Pros/Cons of a fully auto tranny

[Eric.]

...and you've decided that nothing else is acceptable.

...for us. We aren't the ones saying automatic and all forms of flappy paddle and SMG transmissions should be destroyed and everyone forced to drive a six speed H-shifter and clutch manual transmission. The fact is that 80% of US cars are sold with torque-converter automatic transmission. And those people driving them are buying the car with that transmission instead of a manual because they either don't know how to drive a manual or find it to be a chore that gets in the way of the mundane task of commuting to work. "The car as a tool" kind of outlook. Many other people I know don't care about any other performance aspect of a car besides acceleration (yeah I live in hickville) and don't see much difference in having an automatic GTO or whatever. They don't care how the transmission may affect spirited driving or whatever else.

 

[Famine]

Seems like it would be the opposite to me. You have greater horsepower at higher RPM, since your throttle is controlling the flow of fuel, you'll get a greater acceleration per decipedal when operating at higher RPM. I think the higher gear gives you finer control over the acceleration while eliminating the highest accelerations that you can achieve.

The same road speed in a lower gear = higher rpm...

But wouldn't the safest approach of all to simply be ready for left foot braking - which is accommodated by either transmission?

Oh heavens no. Left foot braking is even more clear cut than heel-toe - never use it on public roads.

I got told off for doing it on an instructed lap too (in a GT-R, of all things ). He didn't notice that I still did it on a timed lap though

You're entering a turn slightly too fast, with low visibility and want to be prepared to brake as early as possible in case there is an obstruction around the bend. You figure this out late in the game so in the manual you're able to shift from 5th to 2nd in time for the turn, whereas in the DSG you're only able to get from 5th to 4th. During the turn you find that there is an obstruction, so you take your foot off of the accelerator and hit the brakes. In the manual you have 2nd gear engine braking for that fraction of a second, while in the DSG you have 4th gear engine braking for that fraction of a second. 2nd gear engine braking > 4th gear engine braking, therefore the manual is that much safer than the DSG.

That's largely right, though I'd suggest that 2nd would be too low a gear to block shift to from 5th - 2nd and 5th don't have sufficient overlap. Taking my daily as an example, 2nd does 0-55mph, 5th does 10-140mph - but the sensible range is 10-50mph and 30-140mph in those gears. 3rd has a sensible range of 20-70mph.

However, you shouldn't be entering the turn too fast - advanced driving 1.01, always be sure you can stop in the distance you know to be clear. That's part of the reason you've already shifted into a lower gear. You'd need to add that you're also in a gear that allows you to go much slower before stalling, marginally enhancing the final few feet of stopping distance too.

Here's my question. This is a daily-driving scenario. You entered into a turn too hot and have low visibility - why is your foot on the accelerator? Isn't it safer to be ready to brake as you bleed off excess speed during the turn, or even just braking?

As above - on a public road you shouldn't be going into anything too fast.

If the corner as a whole is unassessable, you assess what you can see and what you know you can predict. This is a great example of such a corner, posted by my mate Reg:

There's actually several clues to what follows in that picture alone, but most people will see, while heading towards it at 55mph, a right-hand bend of some flavour. If you assess that corner as you approach it you may end up going through the corner 5-10mph slower than someone who knows the corner, but you won't smash into the hazard they didn't bother to account for because they drive it every day and the hazard's never been there before. Your limit point is in that picture - theirs isn't (well it is, but they disregard it).

So as you approach the corner, you shift into a lower, more flexible gear and use the throttle to balance the speed that you deem appropriate for the corner, conditions and visibility. As you get closer to it, more information becomes available - the limit point moves - allowing you to reassess. During the corner, more information becomes available allowing you to reassess and when the corner has passed you can shift back into a higher, cruising gear.

You can do the same in a flappy or semi, but you need to unbalance the car twice to perform the same action as unbalancing the car once with a full manual (and twice more after the corner) and you can't do it at all in a full auto. CVTs would be awesome at it. because you don't need to unbalance the car at all and they're always in the right gear.


