[karthi.stark]

http://www.team-bhp.com/forum/indian...c-gearbox.html (The 2017 Poll: Manual vs Automatic Gearbox)

The above thread inspired me to make this one. Automatic cars are becoming increasingly popular with every passing day. Just some 10 years ago, AT's were struggling to make their way into the Indian Automotive market because of the dominance of the Manual Transmission. I still remember, at the time of buying our 2006 Honda City GXI AT, we were looked upon as some weirdos who didn't know what the hell we were doing! And today, every other car which enters our market comes with an AT (barring a few exceptions). What's more, we now have a variety of AT's available - torque Converter, CVT, DCT and the latest AMT. Following are the pros and cons of each of them:

CVT

Advantages:

• Allows the engine to revv almost immediately; no lag is seen during quick acceleration like conventional AT's and MT's.
  
• Offers the highest FE among all the AT's present, thanks to its ability to vary gear ratios according to the situation.
  
• Simple design and working implies fewer complications and issues.
  
• Power and torque loss are minimal when compared to other transmissions.

Disadvantages:

• Replacement and repairs of a CVT transmission can get expensive
• High speed of belts on pulleys implies greater friction which in turn accounts for more wear.
• Requires a different driving style altogether, as one wouldn't feel the vehicle accelarating, nor do they feel the shifts.
• One rarely finds CVT's in cars having high power and torque, as they don't exactly give the feel of an enthusiasts' car.

Dual Clutch AT

Advantages:

• Offers the quickest shifts among all conventional AT transmissions, thanks to the presence of two clutches as opposed to one in all conventional transmissions.
• Unlike a CVT, a DCT can withstand higher amounts of power and torque as compared to any other transmission. This is the reason for its use in performance cars.
• As the 'shift shock' is nullified, one can expect better FE from a DCT than
  that from a conventional AT. (ignoring the CVT here)
• The driver can choose between allowing a computer to do the shifts or manually carrying out the shifts.
• The DCT is designed to adapt to the driver's style of driving.

Disadvantages:

• DCT's, on account of their complex mechanism, are known to be highly unreliable. Chances of gearbox failures are really high.
• Expensive to manufacture compared to other transmissions. This in turn translates into more $$$.
• Expensive to maintain and repair, thanks to its complex mechanism. What's more, finding a mechanic with proper knowledge regarding the DCT is like finding a needle in a haystack!

Torque Converters

Advantages:

• Simple, old school mechanism, as a result of which it is the most widely used automatic. Gets the job done without any fuss.
• The most reliable among all the AT options available.
• Less expensive than the DCT and the CVT. Hence, the price difference between an AT variant with a torque converter and an MT variant is relatively less.
• Maintenance and replacement of a torque converter is less expensive than a DCT or CVT.

Disadvantages:

• Produces the least FE among all AT's.
• suffers from the infamous 'shift shock' during quick accelarations or uphill maneuvers.
• Power loss is quite significant in torque converters, especially at low speeds.
• Can be slow to respond at times.

Automated Manual Transmission (AMT)

Advantages:

• The cheapest among all the AT's available, as a result of which it is becoming increasingly popular among manufacturers.
• It is the most convenient to operate, due to it possessing the most simple mechanism.
• Offers the highest FE among all the AT options.
• Lowest cost of maintenance among all the automatics available.

Disadvantages:

• Not the quickest to respond to sudden acceleration or braking. Hence, not reliable during hilly maneuvers like a torque converter.
• 'Shift shock' is more evident in an AMT than in other AT's.
• Not the best option for those hungry enthusiasts, because of its jerkiness during an aggressive drive.
• No P mode! You have to rely on the handbrake completely while parking the vehicle on a slope.

Now comes the question:

Which one would you guys prefer? It might seem to be a tough call but life is all about that my friend!
Will be interesting to see the poll results.

Regards,
Karthi.stark



Pic sources: all Team-BHP reviews

[Eddy]

Thread moved from the Assembly Line. Thanks for sharing.

