The average driver is awful at changing gears. Almost everybody who I am driven by can't control the clutch properly and give me a smooth ride. So for the average driver an auto 'box would make life more pleasant for their passengers.

People say to me they like to be in control of their cars. Most of the time I don't think they are and they use the wrong gear in my experience.

Having done 85,000 miles or so in DSG vehicles over the last 4 years, I have learnt the art of using the DSG. It is an art and anticipation is the name of the game.

Yes the 'box will sometimes choose what i feel is too low a gear, but more often than not, I should be in the gear the car has selected, by that I mean corners. I need to slow right down so I can always see the tarmac for the distance I can safely stop in.

There are times when it selects 2nd gear at around 15-18mph when I would probably use 3rd if it were a manual going over speed jumps or turning at junctions.

My car will pull 4th at 20mph if I use 'manual' mode. 5th at about 28/29mph and 6th around 38mph.

I have noticed when cold it really hangs on to high gears longer than when hot.

I rarely have a problem with roundabouts, but then I can override the auto with a click of the fingers tips.

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I assume you are talking about 6-speed wet clutch box? I think 7-speed dry clutch is much better as it doesn't have problem with "hanging on" to gears form my experience.

I assume you are talking about 6-speed wet clutch box? I think 7-speed dry clutch is much better as it doesn't have problem with "hanging on" to gears form my experience.

Yes.

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Kiwibacon , that is a debate stopper. Now you have spoken we need discuss no further!

Gotta love absolute statements, I am guilty of them myself way too often

Yes guys, there is nothing more efficient than a manual gearbox. A manual gearbox has nothing inside but gears transmitting the power, they produce so little heat that no oil cooler is needed (apart from a few extreme examples) and there are no circulating pumps or hydraulic pumps inside sucking power (parasitic losses).

Efficiency is defined as energy out compared to energy in. That's it. There are no other valid definitions.

Those of you looking at standardised fuel economy tests are seeing the combined effect of gearbox and engine efficiency. Put simply, the engineers behind these auto gearboxes have spent thousands of hours tweaking their shift points to maximise the fuel economy in the standard tests.

This doesn't make the autos more efficient, it just makes them very good at the standard tests. Often at the detriment of real world driving.

I always thought so, but the published BMW 5 series fuel consumption figures for the 8 speed auto when I last looked at it said otherwise, which surprised me.

That's the standard test at work. Manual gear change points are defined, autos aren't. It's another case of the tests not matching reality.

The 8 speed autos require hydraulic pressures to change gears and engage/disengage clutch packs. This hydraulic pump is a parasitic loss that manuals don't have. Even with the torque converter locked an 8 speed auto is less effcient than a manual.

With the torque converter unlocked the efficiency plummets. But with more gears (i.e. 8 vs 6 or 4) it can be locked up more often and do better than the same vehicle and engine with fewer automatic ratios.

I will do a test and drive a whole tank on manual he usual way (mostly pensioner driving with one redline blast aday) and compare this to my consupmtion figures for D-mode driving. As rockhopper says, new boxes are waay more efficient than manuals in REAL LIFE. Nobody can get published manual box figures in real life, same as in fuel consumption fiction data

Driving in manual-mode does not change the efficiency of your DSG box. All it does is give you some limited choice on which gear to be in. A DSG in manual mode still has all the parasitic internal losses (hydraulic pumps etc) of a DSG box in auto mde.

That test would only be comparing the benefits of your selected gear to the pre-programmed gears. It's not relevant to auto vs manual efficiency.

Kiwibacon , that is a debate stopper. Now you have spoken we need discuss no further!

Indeed. There is nothing more efficient in a production car than a manual gearbox.

A manual gearbox with straight-cut gears would be more efficient than the production boxes with helical gears. But the noise, vibration and comparative strength loss keeps production cars on much smoother, but slightly less efficient, helical gears.

Edited 22 March, 201313 yr by Kiwibacon

Yes, agreed with your theory re parasitic losses in that all there is to it, theoretical energy efficiency. It it completely lost by wrong hear selection, inefficient clutch operation and most of all HUGE amount of time WITHOUT power being transmitted compared to modern box, especially DSG and sequential varieties of it. Funny enough despite that energy efficiency there is no high tier Motorsport class using manuals, all are auto or semi auto boxes, wonder why?