If I had a choice of any transmission in the world for my car, I'd take a CVT on a daily driver and a flappy DCT on a track car. If the car had to be both I'd choose a full manual, but a flappy DCT would be a good second place choice - I'd take the hit of 4th gear for the above job, rather than a second shift. If they could invent a flappy/DCT that blocked two gears with a single button press, I'd be very tempted.

 

[niky]

You'll probably have to wait for them to invent an automated, H-Gate triple clutch box...

 

[Danoff]

The same road speed in a lower gear = higher rpm...

Agreed.... and so I stand behind what I said. Lower gear = higher rpm = higher power = more acceleration per unit of fuel = more acceleration per decipedal.

Oh heavens no. Left foot braking is even more clear cut than heel-toe - never use it on public roads.

Well I don't, because I can't do it without locking up the wheels and scaring passengers. My left foot is good at clutch manipulations, but somehow brake manipulations are too sensitive for the amount of practice I've had.

However, you shouldn't be entering the turn too fast - advanced driving 1.01, always be sure you can stop in the distance you know to be clear.

Seems like remedial driving 101. But if you're not doing anything wrong, entering the turn at the appropriate speed, then you've had ample time to shift into the proper gear in either a manual or a DSG prior to the turn, and so there is no difference between them.

You can do the same in a flappy or semi, but you need to unbalance the car twice to perform the same action as unbalancing the car once with a full manual (and twice more after the corner) and you can't do it at all in a full auto. CVTs would be awesome at it. because you don't need to unbalance the car at all and they're always in the right gear.

Slightly unbalancing the car by shifting prior to and after the turn aren't really concerns though, it's during the turn where shifting is the problem, and even then, only if you're taking it entirely too fast for daily driving.

The conclusion that I keep reaching is that you have to be doing something else wrong to need the minute advantages of being able to block shift. I'm certainly willing to admit that it's something that a DSG doesn't do, and it's a slight win in the manual gearbox column (although I certainly think the DSG has plenty of wins over the manual too), but I'm still not seeing this as a necessary safety feature.

So far all I've got is that if you screw up royally, you can get into a lower gear faster in the manual transmission which gives you access to higher power during the turn (for drifting), and a bit more engine drag in the moment where you take your foot from the accelerator to the brake. Incidentally, I imagine this little bit of engine braking is also higher with a stick than a CVT.

 

[Famine]

Agreed.... and so I stand behind what I said. Lower gear = higher rpm = higher power = more acceleration per unit of fuel = more acceleration per decipedal.

Yes, you can change speed quicker (which lends a hand to the decelerative effort) but you can also change speed smaller - which is a double bonus. You can go from 53 to 52mph (or vice versa) faster and more accurately in 3rd than in 5th.

Well I don't, because I can't do it without locking up the wheels and scaring passengers. My left foot is good at clutch manipulations, but somehow brake manipulations are too sensitive for the amount of practice I've had.

Yeah, I tend to put people through the screen in an auto.

Seems like remedial driving 101.

You'd think, but that's not taught in either of our countries' drivers' ed.

But if you're not doing anything wrong, entering the turn at the appropriate speed, then you've had ample time to shift into the proper gear in either a manual or a DSG prior to the turn, and so there is no difference between them.

Slightly unbalancing the car by shifting prior to and after the turn aren't really concerns though, it's during the turn where shifting is the problem, and even then, only if you're taking it entirely too fast for daily driving.

The conclusion that I keep reaching is that you have to be doing something else wrong to need the minute advantages of being able to block shift. I'm certainly willing to admit that it's something that a DSG doesn't do, and it's a slight win in the manual gearbox column (although I certainly think the DSG has plenty of wins over the manual too), but I'm still not seeing this as a necessary safety feature.

That wholly depends. Is the road surface clean, dry and intact?