[wilful]

I’ve owned cars with CVT (Honda City 2006), Torque Converter (Honda City 2012) and DCT (Ecosport, my current ride). Aside from these I’ve used the AMT in the Nano and the DCT/DSG in the Vento. My vote goes to the DSG (DCT) despite the horror stories.

[Yieldway17]

Voted for Torque Converters. Torque Converter is the most mature of all and hence the less need to babysit them. Internet is full of articles of Do's and Dont's of CVTs, AMTs and DCTs but TCs on the other hand are abuse and pocket friendly.

[Shreyans_Jain]

Nothing quite like the good old torque converter. Proven, reliable, and they are actually damn good to drive as well. Anyone who has experienced the ZF 8 speed in a BMW or Jag, or the PPG 6 speed in the Hexa (at a lower price point), knows what the fuss is all about.

Give me a well tuned 6 speed TC with sport mode and manual override any day over a temperamental DSG. CVTs are just not up to the task in my book. AMT, well,

Sometimes, things work best the old fashioned way.

[dark.knight]

Despite all of the technology on earth, to me there is NO perfect automatic transmission at all.. of all things automotive, it is possibly the most poorly researched, poorly described and poorly thought out ways to eliminate clutch and gear changes on the car. I've heard people saying that CVT is super-fast and is THE ultimate transmission, I couldn't grimace any more even if I try, some say that torque-converters are the best but they aren't, way too much torque loss and it simply sucks the fun out of driving because they are slooowww to respond when put under pressure. DSG is the ultimate automatic for driving purposes, but despite all the claims of its users that it is very fast to respond to throttle inputs.. NO!!! ALL DSG's also suffer from initial lag when put under reasonable pressure and I know it all too well. Let me put these automatics comparison into student's parlance for some amusement :

1) CVT : A slow and steady student, doesn't like to be pushed but leverages on what studies have already been done and gets home 60% always.

2) Torque Converter : A bit confused, kind of steady but definitely not slow, can score 80's and 90's at times but just scrapes through when under pressure.

3) DSG : A super hard-worker but is known to get over-heated *pun intended* as a result.. is the class topper always but could completely fail *pun intended again* certain subjects and as a result has to start the academic year all over again.

4) AMT : A flaky student who just scrapes through all the time.. borderline pass with 35 in all subjects.

I'm not taking into account the expensive transmissions like GETRAG 6HDT200 Hybrid Box, GETRAG 1eDT200, 6DCT200, ZF 8/9 Speed boxes etc, they are great and quick to respond but cost a bomb as a result.

Affordable automatics are great for the city slickers, the office-goers and the go to the mall or restaurant with family kind of people. I'm hardly demanding when it comes to speed but most of the affordable automatics are dimwits/retarded with regard to off-the-block speeds, engine braking and shifting at the right time. They are NOT telepathic at all. I'm a manual kind of guy.. and I LOVED it, many people couldn't praise me enough the way I used to shift seamlessly with zero jerks and made the car seem like its cruising on air, not on land, using adequate engine braking, clutchless cruising and early RPM gearshifts to push for every drop of increased FE. Its a pity that traffic jams and endless waiting in lines and on slopes have made the automatic much more tempting and a necessity in these times.

A great automatic in torque converters should be a 10 speed one because even 6 speed ones are dumb.. 4 of those gears should be within 0-40 kmph and rest of the 6 higher up the rev chain. Kidding, I know its not practical but torque converter automatics really do flop when it comes to sheer quickness. I voted for the least of all evils.. the DSG, albeit at the cost of reliability but that's ok because they are very fuel efficient. Torque converter fuel efficiency makes my eyes water.

[GTO]

Voted for the torque-converter. Reason = it's robust & reliable nature (compared to the DSG). Torque-converters are continuously improving and some of today's gearboxes (like the ZF 8-Speed) are as fast as DSGs, and also smooth as butter. The Hexa's 6-speeder is superb & even Hyundai's 6-speed ATs (Creta etc.) have come a long way.

