Dsg fart

[s4boost]

Some s4s have dsg fart like crazy 1-2 and 2-3 shift. I don't know if I've ever heard mine fart on the 2-3... Any reason why?

[pfft]

Usually gotta be going as fast as you can and at highest RPM for the 2-3 fart. You're saying you are doing that but nothing?

[bizzy]

Yea I noticed it only farts if you shift above like 3.5k to 4k rpm.

[s4boost]

Usually gotta be going as fast as you can and at highest RPM for the 2-3 fart. You're saying you are doing that but nothing?

Correct. Maybe I'm just not hearing it. Any other thoughts?

[mjr034]

can someone elaborate as to what the DSG fart is..?

[Lamprey]

can someone elaborate as to what the DSG fart is..?

https://www.youtube.com/watch?v=hEin3vVF3SQ

4 Second mark

[grovlet]

Supposedly it's tuned out of Stage I and Stage II tunes.... So more of stock thing - but you really can't miss it - aptly named "Fart" because it sounds like exactly that - and just like "Farts" it's highly entertaining drawing giggles and laughter from almost all (except most wives....)

[Silverbullet S4]

Supposedly it's tuned out of Stage I and Stage II tunes....

Mine still farts....

[grovlet]

Mine still farts....

Good to know - as I often cause it to occur - for S78ts & giggles.... So if I ever go Stage II - it will still be part of the fun!!

[hotleadsingergu]

can someone elaborate as to what the DSG fart is..?

Long story short, the DSG can shift quickly enough that the drop in engine speed because of the difference in rotation speed would cause damage to the clutch packs. To remedy this, the ECU temporarily stalls the engine to quickly drop the speed to match the other clutch system. The "dsg fart" is the temporary stalling of the engine.

In higher gears it's not as necessary because the torque potential is much lower, therefore it has less of a chance of damaging wearable parts.

It also sounds freaking awesome.

[Woodybangs]

It's the ECU reducing timing during shifts.

[CELison]

Long story short, the DSG can shift quickly enough that the drop in engine speed because of the difference in rotation speed would cause damage to the clutch packs. To remedy this, the ECU temporarily stalls the engine to quickly drop the speed to match the other clutch system. The "dsg fart" is the temporary stalling of the engine.

In higher gears it's not as necessary because the torque potential is much lower, therefore it has less of a chance of damaging wearable parts.

It also sounds freaking awesome.

All of this is wrong.

[jimrobbington]

All of this is wrong.

Lol, well what's the right answer? I was thinking it was the release of bypass boost during shift?

[SteveYem]

FWIW, every time I see "dsg fart" written, my brain initially reads it as "dog fart". Every time.

[mrmomo313]

Some s4s have dsg fart like crazy 1-2 and 2-3 shift. I don't know if I've ever heard mine fart on the 2-3... Any reason why?

You should have the blip on all upshifts if you don't have the TCU tune from APR (when in AMAX mode the blips are gone)...

You can hear mine blip every single gear on this pass.. I am running stock TCU in this video, just stg 2 APR v3.1 ecu tune. As for your car, I'm really not sure why it wouldn't be doing that... I think I remember you posting about some weird shift behaviors. Hopefully it's not an actual issue with your mech unit...

My other guess would be that you're on the earlier version of the ecu tune from the newest release. My car kept hitting the rev limiter on v3.0 thus why they released a v3.1. Can't remember if the "fart" was also affected by that version...

[hotleadsingergu]

All of this is wrong.

Thanks for your helpful response. Care to elaborate, instead of just being a negative nancy? The DSG Fart is the ECU diverting a bit of fuel into the exhaust to reduce torque differential by slowing engine speed. Please...explain how I'm wrong.

EDIT: For those thinking it may be a way to maintain Supercharger/Turbo pressure, it occurs on NA cars, as well. It also occurs on extremely-quick manual shifts for manual cars and motorcycles. It IS the ECU determining that the differential is too high and cutting acceleration by diverting the fuel into the exhaust. The "Fart" is the fuel burning in the exhaust system directly.

DOUBLE EDIT: This guy is someone that has told people his tuned car can't be overheating because it's only 15F outside and that if you don't know how to drive manual it's probably because you were "raised by 2 women". Thanks for your input, CELison.

[Woodybangs]

That would destroy catalysts. All it is is reducing timing and therefore power quickly during the shift.

[CELison]

It cuts spark so the fuel dumps into the exhaust. That is the "fart" sound. Anyway, the tq potential is higher in higher gears as there is much more load on the clutch packs. Saying that it's only applicable in lower gears makes no sense. FYI, the car will do this at all WOT shifts, not just in low gears. Overheating and heat soak are 2 completely different things. You should look into that as well. I'm so sorry I hurt your feelings though.

Cheers

[CELison]

That would destroy catalysts. All it is is reducing timing and therefore power quickly during the shift.

That what's it is. You can see the black smoke out of the exhaust from the fuel burning.

