TRZ06

Be careful with what you read online, go to the manual. MDM mode on BMW's "reduces the level" of intervention for BOTH traction control and stability control.

If you read the GT4 manual, when you push the ESC button, you lose ALL stability control but retain traction control. When you push ESC + TC OFF button, you turn off both systems. There is no MDM functionality mode on the GT4 where you have a lower threshold of both systems.

Avera

@jmartpr

I hear you loud and clear and my last name is most certainly not Ester or Bernhard.

I do not know if you mean completely or partially 'off'? I am under the impression ESC mode is similar to MDM mode.

To be clear, I am not a hooligan on the roadways, but I never felt unsafe or careless in MDM mode. I know we are not talking about ///M cars, but I am trying to relate my experiences to the discussion.

After all the excellent feedback provided in posts by members, I feel inclined to try ESC mode. Seems to be safe and a bit liberating. Once I get the chance I might very well find no enjoyment advantage over having stability/traction control fully activated?

Avera

YMGT4

again- there is no MDM mode in a GT4, which allows playful but safe-ish levels of slip angle and wheel spin (there are still nannies intervening here).

on a GT4- it's either no stability control but TC still, or nothing at all.

if you put ESC off on a road and over cook a turn and don't catch it you will crash. there is no level of yaw where it intervenes to save you. Don't play around with ESC/TC settings on the road please. go to a skid pad if you're going to do this.

TRZ06

Go read the GT4 manual before you go there. See my last post.

Avera

@TRZ06

Another excellent post . . . thank you.

You and many like you on these forums are the best source of information. Have you ever spoken with a BMW 'Genius?' If it were not for Bimmerpost, BMW owners would be in the dark about their cars. No different here on Rennlist when it comes to our P cars.

I am going to give ESC a whirl to see what it is all about, but no interest in having both traction and stability control completely turned off. Again, I do not want to give the impression I am a hooligan on the roadways.

Avera

P.S. you got another post in before I could respond to the one before it I am hearing what you are you saying.

TRZ06

Try to find a huge empty parking lot to play with or go do an autoX. You don't want to be going to 10/10th of adhesion on a curvy public road with stability control off.. Just my opinion.

At the very least an empty on/off ramp with a lot of run off on both sides.

It doesn't take too much to get the GT4 out of shape with the right circumstances. I once got about a 30 degree yaw rotation with all systems on, exiting an off-ramp that had a bit of loose gravel on it with worn Cup 2 tires.

Avera

@YMGT4

Your post slipped by me . . . I will not be exploring ESC unless in a safe environment to do so. I value my well being, as well as other with whom I share the roadways

Avera

Avera

@TRZ06

Yep, per my prior post, I will explore in an appropriate environment.

Avera

TRZ06

That is the double edge sword of having a relaxed system fully on. While it gives you more room to play and to not be intrusive, it also can catch you off guard as well and gives you too much slip at times when you don't want it.

I

Avera

I hear you and others . . .

One thing I believe is worth mentioning is the difference between turbo engines like the S55 and S58 vs the GT4 NA flat6.

The S55 and to a slightly lesser degree the S58 tend to 'throw up' their torque in the lower RPM range. In other words, a little throttle input goes a long ways and the torque can really 'kick in' quickly. If not respected, this be really brutal with traction/stability control not fully activated. You can get sideways in the blink of an eye.

The nice thing about the GT4 NA flat6 is the more predictable (e.g., linear) throttle response. I am not saying this is a license to be frivolous with ESC in-play, but it does offer a more predictable chassis response.

Avera

kwikit356

I hope some engineer will be able to explain this far better than I can, but my basic understanding is that the term moment of inertia is actually applied as the second moment of mass, which is the rotational motion resistance of a massive object. The Cayman/Boxster platform has most of its mass near its center, while the front end and rear end of the car are relatively light. ESC, or electronic stability control, is designed to assist the driver to prevent rotation/spinning of the car as the rotational forces become greater than the force of resistance.

In theory, the Cayman/Boxster should be more likely to spin than say the 944 platform, where there is greater weight at each end (therefor creating more resistance to spinning). This also applies with lightweight flywheels and figure skaters. With early 911s having great mass at the rear end (and no ESC) there was good resistance to actual spinning, but lifting/braking would lower the rotational resistance, allowing the car to swap ends (thus leading with the rear due to its great mass, as opposed to fully begin spinning).

For those of us who are not mathematically gifted, calculating these forces can easily become a mind-f**k! I can only think of all this as not running out of talent in corners, unless there is coolant or oil on the road/track surface, in which case I will become just a passenger, hopefully remembering to push in the clutch pedal and be hard on the brakes. I have great respect for you guys who are able to drive fast on the edge with all the nannies switched off.

TRZ06

I know that all too well, I had the F80 M3. I hated that car, but I leased it for 3 years and was stuck with it. Then I moved to the SS 1LE, which was everything I was expecting the M3 to be but wasn't. Now have the GT4

enduro

I run with both off and don't notice flashing. Just constantly illuminated. But I'm also usually keeping eyes up unless settled into a straight, then I scan gauges for temp & etc. FWIW, my situation is a little different than many as there isn't any to hit at the track I usually run on unless I do something pretty impressive. Also my track has a place where you want to get power down, but there's a some mild bumps at a slow corner exit, so you get some slip & grip, slip & grip at a couple places with nannies off, whereas if you have them on, you get some abrupt power cuts, else you aren't taking advantage of the 'grip' portion. Note: it's not driveline killing washboard.

Avera

Yep, here is a quick example of what happens when a Vette drops its coolant on the track in front of you. Traction/stability control or not, this was unavoidable . . . it is comical because nobody was hurt.

Avera

P.S. the driver in the 'flying' Porsche actually had an in-cabin camera and captured it from his perspective. I just cannot find the video at the moment

https://digg.com/video/porsche-flies...ack-in-reverse

enduro

@Avera


First vid was in a Caddy. That vid makes me sad