Sometimes block-shifting is irrelevant (probably most of the time). Sometimes block-shifting is safer than n separate shifts. Manual gives you the option of block-shifting, whereas flappies don't. The only advantage flappies have over full mannies is gearshift speed and that's irrelevant on public roads.

So far all I've got is that if you screw up royally, you can get into a lower gear faster in the manual transmission which gives you access to higher power during the turn (for drifting), and a bit more engine drag in the moment where you take your foot from the accelerator to the brake.

If you're already boned, changing gear is dense. Then you're boned and completely screwed - which brings us back to full autos.

It's all about preparation, anticipation and roadcraft. Manual always gives you the option to prepare and anticipate, flappy is nearly as good and auto is pleh. I have no need for the 0.1ms shifts of a DCT flappy on a public road, but I may need the flexibility of a manny.

Incidentally, I imagine this little bit of engine braking is also higher with a stick than a CVT.

The CVT would be at least as efficient, like-for-like, as a manny (if you can find a like-for-like) in scrubbing speed though I'd have a bit of trouble explaining why* and you wouldn't need to dip the clutch at the last. I'd love to try a CVT in a car that isn't an ecoweenie, but there's just not the option.

* We're pushing the boundaries of my ignorance at this point. Someone more versed in the murky world of vehicle engineering like Scaff, or someone considerably more trained in the land of advanced driving like Venari will be able to help at levels beyond me

 

[Danoff]

Yes, you can change speed quicker (which lends a hand to the decelerative effort) but you can also change speed smaller - which is a double bonus. You can go from 53 to 52mph (or vice versa) faster and more accurately in 3rd than in 5th.

Still gonna have to disagree with this. The accelerator pedal doles out fuel. For a given bit of fuel you're getting more acceleration at higher RPM. That means you have less precision over your acceleration, but access to more.

Sometimes block-shifting is irrelevant (probably most of the time). Sometimes block-shifting is safer than n separate shifts. Manual gives you the option of block-shifting, whereas flappies don't.

I agree that you have a flexibility with the manual that you don't have with the paddle, and in theory that should translate to improved safety somehow. But both manual and paddle offer the ability to be in the right gear for the turn prior to the turn. Manual does it in fewer shifts, but that shouldn't be a problem if it's done prior to the turn. If you're making the adjustment mid-turn, where the number of shifts could be a serious problem, you're doing it wrong.

The only advantage flappies have over full mannies is gearshift speed and that's irrelevant on public roads.

...and 100% accuracy, and the ability to drive in an automatic mode should you break your wrist, and the lack of a clutch should you break your ankle. Also, if some clueless driver who doesn't know how to drive a stick sideswipes you in the middle of nowhere with no help in sight, rendering his car useless, and you unconscious and bleeding to death, that guy has the option of getting in your car and driving you to safety. I know it sounds silly, but the ability for people who don't know how to operate a manual to operate your car could prove to be a safety benefit to you.

 

[Famine]

Still gonna have to disagree with this. The accelerator pedal doles out fuel. For a given bit of fuel you're getting more acceleration at higher RPM. That means you have less precision over your acceleration, but access to more.

We'll have to turn the floor over to Scaff on that one then.

I agree that you have a flexibility with the manual that you don't have with the paddle, and in theory that should translate to improved safety somehow. But both manual and paddle offer the ability to be in the right gear for the turn prior to the turn. Manual does it in fewer shifts, but that shouldn't be a problem if it's done prior to the turn. If you're making the adjustment mid-turn, where the number of shifts could be a serious problem, you're doing it wrong.

Agreed on the last part, but you're not taking road surface into account. Any surface water and you can bet I want one shift even in a straight line and under no change of road speed.

...and 100% accuracy, and the ability to drive in an automatic mode should you break your wrist, and the lack of a clutch should you break your ankle. Also, if some clueless driver who doesn't know how to drive a stick sideswipes you in the middle of nowhere with no help in sight, rendering his car useless, and you unconscious and bleeding to death, that guy has the option of getting in your car and driving you to safety. I know it sounds silly, but the ability for people who don't know how to operate a manual to operate your car could prove to be a safety benefit to you.