[hotleadsingergu]

It cuts spark so the fuel dumps into the exhaust. That is the "fart" sound. Anyway, the tq potential is higher in higher gears as there is much more load on the clutch packs. Saying that it's only applicable in lower gears makes no sense. FYI, the car will do this at all WOT shifts, not just in low gears. Overheating and heat soak are 2 completely different things. You should look into that as well. I'm so sorry I hurt your feelings though.

Cheers

You didn't hurt my feelings, you just think someone else is wrong when they're not, and you're providing incorrect information. What you said would be true if you used "horsepower" instead of torque potential...but in lower gears, the larger gear provides the equivalent ratio of extra torque to the wheels as the differential in gear size. At the same rotational speed of the engine (RPM), you can provide more torque; therefore, the lower the gear, the more potential torque being applied to the contact points. If you shift at 5,000RPM from 1-2 and 5,000RPM from 6-7, you're applying more potential torque to the clutch pack in the former.

As for the 'cuts spark so the fuel dumps into the exhaust'...you haven't proved me wrong, at all. The ECU determines that the differential is too high and cuts the engine speed by stalling it out for a moment. How is that wrong, exactly? (Hint: It's not)

As for the heat soak business...I know the difference well. There is absolutely nothing to say that your intercooler can't be heatsoaked at 17F. It's ludicrous to think that it can't, especially considering that you mentioned in the thread you did a few hard pulls. It's absolutely possible that your intercooler can't handle the amount of heat the car is generating at 17F, which is the entire reason for people to replace their intercoolers with aftermarket units. The outside temperature would have to be in the -50Fs for it to be a nonissue.

Keep acting like a superior tool, though. People love that.

[DGVR6]

It's fuel that makes the fart guys..

http://youtu.be/kXI78224lYY

[mehware]

Love farting.

Matthew

Sent from my SAMSUNG-SM-G925A using Tapatalk

[SForePlayin']

https://www.youtube.com/watch?v=CIDo2DKAMfk#t=04m40s

[garynagra]

Mines giac stg2 with tcu tune and farts are even more aggressive than stock. Also have awe touring and it farts on every up shift under significant throttle, wot it's awesome and everyone looks lol

[Arn560]

Love the fart. Best part of owning an S4!

[acturater]

I remember mine faded away over time. I wonder if there was some kind of carbon buildup somewhere along the way?

It was very prominent in the beginning, I remember loving it and my wife commenting on it as well. I went stage 2 sometime thereafter, but I also put it completely back to stock and didn't notice it as much, so I don't think it was the tune.

[Silverbullet S4]

I remember mine faded away over time. I wonder if there was some kind of carbon buildup somewhere along the way?

It was very prominent in the beginning, I remember loving it and my wife commenting on it as well. I went stage 2 sometime thereafter, but I also put it completely back to stock and didn't notice it as much, so I don't think it was the tune.

Maybe you just got used to hearing it and now it's not as noticeable to you? Wouldn't think it's something that can just go away.....

[sirsycott]

You didn't hurt my feelings, you just think someone else is wrong when they're not, and you're providing incorrect information. What you said would be true if you used "horsepower" instead of torque potential...but in lower gears, the larger gear provides the equivalent ratio of extra torque to the wheels as the differential in gear size. At the same rotational speed of the engine (RPM), you can provide more torque; therefore, the lower the gear, the more potential torque being applied to the contact points. If you shift at 5,000RPM from 1-2 and 5,000RPM from 6-7, you're applying more potential torque to the clutch pack in the former.

As for the 'cuts spark so the fuel dumps into the exhaust'...you haven't proved me wrong, at all. The ECU determines that the differential is too high and cuts the engine speed by stalling it out for a moment. How is that wrong, exactly? (Hint: It's not)

As for the heat soak business...I know the difference well. There is absolutely nothing to say that your intercooler can't be heatsoaked at 17F. It's ludicrous to think that it can't, especially considering that you mentioned in the thread you did a few hard pulls. It's absolutely possible that your intercooler can't handle the amount of heat the car is generating at 17F, which is the entire reason for people to replace their intercoolers with aftermarket units. The outside temperature would have to be in the -50Fs for it to be a nonissue.

Keep acting like a superior tool, though. People love that.

i wouldn't necesarrily put it at "stalling" , i've logged a few cars though the dsg shifting
between all of that happening , i do see the timing change to the new gear to offset, but it never really tries to zero out it does lower rather fast , fueling doesn't cut off beetween the shifts infact stays at max requeested value from one gear into the next shift

timing retarding vs stalling would be better semantics?

i'm just tossing in big words for the fun of it

plus when everyone reads stalling, they're assuming the engine stalled or seized because of a bad manual driver

[xuandatou]

Just curious why would you want dat fart so bad?

[Lamprey]

Just curious why would you want dat fart so bad?

Same reason people want really loud exhausts and shit. Cuz race car. Wish I was 16 again so I could appreciate the fart, but I'm not, so I don't.