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 Issues with Dry Dual Clutch Tranmissions, Ford Focus, Fiesta, VW or Any Other Cars

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dares
post Sep 19 2015, 03:32 PM

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QUOTE(Dwango @ Sep 19 2015, 01:02 PM)
In Sports mode, it does feel like the gear upshifts longer (in light to moderate acceleration) as I recall it drags on to a high RPM before the gear upshifts. Due to the higher RPM in Sports mode, it surely feels like the gear is upshifting longer. In D, the RPM is lower, so the upshifting happens at a lower speed, giving the impression that it doesn't hold on to the gear as long as in Sports mode.

I don't usually drive in Sports mode but do feel that it does hold onto the gear longer before upshifting when compared to D, irrespective of whether it's due to the higher RPM or not. The Fiesta does not have Sports mode?
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Only the facelifted 1.5 Fiesta (aston grille) has Sport mode. Mine is the pre-facelift 1.6S, the only thing resembling sport mode is the hill descent mode which also doubles as a O/D off button. It holds revs as well, but I think not as aggressive as Sport mode in the facelifted Fiesta or the Focus.

QUOTE(zweimmk @ Sep 19 2015, 01:28 PM)
In sports mode (VW DSG7), the gear will downshift automatically at appropriate speeds. But the gear will not upshift until you hit past 6000+RPM. You can manually shift in S mode with the paddle shifters if you want.

If you drive in manual mode, the gear will still upshift itself once the rev counter hits 6000+RPM.

Driving in manual gives you more control and for the sake of preserving my gearbox, I will usually upshift from first gear when the speed counter hits 20km/hr.
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Thanks for sharing
TSSportyHandling
post Sep 19 2015, 04:56 PM

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QUOTE(JunJun04035 @ Sep 19 2015, 03:06 AM)
Regarding the first statement, since you mentioned multi level car park, I will help shed some light into the matter.

As we all knew, parking ramp slope degree varies around 5~6%. And most of us enter the parking with low speed.
The moment the car enter the parking (aka you slow down, even stop completely for a ticket) you will encounter a slope. However, given that you the traffic you drove to the car park is smooth, the TCM (or any gearbox brain) will upshift as soon as the engine permits. Then when you hit the ramp, your car is in 3rd gerar, thus you will press hard to compensate for that.

The TCM will sense your throttle input, making comparison to previous behaviours and try to coup with that. MOST TCM will decide that you are in sudden adrenaline rush, and need some speed, thus hold the gear. Hence the 4K/5K rpm scenario. However, the moment you hit the top of the ramp, you immediately release your throttle, let the car guide thru, tripping the TCM to upshift.

The repetitive jabbing of the throttle confused the TCM. Hence the jerk.

In my previous experience, both DSG and Powershift give the same jerk if you jab the transmission.
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Thanks for the input. I was driving up a multi-level car park in a condominium one night, and since the surrounding is quiet, I can every sound from the gearbox or engine clearly. When going up the ramp, no issues. When exiting the top of the ramp and cruising on the level ground heading to the next ramp (without stepping on the accelerator, the car just gliding along), the transmission is dragging and the engine sound is loud. WHen I stepped on the pedal the car jerks. The same thing repeated when I drove up the car-park 3 to 4 levels up.

WHen driving at low speed with light acceleration, in normal circumstances the RPM should be low and the sound from the engine should be low as well. However, due to the confusion of the Powershift transmission in these situations, the RPM and sound from the engine is slightly higher, coupled by jerks. The slow drive in multi-level parking ramps and roads with a lot of speed bumps is not smooth with the Powershift dual-clutch transmission of the Ford Focus.
Boy96
post Sep 19 2015, 06:27 PM

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QUOTE(dares @ Sep 19 2015, 10:00 AM)
So actually VW's sport mode is fully manual that only shifts automatically when absolutely necessary (eg. hitting the redline)? This would be different from Ford's sport mode, which shifts on it's own like D mode, except at higher RPMs.

