Automatic, manual, double clutch, or CVT?
by wcunning - 8/29/07 4:30 PM
In my recent column, Tranny talk, I wrote about the why I like double clutch transmissions. What kind of transmission do you prefer, and why?
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by: wcunning August 29, 2007 4:30 PM PDT
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Total posts: 26 (Showing page 1 of 1)
Manual all the way!
I've been driving a manual transmission so long it is second nature. The first car I ever drove was a manual. The best manual gearbox still belongs to Honda and I was actually considering the Accord Hybrid until I found it was automatic only.
I prefer manual for several reasons. 1) It usually, but not always, get better MPG. 2) I have more control over the vehicle, which means I always more alert, and 3) It prevents many people from wanting to drive my car since many people don't know how to drive a manual. No computer or machine can give you to control of a manual.
Personally, I think it is a shame that drivers' education only teaches on automatics. Everybody should be taught how to drive a manual.
Less control with manual
I disagree with your item 2, "have more control over the vehicle". I have owned cars with manuals.
Starting from a stop on a steep hill is a pain, and even dangerous, as the car rolls backwards before the clutch engages. Hope the engine doesn't stall.
Having to manualy shift gears means taking a hand off the wheel, which is less control, usually a minor loss, unless you're in a tight situation.
mwooge your wrong about the less control when you shift gears in a manual becuse if you drive with your left hand then you shift with your right and never take your left hand off the wheel.
have you driven a stck shift?
CVT. Hands Down.
I live in Colombia, where about 98% of the cars have manual transmissions. I recently drove a Nissan Primera with a CVT and it's just amazing. I took it on a long hill run, and you could make all sorts of speed changes; no "gear hunting" at all. I then wanted to test acceleration on the highway and hit the gas; instead of getting a kickdown-response, the engine immediately jumped to 5,200RPMS and got pegged there, wich I later saw on the owner's manual are the RPMs which output the highest torque on the curve. Although it feels as if the car wasnt accelerating, the speedo showed totally the opposite. There's also no slippage as with AT, so mileage is better, and the car is always ready to deliver torque. This car has a 2.0L inline 4 engine, and it can easily overtake an SUV. I recommend you read on the wikipedia or howstuffworks about CVTs, they are a wonderful yet simple concept, which I hope gets adopted by many car manufacturers...
Thanks Wizzard, I had been a long time fan of the CVT transmission even though I have neither driver a CVT Car nor seen one but I have read a lot aboutit for the last several years,in fact I have been closely following it's development from it's original belt drive version in DAF cars to the modern steel belt drive. I am from India and eagerly waiting to drive a CVT car . I believe all future mid size cars will use this technology. It is pertinent to note that Toyota use this transmission very successfully for it's famous Prius hybrid car not to mention other production cars.
A minor correction- the Toyota Prius uses a planetary gearset and two electric motors for their CVT. It doesn't rely on a cone and belt arrangement that can slip under heavy load, has too many parts, and wears out far too quickly.
The planetary CVT is the heart of the Hybrid Synergy Drive.
Only just seen your post.You seems to have not read my post correctly.What I have mentioned there was that the cone and belt CVT system in the original form was used in DAF Cars, may be the first production car that used such CVT about thirty to forty years ago. The CVT used in Toyota Pyrus is an improved version of this old belt drive. Instead of rubber belt drive the modern CVT uses steel strips linked steel belt. This design was perfected only in the last ten to fifteen years.
Oh, I read your post correctly. I'm sorry, but you are misinformed. The steel belt and cone CVT is used on some cars, including some models of Honda Civic Hybrid, but has never been used on the Prius. The Prius and other Toyota hybrids use a planetary geared CVT system with two electric motors. For a simple explanation on how it works, see:
No cones, no steel belt. (there is a simple drive chain)
There are other types of CVT as well, including:
Toroidal drive, with input and output sides shaped like a sliced donut, wheels connect the input/output sides and tilt to vary speeds.
