Facelift Strange occasion where Launch Control doesn't allow full boost.

[TR Hamza]

Hey guys,

Quite a strange thing has been happening with my S3, it doesn't happen all the time but occasionally crops up when using launch control.

Now this might sound very odd but it doesn't allow full boost/max launch revs when my central MMI screen is down? REALLY strange I know but soon as I put the screen back up it allows me to launch properly and allows max revs. I can tell this is not just the boost gauge playing up (I have VC) as theres an audible difference when preparing for launch and the fact it holds the revs higher.

An example of this difference is in a launch control video I did a while back, I didn't mention it in there but wanted to know if anyone else has experienced the same thing. Doesn't matter if ESC is off or in Sport. Car is also warm.

To get an idea of what Im on about compare the launch sound right at the start of the video and at the 2:57 mark, you'll notice the second one is allowing more revs.



Oh and yes excuse the rudimentary 60mph measuring system lol*

- Hamza

 

[AudiNutta]

Hm, I can't see any reason why this would ever make a difference and is unlikely. I can hear the difference in exhaust tones, sometimes my car makes a different noise in similar situations, I've done around 10 launches in mine and never had an issues whatsoever as long as you give it a few seconds for the boost to build.

Really, we would need a dash view of the difference so you can see revs and the boost gauge. Initially I thought maybe the artificial sound changed with the screen up or down, but you mean external sound. It could just be that the car is 50rpm less bouncing off the limiter and that's the difference, I say it's a fluke.

 

[TR Hamza]

Hm, I can't see any reason why this would ever make a difference and is unlikely. I can hear the difference in exhaust tones, sometimes my car makes a different noise in similar situations, I've done around 10 launches in mine and never had an issues whatsoever as long as you give it a few seconds for the boost to build.

Really, we would need a dash view of the difference so you can see revs and the boost gauge. Initially I thought maybe the artificial sound changed with the screen up or down, but you mean external sound. It could just be that the car is 50rpm less bouncing off the limiter and that's the difference, I say it's a fluke.

Yeah most of the time it launches as normal, but on three occasions it has refused to allow full boost, with the common factor being the central screen was down. I thought to myself it can't possibly be linked as it wouldn't make sense, yet soon as I pressed the button to raise the screen it allowed full boost.

In terms of what the dash view looks like, the boost gauge only fills around 3/4 of the way up, even when holding the gas for a reasonable amount of time to allow for the boost to build. On that particular day it did this 3 times in a row until the screen was raised. Very very odd.

 

[AudiNutta]

Yeah most of the time it launches as normal, but on three occasions it has refused to allow full boost, with the common factor being the central screen was down. I thought to myself it can't possibly be linked as it wouldn't make sense, yet soon as I pressed the button to raise the screen it allowed full boost.

In terms of what the dash view looks like, the boost gauge only fills around 3/4 of the way up, even when holding the gas for a reasonable amount of time to allow for the boost to build. On that particular day it did this 3 times in a row until the screen was raised. Very very odd.

That is crazy, I never have launched with the screen down to know. I never drive with it down, I did a few days ago just because but it takes too much from the interior without the screen and empties the car. The only benefit is on dark roads, but normally dropping the interior lighting is more than sufficient.

I'd mention this to Audi, very strange! If you can probe it without actually doing a launch, try it.. I wouldn't want to be doing endless launches and giving Audi permission to do it for testing purposes no chance whatsoever. If you are only getting part boost, letting off and it only exiting part boost again.. I'm baffled.

 

[azibux1]

Not wanting to point out the obvious / sound condescending... but are you sure you had your foot HARD on the brake? I've had something before where the boost won't build and it was because my foot was not on the brake hard enough (so the car didn't fully engage launch mode). Slight giveaway of this is that the car will also be trying to creep forwards a bit

 

[Rayner_1704]

I had it the other night where it wouldn't let me launch it foot on brake dynamic traction turned off etc and was just pulling took ages to select it

 

[TR Hamza]

That is crazy, I never have launched with the screen down to know. I never drive with it down, I did a few days ago just because but it takes too much from the interior without the screen and empties the car. The only benefit is on dark roads, but normally dropping the interior lighting is more than sufficient.