Yes, agreed with your theory re parasitic losses in that all there is to it, theoretical energy efficiency. It it completely lost by wrong hear selection, inefficient clutch operation and most of all HUGE amount of time WITHOUT power being transmitted compared to modern box, especially DSG and sequential varieties of it. Funny enough despite that energy efficiency there is no high tier Motorsport class using manuals, all are auto or semi auto boxes, wonder why?

Yes a complete moron of a driver can always destroy the economy. But when all products are aimed at the worst drivers, we've lost.

What do you class as "high tier motorsport"?

Rally cars are sequential manual and they are the closest to road going cars of any motorsport.

F1 the best description I found was electronicly triggered sequential box, the rules forbid automatic. http://www.xtrac.com...ater/product/78

But I'm not convinced a F1 box has any relevance to economical motoring, nor your 7sp DSG.

BTW, time without power being transmitted to the wheels isn't a problem at all. For large portions of driving there is no need for power transfer. This has no effect on efficiency of a transmission.

Edited 23 March, 201313 yr by Kiwibacon

Funny enough despite that energy efficiency there is no high tier Motorsport class using manuals, all are auto or semi auto boxes, wonder why?

Sorry, but you are wrong on that point. I know of no "top tier" rally car that has an auto/semi-auto box. They use a sequential manual change, some with "flappy paddles", others with a stick.

The only use I can think where an auto is used is by some of the 4x4 trials people. It used to be very common to use a Rover V8 and auto box.

You are right in that sequential boxes are called "manual sequential gearbox". The are versions of it where hear change instigated buy gear stick movement rotates a ratchet and this perhaps as close as you can get to calling it manual. In most cases, the "manual paddles" you describe are just electronic switches operating hydraulics, solenoid or other solution in the box with no "linkage" between the two. Even "traditional" sticks in manual sequential boxes have no direct linkage to the box itself and are there because drivers like it that way as opposed to a paddle(s) on the wheel.

F1 is yet different as it employs two clutches and two "cog shafts" similar to DSG but still being sequential in its nature.

None of the above has anything to do with any manual gearbox you find in a road car I any conceivable way .

So yes, I was perhaps wrong in employing a manual gearbox term to a road car H-pattern box ad automatic to everything else, since as I described in all cases (some classes probably have "augmented" shifting mechanism forbidden and only direct link ratchet allowed) there is not much "manual going on really. F1 is the best example where despite the box being called manual sequential box the only manual thing is the fact that in order to change gears driver sends a signal to CPU controlled unit requesting gear change. But hey ho, for the semantics purists it is still manual sequential box, so let's be it, I can call it that as well

Yes a complete moron of a driver can always destroy the economy. But when all products are aimed at the worst drivers, we've lost.

What do you class as "high tier motorsport"?

Rally cars are sequential manual and they are the closest to road going cars of any motorsport.

F1 the best description I found was electronicly triggered sequential box, the rules forbid automatic. http://www.xtrac.com...ater/product/78

But I'm not convinced a F1 box has any relevance to economical motoring, nor your 7sp DSG.

BTW, time without power being transmitted to the wheels isn't a problem at all. For large portions of driving there is no need for power transfer. This has no effect on efficiency of a transmission.

If you looked at schematics (plenty of very good animations on da toobe) you'd see F1 box is exactly the same as DSG but with much simplified "machatronics" units as it is sequential and only needs to move " up and down " the gears in sequence - for those who are not familiar with this.

As an example, did you know there are Mark 2 Ford Escorts with a sequential change Type 9 manual gearbox? The "H" pattern changer is replaced by the sequential system. There is still a clutch pedal although it is normally only used at stage start and finish.

A similar system can be found in Mitsi Evo's and Impreza's.

The "gear stick" can be about 2ft tall!

I didn't and thanks for the info:).

No wonder few systems use purely mechanical solutions as the priority for location of the gearbox, among many other considerations, is to achieve as good a weight distribution as possible. This when the stick/paddles become just a switch located for drivers convenience. Them you have the parasitic loses kiwibacon is so keen outspoken about .

BTW, time without power being transmitted to the wheels isn't a problem at all. For large portions of driving there is no need for power transfer. This has no effect on efficiency of a transmission.

