC, if I went into a sharp turn that exits on to a straight, it did let the rear slide, but once the rear was sliding, it cut the power, so I couldn't accelerate out of the turn and had to wait until the tires were back in line. With DTC OFF, this was no longer an issue. Again, it was more than a couple months ago, but from what I remember, I was able to create much larger drift angles and without much care, I didn't have any trouble catching the car out of the turn. I assume this was due to the e-LSD working with me. In the end, my times were faster with DTC off. The other difference that could have accounted for the times was the normal vs sport throttle response. The sport throttle is much more twitchy and having smooth throttle inputs is important to fast lap times.

DVC...I'm not sure how fast you were going in the parking lot, but I feel like you need 30+mph to really feel the difference.

[DVC]

Originally Posted by momo3605

So the thing is, this thread wasn't created until after I had autocrossed, so I didn't even know the car had e-LSD, hence I wasn't paying attention or feeling for it, but I will say with DTC, if I went into a sharp turn that exits on to a straight, it did let the rear slide, but once the rear was sliding, it cut the power, so I couldn't accelerate out of the turn and had to wait until the tires were back in line. With DTC OFF, this was no longer an issue. Again, it was more than a couple months ago, but from what I remember, I was able to create much larger drift angles and without much care, I didn't have any trouble catching the car out of the turn. I assume this was due to the e-LSD working with me. In the end, my times were faster with DTC off. The other difference that could have accounted for the times was the normal vs sport throttle response. The sport throttle is much more twitchy and having smooth throttle inputs is important to fast lap times.

DVC...I'm not sure how fast you were going in the parking lot, but I feel like you need 30+mph to really feel the difference.

Interesting... so maybe the eLSD does a better job than DTC at allowing a little power down while the back end is still drifting a bit. (Of course your skills have no doubt continued to improve, which of course lowers your times too ; )
Regarding your DTC experience, it will certainly cut power when the wheels are spinning a bit - but slip angles don't affect it. So regarding the issue you mention above with applying power coming out of the turn, DTC was cutting power due to wheel spin, not (directly) due to the slip angle. In theory, the eLSD would have intervened also, don't you think? Maybe the effect of the eLSD is just more mild on dry asphalt... (?)

[momo3605]

Originally Posted by DVC

Interesting... so maybe the eLSD does a better job than DTC at allowing a little power down while the back end is still drifting a bit. (Of course your skills have no doubt continued to improve, which of course lowers your times too ; )
Regarding your DTC experience, it will certainly cut power when the wheels are spinning a bit - but slip angles don't affect it. So regarding the issue you mention above with applying power coming out of the turn, DTC was cutting power due to wheel spin, not (directly) due to the slip angle. In theory, the eLSD would have intervened also, don't you think? Maybe the effect of the eLSD is just more mild on dry asphalt... (?)

Yup! I think you're exactly on the mark. Regarding my lower times, that is probably a big factor too haha. And yea I think the eLSD was intervening, but very mildly just like you said. Unlike the DTC which literally just felt like it stopped sending power at all, the eLSD felt more gently and mild. From what I could tell, the eLSD felt like it was just nudging you into stopping your slide by braking on the wheel that was spinning too much.

Someone correct me if I'm wrong, but traction control doesn't use the brakes right? It just cuts power to the engine. eLSD in most cars works by applying brakes to one wheel to bring it's speed down to that of the other wheel.

[momo3605]

Also, quick question based on the chart above. Launch Control?? How does that work on the 3 series?

[DVC]

Originally Posted by momo3605

Yup! I think you're exactly on the mark. Regarding my lower times, that is probably a big factor too haha. And yea I think the eLSD was intervening, but very mildly just like you said. Unlike the DTC which literally just felt like it stopped sending power at all, the eLSD felt more gently and mild. From what I could tell, the eLSD felt like it was just nudging you into stopping your slide by braking on the wheel that was spinning too much.

Someone correct me if I'm wrong, but traction control doesn't use the brakes right? It just cuts power to the engine. eLSD in most cars works by applying brakes to one wheel to bring it's speed down to that of the other wheel.

Sounds like eLSD mode may have some advantages over DTC on the track (DTC only cuts engine power; no application of the brakes).
I'm curious about exactly how thorough eLSD effects actually are... like, does it just slow the spinning of the wheel a little so that the loss of grip isn't as impactful, or does is clamp down hard enough so that the open diff actually switches torque over to the other wheel? I've heard that an eLSD is no substitute from a performance standpoint for a mechanical LSD, but it sounds like it's still pretty good at putting a little power down while still mitigating over steer.
I've also heard that eLSDs can be hard on brake pads... have you noticed any additional rear brake wear after autocrossing in eLSD mode vs DTC?

Originally Posted by momo3605

Also, quick question based on the chart above. Launch Control?? How does that work on the 3 series?

Launch control is new on the 2014 8ATs. Being a torque-converter auto, there's not as much going on as there is with LC on a DTC-equipped M car, but apparently it does work well at integrating all the systems automatically to yield the fastest launch.