I'd mention this to Audi, very strange! If you can probe it without actually doing a launch, try it.. I wouldn't want to be doing endless launches and giving Audi permission to do it for testing purposes no chance whatsoever. If you are only getting part boost, letting off and it only exiting part boost again.. I'm baffled.

Yeah same I rarely drive with the screen down for similar reasons to what you stated. It is very baffling! Might try to replicate it this week and see if it happens again.

As you say I wouldn't want Audi to test it out, just thought I'd see if theres any logical reason for it why this is happening lol. Now, if it didn't allow full boost with the screen being up or down that would be a bigger issue!

 

[TR Hamza]

Not wanting to point out the obvious / sound condescending... but are you sure you had your foot HARD on the brake? I've had something before where the boost won't build and it was because my foot was not on the brake hard enough (so the car didn't fully engage launch mode). Slight giveaway of this is that the car will also be trying to creep forwards a bit

Foot is HARD on the brake as much as you can press it, I took my foot off a few times in succession to retry but no luck! Did the same on the previous occasions it happened. I tend to launch my car every so often and rarely have the screen down so its never usually an issue. Just strange that a screen is holding it back at times! Thought there may be some explanation

 

[TR Hamza]

I had it the other night where it wouldn't let me launch it foot on brake dynamic traction turned off etc and was just pulling took ages to select it

Yeah sometimes I get a slight lunge when trying to launch where revs won't build if I press the gas really hard straight away. To remedy this I lightly press the gas with the brake pressed (letting revs build) and it starts engaging, then once its at launch revs, press the gas fully to get max boost and then release brake.

Hope that made sense lol

 

[Terminator x]

You CAN test the boost without launching every time you know

TX.

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[azibux1]

Foot is HARD on the brake as much as you can press it, I took my foot off a few times in succession to retry but no luck! Did the same on the previous occasions it happened. I tend to launch my car every so often and rarely have the screen down so its never usually an issue. Just strange that a screen is holding it back at times! Thought there may be some explanation

Very odd

May try it in my PFL to see if I can recreate the same problem if I remember

 

[OliS3]

It varies depends on a lot of factors, engine temp, oil temp, intake temp, exhaust gas temp. Holding the power down for longer just seems to make it more inconstant. Personally I take my foot off the brake before the rpm is at 4k and it launches really well and I get sub 4 sec runs every time (mine is modified)

 

[TR Hamza]

Very odd

May try it in my PFL to see if I can recreate the same problem if I remember

Yeah try it out if you want and let me know if it occurs mate Very odd

 

[TR Hamza]

It varies depends on a lot of factors, engine temp, oil temp, intake temp, exhaust gas temp. Holding the power down for longer just seems to make it more inconstant. Personally I take my foot off the brake before the rpm is at 4k and it launches really well and I get sub 4 sec runs every time (mine is modified)

Yeah that's understandable, but I found that usually they launch in a predictable manner (same revs, max boost gauge etc) but in this case the boost gauge literally stays on 70% average.

Also I believe I saw a pic of your car on MSL dyno? Made good power you're tempting me into getting a JB4 with the other thread. I'm local to MSL would have been good to see!

 

[OliS3]

Yeah that's understandable, but I found that usually they launch in a predictable manner (same revs, max boost gauge etc) but in this case the boost gauge literally stays on 70% average.

Also I believe I saw a pic of your car on MSL dyno? Made good power you're tempting me into getting a JB4 with the other thread. I'm local to MSL would have been good to see!

I've been through what you are and just gave up and enjoyed it for whatever it does at the time.

Yes that was my car, really happy for £400 and a lot of fun logging it for George to advise on the settings.

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