GBOL & DSG Gearbox

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MichaelAC
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GBOL & DSG Gearbox

Postby MichaelAC » Sun Jul 30, 2017 6:52 am

Hi,

with a sequential gearbox like VAG's DSG or S-tronic the ability to block gear change is removed. The problem here is that having removed your speed prior to a junction (roundabout or otherwise) having just left yourself time to change to the appropriate gear to advance my DSG box can sometimes be in the wrong gear. I may have been in sixth gear and when I've slowed it won't automatically change down quickly enough leaving me to try and click through several gears or if I had it in full auto mode (which I generally don't) it would simply leave me in the wrong gear to move me into the identified gap on a roundabout, for example.

The DSG rev matches and you don't need to remove hands from steering wheel so as long as I have completed my change downs before I make the manouvre, is BGOL actually relevant?

I'd love to hear your views and if you have a DSG and manage to avoid BGOL I'd be interested to know how you do it.

Thanks in advance.

Michael.

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jont-
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Re: GBOL & DSG Gearbox

Postby jont- » Sun Jul 30, 2017 8:06 am

Why would you? IME most of these boxes change more smoothly when you're on the power or brakes. Changing without either (which is what you'd be doing to avoid BGOL) tends to give the most lumpy changes.

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GTR1400MAN
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Re: GBOL & DSG Gearbox

Postby GTR1400MAN » Sun Jul 30, 2017 8:43 am

Not sure i understand what is happening. In my Renaultsport Clio if in full auto mode it changes down in line with the speed you are going. If you are having to decelerate quickly and using the brakes it will blip and down change for you.

If in full manual it still won't let you labour the engine and will change down as you slow down.

You drive these things on the throttle. How quick or slow you press/release it encourages the box to change gear. Braking also encourages a down change.

The only time I sometimes have to override is as I arrive at a RAB where it likes to hold on to 2nd too long for a nippy joining of moving traffic.

Having changed to this my first dual clutch it took a while to learn a new driving style. But having done so, I love it and I'm hooked. (Having said that I still think CVT is the future).
Mike Roberts

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AndyP
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Re: GBOL & DSG Gearbox

Postby AndyP » Sun Jul 30, 2017 8:46 am

I understand where you are coming from.
Briefly:-
I would look for perfection in this area from my own drive.
You could just allow more time to roll off the brakes and paddle down as if in a manual.
----------------------------------------------------------------------------------------------------------------
It seems test candidates are confused playing tunes on the various controls in various modes.
One even selected MANUAL from SPORT or DRIVE on the approach and paddling down??
Forgetting where they were/what exactly had they done and getting in a muddle on the exit.

I have driven/sat in may cars with varying systems.
In the Last Audi RS Q3 and Golf R 7.5 I drove it was annoying as when you accelerated and picked up the drive or chased the limit point it dropped one or two or more if I saw an overtake off the exit or speed a bit low.
Ended up selecting sport if on a mission or enjoying myself and it was always at the right gear for my entry speed.
I found pressing /pulling and holding the Merc paddle it scrolled down to the lowest in a 'moment.
So after braking did that.

It would be a technical BGOL if you braked whilst doing that or as you say pulled a paddle 2 or 3 times. I know an Examiner that would Critique that.
I have discovered even more idiosyncrasies. and modes available which confuse the less technical.

In the new Guilia it chose the gears [obviously] however IF I CHOSE and we were at odds [I saw it as a second gear junction so did the car, I dropped from 3 to 2 it dropped it to 1---jerk--- [me and car] ha ha

[New Passat had "COAST" mode enabled, so on a light throttle or not accelerating or lifted off for a period it DISENGAGED the gear box. If you braked or accelerated it RE engaged it. A new feature enabled/disabled in the menus (somwhere)]

I await interesting follow up replies.
It is not WHAT you drive, BUT:-- the WAY that you drive it.
It is not HOW fast you drive, BUT:-- HOW you drive fast.

Cheers Andy

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GTR1400MAN
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Re: GBOL & DSG Gearbox

Postby GTR1400MAN » Sun Jul 30, 2017 9:10 am

Sport mode does solve a lot of issues people have (in auto) with early up changes and holding on to gears too long when slowing.

My follow up question though is why try to avoid BGOL in a dual clutch equipped machine? Avoiding it in a manual car is down to physical elements of changing gear and keeping the vehicle smooth and stable. In a DSG/DCT the drive is NEVER disengaged. When driving a manual car I'd avoid changing corner mid bend due to destabilising the car. In a DSG/DCT you can flick the paddle and the clutches blend the change so you are never not under power.

