Efficiency and power of modern Auto versus modern manual transmission.

Factual Questions
21

[QUOTE=Spartydog]
The cranky old timers with their blinders on will always contend that a manual tranny is somehow superior. Yet, any truly high performance car or race car has paddle shifters which are basically an override of an automatic transmission.

Back in the day (the 60’s and 70’s ?), the dragsters were using the old Chrysler push button transmissions because they were faster than the manuals.

If you want to pretend to maintain your masculinity by insisting on operating a manual transmission then be my guest. Otherwise, an automatic can provide the best performance unless you are so adept at out thinking the driving conditions that you can override it in the most extreme circumstances. If you are that good, get a job on the F1 circuit, there’s a lot of money there.
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This is a really puzzling post.

First, manual tranny is a manual tranny. Whether you shift by pulling stick or pushing a paddle, if the driver is in control of the current gear then it’s a manual transmission

Lots of cars now have “soft” gear override controls - you can click up or down a gear if you so desire. I suppose this is auto tranny with manual override. In my experience with many (I rent a lot of cars), the car will override you if you try something dangerous (e.g, going into 2nd or 1st at highway speeds)

For fuel efficiency - by now, autos are probably at parity or slightly more efficent. Torque converters have improved, and probably 95% of manual drivers will not do better than an auto for fuel efficiency.

For performance - autos have come a long way. With some good programming, autos can tell when you want acceleration and will set the gear appropriately. Modern autos are pretty good at this. And shifting in an auto is almost always smoother.

The “masculinity” thing? Grow up. I drove an auto tranny for my first 10 years as a motorist. Then I bought a manual, and hell, it’s 10x as fun to drive. I can accelerate hard when I want to, and keep the gears high when I want efficiency. There’s just a lot more control over the automobile when you drive manual. And driving a manual keeps you always engaged in the driving act, which I enjoy. And I’m not an “old timer”, I’m 27.

22

[QUOTE=FoieGrasIsEvil]
Funny. I have a 2006 Scion Xa, with advertised MPG of 38HWY, 32 city.

The problem is, I selected a manual shift because it was cheaper than an auto trans and had higher rated economy.

I don’t think I’m getting that economy. When I drive 80mph in 5th gear, the car revs exactly at 4000rpm, which is abnormally high IMO.

My Grand Caravan (auto trans) loafs along at 80mph at 2600rpm’s.
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The Grand Caravan has a V6, doesn’t it? A 4-cylinder Scion will certainly have to rev somewhat higher.

That does seem abnormally high, though. At 2000 RPM, my Corolla is doing about 45 MPH in 4th or 55 MPH in 5th. Your fifth gear is lower than my fourth gear!

23

[QUOTE=amarone]
I happen to have a Boxster brochure by my desk. Dreaming.

0 - 60 mph. Manual = 5.8 sec, Auto = 6.7 sec.
Top speed. Manual = 160 mph, Auto = 156 mph.
Fuel economy. Manual = 20/29, Auto = 19/26.
[/QUOTE]
I drove an old 914 a couple of years ago and although it was a little short on hp it was a blast to drive. Without any practice at all I was sliding through turns. I would be in the camp that prefers a manual when driving a sports car.

24

[QUOTE=Magiver]
If you’re in a Jaguar XKR automatic and want to see aFord GT-40 you’ll have to look at it’s tail lights because that’s all you’re going to see of the manual-only car. Same for the Shelby GT500KR (OPTIONS).. Same with the Dodge Viper.

Jaguars are built for a more genteel clientele who want luxury with their performance. And while you can get an automatic in a Porsche 911 it’s an option. “Real” sports cars have manual transmissions because they are more efficient (more hp reaches the road). The skill required is part of the experience.

In sporting events where a lot of shifting occurs in short time frames the automatic is worth the power penalty. Events where extended raw hp is needed the manual transmission is used.

So “real” drivers still benefit from manual transmissions.
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Or you could drive this slush box pasta mobile and be side by side with the GT40 going 0-60. :smiley:
The same debate rages on over anti-lock brakes on many car forums. Bottom line is the computer can do many tasks better than the driver. One of the tasks a computer can do better is shift a transmission. Hence the advent of paddle shifters. The computer never misses a shift.
As with many other things, YMM does V. Just as there are some flat out terrible ABS systems out there, not every auto box is as good a the one of a F430. However when you get a car with a good auto trans, it can be a joy to drive.

25

This is somewhat anecdotal, but Honda has put out a warranty extension on its CVTs due to a defect that can result in judder/slippage.