Hydraulic drive, which uses a hydraulic pump and hydraulic motor.
Electric drive, which uses an electric generator and motor (sometimes called "serial hybrid")
Ratchet cam drive, uses cams to convert rotary motion into reciprocating motion, and a ratchet mechanism to convert the reciprocating motion back into rotary motion.
I had no idea that new transmissions where being designed based on the CVT principle. I really see the future standard for car's transmissions as some sort of CVT. I will read more on the designs you mention present on the hybrid, and I would definitively love to take a drive on a car with such specs (no priuses or the like in Colombia yet)...
Interesting discussions.You are right, my information was not correct, may be I was misled by the photo of the final chain drive( which looked almost like the CVT drive used in some cars).Any way thanks for the information particularly the site of 'John1701'. Let me pay tribute to that one man army who is doing a lot for popularising PHEV.
About 40 years back there was nothing but CVT tech in my head, I had even patented, and developed a new rotary hydrostatic CVT design that contained even a reverse drive mechanism.Finally it was given up after testing due to the same problem all Hyrdrostatic drives show- thermal loss and consequent loss in inefficiency.
Yes there are a number of designs in CVT, some installed in limited edition of production cars. But I still believe that the steel belted CVT system ,modern version of the original design from DAF, Denmark,is the most succcessful of all so far.Honda still use it and is popular in Europe, but it has not be came popular in US. Toyota used it for their ist model of Prius, but when they started using the power spliter dign from 2nd model onwards it was abandoned.
A few sites given below for those who would like to know further on CVT.
The power-split design ( credit for the design belong not to Toyota)I must say is an ingenious mechanism to synchanise three power drives, and the beauty is that it can also be used as a CVT, though, I believe,it is not a true CVT system as it cannot be used in any car with a ICE only.
Still self-shifting after all these years
Now that I've finally driven one, I will admit that the DSG box that VW uses does account for itself quite nicely. But the SMG monstrosity that I tried in a M3 a year or two ago was a serious letdown.
There have been times that it would be nice not to shift (long, crappy day...gridlock...just plain worn-out), but in the end I've to answer my "restless left-foot syndrome". Can't do that with any sort of slushbox (unless you're into left-foot braking), no matter how good it thinks on its own.
Can you imagine a vintage Italian sports car with a pseudo-manual? Part of the thrill is depressing the clutch pedal and rowing through the gears, blipping the throttle just right on the downshifts to get that perfect sound out of the engine. But then there's traffic. I might compromise on a modern car if I had COMPLETE control over the transmission. When I flick that paddle shifter, it shifts then and only then. If I want to hold it at redline for five minutes, so be it.
I prefer the stick and clutch for sure. Automatics tend to be more expensive, less reliable, less fuel efficient, and a bit slower than manuals. I do admit that the CVTs are overall better than a manual (since they are more fuel efficient and faster), but a manual is so much funner.
Maybe the DSG is an improvement over the traditional automatic, and I suppose with manual shift feature it would do in a crunch, but it lacks the clutch (meaning less control and not being able to go straight to any gear). The clutch is a huge part of what makes a manual fun, and I would never take a DSG or any traditional automatic over a stick shift.
Dual Clutch is the way to go
I prefer the dual clutch transmission for the following reasons.
1. Better fuel economy gains can be had over a conventional automatic.
2. You get MUCH quicker gear changes than with a manual transmission.
3. And while the CVT has more ratios and no discernable shift shock, the dual clutch (when tuned properly) is almost just as good and doesn't feel like you're driving a golf cart.
4. And finally...it is a Racecar proven technology, which shows series like Formula 1 and the 24 Hours of Lemans are a lot more than just cars going round and round a racetrack. A lot of the modern automotive technology was proven here before it made it into your automobile!
Manual gearbox - no clutch
I have been driving a Mercedes A170 diesel for 6 years which has a manual gearbox but no clutch - the clutch control is done by electronics.