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QUOTE(zweimmk @ Sep 19 2015, 01:28 PM)
In sports mode (VW DSG7), the gear will downshift automatically at appropriate speeds. But the gear will not upshift until you hit past 6000+RPM. You can manually shift in S mode with the paddle shifters if you want.

If you drive in manual mode, the gear will still upshift itself once the rev counter hits 6000+RPM.

Driving in manual gives you more control and for the sake of preserving my gearbox, I will usually upshift from first gear when the speed counter hits 20km/hr.
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Erk, where got until 6k only shift..

Just now I tried very light throttle in sports mode, S1 ➡ S2 2.8k, S2 ➡ S3 3.2k already shift..



This post has been edited by Boy96: Sep 19 2015, 07:37 PM
zweimmk
post Sep 19 2015, 07:34 PM

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QUOTE(Boy96 @ Sep 19 2015, 06:27 PM)
Erk, where got until 6k only shift..

Just now I tried very light throttle in sports mode, 3.2k already shift..


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I just retested again and you are right. The gear will upshift quite quickly in the 1st gear. Intentionally programmed this way to protect the gearbox I believe. If you throttle the car harder, it will upshift later but still relatively early. For the other gears, it will hold as long as you keep the foot hard on the throttle.

If you go light on the throttle in S mode then it will upshift early like how D mode behaves.
kcng
post Sep 20 2015, 03:02 AM

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light throttle application sure upshift earlier la even if u are in S-mode...

adoi...

if u are light on the throttle, the ECU thinks u are driving lightly and dont need the power hence the earlier upshift...

try be aggressive on the throttle and see....
u can drag S1 all the way to the red line...
fr0sti3
post Sep 20 2015, 11:09 AM

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i drive my polo 1.2 manual 90% of the time, shifting 1st to 2nd when rpm more than 3k
so far it's been 4 years already, gearbox still working fine
Yapmy
post Sep 20 2015, 10:35 PM

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Is that full throttle for that Fiesta? Looks very sluggish. Even gear shifts seem slow...
Dwango
post Sep 21 2015, 10:25 PM

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QUOTE(Yapmy @ Sep 20 2015, 10:35 PM)
Is that full throttle for that Fiesta? Looks very sluggish. Even gear shifts seem slow...
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You can't expect much from a 1.0-litre car, even though it is turbocharged. It is a very respectable car at its range to have the best of both worlds - good power in its class and at the same time good fuel economy. Usually you can't have both at the same time. At least it is still more powerful with better acceleration off the blocks when compared to say Honda City or Nissan Almera, those 1.5 or 1.6-litre cars in the same segment or higher segment.
Boy96
post Sep 21 2015, 10:54 PM

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QUOTE(Yapmy @ Sep 20 2015, 10:35 PM)
Is that full throttle for that Fiesta? Looks very sluggish. Even gear shifts seem slow...
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It actually goes from 0-200 (yes, 200 not 100) faster than a Preve/Suprima with 1.6 turbo CFE

But then the Proton will go further after 200 because of the higher displacement

This post has been edited by Boy96: Sep 21 2015, 10:55 PM
yrh0413
post Sep 23 2015, 11:01 AM

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QUOTE(fr0sti3 @ Sep 20 2015, 11:09 AM)
i drive my polo 1.2 manual 90% of the time, shifting 1st to 2nd when rpm more than 3k
so far it's been 4 years already, gearbox still working fine
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My Polo 1.2 TSI is closing 5 years old, still no issues with my clutch and gearbox.

For VW 7DSG you really need to understand what is under the hood. It's a manual gearbox with computers doing the shifting for you.
Judder does occur on my Polo, but it is predictable and usually can be minimized/avoided.

My driving habits:

1. If lights just turned red at traffic lights and you know it will take a while before you can move, shift the gear from D to N. This is to stop your gearbox from engaging in D1 resulting in rise in internal temperature. On my 5yr old Polo you can actually hear less engine noise when you shift from D to N at standstills.

