The definitive word on the "throttle lag" issue (hopefully)
 

So I just spent a good amount of time going through the 12 + pages of the thread about the dreaded throttle lag issue. I was also off from work today so I decided to do some experimenting.

Bottom line: There is no systemic problem here, individual defects notwithstanding.

There are a number of factors that need to be considered when looking at acceleration properties of the S6.

1. High power/torque. Proper engineering should allow for this power to be used when desired, but also allow for it to be controlled, made safe, and easily modulated for more mundane and practical transport needs.

2. Turbocharging. You can not expect this engine to react like a high revving, high compression or a big displacement normally aspirated motor. Until the boost kicks in, it is a medium displacement, lower compression motor. This is very typical for turbocharged engines and it is the price you pay in safety and reliability for that huge mid-range swell of torque. Low rpm throttle response will be blunted a bit.

3. Dual Clutch Transmission. Every dual clutch has issues in first gear off the line. With a proper manual, a human being can finesse the clutch/throttle relationship, but a computer can not do this. It can not act subjectively. It does one thing or another. This will lead to quirkyness from standing starts and coming to a stop.

4. Stability/traction control systems. This in relation to #1 above. Depending on what you do, and what mode you are in, these systems will interpret things differently, and react differently. If your driving style is not matched the the proper mode of the car, it will lead to a less than optimal result.

Anyway, based on these principles, here's what I disocvered today and what I have concluded.

The first thing I did was to do hard launches (without launch control) in D, S, then M. If you mash the pedal to the floor in D, the car bogs. This is when you experience the dreaded "lag". D is not meant to function for throttle mashing. The ESP is also in maximum sensitivity and power will be cut immediately so the wheels don't spin. Remember, these systems detect extremely minute amounts of spin or slide tendencies, long before you would actually feel it.

If you are in D, try this: do like a 2-3 foot roll out with light throttle. Then progressively push the pedal to the floor. You will launch very smoothly and confidently.

At the other end of the spectrum, I did launches in full manual mode with the ESP off. No initial lag whatsoever. The car just took off. Again, not like a high powered normally aspirated motor. It definitely took a little time to really feel the torque swell, but there was no lag other than the expected relative feeling compared to a turbo being on boost.

Adding in turning starts also led to varying results depending on the mode. Trying to drive gently in Sport, likewise, gave a lot of low speed jerkiness.

Bottom line: Use aggressive modes for aggressive driving and use gentle modes for gentle driving. It is when you don't follow this recipe, that the result is less than desireable. If you do follow this recipe, your car will respond exactly as the situation necessitates. Seriously, I am glad that there is "lag" in D mode. I would hate to be in bumper to bumper traffic and have the car leap forward with its 400+ lb-ft of torque at every jab of the throttle. It would be dangerous.

I didn't exhaustively read the other long thread, but it seems there are two issues that people are calling "throttle lag":

1. Lag off the line from a standing start, in the traditional sense of lag when talking about turbo motors.

2. Lag when getting on the throttle immediately after braking.

Your experiments are more relevant to case #1. I personally do not experience this at all and have great throttle response off the line either in drive or sport modes.

My issue is #2. It occurs in a straight line or in a turn. If you brake to slow down but don't come to a complete stop, and immediately try to accelerate again (either lightly, moderately, or aggressively), there is a significant lag, or pause, where there is virtually no reaction. It's as if the ECU is saying "you just applied the brake, are you sure you meant to accelerate again so soon?". After a couple seconds the motor responds as you would expect.

Once you get used to this, you learn to not try to scoot across traffic after slowing down, or pulling into traffic immediately after braking. I consider this a safety issue, but I also believe this was intentionally programmed in.

Safety issue?
 

I agree that its mainly the second circumstance. However, why would they intentionally program this in only the S6 and not in other (especially S series) models. Isn't it also a safety issue with the others?

I have no evidence, anecdotally or empirically, that it's an issue in other DSG/tip cars since my other car is a 6-spd manual. I personally think it's Audi's response to "unintended acceleration" issues that have plagued them in the past, and more recently Toyota, etc. Others will have to chime in whether other Audis behave this way.

It would be interesting to hear from S7, S8 and RS7 owners. These are the only "daily drivers" that have this level of power and torque. The R8 is a totally different beast with a NA motor at that, so it doesn't count. I think there are definite safety mechanisms built in to allow a car with this much power and torque to be driven safely, slowly and smoothly. Put it in the right mode for aggressive driving, however, and you are good to go.

Our S4 doesn't have the lag the S6 has. The S4 reacts as you would expect, and also has the benefit of the same (or similar) lightning quick shifts. The S6 is better in nearly all respects with the exception of the long delay before engaging the throttle.

