[TeeG]

I'm buying an E91 shortly, and am deciding between manual or automatic. Some of the reasons obvious, I know, but I'm still curious to hear why people chose what they did.

[linus]

Originally Posted by TeeG

I'm buying an E91 shortly, and am deciding between manual or automatic. Some of the reasons obvious, I know, but I'm still curious to hear why people chose what they did.

This is taken directly from the wikipedia website:

Comparison with automatic transmissions
Manual transmissions are typically compared to automatic transmissions, as the two represent the majority of options available to the typical consumer. These comparisons are general guidelines and may not apply in certain circumstances. Additionally, the recent popularity of semi-manual and semi-automatic transmissions renders many of these points obsolete. It should be kept in mind that some of these points are true of "conventional" automatic transmissions which shift gears and are coupled to the engine with a torque converter but are not a true comparison or do not apply to other kinds of automatic transmissions, like the continuously-variable transmission.


Advantages
Manual transmissions typically offer better fuel economy than automatics.[1] Increased fuel economy with a properly operated manual transmission vehicle versus an equivalent automatic transmission vehicle can range from 5% to about 15% depending on driving conditions and style of driving -- extra urban or urban (highway or city). There are several reasons for this:

Mechanical efficiency. The manual transmission couples the engine to the transmission with a rigid clutch instead of a torque converter that introduces significant power losses. The automatic transmission also suffers parasitic losses by driving the high pressure hydraulic pumps required for its operation.

Driver control. Certain fuel-saving modes of operation simply do not occur in an automatic transmission vehicle, but are accessible to the manual transmission driver. For example, the manual-transmission vehicle can be accelerated gently, yet with a fully open throttle (accelerator pedal to the floor), by means of shifting early to a higher gear, keeping the engine RPM in a low power band. By contrast, in an automatic transmission, the throttle position serves as the indicator of how fast the driver wishes to accelerate. If the accelerator pedal is floored, the transmission will shift to a lower gear, resulting in high engine RPM and aggressive acceleration. The thermodynamically efficient combination of open throttle and low RPMs is unavailable to the automatic transmission driver. Fuel-efficient acceleration is important to achieving fuel economy in stop-and-go city driving.[2]

Fuel cut-off. The torque converter of the automatic transmission is designed for transmitting power from the engine to the wheels. Its ability to transmit power in the reverse direction is limited. During deceleration, if the torque converter's rotation drops beneath its stall speed, the momentum of the car can no longer turn the engine, requiring the engine to be idled. By contrast, a manual transmission, with the clutch engaged, can use the car's momentum to keep the engine turning, in principle, all the way down to zero RPM. This means that there are better opportunities, in a manual car, for the electronic control unit (ECU) to impose deceleration fuel cut-off (DFCO), a fuel-saving mode whereby the fuel injectors are turned off if the throttle is closed (foot off the accelerator pedal) and the engine is being driven by the momentum of the vehicle. Automatics further reduce opportunities for DFCO by shifting to a higher gear when the accelerator pedal is released, causing the RPM to drop.[citation needed]

Geartrain efficiency. Automatics may require power to be transmitted through multiple planetary gearsets before attaining the desired gear ratio. In comparison, manual transmissions usually transmit power through one or two gearsets at most.[citation needed]

Manual transmissions are still more efficient than belt-driven continuously-variable transmissions.[3][4]

It is generally easier to build a very strong manual transmission than a very strong automatic transmission. Manual transmissions usually have only one clutch, whereas automatics have many clutch packs.[citation needed]

Manual transmissions are generally significantly lighter than torque-converter automatics.[1]

Manual transmissions are typically cheaper to build than automatic transmissions.[citation needed]

Manual transmissions generally require less maintenance than automatic transmissions.[citation needed]

Manual transmissions normally do not require active cooling, because not much power is dissipated as heat through the transmission.[4]

The heat issue can be important in certain situations, like climbing long hills in hot weather, particularly if pulling a load. Unless the automatic's torque converter is locked up (which typically only happens in an overdrive gear that would not be engaged when going up a hill) the transmission can overheat.[5] A manual transmission's clutch only generates heat when it slips, which does not happen unless the driver is riding the clutch pedal.