2. When light turns green, shift to D early if you are not the first car to move off. Lift your pedal brakes let the torque roll your wheels 1-2 seconds before you tap on the accelerator. You sure to get judder if you floor the accelerator immediately after you lift your foot from the brakes.

3. At traffic jams, shift to Manual mode. 1st gear if you are going bumper to bumper.

4. Make it a habit to brake early, if you need frequent downshift change e.g. at multi-storey car parks consider switching to Sports mode.


dares
post Sep 23 2015, 02:14 PM

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QUOTE(yrh0413 @ Sep 23 2015, 11:01 AM)
My Polo 1.2 TSI is closing 5 years old, still no issues with my clutch and gearbox.

For VW 7DSG you really need to understand what is under the hood. It's a manual gearbox with computers doing the shifting for you.
Judder does occur on my Polo, but it is predictable and usually can be minimized/avoided.

My driving habits:

1. If lights just turned red at traffic lights and you know it will take a while before you can move, shift the gear from D to N. This is to stop your gearbox from engaging in D1 resulting in rise in internal temperature. On my 5yr old Polo you can actually hear less engine noise when you shift from D to N at standstills.

2. When light turns green, shift to D early if you are not the first car to move off. Lift your pedal brakes let the torque roll your wheels 1-2 seconds before you tap on the accelerator. You sure to get judder if you floor the accelerator immediately after you lift your foot from the brakes.

3. At traffic jams, shift to Manual mode. 1st gear if you are going bumper to bumper.

4. Make it a habit to brake early, if you need frequent downshift change e.g. at multi-storey car parks consider switching to Sports mode.
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Good tips, I practice 2, 3, 4 on my Fiesta.

Not sure about item 1, since my thinking is that when braked, the clutch is opened, so the transmission shouldn't be spinning anyway
dares
post Sep 23 2015, 02:24 PM

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For Ford Powershit owners....This is what your gearbox looks like and how it works.

*warning long video (1 hour)



Quazacolt
post Sep 23 2015, 02:29 PM

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QUOTE(dares @ Sep 23 2015, 02:14 PM)
Good tips, I practice 2, 3, 4 on my Fiesta.

Not sure about item 1, since my thinking is that when braked, the clutch is opened, so the transmission shouldn't be spinning anyway
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it makes sense on 1 similar to how a normal manual works.
the thing is that unlike auto with torque converters, dct doesnt have that to keep the transmission "connected" and just merely moving atf around with the torque converter.

although as you said, it doesnt make sense for the transmission to hold half clutching all the time as temperatures would rise/clutch wear.
dares
post Sep 23 2015, 02:47 PM

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QUOTE(Quazacolt @ Sep 23 2015, 02:29 PM)
it makes sense on 1 similar to how a normal manual works.
the thing is that unlike auto with torque converters, dct doesnt have that to keep the transmission "connected" and just merely moving atf around with the torque converter.

although as you said, it doesnt make sense for the transmission to hold half clutching all the time as temperatures would rise/clutch wear.
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no understand rclxub.gif
yrh0413
post Sep 23 2015, 03:01 PM

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QUOTE(dares @ Sep 23 2015, 02:14 PM)
Good tips, I practice 2, 3, 4 on my Fiesta.

Not sure about item 1, since my thinking is that when braked, the clutch is opened, so the transmission shouldn't be spinning anyway
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In Drive mode your dual clutch will always be partially engaged even when you step on the brakes. It is like in a horse race, your horse (clutch) keeps engaging and ready to burst out of the gates when the gates open.

When idling for more than 1 minute, switch gear to Neutral to release your clutch. This prevents unnecessary temperature buildup in the gearbox.

