My car has a 6 speed torque converter automatic gearbox. In normal use it's fairly clever, shifting ratios smoothly and with as much common sense as its little electronic brain can muster. It will, like most of its kind suddenly decide to change gear mid-bend when you would prefer that it didn't but one has to allow for its single mindedness of purpose I suppose.
Where it gets churlish though, is at or around 40 mph. Even on a flat surface with no real intended change of speed it dithers between 4th and 5th gear, trying both alternatively and much to my annoyance it simply fails to make a firm decision and stick to it, instead hunting between the two ratios like an overexcited dog.
Fortunately, it also has a facility to over-ride the full auto system by moving the gear lever to the right allowing a form of manual sequential shifting which calms its nerves a bit. This "tip forward to go up and tip backwards to go down" system is also a bit more involving and amusing when bowling along a country road.
I have though sometimes wondered if I would be a better judge of things than it or not and whether, if I could be bothered, I'd be able not only to outwit it for practical reasons but also to achieve better fuel economy by selecting gears more appropriately than it would.
So next week, when I'm due to do a few hundred miles, I may decide to drive it "manually" just to find out. Of course I run the risk of being proven wrong by a machine but at least it doesn't have the ability to gloat other than with its little average mpg display.
What do you think will be the outcome? Am I in with a chance, or is it going to humiliate my efforts?
I'll tell the truth on here of course when the experiment is complete but who do you bet on, the machine or the human?
:-)
Last edited by: Humph D'Bout on Sat 26 Feb 11 at 20:48
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You could always drive at 41mph....
Or set cruise at 40...
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As it's a torque converter auto i doubt you'll improve on the machine's economy..unless the machine needs a service/update...has it always hunted between gears at that sort of speed?
Most torque converter's require an oil and filter change anywhere from 50 to 100k miles..some tried the sealed for life comic cuts, but when their gearboxes started falling apart that was quietly dropped, and servicing returned...does the Cashcow have a gearbox service due.
If your car was an automated manual i have no doubt that driven manually by someone as old as...sorry...as experienced as you, could improve economy and have a smoother more flowing constant drive...i've proved it with trucks.
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>> As it's a torque converter auto i doubt you'll improve on the machine's economy..unless the
>> If your car was an automated manual i have no doubt that driven manually by
>> someone as old as.
Sorry GB, I think you have that the wrong way round. In my experience anyone can beat a slushy torque converter over an auto that selects between fixed gears.
And NC is right of course. Humph will be driving differently, very differently - the results will be skewed.
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>> Sorry GB, I think you have that the wrong way round. In my experience anyone
>> can beat a slushy torque converter over an auto that selects between fixed gears.
I confess i've not had the pleasure if that's the right word of fully electronic torque converter auto's, my ownership and high mileage experiences are of older simpler designs which probably use hydraulic valving to control gearchanges, little to go wrong and difficult to beat IMO, whatever speed and position of throttle the hydraulics will instantly find the most suitable gear...difficult to see how you can beat that.
My two long term recent auto's, the MB and the Hilux both have smooth gearboxes (Hilux possibly even smoother changing than the Benz), you could not beat either of them for being in the correct gear for (nearly) all circumstances, about the only time i ever override either is to increase otherwise non existant engine braking, or for that split second power burst (not Hilux..;) when pre planning a lightning quick overtake.
Whereas in automated manuals, without fail i've found them overreving/underrevving, slow to choose the inevitably wrong gear when faced with junctions/hills which leads to jerky (lost momentum) progress and revs far higher than needed due to changes not needed (more momentum lost)...not the fault of the gearbox as such if one can bear such a contraption, the box cannot possibly read the road ahead so can only be programmed for a limited set of variables.
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I was looking at it from a pure economy perspective.
As for smoothness you are right. Automated manuals are nasty jerky things.
There a nice pleasure in being able to make a slushmatic change well, the gentle lifting off the gas to encourage the next gear change and giving a wee bit of gas as it does to smoooth the change.
