Is conventional automatic transmission the best choice?

[Alberto Michelatti]

http://www.onirc.com/votazioni/vota.asp?ch...e=1&voto=10" target="_blank">

I think that nowadays is out of our era that a human being has to think at what gear is better to shift to (an ECU can do this perfectly) and, moreover, having to move directly the clutch pedal that, for me, would haven't to exist. So I would like to explain because for me the conventional automatic transmission with hydraulic torque converter is the best choice:

1) since the birth of the automatic transmissions, there is no power flow interruption during gear shifting, like in the more quick Direct-Shift-Gerabox system of Audi/Volkswagen group; not even a robotized manual transmission like, for example, the BMW SMG (or Ferrari F1) can do this;

2) an ECU always knows exactly the input shaft rpm and the output shaft rpm, matching them perfectly just at the right moment (an human being never could do this so: in my opinion, this is quite impossible);

3) the engine can't never stall, shutting off by its own: with a manual transmission, when you take-off and don't apply sufficient throttle or release too fast the clutch pedal the engine can stall (very dangerous in the road traffic!); also when you have to do an emergency braking, maybe that for the panic you release the clutch pedal wrong and, as well, the engine can stall, leaving you with a much more less efficient braking system just in the wrong moment;

4) the automatic transmissions are electronically and perfectly self-protected against drivers mistakes and, moreover, there isn't to worry about clutch overheat or synchronizers wear;

5) for the life of car, there isn't to worry about the expensive clutch-disc substitution;

6) with a manual transmission, how many burning-wheels dragster-style starts can you do without the clutch overheats? With an automatic transmission, instead, you can do this for the times you want, endlessly;

7) with a manual transmission, when you are at a stop on a uphill, when you have to start you have to release very carefully the clutch pedal, risking to overheat it; with an automatic transmission, instead, you have just to apply trottle, regardless of the weather, grip, slope, car load and anything else;

8) due to the automatic transmission creep feature, at the stops on uphill it's like having a Subaru-like hill holder feature, because the car almost never go reverse;

9) with automatic transmissions there's less wear than on a clutch, and there's less wear on suspensions and crankshaft/lower engine because of lack of transmission snatchs;

10) due to the automatic transmission kick-down feature you can get speed very fast, pulling yourself out fastly from bad and dangerous traffic situations;

11) due to the up-to-3.0x torque multiplication feature of the torque converter, a car has more acceleration when you accelerate out of a stop. Moreover almost all automatic cars today have the torque converter lock-up clutch, that eliminates the slippage between the pump (input power, engine side) and the turbine (output power, transmission side) of the torque converter. This by-pass function is studied to improve fuel economy at constant speed.

12) for the ultimate, the comfort and satisfaction given by an automatic transmission in the city traffic, in my opinion, are really priceless; it's true that the fuel consumption in this condition is higher, but you also have a lot more acceleration and this is undoubtedly a safety factor;

If someone is interested in a very detailed description of an automatic transmission, here there is the explanation for the ZF "4HP18 Q/EH" one (using the Ravigneaux gear train arrangement): http://www.digest.net/alfa/FAQ/164/pb94/pb94-6.htm.

Here there is the description of the state-of-the-art 6 speed "TR-60SN" Aisin AW automatic transmission (using the Lepelletier gear train arrangement), fitted on the Porsche Cayenne and on the Volkswagen Touareg (as well as, for example, as on the Volkswagen New Beetle, Audi TT and Audi A3): 6speedautotranny.zip.

Alberto.

P.S.: please don't say this to anyone, but this is the untold reason why the automatic transmission is absolutely the best choice...

Edited July 24, 2007 by Alberto Michelatti

[Saiya]

Could not have said it better myself! :D

Nowadays because of the terrible traffic, especially in Sydney, auto's are the way to go.

[steinny72]

got to disagree with u mate

i had an auto 2003 corolla hatch and changed it for a manual (yes i got a Sportivo this time) but i drove the normal manual corolla (an 04 hatch model) and it has so much more torque and 'pull' feeling than the auto...

my biggest issue with the auto was if you were going between 20 and 50 k’s an hour up a hill ...... the car had like 0 power and took ages to build speed. Although i have a Sportivo now .... if I’m in 2nd going up a hill at 30 ks an hour ... it plenty of pull . (Remembering that the Sportivo has pretty much the same power as normal corolla below 6100 revs)

I realise the Sportivo is a 6 speed compared to the 4 speed auto … but I did in fact drive the normal manual corolla and found it substantially more powerful than the auto

[DHC09]

Keep in mind that the corolla auto box is pretty sh!t compared to ones from other manufactures, and not to mention the very very long gears <_<

I'd like to try a 2zz with DSG

[DANZZT231]

I reckon the best of both world would be something in the form of DSG by Audi/VW and Selespeed Alfa (designed by ferrari some said, same one in F1 model originated in F355). Its true robotised manual as there is no tourqe converters and it allows you to choose fully automated manual if you want to, or you do the gear shift yourself. If I remember correctly, SMG is not true robotised manual like DSG and Selespeed as it uses tourqe converters. It really is like driving a car in video game arcades and its very cool, and you don't get that artificial feeling like using the manual mode in automatic gearbox. Most importantly robotised manual gearbox react as fast, if not faster than manual transmission gearbox. Just don't get mixed up thinking its auto as you will roll down on uphill.

However, some likes the purist approach where it requires full driver involvement and I believe only manual transmission can do that. Controlling 3 pedals and a gear stick, and uses all of them in mere seconds (rev matching down shift for example) is very cool and rewarding, and is almost like foot dancing. Be one with the machine.

Manual can be tiresome on city traffic, and driving in a city like Jakarta in Indonesia really worn me out (no traffic takes 20 mins, with traffic takes 1 hour for the same destination). So in condition such as that I would pick automatic. Thankfully Melbourne traffic is not bad during rush hour, I can still tolerate it with manual. Sydney is more hectic, so its no wonder many choose automatic over there. But not all automatic is bad, for example the German made ZF gearbox found in Ford and now Maseratti, and SMG found in BMW.

Automatic transmission is getting better and better, so perhaps one day manual is left for option instead of standard in most brands of car. Plus, most buyers pick automatic, such as in Australian market.

Edited May 30, 2007 by Danz

[Alberto Michelatti]

Maserati GranTurismo 4.2 V8

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Maserati GranTurismo 4.2 V8: just one transmission choice, a ZF "6HP26" 6-speed adaptive sequential automatic transmission with hydraulic torque converter, lock-up and paddles behind the steering wheel.

The BMW SMG (Sequential M Gearbox) I-II-III transmission, like wichever other robotized manual transmission, never used torque converter instead of the clutch disc.

BMW SMG transmission

Adaptive sequential automatic transmission with hydraulic torque converter for the winner!

Alberto.

Edited June 4, 2007 by Alberto Michelatti