kosmaras

There were not DTC's stored. If this isn't clutch slip, what would explain the sudden increase in RPM at peak torque and then a decrease in RPM, all while WOT?

Goned

In your video I don't see the problem.

Slippage is when the RPM rises faster than the speed while experiencing no torque.

Like for example a DCT transmission

I don't think this is the case, namely that at 3000 RPM this is when there is maximum torque.

If you start from 1000-1500 RPM what happens? the same thing ?

kosmaras

I've had manual trans cars with bad clutches, so I know what you mean. Perhaps this is just the beginning of too much torque being applied for the clutches to hold? When I start at 2,000, it doesn't occur since the torque ramps in much slower.

Goned

That's what I think as on the other forum, you surely reach the limit and therefore the torque limiter possibly intervenes to limit the max which is set by IE in the ECU... it sure works on a TCU tune but... they always said not necessary even for stage 2.

kosmaras

Update from my side: I posted a video and log screen shot in the IE Customer Group on FB. Someone else chimed in that had the same problem, even after the UNI TCU tune. I tagged the IE folks in the thread, but Tyler and Cristian have both ghosted me since I asked if it was clutch slip. Pretty disappointing to get no acknowledgement on the issue. I've usually had good customer service experience with them.

Thumper3

So someone with a TCU tune that increases clamping force had the same issue you had without it? When you hit peak torque from a different set of variables it doesn't happen. Seems to be more complex than just a torque limited clutch pack design, after all if the clutch packs have a hard limit then they don't care how you get there. The only thing that could be affected by how fast you arrive at peak torque would be the computer responding by raising the clamping force too slowly. This should be handled by the TCU tune but sounds like it did not for the other person. No idea why they are saying a TCU tune isn't needed, everyone runs around claiming you can't even go Stg1 on a manual without completely replacing the clutch, but somehow the ever more complex DSG should just be fine?

You didn't mention it but I am assuming when this "slip" event happens you feel the car drop power, or is the log the only way you notice this? When it does this do you have traction control on or off? With as fast as it happens it could be tire slip depending on how repeatable it is. If you slip a traditional manual clutch it doesn't just start to grab again while it is slipping and you keep giving it power. The DSG clutch pack would be similar, if it was really slipping from a physical threshold staying on the power wouldn't make it suddenly grab. To me if it is slipping it's due to clamping force lacking due to the tune taking the engine performance outside the specs of the trans programming with regards to speed of spool and power curves.

kosmaras

From my understanding, there is no proof that Unitronic increases clutch pressure. I don't think I've seen them confirm that and the product page for their TCU tune does not specifically mention that (if so, please correct me!). I know TVS offers that, but the drivability is sacrificed as a result.

When the slip happens, you can feel it. It results in a staggered acceleration feeling. It doesn't matter if ESC/Traction is off and it happens in 4th gear at highway speeds. No way is this car breaking traction at that speed.

Thumper3

Agreed if they won't confirm it than likely they aren't, but not sure WHY a TCU tune wouldn't do so. Happy to be proven wrong by the engineers but seems like increasing clamping force would be one of the main jobs of the TCU tune with improved shift points and speed being a close second.

It could if you had ****ty tires worn into replacement zone. But seriously, you're logs are just of 4th gear? If a clutch is going to slip, again from a physical issue, it will slip when the same conditions exist. So what does it show the torque and RPM doing at 4000 RPM in 2nd gear? 3rd gear? As was mentioned (here or any of the number of threads going on lol) it may just be increasing RPM that little bit in anticipation of an upshift coming. Or it could be the start of slip where it just slides instead of fully letting go. But it's so LINEAR. It rises, then plateaus and stays steady before dropping back down smoothly. Slipping and catching I would expect to see some jitter. Unless the sample rate is slow and just making the data look smooth.

Look at your logs, the one where you claim you have slower build to torque and no "slip" you actually peak at a HIGHER final torque number. Certainly the RPMs are lower which factors in some but there's so much that just seems to not say traditional slip but something else going on. This is where you have to rely on your tuner and send them logs and have them pour over data. If this is a common issue they must have seen it in testing and have at least some ideas. If they've never seen it and the issue is not widespread they would need to look into it.

Given the OP came here just to post this thread and has not posted here for 2 months it seems likely they either solved their problem and as always did not update the community or gave up and equally did not update. If you end up continuing to diagnosis this I hope you keep us updated.

Goned

IE are looking at the kosmaras situation. The principal engineer was on personal leave.

kosmaras

Finally got a response from IE acknowledging the clutch slip....

"We have only seen this Behaviour on very few cars. and it has happened over time. It is clutch slip but a very mild slip that should be sorted with the upcoming updates for the platform."