A driver has more direct control over the state of the transmission with a manual than an automatic. This control is important to an experienced, knowledgeable driver who knows the correct procedure for executing a driving maneuver, and wants the machine to realise his or her intentions exactly and instantly. Manual transmissions are particularly advantageous for performance driving or driving on steep and winding roads. Note that this advantage applies equally to manual-automatic transmissions, such as tiptronic.

An example: the driver, anticipating a turn, can downshift to the appropriate gear while the steering is still straight, and stay in gear through the turn. This is the correct, safe way to execute a turn. An unanticipated change of gear during a sharp turn can cause skidding if the road is slippery.

Another example: when starting, the driver can control how much torque goes to the tires, which is useful for starting on slippery surfaces such as ice, snow or mud. This can be done with clutch finesse, or possibly by starting in second gear instead of first. The driver of an automatic can only put the car into drive, and play with the throttle. The torque converter can easily dump too much torque into the wheels, because when it slips, it acts as an extra low gear, passing through the engine power, reducing the rotations while multiplying torque. An automatic equipped with ESC, however, does not have this disadvantage.[citation needed] Some cars, such as the Saab NG900 Automatic transmission, have a special mode for low traction situations.

Yet another example: passing. When the driver is attempting to pass a slower moving vehicle by making use of a lane with opposite traffic, he or she can select a lower gear for more power at exactly the right moment when conditions are right to begin the maneuver. Automatics have a delayed reaction time, because the driver can only indicate his intent by pressing the throttle. The skilled manual transmission driver has an advantage of superior finesse and confidence in such situations.

Driving a manual requires more involvement from the driver, thereby discouraging some dangerous practices. The manual selection of gears requires the driver to monitor the road and traffic situation, anticipate events and plan a few steps ahead. If the driver's mind wanders from the driving task, the machine will soon end up in an incorrect gear, which will be obvious from excessive or insufficient engine RPM. Related points:

It's much more difficult for the driver to fidget in a manual transmission car, for instance by eating, drinking beverages, or talking on a cellular phone without a headset. During gear shifts, two hands are required. One stays on the wheel, and the other operates the gear lever. The hand on the wheel is absolutely required during turns, and tight turns are accompanied by gear changes. If the hand leaves the wheel, the steering will begin to straighten. In general, the more demanding the driving situation, the more difficult it is for the manual driver to do anything but operate the vehicle. The driver of an automatic transmission can engage in distracting activities in any situation, such as sharp turns through intersections or stop-and-go traffic.

The driver of a manual transmission car can develop an accurate intuition for how fast the car is traveling, from the sound of the motor and the gear selection. It's easier to observe the lower speed limits—like 30 km/h and 50 km/h or their U.S. and Imperial counterparts, 20 mph and 30 mph—without glancing at the instrumentation.

Cars with manual transmissions can often be started when the battery is dead by pushing the car into motion or allowing it to roll downhill, and then engaging the clutch in third or second gear. This is commonly known as a "push start" or in the USA as "popping the clutch", which in the UK describes the action of suddenly releasing the clutch pedal after putting it in gear.

Manual transmissions work regardless of the orientation angle of the car with respect to gravity. Automatic transmissions have a fluid reservoir (pan) at the bottom; if the car is tilted too much, the fluid pump can be starved, causing a failure in the hydraulics. This could matter in some extreme off roading circumstances.[citation needed]

It is sometimes possible to move a vehicle with a manual transmission just by putting it in gear and cranking the starter. This is useful in an emergency situation where the vehicle will not start, but must be immediately moved (from an intersection or railroad crossing, for example). It is also easier to put a car with a manual transmission into neutral, even when the transmission has suffered damage from an accident or malfunction. Many modern vehicles will not allow the starter to be run without the clutch fully depressed, negating this advantage.


