Strange "Hop" in 1st for DCT

redfox · 07-01-2014, 11:49 PM

Anyone else experiencing this?

If I am in S2 or S3, starting from a dead stop in 1st gear, applying moderate throttle (as in not light and not wide open), the transmission engages but hops as it moves up the rev range. It's not wheel hop, but rev hop, which in turn makes the car bop...

Haven't tried it in D yet, but has only happened in S2 and S3.

redfox · 07-01-2014, 11:58 PM

More info...

I'm coming from driving MT for 15 years. First time in a DCT. I read something called the "wash cycle".

http://www.m3forum.net/m3forum/showthread.php?t=9029

Any who can provide more color? I couldn't find anything else on this topic.

JTO24 · 07-02-2014, 11:17 AM

I've experienced this so-called wash cycle under 3/4-ish throttle on my e92 m3.. never knew it had a name until now lol but it's been talked about before over on the e9x forums.. I can't comment on the DCT aspect but if your issue seems the same as this wash-cycle I think it's normal.

jbraslins · 07-02-2014, 12:48 PM

Had it happen in my E90 M3 w/DCT all the time on aggressive throttle maps until I learned to control my foot better. Had it happen in my manual e46 M3 too. It's normal. Just feedback loop from your foot backing off throttle as car lurches forward, then back on throttle as car slows down. Gets worse and worse with each oscillation.

With time you learn to avoid it as you become smoother with your foot.

redfox · 07-02-2014, 09:21 PM

Thanks. At first, I thought there is something wrong with the DCT. Phew!

GrussGott · 07-08-2014, 09:01 PM

Quote:

Originally Posted by jbraslins

Had it happen in my E90 M3 w/DCT all the time on aggressive throttle maps until I learned to control my foot better. Had it happen in my manual e46 M3 too. It's normal. Just feedback loop from your foot backing off throttle as car lurches forward, then back on throttle as car slows down. Gets worse and worse with each oscillation.

With time you learn to avoid it as you become smoother with your foot.

Yup, same here - it's just like teaching someone to drive a stick:

they let out the clutch too fast and the car hops forward so they let off on the gas and the cars hops again so they push the gas and it dies. Same thing with the DCT only the computer is controlling the clutch so it doesn't die. At least that's my non-technical assessment

In the morning on cold start, she's pretty groggy and doesn't like to wake up - just like with a MT - so you have to over apply the gas to get 'er going.

You'll also roll backwards at stop lights if you take your foot off the brake.

It's an MT with a computer controlled clutch.

swamp2 · 07-08-2014, 10:33 PM

This was discussed in some detail when the M-DCT was brand new in the E9X M3. I think we called it something like throttle acceleration induced feedback. It all about acceleration and inertia. Under acceleration you and your whole throttle leg/foot can move away from the pedal, that then causes deceleration which in turn drives your foot leg forward leading to an increased throttle actuation and the effect then repeats. It can also happen in a MT, I'm not sure why it is most observed in M-DCT cars.

Move your throttle foot to the side a bit garnering some friction between it and the nearby interior trim panel. This nearly stops the effect entirely. Also, don't use the most sensitive throttle mapping. There is no benefit to doing so, other than a very small psychological benefit of feeling "more power". The sensitivity of the pedal is bad for achieving either ideal throttle control at launch or in a cornering situation.

CurbBender'90 · 07-09-2014, 06:54 AM

I'm glad this was touched on because I've had this happen in my e92. I was thinking " I know this is a "race" transmission but damn. Reminds me of a horse and she wants to buck, calm down girl! Love learning new things about this amazing machine.

parky1215 · 08-10-2014, 08:58 PM

I am not sure if it's same thing, but I encountered this issue in MDM with dct in S2 and S3 mode in 1st gear.
When pressing gas pedal, powers comes then immediately gets cut off. Power then comes again and cut off. It does this 3 times in a row in very short amount of time.
It doesn't happen always though. I am going to hold off using MDM for now.

redfox · 08-11-2014, 09:19 AM

Quote:

Originally Posted by parky1215

I am not sure if it's same thing, but I encountered this issue in MDM with dct in S2 and S3 mode in 1st gear.
When pressing gas pedal, powers comes then immediately gets cut off. Power then comes again and cut off. It does this 3 times in a row in very short amount of time.
It doesn't happen always though. I am going to hold off using MDM for now.

It's your right foot that's the problem. Stiffen up that ankle and the problem will go away.