My 2003 Civic hybrid is one of the impacted. I get to take it into the shop and have it looked at – I was wondering what happened with the loss of 6-7 MPG. :frowning:

26

[QUOTE=Rick]
Or you could drive this slush box pasta mobile and be side by side with the GT40 going 0-60. :smiley:
The same debate rages on over anti-lock brakes on many car forums. Bottom line is the computer can do many tasks better than the driver. One of the tasks a computer can do better is shift a transmission. Hence the advent of paddle shifters. The computer never misses a shift.
As with many other things, YMM does V. Just as there are some flat out terrible ABS systems out there, not every auto box is as good a the one of a F430. However when you get a car with a good auto trans, it can be a joy to drive.
[/QUOTE]
an Automatic transmission will lose power so it’s a bad thing in a sports car. Paddle shifters are useful when the power loss of an automatic is offset by the faster shift such as a really twisting rally course. You’re going from curve to curve constantly. In an Indy car, you’re traveling at much faster speeds and the need to shift quickly is not as important as hp.

And the Ferrari may hang close to the gt-40 until the 1/4 mile at which time it will be looking at the tail lights. That would be the European version. The American Ferrari doesn’t have launch control so it’s a little slower.

27

[QUOTE=GameHat]
The “masculinity” thing? Grow up.
[/QUOTE]

Agreed.

Last time I bought a car at a dealer, I mentioned to the shiny-suited spiv that we wanted a manual. He went ito macho mode: “aah, the manuals are great, maaaaaate..” I said, “Actually, I do prefer them, but an automatic is not a dealbreaker in the right car for me, but my wife here DEMANDS a manual.”

Only then did he notice the small Vietnamese woman standing by my side.

“Oh.”

It was priceless.

Anyway, I think this “autos are superior these days and if you drive a manual it’s because you have a small dick” argument is utterly false. Yes, automatic gearbox technology has gotten to the point where fuel consumption and performance is equal or superior to Joe Average in a manual - but that’s at the top end of the market. Quote figures all you like, but has this stuff filtered down to the five year-old Toyotas that real people drive? No, it hasn’t. This argument also forgets that while automatics have been improving, manuals have too.

the manual tranny will be obsolete one day. That day has not come yet.

28

[QUOTE=Magiver]
Yah, that is high reving. I checked my car last night and at 65 I’m turning 2300 rpm. at 80 I’m turning 2800 rpm. If I got it to 4000 rpm I’d be doing 114 mph. I guess if you get good gas mileage that’s all that counts.
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Well, that’s just it…I would get better mileage if the gearing on this car wasn’t forcing the engine to rev so high at relatively “normal” speed.

I understand that it’s only 103hp in a 2000lb car, but they needed to close-ratio the lower gears and left fifth as overdrive or added a sixth gear.

Methinks my car’s model was a cheap combination of parts as an afterthought/marketing gizmo.

29

[QUOTE=Mr2001]
The Grand Caravan has a V6, doesn’t it? A 4-cylinder Scion will certainly have to rev somewhat higher.

That does seem abnormally high, though. At 2000 RPM, my Corolla is doing about 45 MPH in 4th or 55 MPH in 5th. Your fifth gear is lower than my fourth gear!
[/QUOTE]

yea, the Caravan is a 2006 3.7l V6 packing 227 hp…for a 4200lb vehicle. It probably isn’t faster than my Scion (neither are fast) but it does rev at significantly lower rpm’s at 80mph…like, 1700rpm’s lower. That ain’t right.

30

[QUOTE=FoieGrasIsEvil]
I don’t think I’m getting that economy. When I drive 80mph in 5th gear, the car revs exactly at 4000rpm, which is abnormally high IMO.
[/QUOTE]
Sometimes that happens if you leave the parking brake on. Did you check that?

:smiley:

31

[QUOTE=Magiver]
I drove an old 914 a couple of years ago and although it was a little short on hp it was a blast to drive. Without any practice at all I was sliding through turns. I would be in the camp that prefers a manual when driving a sports car.
[/QUOTE]
Me too. If the dream becomes a reality, I will be buying a manual. And a proper one. I have driven using the Tiptronic manual (shifting with buttons on the steering wheel) and it’s just not the same.

32

[QUOTE=GameHat]
Yes, but they’re almost unheard of in modern autos.

A perfect CVT could in theory max the efficiency of an engine.
[/QUOTE]

Are you sure about that? :confused:

I can name three cars off the top of my head that have CVT: Honda, Lexus, and Audi.

I agree with Magiver depending on what your doing, the manual may be better. My drive is laden with stop and go traffic that comes out of no where (in theory, I have a reverse commute, but with eternal construction and re-routing…), so I love an automatic, especially when I’m hanging out in the city. But, if I want to ‘launch’ myself around, even in tight city driving, it’s way more fun to do in a manual.

My gf got me a weekend of driving school for our anniversary b/c I’m always raving about how an efficient driver I am, and my instructor was like “99% of all drivers out there are not driving efficiently and moreso if they’re driving a manual.” I knew I don’t drive manuals that well, but I was surprised at what I could do in a manual, and how efficient it could be. But, as others have said, anything requiring a lot of quick shifting, a cpu will outperform a human almost all of the time in the long run. Welcome your new overlords :slight_smile:

33

[QUOTE=lizardling]
This is somewhat anecdotal, but Honda has put out a warranty extension on its CVTs due to a defect that can result in judder/slippage.