If I broke my wrist or ankle, I wouldn't drive. Any injury which would impair my ability to drive would result in me making the call not to drive. I did drive once with a suspected broken foot (it wasn't, probably, but it hurt like a ****), but it wasn't an issue - I put the car in third and did the whole journey like that, with some judicious anticipation applied. Four-way stops might goose that idea, but luckily we don't have them


Incidentally, in the above situation in the UK, the guy would be arrested and charged for TWOC and driving without valid insurance. But then the UK is insane.

 

[homeforsummer]

I'd love to try a CVT in a car that isn't an ecoweenie, but there's just not the option.

Give a knock on Nissan's door. They seem to use the things a fair bit. Off the top of my head, I can think of the Murano and the 180bhp Juke that both use CVT, and neither are set up like Prius-style eco things.

I've never really considered CVT to be a particularly sporty transmission anyway, but then many go-karts and snowmobiles use CVT-type transmissions and both of those are almost exclusively sports vehicles, so I think the lack of CVT used as a widespread automobile transmission is either due to cost or prejudice, probably both.

That said, the U.S. gets far more CVT-equipped cars than we get here in the UK. Again, most of them are Nissans.

 

[Jim Prower]

Williams tried to make a CVT for Formula 1 one year, and it was quite fast. Who knows what might have happened if it hadnt' been banned...

But, yeah, Nissan has a lot of "scooter trannies" in their lineup. (and I say that in an endearing way.)

 

[kingcars]

...and you've decided that nothing else is acceptable. I personally find driving with a DSG to be a much more enjoyable and pure driving experience. Instead of dancing around trying to finesse a gear change with my whole body, it happens in the blink of an eye with a twitch of my finger. I think it, and it happens. It's precision, instant, even digital.

But then, this is why I don't like Apple computers. Everything is supposed to be organic. You're supposed to see things moving, blinking, shrinking, expanding, scrolling. I prefer for things to appear and disappear the instant I indicate that it should. Perhaps I'm a product of the digital age, but to me, the manual gearbox is an unnecessary and unwelcome interface. It's a ramp instead of a step function. It's an art rather than a science (and not the art I'm interested in). It's an organic version of something that should be digital.

Cars are not digital. What is digital about dumping fuel and air into a combustion chamber and blowing it up? What is digital about actual gear changes? Flapping a paddle is not my idea of a pure driving experience. Also, if you need your whole body to "finesse" a gear change, you have serious problems driving a car.

 

[Keef]

But then the UK is insane.

Jealous! Most Americans are completely dumbfounded when they encounter a roundabout to the point that they call them "traffic circles". A what? While they're thinking about it they crash.

 

[Danoff]

What is digital about dumping fuel and air into a combustion chamber and blowing it up?

Actually, combustion is fairly digital and rigidly timed.

What is digital about actual gear changes?

Quite a bit actually. Machines don't operate in an organic way. What's organic about a mechanical process that starts and stops in 8 milliseconds?

Flapping a paddle is not my idea of a pure driving experience.

That's because you won't divorce the process of driving from the process of manipulating a gearbox.

Also, if you need your whole body to "finesse" a gear change, you have serious problems driving a car.

Feet, legs, hands, arms... close enough. You're right, I don't use my ribcage to shift gears. Thanks for bringing that to my attention. Nothing gets by you does it?

 

[Keef]

Nothing in nature is digital. Computers are digital, but there is nothing digital about combustion, or gears turning, or clutches clutching, or tires squealing.

The only thing digital about combustion is the way the controlling computer organizes its information. Everything else, including the spark, is not digital.

 

[Danoff]

Nothing in nature is digital. Computers are digital, but there is nothing digital about combustion, or gears turning, or clutches clutching, or tires squealing.

The only thing digital about combustion is the way the controlling computer organizes its information. Everything else, including the spark, is not digital.

