+ and - of automatic gearbox - is manual better?

It is. Energy in = fuel used, Energy out = weight of car * 60 mph ^ 2

I am saying I am correct (even though the original comment was qualified with an "AIUI", my further reaserch shows this to be correct as shown by the graph linked to previously).

Considering a bigger picture, yes it is good to have "the most efficient way to travel a given distance, assuming accelerating at some rate (this rate to be determined) to a given speed then cruising?". I maintain that is not with a convensional automatic gearbox. A CVT may get closer to it than a manual however.

I do have a clue, but only about 1 particular car. You may be right about expensive modern autos, but that is not all of them. I would guess there are more crap ones around than there are good ones, and do good ones deal with all the concerns? You are talking about spending a shed load of monay, do you want a car that restricts you at all, just for the sake of not having to go to the effort of changing gear?

Buy yourself a cheap Volvo 740 2.4 to play with [1] - mine goes like a mad thing if I want it to; instant power all the time and plenty of it. The kickdown is easily as quick, if not quicker, than changing down manually, and the scenery goes by really quickly. It's the first car I've owned where I can actually feel my head being pushed back during acceleration.

[1] If you can afford the petrol!

Si

I don't know about other autos but my 740 shifts itself down to a lower gear when the throttle is pushed down half- to three-quarters of the way down but then there's a button/switch which you can feel actuating when you push the throttle right to the floor and it shifts down into the lowest gear it can and holds it to the red line all the time the button/switch is pushed. This is called the "HNNNNGGGGGG!!" button.

Si

Tried a modern "smart" auto? I think you'd be pleasantly surprised.

I'd go for a smart auto with manual override or CVT every time.

Modern boxes know about steering angle and its rate of change and will suppress mid-corner changes.

Although the surprise mid-corner change is one of the more disconcerting aspects of a dumb auto for the new user they are quite easy to predict and can be controlled with the throttle.

Modern adaptive autos are integrated with the ECU and have an almost prescient ability to be in the gear you would want. CVTs are effectively incapable of being in the wrong gear.

There are methods for tyre smoking take-offs with autos, mostly with fewer mechanical consequences than the method you describe. I've never had problems moving off briskly, on cue, by simply pressing the throttle with either the 4.6l or 1.0l autos that I regularly drive.

That sounds like a sick or ancient autobox.

Every manual mode I've met is sequential - one up one way, one down the other - and many have wheel mounted controls.

Much less bother than an old fashioned H-gate IMO.

Even with old fashioned high gear lock-out selectors (PRNDL, PRND432, etc.) it just needs a little acclimatisation since you are only suppressing upshifts, not downshifts.

Much less of a problem with modern 4-6 speed boxes with lockup top than with the old 3-speeds but can still cause an occasional niggle.

That's broken. I've never had a box do anything like that.

...it might be operating correctly to some 'merkin spec but it's still broken.

Many autos have a winter mode but it sounds as if over keen ABS was your main problem.

I was an involuntary convert to autos but I'd not go back.

A

Only with naff boxes; kickdown should be near instant.

That can be worrying with a sluggish box...

You can of course move from D to [L,3] in anticipation just as you would with a manual.

Working along a queue of slow traffic is probably the situation where I find manual mode most useful although adaptive does surprisingly well in the same situation.

A

I suppose if you _really_ only want to consider the fuel required to get to

60, then you can use this - but out there in the real world people would normally consider the distance travelled to be an important factor in determining efficiency.

No it doesn't. It shows the fuel used by the engine at various rpm at what is presumably full throttle. There simply isn't enough information to determine what is the most fuel-efficient way of getting to 60 taking into account distance travelled while doing so.

FWIW I'm not talking about auto v manual here - I'm talking about different driving styles with the same gearbox.

Of course one could point out you're obviously not that concerned about economy given what you drive :-)

cheers, clive

Any two taxes, and two insurances, two lots of maintanance...

D

I can't disagree that 4 wheel braking may well be best - but read what I posted! I don't *have* 4 wheel braking in any meaningful sense. The rear brakes on a Citroen GSA regularly seize up unless you remember to carry a sack of cement around in the boot from time to time - that's the only thing that makes them actually do anything.

Effectively, I'm using the front wheels to slow the car, whatever I apply to them.

"The loss of road speed by engine deceleration will be more pronounced when a low gear is engaged, including an automatic gearbox. This will be valuable when driving on slippery roads when normal braking could lock the wheels" Roadcraft, 1977

"Changing to a lower gear can help when... on slippery roads, where engine braking is used to lose speed gently, so as to avoid skidding." Roadcraft, 1997

There's another way?

This is the scariest aspect about them. They _know_ what you're about to do. :)

[snip]

:)

So what do you reakon is better?

That is of course true.

[...]

The thing I find spookiest was how the box *always* spots when I was stitching my way up a queue of slow traffic and won't upshift between overtakes...

A

Tim S Kemp ( snipped-for-privacy@timkemp.karoo.co.uk) gurgled happily, sounding much like they were saying :

But mine uses *proper* fuel, not this strange expensive stuff.

David Hearn ( snipped-for-privacy@NOswampieSPAM.org.uk) gurgled happily, sounding much like they were saying :

Free tax, classic insurance, and plenty of enjoyable afternoons in the garage. What's the problem?

I did read, and understood what you posted. It doesn't alter my point. Even if the rear brakes only brake at 5% efficiency, it's still offers that much less chance of the front wheels sliding under braking., and should mean a shorter stopping distance.

The

I've known of those recommendations, for longer than I can remember. It's as obviously untrue today as the most effective way of slowing on slippery roads, as it was when I first heard it. Braking on 2 wheels can't better than braking on 4. It might help a novice driver to avoid a skid, but it certainly wont help as much as learning to use the footbrake properly in the same conditions. Mike.

My car was 6000 quid, it restricts nothing, has five ratios, and self shifts almost all the time. If I want manual control I can run the stick left and right to change down and up.

My last auto car was a Cavalier, it cost £300 and worked fine, could also be locked down into 2 or 1. It was X reg (X suffix...) and was also fine.

I've driven many autos, Vauxhalls, Volvos, Saabs, VWs, Audis, Mercedes, BMW, Jaguar, Ford, Renault. None of them have had any real disadvantage over manual versions of the car. I like manuals, but am happy with either.

Check autotrader, yes there's often a premium for auto, but it's worth it, and generall automatic cars have not been thrashed or laboured and are in better mechanical condition than manuals.

Can only agree to disagree, then. I've locked up loads of times by using the brakes - I've never done it by changing down.

Works for me.

Depends :-)

I'll stick to a manual for now, but that's because I'm a tightwad, and also because I don't actually do much gear changing - no town driving or commuting queues for me.

There is normally an economy hit for autos (ok, the best ones are getting pretty good - but they're not in budget yet) - but not for the reasons you gave.

cheers, clive