Just pottering about at steady speeds it indeed doesn't matter. At heavy acceleration through the gears it makes massive difference. Even when you are not trying to set a new 0-60 record it still matters. From the moment you depress the clutch pedal to the time you fully released and applied throttle your car slows down. That loss of momentum has to be recovered. Is all but rectified by DSG box. The best example is going uphill.

I haven't bought a car yet for the 0-100km/h time.

I had a Mk2 Cortina with the Sequential Gearbox, but 5 years ago, not 35.

(back in 1977, it was fitted with a Column Change Auto, a 1.6, then a 2000E & was still great fun.)

The Engine and Sequential Box alone was 4 times the value of what the 1970 car was worth in 2007.

http://www.ruthmotor...p-gearboxes.php

My Punto 1249cc Speadgear with Sequential Shift of the CVT was just about as much fun,

george

This was ahead of its time on UK road cars & great fun.

I haven't bought a car yet for the 0-100km/h time.

You should change that. It will bring a smile to your face and a kindness and understanding of your fellow forumites!

Surely you can only get to 60 or 70 mph as quick as the traffic in front lets you,

Then you go at their pace anyway

and if its an open road,

what do you do with that extra 3, 4 or 5 seconds you have saved getting to 60 mph quicker ?

george

I just like the thrill of unbroken acceleration and sensation of travelling at speed and I am willing to pay for it

0-30 or 0-40 can be easy, exciting and practical,

and is often done best for the laughs in cars that surprise those ones that have amazing 0-100km/h times.

ie Little City Cars & run abouts.

Those 'fast ones' often suffer the No Traction no action off the line,

maybe the driver forgot to switch off the Traction Control and the power is cut before 30 mph is ever reached.

george

Tell me about it This morning on our way to County Swimming finals a Merc S320 was one of those cars. All he managed was to stink out my car with the plumes of black smoke coming out of it before he finally changed lanes lol

The one thing the DSG gearbox cannot do is read the road and anticipate, and this leads to the dimwittedness at roundabouts and some junctions that I mentioned. As you slow down on the approach the DSG lets the revs fall almost to idle before changing down. This is nice, because it gives smooth downchanges. However, this means the box is often caught out in too high a gear when you have enough information to decide that the roundabout/junction is clear and you put your foot back down. It's worse with a turbo diesel engine because you have a pause both for the gearbox to select the right gear and for the turbo to spool back up. In the Superb i reckon that this pause could be at least a second, which can feel like a long time with no power.

With the manual box in the Yeti I can distinguish between a situation where I am stopping (and will therefore allow the revs to fall) or a roundabout, where I can select a gear on approach that will ensure the car responds as I want it when I make my decision to go or stop. Similarly the slushmatic auto box in the Memsahib's car has no problem because the torque converter takes up the strain and the car responds instantly. Yes, you can override the DSG using the lever or paddles to get around this,but to me that somewhat defeats the point of an automatic to me.

Don't get me wrong - I think the DSG is a great gearbox (I've had two after all!) - I just don't think it's perfect.

Needs making clear, IMO.

its a Diesel Yeti or other Diesel and 6 speed DSG, you are saying that about.

Or is it true of all Vehicles with DSG in your experience

Do you mean with all DSG's including Petrol engines and 7 speed?

george

Sorry, diesel Octavia 6 speed and diesel Superb 6 speed. My current Yeti is manual, and the Memsahib's Toyota has a "trdaitional" auto box.

The 7 speed with petrol might be better: I'd still check for it on a test drive though.

Edited 23 March, 201313 yr by patnmand

I'm puzzled.

On my 2010 6 speed DSG when I slow down for a roundabout it changes down early, like to 3rd at 35-40mph, so it is using engine braking. It drops into 2nd early as well and doesn't select 1st unless almost stationary at less than 5mph.

This doesn't appear to be what others are saying happens in their cars.

I know it didn't on my 2006 Octavia, but the 2010 box is completely different in the way it drives to my previous box, even though they are basically the same design. (I think).

Sent using whatever device I'm using at the time.

On my 2010 6 speed DSG when I slow down for a roundabout it changes down early, like to 3rd at 35-40mph, so it is using engine braking. It drops into 2nd early as well and doesn't select 1st unless almost stationary at less than 5mph.

Interesting. From what I remember the Superb tended to change down to 4th just below 30, 3rd just below 20 and 2nd when almost at a standstill. It would only select 1st once you had completely stopped. Octavia was the same.