In the most-technical sense, this is obvious. I'm sure you weren't assuming that I meant it was literally digital. Now that I've cleared that up, feel free to re-read my previous posts without assuming that I'm incorrectly using the term digital in the most technical sense.

 

[McLaren]

Oh heavens no. Left foot braking is even more clear cut than heel-toe - never use it on public roads.

I got told off for doing it on an instructed lap too (in a GT-R, of all things ). He didn't notice that I still did it on a timed lap though

I really wish you had chimed in when this topic came up in the GT5 forum. Too many special folks saying it was alright to do on the streets & claiming they had track experience or the 1 weenie who claimed he & his father laughed at everyone who didn't do it b/c they couldn't co-ordinate their feet.

Jealous! Most Americans are completely dumbfounded when they encounter a roundabout to the point that they call them "traffic circles". A what? While they're thinking about it they crash.

What they call them isn't the issue. It's that they don't understand how to yield to people. AFAIK, the person in the circle has the right of way, not you coming off the side street.

 

[Danoff]

Proper roundabout (traffic circle) technique:

 

[Keef]

I know you know what digital means, but as you think a Mac is trying too hard to be organic, I think DSGs et al. are trying too hard to be digital. Computers are inherently digital, as machines are inherently organic. Trying to mix them just doesn't work. We both dislike Macs for the same reason, but whereas I respect a machine for what it is, you think it should be something else.

Call me stubborn, but a machine is a machine. I operate it, it does what I tell it to. A computer is a computer. It does what I tell it to, but not before it thinks about it.

EDIT:

Proper roundabout (traffic circle) technique:

Awesome. My addition:

 

[McLaren]

I
Call me stubborn, but a machine is a machine. I operate it, it does what I tell it to. A computer is a computer. It does what I tell it to, but not before it thinks about it.

In the case of transmissions, they think beforehand for your sake most of the time. I don't know how many people have tried to play with the shifters themselves and try to downshift in to gears that would normally destroy a manual.

 

[Keef]

I have never missed a downshift while driving manuals. I have accidentally tried to downshift flappy boxes. Why? I don't know. Maybe it's because they lack the same feel? The sound? The subconscious thought that "If I downshift wrong it'll blow up"? There is certainly something different about them that makes me basically have no idea what gear I'm in without looking at the display. I have never had that problem in any manual, from my clearly audible RX7 to my friend's buttery smooth and silent IS300.

What I mean by "never missed" is that I've never gone from 5th to 2nd. That takes effort. 4th to 1st? That takes effort. 4th to second at 100mph? There's a tach in front of me and I've been around the block a time or two.

I have gone from third to third though. Whatever.

 

[Danoff]

What I mean by "never missed" is that I've never gone from 5th to 2nd. That takes effort. 4th to 1st? That takes effort. 4th to second at 100mph? There's a tach in front of me and I've been around the block a time or two.

Good luck doing those things in a DSG.

 

[McLaren]

I have never missed a downshift while driving manuals. I have accidentally tried to downshift flappy boxes. Why? I don't know. Maybe it's because they lack the same feel? The sound? The subconscious thought that "If I downshift wrong it'll blow up"? There is certainly something different about them that makes me basically have no idea what gear I'm in without looking at the display. I have never had that problem in any manual, from my clearly audible RX7 to my friend's buttery smooth and silent IS300.

Just because you have never missed a downshift does not mean a thing. Good for you Mr. Senna but there are people who have accidentally downshifted into a gear at a speed they shouldn't have (& have done the same upshifting) and it's not just a simple 5th to 2nd or 4th to 1st. For these people, the engine pays the price.

For DSG cars, they think beforehand so this doesn't happen.

 

[Keef]

Well then they can have them. That doesn't make it better.

 

[kingcars]

Just because you have never missed a downshift does not mean a thing. Good for you Mr. Senna but there are people who have accidentally downshifted into a gear at a speed they shouldn't have (& have done the same upshifting) and it's not just a simple 5th to 2nd or 4th to 1st. For these people, the engine pays the price.