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My partner has a 4 speed auto 206. On the odd occasion when I drive it I tend to use the manual/clutchless selection around town. This is because I have noted it seems to like to rev away in 3rd gear when, if it was a manual, your ears alone would be telling you to use 4th. She gets pretty dire fuel consumption from it but I have no way knowing if what I do improves it
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It has always done it GB but it is now up to 60 something thousand miles too so maybe it'll need a fettle some time soon.
Last edited by: Humph D'Bout on Sat 26 Feb 11 at 21:16
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I once got 90-odd MPG out of a Maxi on an economy run. A guy in an auto complained that when I overtook him on an downhill bit of road, he couldn't hear my engine running.
You can't do that in an auto.
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Sadly, the results won't mean anything. Humph will be driving differently - whether he realises or not, however hard he tries, and the effect is very difficult to avoid.
With all of their faults, this is why the fuel consumption tests tend to use machines rather than people.
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You exaggerate as so often N_C (of course you are not alone in this).
There's no reason to suppose Humph will drive very differently from the auto in his car. As we all know our road speeds are governed essentially by the other traffic, so that will be a constant. Experienced drivers (like the OP) tend to drive at similar cruising speeds when not obstructed whether they are driving a manual or auto car.
So I really don't see why the experiment won't mean anything. Especially as no experiment or measurement has been suggested.
Obviously the important parameters are average speed and fuel consumption. It may be difficult to measure these accurately but it isn't impossible.
My guess is that there won't be much difference in those measurements, but poor Humph won't be tortured by his car's evidently not-quite-perfect trick transmission shunting and snorting when he is being held up by a load of mimsers (or exaggeratedly law-abiding citizens in a 40 limit).
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>>You exaggerate
No, I don't agree.
People clamping magnets onto the fuel pipe will report a fuel economy improvement which is quite spurious because that's what they want to measure. Humph doesn't like the gear electronic gear selection, and the same kind of bias is at work.
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>> I don't agree.
You're still wrong though NC. The statement that a driver 'drives differently' and can't avoid doing so is spurious and obscurantist. Of course he will drive differently if he uses manual mode instead of automatic. But a comparative test properly designed can still eliminate any bias effect.
As I pointed out in my first post, there are two parameters, not just 'economy'. On the same route at the same time - do it a dozen or a hundred times in each mode if you like - you measure journey time or average speed, and fuel consumption. Consistent improvement in one without a decline in the other will certainly indicate something. Humph shall be our guinea-pig (get a notebook and remember to write the numbers down carefully Humph).
Naturally to a driver, measuring fuel consumption alone without reference to average speed is indeed meaningless. But only a halfwit would try to check Humph's dilemma, and its solution, like that.
There may also be intangible benefits from driving in one mode rather than the other. A driver might be willing to trade a couple of mpg, or even mph although I doubt it, for a civilised drive instead of being jerked around by an insufficiently developed bit of clever-clever Heath Robinson carp.
Last edited by: Armel Coussine on Mon 28 Feb 11 at 04:40
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>>You're still wrong though NC
No.
Let me put it like this. You're trying to suggest that a one off test carried out under conditions which are not under any kind of control by a driver who is clearly biased has some kind of meaning. Who are you trying to kid?
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Or to put it more politely, you are suggesting that an ordinary driver over a period of time with many repeated journeys over the same route in both modes would be unable to tell if one mode was significantly more or less economical than the other.
The difference would probably be quite small though. That might make it difficult to measure.
Needless to say I am not trying to talk about a test whose results could be published and used in advertising (Buy the manual! The auto's rubbish!) but something that would establish to the driver's satisfaction that manual mode without the busy behaviour didn't dramatically increase fuel consumption.
I know you have a low opinion of drivers in general and their understanding of the magic machine, but some of them at least could manage that one. Humph could, and so could I.
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>>That might make it difficult to measure.
Yes!
A week's worth of driving with a biased driver would come nowhere near demonstrating anything.
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If we venture beyond the cosy world of internet fora, and actually try this, you would very quickly find that the care you need to take to establish a reliable and meaningful baseline, and then the care you need to take to change only one thing far outweighs Humph taking a few jottings in a notebook for a week.
