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DSG-crawl when stopped

GTT

Touring Car Champion
Location
US, Chicago
I don't know about you DSG owners, but my last drive of a DSG GTI bothered me.
Why does the DSG GTI crawl when it's supposed to be stopped?
In my manual cars when I am stopped and the clutch is disengaged the car does not move.

Now, I understand that from a safety standpoint it's better to have the gear engaged and keep your clutch "covered" so that you can move quickly if need be. However, the DSG has an automated clutch that can engage and disengage by way of throttle input.
Thus, it should sit still when stopped and my foot is not on the brake.
Instead, if you take your foot off the brake or simply lessen the pressure on the brake, the car moves forward just like an automatic slushbox would, or just like a true manual would if you were "feathering" the clutch or "riding the clutch. The bad part is that riding the clutch is a
no-no as keeps the clutch engaging slightly and thus wearing the clutch and causing excess heat build up, which is not a good thing for long clutch life.

So, that has me a bit concerned as to how long that 1,3,5 gear clutch plate will last.
And, if it does wear quickly it will wear quicker than the 2,4,6 and we'll be replacing 2 clutch discs instead of one in the process.
The biggest concern is one of wear and heat build up. In stop and go traffic it seems this clutch is continually slipping and riding the clutch. In my manual I try to avoid that as much as possible. I guess it's convenience vs. long clutch life.
The slushbox auto has the advantage here as it's "slip" doesn't hurt it.

So, I wonder if launch control, then, simply disengages the clutch while the engine revs to it's 3000 rpm limit? I hope so, cause if it isn't disengaging the cltuch it's seriously slipping that clutch and creating lots of heat.

I wonder if less "crawl" can be programmed into the DSG?
 

awilson529

Ready to race!
Location
Houston, Tx.
I think that is a very valid concern. I test drove a DSG'd GTI a couple days ago and plan on buying one within the next year.

I would love to know what's up with this also.
 

cmdrfire

FIA World Rally Car Champion
Location
UK
GTT said:
So, I wonder if launch control, then, simply disengages the clutch while the engine revs to it's 3000 rpm limit? I hope so, cause if it isn't disengaging the cltuch it's seriously slipping that clutch and creating lots of heat.

I wonder if less "crawl" can be programmed into the DSG?

Don't have much to say about the crawl... but the launch control disengages the clutch whilst revving to 2.8-3k RPM, unlike the (crazy) BMW SMG system which slips the clutch.
 

BMWDavid

Drag Racing Champion
Location
Indiana
OK, here is what I know. With the footbrake on the clutches are disengaged. When you release footbrake the clutch will lightly engage/slip giving some creepage. I believe this is to avoid backward roll on inclines as well as smooth the take off roll as throttle is applied.

I noticed during a test drive of a GTI/DSG that when stopped on a hill when I released the footbrake there was a brief backward roll of a few inches before the clutch engaged to hold car still or slightly creep forward. So keep your foot on the brake unless ready to roll. This should eliminate any concern for premature clutch wear.

David
 

davesee

FIA GT Champion
yes, with my brake pressed down all the way the clutch completely disengages.. because as BMWDavid says, when I start letting up on the brake (on an incline) the car will roll backwards until the clutch actually starts to engage.
 

dwl137

Touring Car Champion
Location
Pennsylvania
plus due to the fact the the DSG imploys "Wet Type" clutches, I dont think slipping is as hard on it as it would be in a typical pedal clutch manual. Just my thoughts, not validation on that.
 

GTT

Touring Car Champion
Location
US, Chicago
BMWDavid said:
OK, here is what I know. With the footbrake on the clutches are disengaged. When you release footbrake the clutch will lightly engage/slip giving some creepage. I believe this is to avoid backward roll on inclines as well as smooth the take off roll as throttle is applied.

I noticed during a test drive of a GTI/DSG that when stopped on a hill when I released the footbrake there was a brief backward roll of a few inches before the clutch engaged to hold car still or slightly creep forward. So keep your foot on the brake unless ready to roll. This should eliminate any concern for premature clutch wear.

David

I didn't feel that in that last DSG I drove. I lightly released the pressure on the brake to test this. I could feel the "tug" of the engine against the brakes. Thus, there is added drag and heat buildup. In my manual cars if I let go of the brake the car won't move if I'm on a flat road.
If I'm on a hill yes I need to feather the clutch and work the brake to avoid going backwards.
But, in the DSG this feels different. It feels like the cluch is engaged all the time, even if ever so lightly. That is what I'm wondering.

Also, that DSG I drove didn't feel the same as the 2 I drove before that. There was a sluggishness like turbo lag that the other 2 DSG's did not have. I didn't feel pull against the brake in the other 2 DSG's like I did in this one. Perhaps it needed adjustment, but how much adjustment is there, and how is it done?

From what some of you are saying it seems clutch engagement is connected to the brake pedal action, but how? Is the clutch responding by sensing the pedal pressure is released or releasing and applies the clutch? Or, does it work by sensing wheel roll, and/or throttle application? Maybe, I'm sure it is, it's a combination of things? Does anyone have a technical material on how the system works?
 

jeff_faye_lo

Autocross Newbie
Location
Toronto
I heard that they put the 'crawl' there for a purpose.

they intended to add a little bit of gas so that when u switch gear, you wont feel the 'lag' of torque.

correct me if i am wrong.
 
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