For DSG cars, they think beforehand so this doesn't happen.

There is this really cool thing called a rev limiter. Those people should look into one

As for Danoff, the problem for me is that there is a whole extra step going on between me and the car. I want to feel directly in tune with the car, not separated from it. No matter how fast or good an auto or flappy paddle gearbox may be, I will always prefer shifting my own gears (notice how I'm not saying anything stupid like "D00D AUTOS SHOULD BE WIPED OFF THE PLANET LOLZ"). I feel bad for those who find it to be a nuisance.

 

[Kylehnat]

Rev-limiters don't (and can't) do anything to prevent the transmission from forcing the engine to spin too fast.

 

[Danoff]

There is this really cool thing called a rev limiter.

As McLaren said, this is not the point of a rev limiter.

As for Danoff, the problem for me is that there is a whole extra step going on between me and the car.

I suppose you don't have power steering.

 

[kingcars]

I suppose you don't have power steering.

Hahahaha now you're just grasping at straws. In no way does power steering compare to having a whole computer system sitting between driver input and car.

 

[Danoff]

Hahahaha now you're just grasping at straws. In no way does power steering compare to having a whole computer system sitting between driver input and car.

I want to feel directly in tune with the car, not separated from it.

.

 

[kingcars]

.

Your point is what? Power steering doesn't disconnect me from the car like having a computer doing my shifting and clutch work for me does.

 

[Keef]

Power steering is a hydromechanical system that affects feel. Electronic throttles, electronic transmissions, whatever, don't provide any sort of mechanical connection.

 

[niky]

For DSG cars, they think beforehand so this doesn't happen.

Actually, all a DSG can do is prime whichever gear (one higher or one lower) it thinks you might want next. So if you're accelerating gently, the next gear up is primed and it won't be able to shift down one as quickly. Especially if you're cruising, and it's shifting up as quickly as possible to save gas.

And a DSG will never be able to shift two down at once without some difficulty. And it will do it much slower than an average user. The one solution to this is "sports mode", where the DSG always resorts to the lowest gear possible.

Let's face it. 99% of everything you do in a car nowadays is artificial.

Any car with power steering, be it hydraulic or electric, has a layer of artificiality between you and the road. Hydraulic systems have an annoying amount of slop built in to prime the system. Electric steering is actually better because it's more direct, and mounting the assist motor on the rack (instead of at the wheel) gives it as much "feel" as a hydraulic rack.

Combustion is digital. Since the advent of EFI, we've had less and less connection with the running of our engines. No longer do you have monster bog as in the old, carburetted days, nor do you have to feather the throttle to keep a car idling (most times). With electronically timed ignition, they've elminated many of the dips and troughs in the powerband. And now with electronic throttles, it's difficult to bog the car on purpose. I've driven e-throttle cars that will blip for me when I let off the clutch to keep the engine from dying. Actually... give me a manual that does that all the time and I won't need an automatic, or a second foot..

You can still enjoy a car with an electronic throttle and electric steering... as long as it's programmed right. And that's the one problem with new technologies. The programming is all over the place. Recently, I've had the chance to drive cars that get it more right than ever before, so I have hope for the future.

Give a knock on Nissan's door. They seem to use the things a fair bit. Off the top of my head, I can think of the Murano and the 180bhp Juke that both use CVT, and neither are set up like Prius-style eco things.

The Sentra CVT is fantastic. Nissan uses a D-S-L set-up instead of D-3-2-1. In "S", the CVT holds on to higher revs on acceleration at lower pedal inputs. In "L", it will go all the way to power peak before "upshifting", and it will hold revs on deceleration. Which gives great performance and allows for some pretty gnarly lift-off oversteer. Not something you expect from a "safe" and "boring" CVT. Hell, I'd be glad to see this kind of box in a go-kart... as it's fantastic.

Still sounds like an electric train pulling out of the station on acceleration, but it's a terrible engine, anyway.