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Author Topic: TFSI Gear change sound  (Read 14603 times)
slklite
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« on: October 16, 2015, 11:56:38 AM »

Hello guys, I've been crazy about this gear change for quite some time now. We see it a lot on new sportscars.

It is a kind of pop at gear change, I don't know how to explain it, so here is a video...

Have a look at this golf 7 R

https://youtu.be/Kb-qFcqa6B4?t=52s

We hear it a lot on this RS3 too

https://youtu.be/GPnvj0nqcws

Can someone explain how this works ? Is it something coded into the ECU or something that's "natural" with the exhaust turbo ...

The most important question, can this be ported to a ME7 (S3 BAM) ECU ?

Thank you guys Wink
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adam-
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« Reply #1 on: October 16, 2015, 02:04:05 PM »

It's DSG farts?
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slklite
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« Reply #2 on: October 17, 2015, 03:21:35 AM »

Is it specific to DSG gearboxes ? Because I think I saw on some manual gearbox cars ...
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slklite
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« Reply #3 on: October 17, 2015, 06:44:02 AM »

This is exactly what I'm talking about !!!

https://youtu.be/kXI78224lYY

The cars I heard it from, do iton gear change but also when you let go of the accelerator pedal after a heavy load ...

Would be nice to have something similar on the 1.8t or ME7 ecus...
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slklite
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« Reply #4 on: October 17, 2015, 06:46:34 AM »

here are a few other ones ...

https://youtu.be/BtANoW-7IXE

https://youtu.be/NBkJYuP6j2k

https://youtu.be/P_CYxLNkIqs

https://youtu.be/ulapBd4dq18
« Last Edit: October 17, 2015, 06:56:25 AM by slklite » Logged
mbkr89
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« Reply #5 on: October 17, 2015, 08:45:34 AM »

a late ignition angle make this effect
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adam-
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« Reply #6 on: October 17, 2015, 10:16:46 AM »

It's peculiar to the DSG boxes I'm sure.  Don't see how you could replicate this on a manual as the change speed will always be different.
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slklite
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« Reply #7 on: October 17, 2015, 10:58:40 AM »

"Dommage" as they say in french ...
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mbkr89
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« Reply #8 on: October 18, 2015, 02:12:13 AM »

Sorry for my bad engish  Wink
to shift you habe to reduce torque, the fastes way is ignition. So the gearbox change the ignition angle. In manual gearbox you have the chang is yourself.
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slklite
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« Reply #9 on: October 18, 2015, 05:29:53 AM »

All right, so this means that it could work with the clutch switch only right ?
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mbkr89
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« Reply #10 on: October 18, 2015, 06:47:41 AM »

Every time the engune reduce torque fast
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hackish
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« Reply #11 on: October 19, 2015, 12:20:13 PM »

It's called a fast path torque reduction. It's very common on motorsports sequential boxes. The fastest way to pull torque for a smooth gearshift like that is to cut fuel/timing so that's what they do. In motorsports we will frequently just do a spark cut which keeps the turbo going and spits a nice flaming fart out the tailpipe. You could sort of do it on a manual box by tying the clutch signal in for flat (no lift) shifting.
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slklite
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« Reply #12 on: October 26, 2015, 09:14:45 AM »

Difference is that you sometimes hear this sound even when drivers, just release the accelerator pedal, we can hear this sound too.

Here are some examples on ford focus rs with manual gearboxes (not only when accelerator pedal released...) ...

https://youtu.be/umkbehSxfHE

https://youtu.be/cDPsEtyq6NU

https://youtu.be/bf3UDRH9VOI

I was alaso wondering about something else. Excuse me for answering that many questions, but I like to understand how things work ... So it is about when you accelerate (while stationary or while driving) and release the accelerator pedal and you hear multiple "farts" on the exhaust (not necessarly  with flames ...)

THank you guys Wink
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hackish
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« Reply #13 on: October 26, 2015, 10:36:02 PM »

I hear what you're talking about now. I think you'll find it's excess fuel in the manifold that suddenly has some air to burn when you let off the throttle. The fast path torque thing is more with the throttle depressed. It sounds similar but the two are different. You can also make a car really farty by retarding the timing at low throttle. Some manufacturers do this on purpose to make the car sound more aggressive. Dodge with their SRT4 comes to mind.

Difference is that you sometimes hear this sound even when drivers, just release the accelerator pedal, we can hear this sound too.

Here are some examples on ford focus rs with manual gearboxes (not only when accelerator pedal released...) ...

https://youtu.be/umkbehSxfHE

https://youtu.be/cDPsEtyq6NU

https://youtu.be/bf3UDRH9VOI

I was alaso wondering about something else. Excuse me for answering that many questions, but I like to understand how things work ... So it is about when you accelerate (while stationary or while driving) and release the accelerator pedal and you hear multiple "farts" on the exhaust (not necessarly  with flames ...)

THank you guys Wink
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Geremia
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« Reply #14 on: October 27, 2015, 05:21:56 AM »

Could it be the ecu monitors also the turbocharger intake pressure, instead of blindly cut spark or whatever?
I've no clue about A2l/maps, but when my wastegate got blocked in open position, i had a lot of farts from dsg. Even farting in N when fulltrottle reving up then releasing, engine was making small delay untill "accepting" my gaspedal release, then reving down with "machine gun" farts, like if ecu wanted the intake pressure to not go below xx value.
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