The S7 owners have complained about the same thing. No idea about S8 though.

The only thing difinitive about this thread, is that it will become as long as the other thread that was not titled as difinitive :-)

I don't experience any throttle lag with my RS7 (nor did I with my Stasis A7, but that of course was supercharged so no boost lag). Now, I have the trans set on dynamic and I am usually driving in manual mode. After 40 years of exclusively manual transmission cars I still find it difficult to leave it in auto. When I do let the transmission do the work it is in S mode, I never have it in D.....

There is none of this throttle hesitation with the TT PDK, it's not inherent to a high hp/tq turbocharged engine or dual clutch tranny.

There is most definitely something wrong w/ the S6 in regard to this issue.

FWIW, I believe this delay is coded INTO the ECU/TCU. The definitive way to find out would be to purchase the GIAC or APR tunes and compare the difference to OEM. They both claim to have significantly improved throttle responsiveness...

It would be interesting to analyze the tunes, or if APR or GIAC has any word on it, because no one with the tune complains of lag. People previously with the lag say it is disappeared or much improved after the tune.

Yes, this is what I experience as well, and its what I experienced in my 2011 S4 DSG and in my B6 S4 with the tiptronic. So your theory about it being intentionally programmed in as a result of "sudden acceleration" lawsuits sounds reasonable. Based on my experience, this is NOT an S6 issue, or a 4.0T issue. Its an Audi programming "feature".

I should add, it is less in sport vs auto / comfort. So either the programming changes when you change modes, or there is some connection to quicker gear selection. My experience makes me believe the former.

#2 is also my experience. I bought a new brake light sensor for $15 on eBay: going to try that as one poster in the other thread said that was the problem with his Q7. Not sure it's the correct part though; I emailed and PM'd him but never got a confirmation.

Unfortunately, I am in Taiwan for two weeks on business and won't get to try this for awhile. Could be worse: my colleague here paid more for his Q5 than I did for my S6!

This is keeping me away from an S6
 

Rob has described the issue with the BMW M3 DCT transmission perfectly. 90% of the folks replying to these two threads have never experienced issue #2, which is a serious problem. It is terrifying to have your foot into the throttle, trying to get around a car or across an intersection and have the car go dead for up to 2 seconds. I was lucky in the M3, that it never caused an accident. I logged data from the OBDII port which conclusively shows the problem for the M3. Someone here should do the same thing with the S6. Then make it available to anyone that has an accident due to a "dead-in-the-water" S6. That ought to wake up Audi. This is an unacceptable condition that will keep me away from an S6 until solved. BMW took two years to fix theirs.

Can i just chime in here on this OLD thread? As an Audi owner of 4 audis in the past. 2007 A6 4.2, 2009 A3 2.0T, 2009 A4 2.0T, 2010 S5 4.2 The ONLY one that does not have this 'lag' issue is my S5 and that's because it's a manual transmission. Recently, I had a 2013 A6 loaner and I was reminded of this lag while accelerating and decelerating. IMO, it's a transmission issue(flaw, feature, whatever). Total lag off the line. My A3 was the worst at it. I would accel and the car would immediately try to shift to second after a terrible boggy launch. My workaround was rolling starts. This tranny seems to like that kind of start. Let it roll and then GO. Or switch to M and use your flappy paddles. My S5 is a true pleasure because, let's face it, manual transmissions reduce the complexity between driver and engine.

I assume you're referring to the loaner 2013 A6 with the 2.0T turbocharged engine. The supercharged 3.0T in the A6/A7 has zero lag.

Here's the definitive answer

Work around?
 

I believe that this is the correct explanation for the "lag". I see it when I am getting off the highway and brake at the bottom of the ramp before entering traffic. I slow from about 60 to perhaps 10 mph and I am sure the tranny downshifts given enough time. If I stop, there is no problem, but if I roll without stopping I probably hit the throttle before downshift. I will try manual downshifts under these circumstances - before I accelerate - to see if it makes a difference.

What is the main advantage to a DSG tranny anyhow? Audi seems to prefer the non DSG in other applcations.

Thank you for posting this. Sounds like a logical explanation that ties to exactly what some of us have felt in certain situations. I think people continue to confuse this issue with normal throttle/turbo lag that these cars can present.

I won't argue that the clutch may be disengaged while braking at slow speeds, but does it really take seconds for the transmission to react to reapplication of the throttle after braking? With its propensity to start in 2nd gear (if you don't come to a complete stop for more than a half second) I expect the transmission to remain in 2nd gear as I'm slowing down, needing only to re-engage the clutch when I reapply throttle.