This has the better mpg (1000 miles to Austria at high speed is just two 50 litre tanks of diesel) and lower emissions of the normal manual gearbox.
My wife didn't like it because her previous car was manual with a clutch and she forgot to use the clutch when she got back in her car some of the time. Because you get into the habit of matching the revs when you change gear without thinking with the electronic clutch, she was frequently changing without the clutch on her true manual without crunching the gears (just like in the old days before we had synchromesh gearboxes).
She now has a full auto - as she is a teacher stood up all day and has varicose veins, it does cut the strain in driving. The one time I really like her auto (A Jeep Cherokee) is when I put it in low 4WD to tow my boat up a steep slipway out of the water - with only a gentle touch on the gas with one foot, you can turn and look over your shoulder to see what is happening in a way that you simply could not do with a manual.
Here in the UK, if you take your driving test in a car with an automatic gearbox, you are only allowed to drive automatics until you pass a test with a manual gearbox. Been like that for nearly 40 years - since I took my test.
One other thing about automatics - in the 1960s, some automatic geraboxes had two hydraulic pumps - one on the input shaft and one on the output shaft. Thus, they could be tow started because you had hydraulic pressure. Most modern automatics are stuffed if they won't crank e.g. failed starter.
We will see the demise of the old style hydraulic automatic gearboxes in the next few years as the cost of electronics continues to come down. Eventually car manufacturers will have one gearbox, and it will simply be a case of fitting a clutch pedal for those who want a manual, but the clutch will probably be "clutch by wire"
Automatics Don't Let YOU Control the Car
With a manual tranny, YOU have full control of the car. You can use engine braking (which doesn't unduly wear out the clutch) you can skip gears and you can get better mileage. I get better mileage in the city than on the open road (when I want to!). Other times I just have the fun of really knowing I'm in control. Some automatics let you choose when to upshift--none of them let you choose when to downshift if their programming says that it will rev the engine too high. (Now you're thinking I'm gonna hurt my engine 120,000 miles & no problems...) No automatic lets you choose to freewheel or have some engines braking. You decide when you buy the car and you are stuck with your choice. I don't blame anyone who has to commute in rush hour traffic for choosing an automatic--but don't try to tell me that you are a real DRIVER or that you are having fun driving--you just aim the car and it does the rest....
Manual is for drivers
My wife doesn't know how to drive a manual and has no desire to learn but she needs transportation so I drove them all. After driving a VW with the dual clutch, the Nissan CVT and a regular Honda 5 speed auto, I'll tell you this, the Nissan CVT is not an economical transmission, it does no better than their regular automatics although it's fun to drive. The VW Dual Clutch is one fast shifter which is economical. To make a long story short, I bought the Civic with the old 5 speed automatic because it's a Honda. Personally I drive a 350Z 6M and I don't know how to drive automatics.
Automatic vs Manual transmissions
The first slush box I ever drove with, was a 1950 Chrysler and it drove with either the clutch or without. The article brought back memories of delivering newspapers in the country, as it was able to be shifted normally using the clutch and column shifter, or it could be left in 3rd and driven like an automatic, though the slippage in the transmission would cause loss of most of your takeoff power.
I took my first drivers license test with a manual tranny, back in 1960, because back then if you took your test with an automatic, you were restricted to driving a vehicle with an automatic only. When I got my first Class A Commercial license, in 65, I didnt have to take the drivers test because I didnt have a restricted tranny code on my old one. I have driven almost anything imaginable on the highway, and I still carry a full Class A CDL now.
The manual transmission is the most efficient in power transference. Even though, the automatic is a better transmission for in town driving, because the majority of drivers tend to lug an engine during short stop and go traffic, causing extra wear and tear on metal components in the drive train. Semi tractor manufacturers are now putting automatics in a lot of their trucks but the debate is still out among drivers because not many have had a chance to drive them. When I watch an inexperienced driver hauling a heavy load, and popping the clutch as the truck twists and rears up against the torque, I see now why a lot of common carriers are going to automatics in their fleet trucks. Its a lot less strain on drive train and frame components.