My second choice would be a CVT, especially when mated to a big engine or a torquey diesel. I like the CVT of the City petrol & Amaze diesel. But CVTs are a distant 2nd in my books.

Could never live with a jerky AMT. And DSG? Nope, I am still not convinced of its long-term reliability. VW & Ford have both suffered many headaches due to dual-clutches.

[Sahil]

Voted for DSG but there are varied versions of it- my fav and least fab gearbox are both DSGs.
Fav: Porsche’s PDK which is a DSG but made by ZF not VW !
Worst gearbox: DSG200 which I had on my Skoda Superb that made my life hell

[R2D2]

Voted for the torque converter. With second choice being the CVT and then the DSG.

Reliability ranks very high on my list of features. I am not kindly inclined to temperamental products (or cars) that let me down for no good reason no matter how gee-whiz they may be from a technology point of view.

[VineetG]

Voted for Torque convertor, mainly due to horror stories of Volkswagen/Skoda DSG issues.
Otherwise, DSGs are superior.

However, for city driving, Torque convertors are much smoother and give a nice acceleration from stop.

Rgds

[gkveda]

Any day Torque converter for me. It is just proven, reliable and latest technologies have made it butter smooth as well. What more do I need to expect from the Gears. It is like a All Terrain Tires. Suits everywhere especially when you have powerful engine like Fortuner

[graaja]

This is the order of preference for me: Torque Converter, DSG, CVT, AMT (voted for TC)

When it comes to shift speed, nothing beats a DSG. I had a Jetta with a 6 speed DSG and now a Polo GT with a 7 speed DSG, and I just love them - the lightning fast up shifts and rev matching while downshifting in manual mode are to die for. But they also need to be babied a little, like shifting to neutral during long stops to prevent clutch wear. And due to the complexity they are prone to failures like mechatronics failure, early clutch wear etc.

Torque converters, on the other hand are very rugged and are very robust. There is no clutch that wears out, no need to worry about shifting to N in traffic stops etc. The disadvantages are the poor FE and the slower shifts. But the latest TC boxes are becoming better in both these aspects.

[rajshenoy]

Frankly i don't think i can choose a single option as of today. Every transmission has its own share of negatives(as rightly summarized)

Depending on the usage
City usage - CVT or AMT
Highways - DSG

AT times i feel CVT rubber band effect to be more worse than the Shift lag in AMT. Having driven manuals for over 2L kms, AMT feels more predictable to me but CVT has a mind of its own and irritates with that high engine revving.

[Rajeevraj]

I would prefer a VW Dual Clutch with the reliability of a 6-speed TC and the smoothness of a CVT.

Choosing one is tough. Depends a bit on the flavor of the AT Box a company provides and also to the engine it is mated to.

• For example, I drive a VW DSG and keeping aside the reliability issues, it is probably the best out there from a drivability and performance perspective and in addition across the range, VW DSG's are mated to good engines. This is why a car like the GT TSI is still so popular. At the same time, I also drive a Ford Ecosport DCT occasionally and I find it totally messed up. The DCT is not great and it does not really match well with the engine it is mated to.
  
  
• Coming to TC based AT's, there are plenty of 4 speed TC's which have been around for a long time. Reliable-yes, but I don't think I would chose one of these. At the same time, the 6 speed ones-Example, the one on the XUV is brilliant (of course helped by a potent engine) and very close to the DSG.
  
  
• Have not driven CVT's much, but from what I read, there are good ones matched well with the engines (Honda's CVT would be a good example)
  
  
• At this point AMT's are a definite no-no. But would not exclude the possibility of buying an AMT if I am looking for a simple cheap car to potter around small distance.

End Summary- My preference will change depending on the manufacturer and car- Hence not voting

[heydj]

Originally Posted by GTO

The Hexa's 6-speeder is superb & even Hyundai's 6-speed ATs (Creta etc.) have come a long way.

In comparison to DSG in Rapid TDI or Vento TSI how good is Hexa's AT? In terms of quick shifts & lag.