VM

That roughly mirrors my experience, but you have to be VERY careful about the 'easing off just before the car comes to a full stop'. If you don't ease off enough, boom, the instant the car hits 0km/h... engine off. Very annoying. The thing is, I have nothing against the start-stop system if stopped at a light, but if stopped at a stop sign or about to make a turn, it is very annoying.

Then again, this system, by encouraging gentle braking, probably increases brake pad life...

superswiss

Yes, there is the occasional situation where the engine turned off, when I intended to get going again right away. It's very rare, though and hasn't really bothered me so far. I feel like if you overthink it, it will turn into a problem. In those situations, I just quickly ease up on the brake pedal some more to restart the engine. As far as I remember that really only occasionally happens at a stop signs. Can't remember it happening when about to turn.

What's much more concerning and annoying is the lag from a stop with this engine that others have commented about when the car is driven in D and you want/need to peel off from a stop to make a window in traffic. After my 1300 mile road trip I got the impression that it is a deliberate cutting of the torque to protect the drivetrain. Audi may have put rather weak clutch packs in the S-tronic for the A4 and needed to program the ECU to limit torque. Combined with the turbo lag, I'm still not a fan of the 2.0T at all. Some have mentioned that it's better if you put the transmission in S, which may be true, but I also find that rather annoying having to put the transmission in S, just to get going and then back in D. I resorted to just screw both D/S and shift myself in manual mode. The tendency of this engine wanting to hang out in the no boost zone of the rev band makes it rather non-responsive when you want some go, but shifting manually and keeping the engine in boost avoids much of this. Essentially that's what S does as well. It increases the idle rpm to reach boost sooner and keeps the engine in the boost band. It's nice to easily get an average of 30 mpg on a road trip, even with some aggressive passing in between, but around town I'm not impressed.

VM

I don't know what you guys are comparing it with, or what the road conditions you drive in are, but I don't think I've ever really noticed such a lag. I presume my car behaves the same as every other North American 2.0T/DSG/quattro though...

The one annoying engine thing I've noticed is the shuddering at slower highway speeds (maybe 95-105km/h) with adaptive cruise where the transmission is trying to avoid shifting out of 7th when accelerating and it's lugging the engine.

Oddly, I'm a big fan of the 2.0T, but... I think you have to view it as an alternative to N/A V6s designed for the Chinese 2.0L tax.

CoolWalnut

Excellent description. I've notice a subtle low rpm shuddering when accelerating from a slow rolling stop. A very delicate feeling that the engine is just about to stall but doesn't.

This happens more frequently when driving in Auto and less so in Sport.

superswiss

The comparison is essentially to the instant and linear response of an NA engine, or even a supercharged engine, but you don't even have to go down that path. You can just compare it to itself. How the engine accelerates and responds when you are already moving and in boost vs how it responds when jetting off from a complete stop. One example of an "oh ****" moment I had over the weekend, was at an intersection where the cross traffic didn't stop and I was trying to cross. I saw an opportunity and stepped on the throttle all the way to the floor. The car felt like it was attached to a bungee cord pulling it back. It moved way underpowered into the intersection and what felt like a second or two later all the sudden boost kicked in and it shot out of the intersection, not a moment too soon. It's a very eerie behavior, because otherwise if you step on the throttle, the transmission shifts down to get the engine in boost or you are already in boost and it surges. But starting from a stop is like driving a Prius until it remembers it actually has 273 lb-ft of torque. I probably should have put it in S, but that didn't cross my mind, because I'm used to my car, which I don't have to put in S first before I can take off in a hurry.

