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isaac Jan 15, 1:29pm
2001 Absolutely Red Toyota Celica GT
ECelica Admin

2001 Toyota Celica GT

Posts: 6012
Joined: May 2002
Los Angeles, CA
[ENGINE] Transmissions, Manual vs Automatic - Pros & Cons

The Automatic transmission vs the Manual transmissions - its pros and cons.

Firstly, as we all know that the AT (Auto Transmission) is much more convenient and enjoyable than the MT (Manual Transmission). Well, lets talk convenience here. We know that the car is run on 4 basic things besides the judgment of the driver. They are the steering wheel, the pedals, the gear shaft and the other control including lights, wipers, horn etc. If we subtract one of those jobs, we reduce our efforts in driving by 25%. All you have to do is relax both your hands evenly on the steering wheel rather than constantly engaging yourself in switching gears as per the changing speeds. Also one of your leg is as good as not required as there is no clutch pedal. When we talk about the driving pleasure, well with the efforts reduced the car definitely seems to be a much better machine than otherwise.

Some Basics - Just like that of a manual transmission, the automatic transmissions primary job is to allow the engine to operate in its narrow range of speeds while providing a wide range of output speeds.

Without a transmission, cars would be limited to one gear ratio, and that ratio would have to be selected to allow the car to travel at the desired top speed. If you wanted a top speed of 80 mph, then the gear ratio would be similar to third gear in most manual transmission cars.

Youve probably never tried driving a manual transmission car using only third gear. If you did, youd quickly find out that you had almost no acceleration when starting out, and at high speeds, the engine would be screaming along near the red-line. A car like this would wear out very quickly and would be nearly undriveable.

So the transmission uses gears to make more effective use of the engines torque, and to keep the engine operating at an appropriate speed.

The key difference between a manual and an automatic transmission is that the manual transmission locks and unlocks different sets of gears to the output shaft to achieve the various gear ratios, while in an automatic transmission, the same set of gears produces all of the different gear ratios. The planetary gear set is the device that makes this possible in an automatic transmission.

We clearly can make out, that the AT vehicle is very convenient and a smooth drive compared to the MT, but there are a few drawbacks in the AT. Firstly, the At gives a much lesser mileage than the MT, besides if you ask some of the good drivers, they really prefer the MT to the At. WHAT????? WHY would anyone prefer a MT over an AT? Well, the fact is that the AT is designed to change gears at a specific range of speeds, for example, the gear might shift from the first to the second lets say when the car hits 20 KMPH and then from second to third when it is doing a 50 KMPH and so on. That leaves a driver with little option to choose his drive mode. Some drivers prefer to rev the engine on every gear, which would mean, he probably would like to hit the second gear only when the car hits a 30 KMPH and the third when its about 65 KMPH whereas the others who would like to conserve fuel, might switch to a higher gear a little early.

The difference - AT being very easy to use and smooth, MT gives you more options and is easy on the budget month after month. Having driven both, seems like, the AT is really good when you out on a vacation or generally if wanna enjoy a drive, but the MT is good when you going to work, braving the traffic.


The Benefits of a Manual Transmission...
1. Acceleration. A manual transmission accelerates more rapidly, and evenly throughout the gears, especially in a situation where one needs to merge into traffic more quickly. Automatics, on the other hand, start off very slowly in the lower speeds, then accelerate more in the higher speeds. This makes it very difficult to predict just how long it will take to reach the targeted speed. Score 1 for the manual transmission.

2. Maneuverability. Due to the acceleration differences above, an automatic is less maneuverable in a crisis situation (say, quick lane changes when being cut off), whereas a manual is just as peppy as its owner. Advantage: manual.

3. Assistance in maintaining alertness. Since one is constantly shifting gears in a manual transmission vehicle as traffic speeds change, one is forced to stay alert. This is especially important in stop-and-go traffic situations, where the car can stall if one isnt alert. Automatics on the other hand, require no adjustment or attention, as the correct gear is always engaged. In a traffic situation, this could cut down on ones alertness. This is especially dangerous when dealing with erratic drivers who will change lanes without signaling in tight quarters or any of the other myriad hazards such as rear-endings that come with thick traffic. Advantage: manual.

4. Fuel efficiency. An automatic guzzles far more gas than a manual vehicle-- EPA statistics and ratings on fuel efficiency show exactly that. This is because some energy is used to power the gear-shifting mechanisms in an automatic vehicle. A manual transmission requires none of that energy, since the driver does all of that him or herself. Advantage: manual.

5. Calorie burning. An automatic requires the actions of only one bodypart, the right leg, alternately pressing the gas pedal or brake, and maybe the hands for some occasional steering. A manual transmission, on the other hand, requires the use of both legs, with the left leg engaging the clutch as necessary, the left arm constantly steering, while the right arm shifts gears. The right leg is used in the same manner as the automatic. So, driving a manual transmission is more of a workout than driving an automatic. Advantage: manual.