Anyone who has ever spent any time and effort in experimentation will realise that to obtain a statistically significant change which can be reliably pinned down to just one parameter changing in a complex system is not a trivial task.
Add to this non-trivial task real life traffic and ambient conditions, and a biased driver, and you have meaningless rubbish.
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Well, perhaps we are talking at cross purposes after all. I thought that what Humph, a very high-mileage driver, wanted to do was establish (in a rough sort of way) that using manual mode to avoid excessive gearchanging at certain road speeds wouldn't cost him more in petrol.
Real life traffic and ambient conditions are where most of us drive. Over time though it isn't hard to establish whether a change in driving behaviour - using cruise control say, or driving an auto in manual mode - makes the jalopy use more or less petrol, or leaves the driver feeling irritable or relaxed.
Ah yes, the 'biased' driver who suddenly develops Economy Run skills because he 'wants' the car to be more economical in manual mode... that's why journey times should be equivalent. And since these vary quite a lot from day to day on the same route owing to slightly different ambient events, many repeated journeys must be measured and the times averaged.
Any findings might seem more convincing to the driver himself than to others, since the differences if any would be quite small. But they wouldn't be 'meaningless rubbish'. To a scientist or technician perhaps, but not to what judges call a reasonable man.
Last edited by: Armel Coussine on Mon 28 Feb 11 at 11:24
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I think we both agree that we aren't looking at a large change in mpg. We are more likely to be looking at whether 35 mpg become 35.1 or 34.9 than a jump from 35 to 60mpg.
Settling that sort of question with one week's worth of driving on public roads by a biased driver is never going to be able to pick out a subtle change like that from the background sources of noise.
Worse still, over such a test it's likely that the background changes will completely swamp the change in mpg caused by the changed driving technique.
This is why I say, and stand by the point of view that the test as described by Humph will have no meaning.
If you'll forgive a tangent.....
It's odd, but most people will set more store by the results of a "test". The difficulty is that it's much more difficult to set up a valid test which will give meaningful output than most people think. Once the test is done, unless it's written up in a very rigourous way, it's next to impossible to really scutinise the work to see where the flaws were. Many people are suspicious of theory and analysis, but, theory is much more easily checked and analysis results repeated than the more difficult work needed to verify test data. Of course, to be sure, you need both theory and test - one without the other is usually meaningless - however, the public misplace their trust in tests IMO.
As a result of having been bitten a time or two earlier in my career, I'm now very wary of badly designed tests; the danger I've seen is that people are too trusting of them, and don't apply the same scrutiny that they would to other sources of data.
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Who the chuffing heck is the biased one here? I couldn't care less whether the mpg result is in favour or otherwise of manual shifting I was just mildly curious to establish or discuss whether a significant difference in either direction could or would be seen. The outcome concerns me not one jot, it's a company car with its fuel paid for. It won't make the slightest difference to me so I utterly fail to see where any bias comes in.
Frankly, due to a significant bias in favour of idleness, and as stated at 09.40 on Sunday, I'll almost certainly not carry out the experiment anyway.
Crickey, some of you would argue about anything ! Find another fight please. Mine's not playing....
So Thzzzzzzzz !
:-)
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>> Who the chuffing heck is the biased one here?
I hadn't realised you were such a sensitive flower Humph.
However, I wasn't suggesting that you would be particularly good or bad in terms of bias, just that you would bring some level of bias to the "experiment". It might be financial, it might be simply a desire to prove yourself superior to the electronics, it might be..... just about anything, but there would be some level of bias.
>> Frankly, due to a significant bias in favour of idleness, and as stated at 09.40
>> on Sunday, I'll almost certainly not carry out the experiment anyway.
Wise fellow. IMO, you couldn't do better.
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>> I hadn't realised you were such a sensitive flower Humph.
Nor had I actually. I would have said that you were less likely than the average driver to get the wildly biased nonsensical result predicted by NC, but now I'm not so sure.
I'd try a month on manual mode and a month on auto, preferably on some frequent regular trajectory if you've got one, and see how I felt about it. Doesn't sound too arduous does it? Unless of course manual mode is more of a pain than auto.
I wash my hands of you, in clean brake fluid with a dash of Grenadine.