I've ridden DCT motorcycles and on a conventional machine while banked over mid-corner you would not want to be changing gear. Yet a DCT in full auto will ... and you don't even notice it (apart from the change in revs). Power is is applied seamlessly.

Strangely, both on cars and bikes I have found that when not in Sport mode, the programmers have built a 'manual' feel to the changes. If you accelerate hard you get a 'manual like' lurch/pause at each change. It's obviously been built in as in sport mode the changes are seamless.
Mike Roberts

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GTR1400MAN
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Re: GBOL & DSG Gearbox

Postby GTR1400MAN » Sun Jul 30, 2017 9:17 am

AndyP wrote:In the new Guilia it chose the gears [obviously] however IF I CHOSE and we were at odds [I saw it as a second gear junction so did the car, I dropped from 3 to 2 it dropped it to 1---jerk--- [me and car] ha ha

Yes, had this happen. :) I try to avoid overriding in auto mode for this reason. My main use of override in auto mode is at a RAB as mentioned earlier and when approaching an NSL to get an early lower gear (rather than use the crude kick down to force a down change).
Mike Roberts

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GTR1400MAN
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Re: GBOL & DSG Gearbox

Postby GTR1400MAN » Sun Jul 30, 2017 9:24 am

AndyP wrote:I found pressing /pulling and holding the Merc paddle it scrolled down to the lowest in a 'moment.

The 'tech' on all these cars is different and it is good to see the IAM encouraging Observers to get Associates to explore the handbook and really understand how their machine works (auto brakes, power modes etc etc).

Here's how Renault implement auto multi-down changes.

Mike Roberts

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AndyP
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Re: GBOL & DSG Gearbox

Postby AndyP » Sun Jul 30, 2017 10:01 am

Thanks for that.
Brilliant, like it.
[Well I like rennos!! but NOT the EDC versions, Nico Hulkenberg does another good job on U tube in the New Megane RS]

That was what I was taught in the merc.
it will scroll down to the 'best' gear.
It worked in any mode.
SO
The original query BGOL.

The criticism was easily seen in some cars on test.
It was being done with one hand OFF the wheel whilst braking using the STICK selector [no paddle use or there were not paddles]
One of the reasons for not BGOL apart from the smoothness value.
It is not WHAT you drive, BUT:-- the WAY that you drive it.
It is not HOW fast you drive, BUT:-- HOW you drive fast.

Cheers Andy

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GTR1400MAN
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Re: GBOL & DSG Gearbox

Postby GTR1400MAN » Sun Jul 30, 2017 10:09 am

AndyP wrote:Well I like rennos!! but NOT the EDC versions,

Here's mine. It's the later mentioned Cup version.

Last edited by Mr Cholmondeley-Warner on Thu Aug 10, 2017 8:21 pm, edited 2 times in total.
Reason: fix quote markers
Mike Roberts

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MichaelAC
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Re: GBOL & DSG Gearbox

Postby MichaelAC » Sun Jul 30, 2017 10:17 am

Thanks for your replies everyone.

Jont, I agree that the harder your driving the DSG the smoother the gear changes are and that is part of why I raise the question I suppose.

GTR1400, I think your Renault is a little more spohisticated than my Mk 1Audi Audi TT which was the first production car to have this type of gearbox. It is good but maybe not so quick on the auto down changes, I only ever use it in manual mode anyway but it will still prevent it stalling with it's own down change if you roll to a stop. The problem is that if this is on a high speed road approaching a roundabout whith good sight lines, it can still leave me with more than one gear to sift through after my breaking meaning I need to leave more time between my breaking and my final gear selection before proceeding or at least that's my perception but I am still in the experiment phase of this really.

AndyP, thanks for your comments, I think I will try practicing scrolling through a bit more at the 'off brake' point, I am new to trying this with DSG as my other car is a manual and so it might just be a case of practice.

My own view at the moment is that it may not be necessary to avoid BGOL with the twin clutch gearboxes but I'm still working it out. Using my current method I change down smoothly with breaking (using the steering paddles always) on approach and will have the correct gear by the time I'm off the breaks and looking for the gap in the roundabout. That actually gives me one less change to make, on some ocassions, if it is clear to go without a stop at the roundabout.

Having said that, if I do this I'll get into the wrong habit when I'm driving the manual so if I can perfect not using BGOL in the DSG I will use that. I think the idea of sequencing your driving method is sound and as I experiment more I may find that it might be appropriate to avoid BGOL with the early DSG although some more sophisticated gearboxes like in the Renault Sport Clio might be.


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