Try it... leave at Drive mode for more than 1 minute while stepping on the brake pedal. Switch to N see if you can feel any different.
On my Polo the moment i switch to Neutral my car becomes quieter (usually I switch to Neutral then pull handbrake and continue chatting with my passengers, both foot off the pedals).
Quazacolt
post Sep 23 2015, 03:32 PM

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QUOTE(dares @ Sep 23 2015, 02:47 PM)
no understand  rclxub.gif
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manual car you have to clutch in else stall ma kan?

i think bigger difference with a manual, the human knows that theres a jam, he will just remain it fully de clutch (or shift to neutral), where else a dct may have it half clutch as it may think the driver is slowly creeping forward.
dares
post Sep 23 2015, 04:06 PM

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QUOTE(yrh0413 @ Sep 23 2015, 03:01 PM)
In Drive mode your dual clutch will always be partially engaged even when you step on the brakes. It is like in a horse race, your horse (clutch) keeps engaging and ready to burst out of the gates when the gates open.

When idling for more than 1 minute, switch gear to Neutral to release your clutch. This prevents unnecessary temperature buildup in the gearbox.

Try it... leave at Drive mode for more than 1 minute while stepping on the brake pedal. Switch to N see if you can feel any different.
On my Polo the moment i switch to Neutral my car becomes quieter (usually I switch to Neutral then pull handbrake and continue chatting with my passengers, both foot off the pedals).
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QUOTE(Quazacolt @ Sep 23 2015, 03:32 PM)
manual car you have to clutch in else stall ma kan?

i think bigger difference with a manual, the human knows that theres a jam, he will just remain it fully de clutch (or shift to neutral), where else a dct may have it half clutch as it may think the driver is slowly creeping forward.
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I see. I'm not completely sure if it half-clutch or fully declutched when the brake pedal is pressed.

I actually used to practive shifting to N whenever stopped at the lights, but I couldn't notice any difference when shifting between D-N when I'm on the brakes, so now I don't bother anymore. But I'll try again.
zweimmk
post Sep 23 2015, 04:10 PM

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QUOTE(Quazacolt @ Sep 23 2015, 03:32 PM)
manual car you have to clutch in else stall ma kan?

i think bigger difference with a manual, the human knows that theres a jam, he will just remain it fully de clutch (or shift to neutral), where else a dct may have it half clutch as it may think the driver is slowly creeping forward.
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I'm not sure if DSG will stay in half clutch when in D1. Some people tell me it actually automatically disengage when the auto hold function or brake function is engaged.
I simply shift to N whenever I come to a stop, just like how you would drive a manual. and manually shift through gear 1 to 3 when traffics start moving. The only difference there's no clutch for me to step on, it's all automatically done for you.

Btw, I also engage the parking gear in N before moving the gear into D.

To me, it's a design issue, they probably didn't think how bad jams can get in this part of the world. For this reason, I think Ford DCT and VW DSG dry clutches are quite unsuitable for places like Thailand or Jakarta where traffic jams are terrible. Unsuitable if you decide to drive the car fully in automatic mode, because the low speed drive experience is also rather jerky as well, which is characteristic of this kind of gearbox.
TSSportyHandling
post Sep 26 2015, 09:16 AM

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Just an update. My belief that the dual clutch transmission (DCT) will always show jerking during low speed acceleration has been reinforced after the clutch on my Ford Focus has been replaced. It is only a question of the magnitude of the jerks, whether they are minor or major. After the clutch replacement on my car, the jerks are now reduced but still, they are there. An inherent character of the DCT that you will have to live with.

I have no issues with the DCT as long as it does not exhibit major (annoying) jerks during low speed acceleration, especially in basement or multi-level car parks with many speed bumps. The jerks in this circumstance will usually be accompanied with a louder engine sound which is "engine braking" from what I was told.
Boy96
post Oct 2 2015, 09:36 AM

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Just tested my powershift using sport mode in traffic jam, unlike the VW DSG that shifts up at around 3k rpm, this one shifts at 5.5-6k rpm even when feathering the throttle..

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