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I wouldnt trust him to sit the right way on a toilet seat, let alone do a scientific trial on sensitive throttle control, not with those plates of meat and cheap shoddy footwear.
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I used to do the tiptronic thing fairly regularly, more because i could and i liked it than anything else.
First time i jumped in M's manual golf and selected first without using the clutch i decided i'd stop dabbling :-)
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As ever, I have to be the Luddite. A properly designed autobox with a good torque converter just wouldn't need six ratios. And electronics doesn't do the job properly-it's just a cheape manufacturing option. I've said it many times but 30 years ago my Hondamatic Accord drove beautifully smoothly from zero to 100-plus mph with just one gear.
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Humph might be able to beat the box is by coasting, but I'm not sure if the electronics will allow him to do that.
Another way would be to change up just short of labouring, which would be earlier than the box would normally.
Again, I'm not sure if he will be allowed to.
As an aside, the official figure for the auto on the Honda Civic are a few tenths of an mpg better than the manual.
Seems to me the fuel consumption penalty for buying an auto in this size of car is not what it was.
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>> Another way would be to change up just short of labouring, which would be earlier
>> than the box would normally.
I can't make sense of that sentence at all. You change down if the engine is labouring.
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...I can't make sense of that sentence at all. You change down if the engine is labouring...
OK, OK, not my clearest piece of prose.
Change up early, so you are in the higher gear at a speed only just above labouring speed for that gear.
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>> Change up early, so you are in the higher gear at a speed only just
>> above labouring speed for that gear.
My instinct is that Humph will beat the automatics if only because he can do that with anticipation - just as he reaches a crest for example. But as N_C says, if he's economy-driving the chances are he'll improve his mpg anyway.
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Truth be told, I'll almost certainly tire of the notion as soon as the phone rings and not bother. Yesterday though, I drove my wife's manual petrol version of the same car for the first time in ages. I had to keep glancing at the rev counter to check that it hadn't stalled as it was so quiet by comparison. I love the auto box for puddling around London or trickling in motorway queues and such but on balance I think I'm probably a dyed in the wool manual man. Also refreshing was the lack of automated lights and wipers on hers. I'm old-fashioned enough to prefer to make my own mind up about what should be on and when. The 16" wheels on her one make for much smoother progress over speed bumps and pothole ravaged streets too.
Quite different cars to drive despite being the same if you see what I mean.
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It could all be to do with "adaptive learning" sometimes i used to wipe the adaptive learning and allow the car to relearn or some autoboxes can be reproggrammed to overcome issues like these.
ID
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>> It could all be to do with "adaptive learning" sometimes i used to wipe the
>> adaptive learning and allow the car to relearn or some autoboxes can be reproggrammed to overcome issues like these.
The other way, is to just give the car a good thrashing for 10miles or so......
(a boss of mine could always tell when I had borrowed his car...;-) He He)
Last edited by: swiss tony on Sun 27 Feb 11 at 10:17
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Oh, ok then. I'll try the thrashing thing....
Although I have verbally told it what I think often enough it doesn't seem to sink in...
:-)
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Interesting - I had a Mondeo TDCi auto on extended demo a few years ago and that was a pain at 30, but it didn't hunt between gears, it always went for top (5th, I think, but not sure now). It was painfully juddery and really needed knocking down a gear or even two to feel mechanically comfortable.
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Those automated manuals are very odd, and far from perfect.
I've only driven one though. It was a new VW Golf TDI or something, a sporting diesel.
I drove it mostly in slow traffic and it was like Humph's car at 40, shunting between the lowest gears and seeming not to notice gentle throttle inputs. It seemed crotchety and reluctant.
Eventually a couple of hundred yards of straight road opened up and I could give it a bit of foot. To my utter bafflement it changed UP a gear into, I dunno, second or third, and bolted forward like a jackrabbit. Hooray! But there was the pub so that was it.
I am absolutely sure that if I had one of those it would stay in manual mode (which I didn't even try) at least in town. The auto was too busy at low traffic speeds and didn't know what it was doing, like Humph's jalopy at 40.