6. Wear on brakes. When going downhill, in an automatic, one must constantly keep riding the brakes. In a manual transmission, on the other hand, one merely needs to shift into a lower gear, and with minimal usage of the brakes, ones speed can be controlled quite easily. This girl noticed a huge difference the first time she had to go down the other side of the Santa Cruz Mountains-- she merely downshifted to third gear, and her speed was very controlled, while she saw continuous brake lights and smelled burning brake pads from the automatics all around her. Advantage: manual.

7. Startup due to battery failure. In an automatic, a jumper cable and additional vehicle are required, to restart a car with a depleted battery. On the other hand, one merely needs to push a manual transmission vehicle, and get it going at a reasonable speed, then jump in and start the vehicle-- it will start up with no problem, and the battery will recharge as it is driven. Advantage: manual.


Why I prefer Automatic Transmission...
The Automatic v Manual argument will rage on just as long as there are motor vehicles on the road and people to drive and argue about them and neither will be right or wrong. It is all down to the individuals preference and experience.

Before automatic gearboxes came on the scene the argument was about whether floor change or steering column change was the best or easiest to use. Then came the gearbox that required manual handling but there was no clutch and then a pre-select gear box where you selected the gear before using it and depressing the clutch brought the pre-selected gear into play and these forms of transmission were also argued about at length. So this controversy is nothing new.

For forty years I have driven cars with a manual gearbox right from the old days of double de-clutching to the more modern synchromesh gearbox and now an automatic car. In my younger days I wouldnt be seen dead driving a car with an automatic box as young men changed gears as slickly as racing drivers to impress the ladies Actually there werent any automatic cars to be seen dead in, so I was OK. In those days ladies, real ladies didnt drive cars because it was reckoned that they would not be able to master the art of double de-clutching. So the men could show off their driving skills much to the admiration of the ladies beside them. Even when the synchro box came in, it was still reckoned that the lady would not be able to co-ordinate the use of hand and two feet to effectively change gear. Off course time has proved this supposition to be nothing more than that as ladies can drive cars and change gear as slickly as men.

Manual change gave you absolute and total control of how you drove and appealed to those younger persons who liked to pretend to be budding formula one drivers as they changed down to screech around a corner, impressing no one except the traffic cop on their tail but it didnt impress the magistrate in court a few weeks later. Indeed just to show off your driving skill you could slip neatly from second to top or vice-versa. Approaching a tight bend you could change down a gear ready to go in slow and come out fast much to the admiration of the passengers as they hung on for dear life to prevent them being thrown around inside.

Before the advent of motorways, driving was fun where gear changing was part and parcel of the Sunday spin. But now if it wasnt for the multitude of road works on the motorways you could drive a couple of hundred miles and never touch the gear lever let alone actually change gear.

Nowadays the automatic box is as reliable as the manual and on my Vauxhall Corsa I can select which gear I start off in depending on the conditions prevailing at the time. At the press of a button I can select the sporty mode where the cars does its best to misbehave under acceleration and that is handy for showing the boy racers a thing or two at the traffic lights. They just do not expect a Corsa to leave them standing especially when they see an old geezer driving it. When it is snowy and icy I can select the snow conditions where the car will take off in third and for hilly terrain I can select to only go up to third gear. I can also select the same mode for up to second gear and stay in first for really hilly driving. But in normal automatic mode I can still change gear as I want simply by lifting off the accelerator to go up a gear or pressing down hard to come down a gear or I can let the box do its stuff on its own. The automatic box has one drawback for those who do not use it properly and that is fuel consumption. In town where the road speed is restricted to 30 mph you can find yourself in third gear all the time and emptying your fuel tank as if there was no tomorrow. My box changes up to forth at around 35 mph so I have to make it go up a gear myself at 30 mph or risk the wrath of a nearby copper. To get the best out of an automatic box you have to listen to your engine and watch the rev counter as well as the speedo and that compensates for not having to change gears manually.

With my automatic box I have the best of both worlds and still have a leg left over to tap to the music. Just one final thought, Long John Silver of Treasure Island fame would have been able to drive had there been cars in his day, but it would have to have been an automatic. With only one leg he could not have been able to handle a manual box, unless he got the parrot to do it.

Source...
The Consumer Reviews Website

...

How each transmission works...

Manual Transmission:
http://www.howstuffworks.com/transmission.htm/printable

Automatic Transmission:
http://www.howstuffworks.com/automatic-transmission.htm/printable

cooperchien Feb 8, 3:04am
Member

2004 Toyota Celica GT

Posts: 26
Joined: Jan 2004
LA
Well, according to toyota site, the MPG for GT with auto gear 29/36 but the GT with manual is 27/33. So auto gear is more fuel efficient, at least for Celica, right?

FPcelica Mar 21, 11:57pm
2001 Spectra Blue Mica Toyota Celica GT
Senior Member

2001 Toyota Celica GT

Posts: 509
Joined: Jun 2003
Houston, TX
i think the auto gets better gas milage due to the fact that the 5th gear on the gt doesnt seem like a overdrive but still acts like a acceleration gear to me... ill go 60 and have to shift into the 6th gear i dont have


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