The "2nd item" is more plausible to me. I hope that folks report that the DSG tune eliminates this.

Correct me if I am wrong but turbo lag is effectively reduced power until the turbo spools up and not zero response. The issue I have with my s6 is no throttle response for 1-2 seconds when getting back on the throttle after slowing to say 20km/hr. Its dangerous. When at a complete stop I shift into manual to have some reasonable throttle response otherwise this too is dangerous when pulling into heavy traffic. Come on Audi - this needs attention before someone gets hurt.

Completely agree.

For an 'S' car, I find the lack of throttle response not only a safety issue, but it also ruins any fun the car might provide in anything other than a straight line. It is a wonderful GT car, great for soaking up the miles and commuting to and from work. Throw in a 90 degree corner though and the car is just an embarrassment to the 'S' car heritage.

If I don't get an acknowledgment from Audi and recall or fix by late Spring I've decided to sell and purchase something else.

I've learned my lesson when it comes to buying cars without long extensive test drives. I'll never buy another vehicle without putting the vehicle through a rigorous trial. With the S6, I only had a short drive before I placed the order. I won't make this mistake again.

FYI: I finally got around to replacing the brake light sensor switch on the off chance that this corrected the "hesitation" issue seen when trying to accelerate after just having applied the brake. I notice no difference in the behavior after having replaced the switch: I still have a frequent hesitation when slowing (such as for a red light) and then trying to apply the throttle (such as if the light then turns green).

Too bad, that would have been an easy $15 fix.

Hello, my car is now on 80.000 km's
I had the problem from day one.
Yesterday i got a new mechatronic unit (part of the s-tronic gearbox) (warranty) the problem of a delayed gas response and jerky drive from stop is 100% solved !!!!

It feels like i'm driving a new car.

Interesting...I found another guy who had the Mechatronic unit replaced on his B8 S4 to address some jerkiness and clunking. Something tells me this will be tough to get AoA to cover under warranty. I have my 15k next week; I may ask about it again.

That's a lot of miles/km. Is your car a 2013 C7 S6?

Good point. I was assuming from the language/units he's in Europe, where the S6 was available as a 2012, but that's still 25k miles a year, which is quite a bit.

Hi,

Yes i drive a lot!
My car is from 17-9-2012 (one of the first here in Holland)

I would be at 40K miles if the dealership didn't have my car for a month and I picked mine up at the end of Sept. 2012 Just need to be driving the car :)

The miles add up when you are having a good time driving your car.

As I mentioned in my thread here:
https://www.audiworld.com/forums/sho....php?t=2866929

I have my car in for the 15k service. On the way to the dealer, the EPC light came on. I also complained (again) about the throttle lag/hesitation. My SA called me and advised me that they are downloading a SW update that supposedly will solve BOTH of these issues. I am skeptical, but cautiously excited. Unfortunately, since it's 5:00 EST it doesn't look like it will be done today (had a sunroof issue too).

I'll report back as soon as I know more.

Any updates on this?

See new thread that he started.

Bad news for me. The service department said they could not access or download the update to my car since it was so new. I should have the latest and greatest software update. Well obviously I don't because I have the LAG.

That may just be an excuse not to do it on their part, try a different dealer

Will they do this update just to correct "LAG"?
 

My 2013 S6 was built in Feb 2013. I have the lag problem but my ESC light does not go on. Does anyone know if they will do the TSB in the absence of ESC light on at any point? My dealer has always been cooperative. Thanks

I have had this same issue with my 2011 S4 DSG slowing down for a corner, such as a expressway merge lane, then accelerating out of the corner (in ADS auto mode), there is a big lag in throttle response (no power for awhile).

Also in ADS comfort mode the other day, I was slowing down for an intersection, then the light turned green, step on throttle, which made the engine rev, but the clutch was not engaged (disconnected like in neutral), had to wait a couple of seconds for it to engage. For a few seconds, it felt like a complete transmission failure.

This must be part of the Audi programming in the TCU/ECU across multiple platforms. Bad Software - bad software, but one can only get them to fix it by sticking the Mfr. nose in it.

https://cimg7.ibsrv.net/gimg/www.aud...a5c8f55c51.gif

I am not seeing the problem on my Q8.

my Q5 (Tfsi s-Tronic) lag problem was sorted out with DTE PedalBox. Now I drive with zero lag when accelerating from still using sport mode. No more delayed take offs.

For people still reading this, BoostedEuro TCU tune completely eliminates this lag but and adaptation via VAGCOM helps a lot.
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