S3 dsg clutch slip

[Craig_s85]

Hi looking for any advice/opinions.

I have a 2015 s3 dsg,it's stage 2 with a dsg map.

Engine,dsg and haldex were serviced prior to going stage 2 and has done less than 1k miles.

I'm experiencing what feels like clutch slip at wot in 4th gear and above.

My indi assures me dsg fluid was filled correctly, my tuner has done an adaptions reset but the problem still remains and I'm currently awaiting them to call me back.

Has anyone else had this problem?could it be turbo related?

 

[desertstorm]

Who did the DSG map? with VCDS it's possible to see the various input speeds and shaft speeds to see if indeed slip mis occuring. Also look at clutch pressures and other operational measurements. It's possible there is an issue with the gearbox itself.

 

[Craig_s85]

Rather not say who the map is from but it's well known and trusted so I don't think that's the issue.

I Don't have vcd but I do have obd11 Pro,the clutch pressures showed about 13psi,but I only did a short test.

Could it be the mechatronic unit?

 

[Craig_s85]

Does anyone know the standard clutch pressure levels?

Just done some logs and the highest recorded is 13.5 bar.

 

[desertstorm]

I believe the stock pressure is something like 11.5-12 bar . Pressure applied is related to the torque supplied to the gearbox. Applying unnecessary pressure just makes for harder shifts and the pump has too work harder to make the pressure so uses more power.
Is the gearbox a 6 speed DQ250 ?
You can see the amount of torque the engine is producing in the measuring blocks. How much power / torque is the engine making. I think a typical stage 2 DSG map is something like 14 bar, stage 3 16-17 bar it can go upto 18- 18.5 bar but that's maxed out.

 

[Craig_s85]

Yes it's the 6 speed dq250.

Clutch 1 was 13.5 bar at specified torque of 500nm.

Also it seems limited to 500nm as it never goes above that yet my dyno graph after mapping showed 560nm.

I also didn't notice any slip when testing,last time it slipped I had a passenger.

 

[desertstorm]

The gearbox has a max torque vale that it will allow and above that it will request torque reduction from the ECU. On a lot of engine maps they cap the torque value produced by the ECU so that you don't get a torque reduction request from the TCU. The problem with under reporting the actual torque value is that the clamping pressure generated by the gearbox depends on the torque value the ECU sends.
The clutch is more likely to slip when there is more weight in the car or if it is pullling uphill in a high gear. How many miles has the car done. The clutch will slip more if the gearbox oil is hotter.So more likely to see issues when the weather gets hotter.

 

[Craig_s85]

The car has done 30k but only been stg2 for less than 1k miles.

It's booked for another dsg service so hopefully it's just low fluid level.

 

[Morris39]

Who did the DSG map? with VCDS it's possible to see the various input speeds and shaft speeds to see if indeed slip mis occuring. Also look at clutch pressures and other operational measurements. It's possible there is an issue with the gearbox itself.

Ia it possible/practical to log shaft speeds at road speeds as per VCDS channels below ?
IDE02720-ENG103810 Transmission input speed (RPM) shaft 1
IDE02722-ENG101964 Transmission output speed (RPM) shaft 1

 

[Craig_s85]

Ia it possible/practical to log shaft speeds at road speeds as per VCDS channels below ?
IDE02720-ENG103810 Transmission input speed (RPM) shaft 1
IDE02722-ENG101964 Transmission output speed (RPM) shaft 1

I have obd11 and have taken some logs of input and output speeds for shafts 1&2.

I'm not sure what to make of them though.

 

[Morris39]

I have obd11 and have taken some logs of input and output speeds for shafts 1&2.

I'm not sure what to make of them though.

Thanks for the datum point. Guessing only. If you log in a given gear (manually selected) and know the correct gear ratio then slip could be inferred . Maybe Desertstorm can explain.