My 2003 Civic hybrid is one of the impacted. I get to take it into the shop and have it looked at – I was wondering what happened with the loss of 6-7 MPG. :frowning:
[/QUOTE]

I was all set to buy a SATURN VUE -witth CVT-till I read the owner’s compalinst-saturn had so much trouble with the CVT, that they discontinued it after only 3 years!

34

[QUOTE=mazinger_z]
But, as others have said, anything requiring a lot of quick shifting, a cpu will outperform a human almost all of the time in the long run. Welcome your new overlords :slight_smile:
[/QUOTE]
I was in the process of building a sports car (550 hp) and the project died due to fraud (long story). So I have a car with a 5.0L long block and 6 speed tranny bolted up and I’ve been thinking lately, wouldn’t it be nice to have a computer-free car. I’ve got all the parts to go back to an old school beast (so it only puts out 350 hp it would still be fun). I’ve never liked the overlords even though they have treated me well. It was nice to be able to open the hood and fix anything in a couple of minutes.

35

The biggest problem with the CVT is due to slippage. Instead of gears with positive engagement, the CVT has disc, cones, or belts which operate on friction.

Too much torque or load, and something slips: the more it slips, the more the fine tolerances wear out, and the whole thing fails.

The Anderson-A CVT had a positive drive chain that slid up and down gear toothed cones…but the site is down.

36

[QUOTE=GameHat]
Yes, but they’re almost unheard of in modern autos.

A perfect CVT could in theory max the efficiency of an engine.
[/QUOTE]

[QUOTE=mazinger_z]
Are you sure about that? :confused:

I can name three cars off the top of my head that have CVT: Honda, Lexus, and Audi.

[/QUOTE]
GameHat, you might want to check out some “modern autos”. My wife’s Jeep has a CVT. You can get a CVT on a Ford Five Hundred, a Dodge Caliber, I think you can get it on the Nissan Murano and maybe even Altima, BMWs, Mitsubishi Lancer.

I really wouldn’t say they’re “almost unheard of”.

37

[QUOTE=Enola Straight]
The biggest problem with the CVT is due to slippage. Instead of gears with positive engagement, the CVT has disc, cones, or belts which operate on friction.

Too much torque or load, and something slips: the more it slips, the more the fine tolerances wear out, and the whole thing fails.

The Anderson-A CVT had a positive drive chain that slid up and down gear toothed cones…but the site is down.
[/QUOTE]

Just found it on YouTube:

BTW, an IVT (infinitely variable transmission) as stated above couples a CVT with a planetary gearset. The planetary subtracts the input rpm of the motor from the output rpm of the CVT, enabling an infinite number of gear ratios all the way to zero, even reverse is possible, all without a torque converter or clutch.

38

[QUOTE=Magiver]
I was in the process of building a sports car (550 hp) and the project died due to fraud (long story). So I have a car with a 5.0L long block and 6 speed tranny bolted up and I’ve been thinking lately, wouldn’t it be nice to have a computer-free car. I’ve got all the parts to go back to an old school beast (so it only puts out 350 hp it would still be fun). I’ve never liked the overlords even though they have treated me well. It was nice to be able to open the hood and fix anything in a couple of minutes.
[/QUOTE]

Here you go, bolt right in. (Assuming of course when you say 5.0L you are talking a Ford 5.0)

39

[QUOTE=Enola Straight]
The biggest problem with the CVT is due to slippage. Instead of gears with positive engagement, the CVT has disc, cones, or belts which operate on friction.

Too much torque or load, and something slips: the more it slips, the more the fine tolerances wear out, and the whole thing fails.

The Anderson-A CVT had a positive drive chain that slid up and down gear toothed cones…but the site is down.
[/QUOTE]

Yeesh. Thanks for the explanation, that makes a lot of sense in relation to my car. :stuck_out_tongue:

40

While there is only one kind of manual gearbox (with minor variations), automatic gearboxes come in many different flavors.

  1. CVT which has been covered in previous posts

  2. Tiptronic, or whatever each car maker calls it. This is a typical auto box with a torque converter with the addition of buttons, paddles or a special position of the stick that allows manual gear changes. Gear changes are generaly slow and IMO the only reason to use the manual mode is for hill descend or for not letting the gearbox to kick-down on the highway (and therefore improve mileage).

  3. BMW’s SMG. This is basically a standard manual gearbox that has computer controlled hydraulic actuators that control the clutch and make the gear changes

  4. Borg Warner’s DSG. This is maybe the best gearbox ever fitted on road-legal cars. It combines lightning-fast gear changes, and since they have 6 or 7 gears, very good fuel economy.