Disadvantages
Many of the disadvantages of a manual transmission involve the driver interaction with the vehicle. While most of these can be overcome with practice and experience, they should be considered:

Manual transmissions often require the driver to place their full and continuous attention on the road, which may be seen as a disadvantage. Some consider this an advantage, as it prevents the driver from other potential distractions like cell phone or radio use.

Inexperienced drivers may place more of their attention on shifting the gears, potentially distracting them from the road surroundings.

A driver may inadvertently shift into the wrong gear with a manual transmission, potentially causing damage to the engine and transmission, or the vehicle's body and its surroundings if the intended gear was reverse.

Manual transmissions require a learning curve as one must develop a feel for properly engaging the clutch.

The smooth and quick shifts of an automatic transmission are not guaranteed when operating a manual transmission; such changes are dependent on the driver.

For a person with physical impairment, an automatic transmission might be the only available shifting option. The comparable systems for hand operated clutch and brakes for a manual transmission equipped car are usable only by people with just lower body handicap. Retrofit of such a system also requires extensive modifications to the car.

Vehicles with manual transmissions are more difficult to start from rest when stopped upward on a hill because the clutch must be depressed and the gas applied very quickly once the brake is removed to prevent slipping backward. However, this can be overcome with experience.

The clutch disc is a wear item and must be replaced periodically. This is typically a labor intensive process and can be an expensive service.

Even a modern hydraulic clutch can be tiresome to depress repeatedly in heavy traffic.

Applications and popularity
Many types of automobiles are equipped with manual transmissions. Small economy cars predominantly feature manual transmissions because they are relatively cheap and efficient, although many are optionally equipped with automatics. Economy cars are also often powered by very small engines, and automatic transmissions can make them comparatively very slow, while a manual transmission makes much more efficient use of the power produced.

Sports cars are also often equipped with manual transmissions because they offer more direct driver involvement and better performance. Off-road vehicles and trucks often feature manual transmissions because they allow direct gear selection and are often more rugged than their automatic counterparts.

Very heavy trucks also feature manual transmissions because they are efficient and, more importantly, can withstand the severe stress encountered in hauling heavy loads.

Conversely, manual transmissions are no longer popular in many classes of cars sold in North America, although they remain dominant in Europe. Nearly all cars are available with an automatic transmission option, and family cars and large trucks sold in the US are predominantly fitted with automatics. In Europe and Asia most cars are sold with manual transmissions. Most luxury cars are only available with an automatic transmission. In situations where automatics and manual transmissions are sold side-by-side, the manual transmission is the base equipment, and the automatic is optional—although the automatic is sometimes available at no extra cost. Some cars, such as rental cars and taxis, are nearly universally equipped with automatic transmissions in countries such as the US, but the opposite is true in Europe.

In some countries, such as the United Kingdom, Ireland, Germany, Sweden, Japan and Singapore, when a driver takes the licencing road test using an automatic transmission, the resulting licence is restricted to the use of automatic transmissions. This treatment of the manual transmission skill seems to maintain the widespread use of the manual transmission, as many new drivers worry that their restricted licence will become an obstacle for them where most cars have manual transmissions, so they make the effort to learn with manual transmissions and obtain full licences.


Maintenance
Because clutches use changes in friction to modulate the transfer of torque between engine and transmission, they are subject to wear in everyday use. A very good clutch, when used by an expert driver, can last hundreds of thousands of kilometres (100,000 kilometres is equal to 62,137 miles). Weak clutches, downshifting, inexperienced drivers, and aggressive driving can lead to more frequent repair or replacement.

Manual transmissions are lubricated with gear oil, which must be changed periodically in some cars, although not as frequently as the automatic transmission fluid in a vehicle so equipped. (Some manufacturers specify that changing the gear oil is never necessary except after transmission work or to rectify a leak.)

Gear oil has a characteristic aroma, due to the addition of molybdenum disulfide compounds, to lubricate the large degree of sliding friction seen by the teeth due to their helical gear cut, which in turn is done to eliminate the characteristic whine of straight cut spur gears. Some manufacturers, however, such as Honda, do not use this additive in their gear lube, specifying regular motor oil until recently, and now their own brand of gear lube which seems to be an enhanced version of motor oil. On motorcyles with "wet" clutches (clutch is bathed in engine oil), there is usually nothing separating the lower part of the engine from the transmission, so the same oil lubricates both the engine and transmission.