07-01-2014, 11:49 PM	#1
redfox INSTAGRAM: @yaasplease 166 Rep 1,023 Posts Drives: 2015 YMB M4 Join Date: Mar 2010 Location: Toronto iTrader: (4)	Strange "Hop" in 1st for DCT Anyone else experiencing this? If I am in S2 or S3, starting from a dead stop in 1st gear, applying moderate throttle (as in not light and not wide open), the transmission engages but hops as it moves up the rev range. It's not wheel hop, but rev hop, which in turn makes the car bop... Haven't tried it in D yet, but has only happened in S2 and S3. __________________ 2015 ///M4: M/Vorsteiner Aero, P3Cars, HRE R101, Dinan S2, Coils & Intake; Eis/Akra Exhaust 2013 WRX Hatchback: LED Conversion, Blacked Out, Rally Armor 2015 Macan Turbo: Techart Exhaust, Cargraphics Lowering Module, Blacked Out
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07-01-2014, 11:58 PM	#2
redfox INSTAGRAM: @yaasplease 166 Rep 1,023 Posts Drives: 2015 YMB M4 Join Date: Mar 2010 Location: Toronto iTrader: (4)	More info... I'm coming from driving MT for 15 years. First time in a DCT. I read something called the "wash cycle". http://www.m3forum.net/m3forum/showthread.php?t=9029 Any who can provide more color? I couldn't find anything else on this topic. __________________ 2015 ///M4: M/Vorsteiner Aero, P3Cars, HRE R101, Dinan S2, Coils & Intake; Eis/Akra Exhaust 2013 WRX Hatchback: LED Conversion, Blacked Out, Rally Armor 2015 Macan Turbo: Techart Exhaust, Cargraphics Lowering Module, Blacked Out
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07-02-2014, 11:17 AM	#3
JTO24 never could compete with Lloyd Braun 5282 Rep 5,388 Posts Drives: 2022 G80 M3 6MT Join Date: Feb 2011 Location: South Jersey iTrader: (7)	I've experienced this so-called wash cycle under 3/4-ish throttle on my e92 m3.. never knew it had a name until now lol but it's been talked about before over on the e9x forums.. I can't comment on the DCT aspect but if your issue seems the same as this wash-cycle I think it's normal. __________________ 2022 G80 M3 6MT \| Skyscraper Gray \| Kyalami Orange 2018 F87 M2 6MT \| Alpine White (sold) 2016 981 Cayman 6MT \| Jet Black (sold) 2015 F80 M3 DCT \| Tanzanite Blue \| Gold Brown (sold) 2013 E92 M3 6MT \| Mineral White \| Fox Red/Black (sold)
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07-02-2014, 12:48 PM	#4
jbraslins Latvian Gangstah 84 Rep 570 Posts Drives: 2009 E92 M3 Melbourne Red 6MT Join Date: Jun 2010 Location: Wake Forest, NC iTrader: (1)	Had it happen in my E90 M3 w/DCT all the time on aggressive throttle maps until I learned to control my foot better. Had it happen in my manual e46 M3 too. It's normal. Just feedback loop from your foot backing off throttle as car lurches forward, then back on throttle as car slows down. Gets worse and worse with each oscillation. With time you learn to avoid it as you become smoother with your foot. __________________ 2009 E92 M3 Melbourne Red 6MT [SOLD] 2015 YMB BMW M3 M-DCT [SOLD] 2010 Alpine White E90 M3 M-DCT [SOLD] 2002 TiAg E46 M3 manual
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07-02-2014, 09:21 PM	#5
redfox INSTAGRAM: @yaasplease 166 Rep 1,023 Posts Drives: 2015 YMB M4 Join Date: Mar 2010 Location: Toronto iTrader: (4)	Thanks. At first, I thought there is something wrong with the DCT. Phew! __________________ 2015 ///M4: M/Vorsteiner Aero, P3Cars, HRE R101, Dinan S2, Coils & Intake; Eis/Akra Exhaust 2013 WRX Hatchback: LED Conversion, Blacked Out, Rally Armor 2015 Macan Turbo: Techart Exhaust, Cargraphics Lowering Module, Blacked Out
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07-08-2014, 10:33 PM	#7
swamp2 Lieutenant General 612 Rep 10,407 Posts Drives: E92 M3 Join Date: Sep 2006 Location: San Diego, CA USA iTrader: (3)	This was discussed in some detail when the M-DCT was brand new in the E9X M3. I think we called it something like throttle acceleration induced feedback. It all about acceleration and inertia. Under acceleration you and your whole throttle leg/foot can move away from the pedal, that then causes deceleration which in turn drives your foot leg forward leading to an increased throttle actuation and the effect then repeats. It can also happen in a MT, I'm not sure why it is most observed in M-DCT cars. Move your throttle foot to the side a bit garnering some friction between it and the nearby interior trim panel. This nearly stops the effect entirely. Also, don't use the most sensitive throttle mapping. There is no benefit to doing so, other than a very small psychological benefit of feeling "more power". The sensitivity of the pedal is bad for achieving either ideal throttle control at launch or in a cornering situation. __________________ E92 M3 \| Space Gray on Fox Red \| M-DCT \| CF Roof \| RAC RG63 Wheels \| Brembo 380mm BBK \| \| Vorsteiner Ti Exhaust \| Matte Black Grilles/Side Gills/Rear Emblem/Mirrors \| \| Alekshop Back up Camera \| GP Thunders \| BMW Aluminum Pedals \| Elite Angels \| \| XPEL Full Front Wrap \| Hardwired V1 \| Interior Xenon Light Kit \|
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07-09-2014, 06:54 AM	#8
CurbBender'90 S 72 Rep 438 Posts Drives: 2010 S65 Join Date: Sep 2011 Location: West.Bloom iTrader: (1)	I'm glad this was touched on because I've had this happen in my e92. I was thinking " I know this is a "race" transmission but damn. Reminds me of a horse and she wants to buck, calm down girl! Love learning new things about this amazing machine. __________________ DCK
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08-10-2014, 08:58 PM	#9
parky1215 Lieutenant Colonel 573 Rep 1,990 Posts Drives: F90 M5C \| G06 X6 M60i Join Date: Nov 2010 Location: Rancho Cucamonga, CA iTrader: (13)	I am not sure if it's same thing, but I encountered this issue in MDM with dct in S2 and S3 mode in 1st gear. When pressing gas pedal, powers comes then immediately gets cut off. Power then comes again and cut off. It does this 3 times in a row in very short amount of time. It doesn't happen always though. I am going to hold off using MDM for now.
	Appreciate 0 Quote