# Turning off DSC



## Plaz (Dec 19, 2001)

EZ said:


> Could you (or somebody esle) explain how differential brakes can substitute an LSD? Here is my problem in understanding it. I assume that two wheels on an axel (without an LSD) have a rigid connection beteen themselves (don't they?). I.e., if one wheel spins at a certain angular velocity, the other one spins at exactly the same velocity -- not a bit slower or faster.


 No. That would be a "no slip differential." 

The open differential in our cars allow the wheels to spin independently of each other... but do nothing to prevent all the power from going to one wheel which could be spinning madly.


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## EZ (Feb 27, 2003)

Plaz said:


> No. That would be a "no slip differential."
> 
> The open differential in our cars allow the wheels to spin independently of each other... but do nothing to prevent all the power from going to one wheel which could be spinning madly.


Thanks! :beerchug:


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## milski (Aug 25, 2003)

Well, after some testing in the rain tonight - I could not put the car sideways with the DSC being "short disabled". It will let you sping tires in the turn but after a second or two it cuts the power again. Pretty much exaclty what andy_thomas said.


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## BradS (Aug 27, 2003)

EZ said:


> I assume that two wheels on an axel (without an LSD) have a rigid connection beteen themselves (don't they?). I.e., if one wheel spins at a certain angular velocity, the other one spins at exactly the same velocity -- not a bit slower or faster.
> 
> 
> > A quick differential primer:
> ...


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## SLO Town (Oct 18, 2003)

*DSC experience*

I thought I'd add my two cents here. I have a 2003 330Ci with a 5-sp manual transmission, sport package with staggered 18" M72 V-spokes.

I have experimented quite a bit around the foothills here in the Central Coast - always on dry roads - my car has never been driven in the rain. Subtleties in behavior may be different on wet roads.

Regardless of what the manual says or doesn't say, this is how my car behaves:

Default mode: Both throttle and ABS intervention. Though I have felt the throttle intervention several times (a drop off in power even at full throttle), I have never had the ABS system activate in this mode (not to say it wouldn't).

"Short disable": No throttle intervention, but ABS intervention still takes place. For example, I have a nice tight, smooth second gear corner that you can really pitch the car into and stay at full throttle from mid-corner on. I drove this corner and threw the car into the corner with the intent of causing a full power oversteer slide (the back end coming around, the car beginning to spin out). When I did this, the inside rear tire began to spin and almost instantly the ABS began ratching that corner. I remained at full throttle, with no throttle intervention apparent. What was apparent was a horrible drivetrain clatter as the ABS ratched the inside rear wheel, trying to prevent this tire from spinning. It was harsh enough that I tried this only once more to duplicate the results, which I did. The bottom line, it would seem to me this is quite hard on drivetrain components, and on dry roads at least, I will not use the "short disable" mode again.

"Long disable": Same second gear corner, several times, I could toss the backend around and get significant inside rear wheel spin. I did not feel any throttle or ABS intervention. In other words, I felt like there weren't any onboard computers telling me what I could or couldn't do. If I'm going to really drive the car, say at an autocross, track or favorite desolate road, this is the mode I will use.

Do not confuse my ABS comments under acelleration with those under braking. Even with a "long disable" I can get the ABS to intervene under hard braking when turning into a slow to mid-speed corner (the inside rear).

FWIW,

SLO Town


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## crap_shoot (Dec 29, 2003)

SLO Town said:


> I have experimented quite a bit around the foothills here in the Central Coast - always on dry roads - my car has never been driven in the rain.


What do you do when it rains, walk?


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## bimNaround (Jun 19, 2003)

outpost22 said:


> Is there a button for A.D.D.


Q: How many kids with ADD does it take to screw in a lightbulb?
A: Wanna go bike riding?


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## SLO Town (Oct 18, 2003)

crap_shoot said:


> What do you do when it rains, walk?


No, I'm just fortunate to have three cars. Besides that, we get a total of maybe 20 days of precipitation for the whole year. Cars love it out here in SLO. No ice cold starts, pool table smooth roads, clean roads, only moderate sun intensity.....basically, it's just about perfect. Walking or driving.


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## crap_shoot (Dec 29, 2003)

SLO Town said:


> No, I'm just fortunate to have three cars. Besides that, we get a total of maybe 20 days of precipitation for the whole year. Cars love it out here in SLO. No ice cold starts, pool table smooth roads, clean roads, only moderate sun intensity.....basically, it's just about perfect. Walking or driving.


Sounds like the polar opposite of the weather here...cold, icy, snow, sand on roads, etc etc. But to do without your bimmer when it rains? Not me.


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