[SoYank]

I have a manual to keep my feet occupied.

Actually, I just think a manual gives the car a more sporty style of driving instead of popping it in gear and pushing the gas pedal. Ohters may find like an AT better. That is their choice and I have nothing against that.

(BTW, this is my 1000th post!)

[lawdude]

MT because it's the manly thing to do. j/k

My last two cars have been auto and I just wanted a change. It's been fun so far. Plus, since my wife can't drive a stick, it keeps her out of the driver's seat.

[Zeroday]

not this again. use the search!

[tbonecopper]

Because I don't know how to drive a stick
lol

[MacAttack]

Great find Linus. They forgot to add one thing....especially in this day and age....if someone tries to car jack you, they'll realize it's a manual and probably hit another car since they don't know how to drive one.

The best part about MT, is that my wife & kids can't drive MT. That's what I'm talking about!

[BK]

IBTL?

I can't believe I read through that whole giant Wikipedia article. It's actually pretty interesting.

In any case, to the OP, buy whatever tranny floats your boat. I happen to prefer driving a MT no matter what kind of car I'm driving. I just find it more fun.

[SoYank]

Originally Posted by linus

From wikipedia:

It is sometimes possible to move a vehicle with a manual transmission just by putting it in gear and cranking the starter. This is useful in an emergency situation where the vehicle will not start, but must be immediately moved (from an intersection or railroad crossing, for example). It is also easier to put a car with a manual transmission into neutral, even when the transmission has suffered damage from an accident or malfunction. Many modern vehicles will not allow the starter to be run without the clutch fully depressed, negating this advantage.

I know of someone who has driven over their own foot with an automatic.

My 4Runner has a clutch override switch that allows me crank the engine in or out of gear with the clutch released.

[ES-Jet]

If I lose a leg .................. I'll get a car with AT.

EDIT - sorry, not very constructive. I just prefer to have control over the engine speed.

[tbonecopper]

Haha he said tranny

anyway back on topic lol

[s4iscool]

me personally... bmw = manual + inline 6

[Catscratch]

The MT can't cope with a real engine (335d)*







ducks for cover ...

[aerisolphaln]

Well, if you're getting the wagon....

[BK]

Originally Posted by tbonecopper

Haha he said tranny

anyway back on topic lol

[F32Fleet]

Originally Posted by TeeG

I'm buying an E91 shortly, and am deciding between manual or automatic. Some of the reasons obvious, I know, but I'm still curious to hear why people chose what they did.

Wife lacks sufficient coordination to drive a manual.

[Romo]

I`am surprised how many Americans can`t drive a MT car they are all used to AT

In Europe this completly reversed; everybody can drive a MT car, even women
There are also far more MT driven cars compared to AT ones :rocks:

If a person has never driven an MT car, he/she has never driven a car the way it was meant to be .................................

[ALPINE6SPD]

MANUAL
I will probably never own an automatic. Automatic makes driving boring as there is no real involvment with the car. I drove in traffic and put 45k in 1 year on my 2000 toyota celica and never had an issue with it. I get in and drive like its second nature and these are a few of the reasons that I will try to never own an automatic. Espically on a sports sedan like a BMW.

[ALPINE6SPD]

Originally Posted by Socom

Wife lacks sufficient coordination to drive a manual.

Time to find a new wife

[Chesmu]

i switched from auto to manual 7 yeasr ago when I got a porsche boxster. I swear, I'll never go back. There's a feeling of control, aggressive power, and just thrill of driving that you can only get with mt. A third pedal is a necessity to me.

[canucklion]

on a related note, which is better leather or leatherette? and why did you choose one over the other?

[Snowkone]

Honestly, I went with AT because there's too much start/stop traffic in Downtown Dallas. I work in the area, but more importantly, I go to Grad School there and it would be a pain having an MT car in the parking lot we call I75.