Whether all the shunting increases fuel consumption I don't know - perhaps not - but anyone would give up a couple of mpg for a less piggish drive.
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Well, I wouldn't exactly admit to having thrashed it quite today but I drove it with some determination at least. Temporariliy anyway, it has decided to be more obedient. Might be something in all that spare the rod theory.
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Zero:
"There a nice pleasure in being able to make a slushmatic change well, the gentle lifting off the gas to encourage the next gear change and giving a wee bit of gas as it does to smoooth the change."
My wife's EGS equipped Citroën drives exactly that way. I did notice after the 1st service (2nd service coming up) the gear change was not smooth. Take it up to 2k rpm back off the throttle, the car will change up. Do that a few times and the car 'learns' to do this by itself.
iffy:
"Humph might be able to beat the box is by coasting"
If I recall correctly, Humph's car is a diesel. Coasting will actually burn more fuel as the car will be idling, and supplying fuel, whereas coasting shuts off the fuel until it reaches idle rpm when fuel supply resumes.
If it's a conventional torque converter auto then I doubt there'll be much in it, I tried this with my SAAB auto, made maybe 0.1 MPG difference in a 2.5 V6 petrol. The full-auto mode will drive to the conditions, Humph might be able to read ahead and save a little momentum but in the usual cut and thrust of UK traffic, I doubt there'll be much in it.
I've found recently, in my diesel, giving it the beans up to the speed I require then putting cruise on saves fuel.
Last edited by: gmac on Sun 27 Feb 11 at 16:44
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>> iffy:
>> "Humph might be able to beat the box is by coasting"
>> If I recall correctly, Humph's car is a diesel. Coasting will actually burn more fuel
>> as the car will be idling, and supplying fuel, whereas coasting shuts off the fuel
>> until it reaches idle rpm when fuel supply resumes.
>>
Should have read:
If I recall correctly, Humph's car is a diesel. Coasting (putting in neutral?) will actually burn more fuel as the car will be idling, and supplying fuel, whereas backing off the throttle shuts off the fuel until it reaches idle rpm when fuel supply resumes.
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>> "Humph might be able to beat the box is by coasting"
>> If I recall correctly, Humph's car is a diesel. Coasting will actually burn more fuel
>> as the car will be idling, and supplying fuel, whereas coasting shuts off the fuel
>> until it reaches idle rpm when fuel supply resumes.
Eh?
EDIT - Now I get you :)
Last edited by: corax on Sun 27 Feb 11 at 16:56
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I got tied up in the quotes thing and didn't read what I had written. :-(
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Flippin' heck, I nip orf to watch Scotland not quite beating Ireland, well they came second anyway...and all this...blimey !
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gmac,
The argument in favour of coasting - knocking the car into neutral - is less momentum is lost through engine braking.
Shutting the throttle and leaving it in gear may use a little less fuel per second, but you will come to a halt sooner.
I doubt there's more than a shilling's worth in it ether way, even at today's prices.
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I'm not sure how much engine braking there is now.
We have two cars, a 2004 and a 2009, both diesels. The 2009 does not slow down with engine braking I still have to use the pedal. The 2004 diesel I can drive on the gearbox without needing to use the middle pedal. Funnily enough though, the 2004 car is more economical with a 2.4 five cylinder engine over a 1.6 four cylinder. Both cars weigh ~the same, the 1.6 litre has a lower CO2 rating but burns more fuel.
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Sorry to hear that Humph. :-(
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>> Well, I wouldn't exactly admit to having thrashed it quite today but I drove it
>> with some determination at least. Temporariliy anyway, it has decided to be more obedient. Might
>> be something in all that spare the rod theory.
>>
Told ya didn't I!
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Indeed you did. Thanks for the tip.
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Probably cleaned the crap off of the injectors as well.
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>> Probably cleaned the crap off of the injectors as well.
>>
Millers.
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>> Millers = no crap. :-)
Everytime Millers is mentioned I expect the Snake Oil naysayers to turn up :)
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They haven't done an interweb search for "Diesel injector fouling" an increasing problem for Euro 4 and 5 spec engines.
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Nah ! MGD is the Bogs Dollocks.