Here's basically where it gets interesting. The 2.0T makes 273 lb-ft of torque at 1600 rpm. When punching it from a stop, the revs shoot up before the clutch engages, just like one would do with a manual transmission, so you are most likely already in boost when the clutch starts grabbing fully if you give it full throttle. 273 lb-ft is plenty of torque to shot forward from a stop. Just to give you something to compare. My RS5's engine makes only about 210 lb-ft at 1600 rpm. It needs about 3300 rpm to make the same amount of torque as the 2.0T. However, if I punch it from a stop there is zero hesitation. It's like a cheetah digging its claws into the dirt, throw up dust and shoot forward. I've even managed to break the tires lose on dry tarmac. Yes, I'm comparing an A to an RS, and I'm ignoring gearing which can be used to make up low engine torque at the wheels. I'm not expecting an A4 to break the tires lose from a stop, but I expect that the engine gives all it has if you need to get going quickly from a stop and that doesn't seem to be happening with the 2.0T. Either the transmission is taking its sweet time to fully engage the clutch, or the torque is dialed back during a full launch from a stop.

Quattrp

I always have the start/stop system disabled, so definitely not that.

I understand that the transmission will be engaged until slowing down to a stop, but I feel like there shouldn't be the shudder/rumble feeling when it happens.

I actually don't feel the shudder/rumble if I come to a stop VERY slowly. Most of the time I feel it with a regular brake to a stop, doesn't feel jerky or slow.
Had some friends test drive and they felt it too with their regular driving habits.
The shudder doesn't usually occur when I come to a faster than usual stop, however it HAS on some random occasions.
But if I'm reading your comment correctly, are you saying that the car is essentially about to stall due to low RPM, but then disengages the transmission? However I noticed the RPMs are around the 900-1000 mark when I come to a stop, the transmission never dips below 800 during the entirety of braking to a full stop. At these values the engine shouldn't be shuddering due to a potential stall, would it?

VM

The lugging on the highway was probably observed at 1200-1300RPM... so... potential stall at 900-1000 wouldn't be that surprising to me?

superswiss

Once you get into the 900-1000 range you are pretty much in potential stalling territory and things can get a little awkward. If you are just slowing down to a stop, that shouldn't matter. The TCU recognizes that you are stopping and disengages the clutch in time. Shudder would occur if you are still on the throttle and creeping at those rpms. For example it can get really awkward if you come to a slow stop on an incline or try to creep up a hill at low rpms. The S-tronic being mechanically essentially a manual transmission it has a solid connection between the engine and the drivetrain when the clutch is engaged, so there comes a point where the engine can lug or almost stall and the TCU has to act and disengage the clutch to avoid stalling the engine. This doesn't happen with a torque converter that uses fluid coupling and never runs into the risk of stalling the engine. I think w/o driving your car it's gonna be hard for us to really tell if what you are experiencing is normal or if there is something different about your car. You can always go to the dealer and test drive another A4 on their lot and see if it does the same.

Laputa

Well described, just wanted to drop by and say: I have the same situation here in Asia! Car currently at 4000km, did not feel the shudder at early kms, just felt it couple months ago, was wondering if it was the gasoline or should go to the service center for a check up.

It absolutely feels like the engine is going to stall but it didn't, very short vibration where the passengers do not notice about it, had my friend to test driving too but he was lucky enough the shudder did not show up, it just happens occasionally

Quattrp

In my scenario I am only at those low 800-900rpms as I brake to a stop, so no throttle at all.
It makes sense that the engine would shudder in circumstances where throttle is applied with RPMs in the low end, however that should technically only occur in 1st gear as the transmission would automatically downshift at any higher gear, right?​
When thinking of things mechanically, it seems that braking should not cause the shudder, unless it's possible that the TCU is faulty and is disengaging the clutch too late perhaps? In that case wouldn't the engine shudder due to the drivetrain being connected at low RPMs, then disappearing as soon as the clutch is disengaged?
Instead of the dealership's explanation that the sound is due to the clutch, it's more like: braking --> RPM going down and engine connected to wheels --> stall range RPM from braking, however still connected to wheels = shudder --> TCU finally decides to disengage clutch --> no more shudder --> full stop.
Does that sound right?