I've driven manuals and automatics and hated them both.
Far too many automatics have a nasty habit of hesitating or stalling outright just when I wanted to accelerate briskly. Fuel economy isn't very good, either.
Manuals mean having to deal with yet another thing while driving, and it can be a real hassle to shift while turning, and remembering to clutch and downshift when braking - really bad in an emergency! Also, there are the inevitable mistakes of shifting into the wrong gear, or grinding gears, or not releasing the clutch just right and stalling the engine.
My favorite transmission has far fewer moving parts and is far more reliable than any manual or double clutch or cone-and-belt CVT or automatic transmission. It uses a single planetary gearset with two motor/generators to get a smooth continuous flow of power, and achieves higher milage than any type of manual or automatic transmission. It is the heart of Toyotas Hybrid Synergy Drive.
That's why I drive a Prius.
I personally prefer a manual, four-in-the floor stick shift. Good for exercising the old leg muscles, alleviating lower-back pain, and in general being more in touch with what's going on in the drive train. Automatics are fine but not my cup of tea, particularly when pulling a boat or driving off-road.
However, my wife's Prius doesn't hesitate when you pull out to pass, has excellent deceleration in "B" (Braking), and gets 50+mpg in "D" (Drive). It easily held its own at 60mph following my sister-in-law's 4-wheel drive Tahoe up a 20-mile stretch of US421 in the North Carolina mountains. Cost us a whole $57 in gas last March to make a 1057-mile round trip to Disney World. That was $7 over my budget (Oil companies raised gas $0.18/gallon the week before we left), and I only had a half a tank left when we arrived home.
Needless to say, we park the Camry (automatic) and the Mazda truck (manual)when we drive 300 miles round trip to visit the granddaughter.
i have driven every type of vehicle imaginable, i also do the mechanics. the writer of this story should refer to his double clutch tranny as a preselection gerarbox or a semi automatic. these gearboxs have been round for a long time and were first used in big trucks. a real double clutch is a clutch that actually does have two clutch plates to make it a double clutch
these were common in high performance vehicles in the seventies.the double clutch was used to take the oomph out of the gear change in saloon cars that were made to race
one good example is a ford GTHO,phase 2, these were primararily made to race ,but had to have a number sold to the public and used on the road,before the car was eligable to enter race
manual v automatic
In 42 years of driving history I have driven large commercial vehicles, sport cars, sedans, SUV's and vehicles dating back to 1947 to the present. Without a doubt manual transmissions are for drivers. However, since commuting is a daily experience in city areas for a large number of drivers, the automatic is the way to go. The real pleasure of driving a manual in city traffic is lost when you aren't movingmore than 5 mph. The real neat feature of the manual, often not mentioned feature, is that you could start the car by pushing it and popping the clutch. Today's electronics and battery capabilities and roadside service have dented the need for that but it is still a great feature. Another neat feature, discontinued, is the freewheeling feature that SAAB used to have where you could disconnect the clutch altogether from the transmission and allow your vehicle to coast downhills without using extra power. Conclusion: manual transmissions though fun are decreasing in demand because of city congestion and the introduction of greener cars. Electric vehicles do not need clutches.
it's the 21st century....
look... it's the 21st century... i don't need to be shifting gears for my car - (are you bored and need something to do while you're driving).
i like my electic windows... no need to roll them up manually anymore...
i like my electric starter... no need to crank my engine from the front....
i like my electric sunroof... no need to crank it open and closed anymore...
and please.... 'control' - if you drive crazy enough where the incremental difference in control (if there even is a difference)
makes a difference... slow down!
yes - there tends to be a mpg difference - and that is a difference that matters - just not enough in a city where you're in stop and go traffic at times.
I just took delivery of a 2011 Subaru Outback with CVT. It also has a manual mode with paddle shifters. As Mylie Cyrus might say " Best of both worlds!"
Total posts: 26 (Showing page 1 of 1)