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>> "Diesel injector fouling" an increasing problem for Euro 4 and 5 spec engines
What's the panel's recommendation for my Mondeo when I pick it up then? 2.0TDCi 130 Euro IV without DPF, 112k miles. Supermarket or branded fuel, normal or super diesel, what about additives? I'm planning to keep it for several years, might as well start as I mean to go on.
Last edited by: Dave_TD {P} on Sun 27 Feb 11 at 22:36
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supermarket petrol and drive it like you stole it. never failed any of my oilburners.
Last edited by: Zero on Sun 27 Feb 11 at 22:37
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Diesel, surely...
My experiences with super diesel (BP Ultimate) have been mixed: 01Y Octavia SDi 8% improvement in economy, much quicker; 03/53 406 HDi90 no difference from standard; 96P Rover 418GSD estate no less thirsty but smoother and faster.
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Yes of course, slip of the fingers
I meant the oily stuff.
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>> My experiences with super diesel (BP Ultimate) have been mixed: 01Y Octavia SDi 8% improvement
>> in economy, much quicker; 03/53 406 HDi90 no difference from standard; 96P Rover 418GSD estate
>> no less thirsty but smoother and faster.
Can you justify the increased cost?
I never could. It made the renault 1.9dci unit nicer to drive, but failed to do anything in the VW 1.9 pdi,
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It's worth more in its component parts than as a Mondeo.
Drive it how you feel appropriate (you know what feels right from what you write) and break it into bits if it fails.
Last edited by: gmac on Sun 27 Feb 11 at 22:50
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>> Can you justify the increased cost?
I could with the Skoda, not with the others though. I wondered if anyone here had found it to be worthwhile in a Ford.
>> Drive it how you feel appropriate ... and break it into bits if it fails
That's pretty much the plan, yep. Hoping it won't fail for a good few years/miles yet!
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>> What's the panel's recommendation for my Mondeo when I pick it up then? 2.0TDCi 130
>> Euro IV without DPF, 112k miles.
If 'twer mine i'd be sticking the cheapest Derv i could find in it, but treat it to a bottle of Millers at double dose, that'll last you about 6 to 10 tankfulls, and should help to clean things up...according to the blurb which i tend to believe (used it for many years) and many others don't.
Then try without the Millers and see if you can tell the difference, and make your own mind up about permanent use.
Depending on it's previous history an oil and filter change, drain the fuel filter and check the air filter.
Only my opinion, i do overservice my cars mind.
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Sounds about right GB. Car is in mid Beds, collecting it in a couple of days' time. Cheapest Derv there is 132.9 compared to 129.9 up here, planning on putting £40 in to start so for the sake of an extra pound or so I'll do it down there. Millers seems to be around £10 a bottle online so I'll invest in some by the end of the week I reckon.
Oil and filters will get done within a month or so, and at least annually (c. 10k miles) afterwards. It seems to have been looked after (cable ties on wheeltrims, small scuffs on bumpers touched in) but not excessively (rainwater wasn't beading on the roof, remnants of blu-tak on the phone cradle) so a thorough "moving in" clean/wax is in order to start with.
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There have been a few problems with the latest (U2) Ceed engine, mainly smoke on a cold start and initial rough running. I had this problem at 13,000 miles although I do not hang around, some have had it below 5,000. The smoke was grey and smelled strongly of diesel and I put it down to fouled injector(s) leaking fuel overnight. Millers fixed mine.
This may be of interest.
www.seatcupra.net/forums/showthread.php?t=188065
Last edited by: Old Navy on Mon 28 Feb 11 at 07:32
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>> This may be of interest.
>>
>> www.seatcupra.net/forums/showthread.php?t=188065
Good man yourself Navy, i've seen those pictures and that report before but each time failed to log it in my favourites.
That i shall now do, thanks for linking them.
Dave, if you find that Millers is for you long term then it works out about half price by buying a 5 litre can of the stuff, i split a can with a mate as 5 litres will be too much unless you are running a small fleet..;)
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Sounds like a good move! I'll try a 10-tank bottle to start with and see what happens from there.
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Doesn't like 40 mph - hobby
