|
mind boggeling presumption? (manual more efficient than automatic?)
The Argument between getting a manual or a an automatic is trivial. A modern automatic tranny will shift at peak torque, perfectly everytime. With a manual there is human error. Some of the new vehicles have automatic trannys that surpass manual in the epa. would you save more suel over time haveing consistant shift points or variable shift points assuming one wants to save the most amount of fuel possible and is not the only driver of the car (wife).
|
Lol, the manufacturers use "sportier" gearing in a lot of manuals. Look at auto vs/manual in cars designed for efficiency and it becomes much clearer that manual has the lead. And it enables lots of other techniques, where the automatic designers "automated away" your options for more efficiency. You say human error, I see humans doing a much better job at saving fuel when they learn what is going on. Human error exists on many levels, I could say that being "lazy" about shifting and rationalizing automation even though it is demonstrably less efficient than a skilled driver (what a concept!) with a stick is a huge human error, since we are discussing efficiency.
Automatics are getting better, but more pricy too, and they are heavier, and sloppier, harder to repair, and the shift points are built for your average mash and go driver. Heck most of the time you can't even safely EOC in them, they lose big time right there, no contest once you relearn how to drive. |
This is great I would love to take a smash and go driver using both manual an auto and compare te differences in real world scenarios clearly the manual would win but I want numbers thanks
|
Well there is this: EcoModder Fleet list - EcoModder.com
You have to go scroll down pretty far before you get into serious numbers of automatic cars. There are a couple fairly high mpg priuses, but I can tell you from first hand experience it is much harder to drive them uber-efficiently than a stick. You have to outsmart a layer of automation to get there. Or look at something like a 2014 yaris, users are reporting ~30% better efficiency with the stick: Fuel Economy of 2014 Toyota Yaris |
Automatics are heavier and you have to use energy to pump fluid around.
Now once everything is locked up the only real difference is all the extra spinning weight. Think how some here worry just about wheel weights. The perfect tranny for MPG would be a CVT. With proper programming the engine would stay at its peak economy based on load and throttle inputs. But they still have reliability issues. The one thing missing, the transmission nor ECM can look ahead and judge terrain or traffic conditions...YET! |
Automatics have improved drastically over the years, but mainly in adding gears. Some of them are up to 8, 9 speeds?! Automatics usually have higher highway speed RPM which really hurts fuel economy.
I will always prefer a manual. An automatic won't ever let me "chug" around at 900 RPM in 5th gear in town. The most fuel efficient gear at any given speed is the one with the lowest RPM, regardless of engine load (unless you go into open-loop rich mixtures). Automatics can't control the engine/transmission as completely as the driver can. What has changed in manual transmissions over the last few decades? Almost nothing. They are bulletproof if you drive them correctly. Automatics are more expensive to repair/replace/maintain. CVT's are even worse in that area, but have become much better. Also, there is just something fun about slapping the gears around. It feels sportier. You are more connected to the car. |
numbers
Learning about how manuals are operated during the EPA test -- with prescribed (non-eco) shift points and prohibited coasting -- makes it clear why it's far easier to beat the EPA (by a bigger margin) with a stick than a slushbox or CVT:
http://ecomodder.com/forum/showthrea...ing-27416.html Quote:
2014 Mitsubishi Mirage 1.2L: Automatic CVT2012-2014 Nissan Versa 1.6L sedan Automatic CVT & 4-speedFuelly - analyze Fuelly sucks because it doesn't break out transmission type or engine size in its data, but if you comb through details/results for a specific vehicle, you can sometimes put together a comparison based on drivetrain. Quote:
|
Quote:
The manual mode is better on the highway as I can leave it in 6th and stay easy on the accellerator. In auto mode every rise causes a down-shift. The cruse control could be better though. I rented a Mazda 3 with "Sky active". (whatever that is?) Also an auto, that cruse control was great. I'm pretty sure it was engine off coasting on cruse control at times. |
Almost 10 years ago the consortium of the EPA, University of Michigan, Ford, Parker Hannefin and some others predicted some amazing numbers for fuel economy in vehicles. I have posted that document here before.
Their precitions included an 80% increase in economy through powertrain improvements, with all other improvements combined for a total 120% improvement. They also predicted that a class 2 truck with a GVW of close to 10,000 pounds would achieve 58 MPG. I have the chart that breaks down the stages of improvement. The date those predictions were supposed to be in place is NOW. I have my own favorite powertrain configuration, where the transmission replaces friction brakes completely, the exception of the emergency brake, but it will be a while before a functional example is built. The original post title is provocative. Extreme techniques, combined with very low average speeds, about half of my own, will always produce exceptionally high MPG averages. Where you live can make a huge difference. That's great for those who are in that situation, which is not and never will be my own. Mag Pearl is number 36 close to the top 10%. Only 9 of the 35 higher vehicles are less than 14 years old, and some of them are models never sold in the US. The gap is closing. My Fiesta's automated manual transmission is one pathway to the future of shiftless driving, My dream is another. Only time will tell which one prevails, but when all the factors are combined with the capability of the vehicle to anticipate where it is going and when it must stop the automated choice will prevail. regards Mech |
Quote:
https://encrypted-tbn3.gstatic.com/i...RjeFxRitU7VJRI |
Quote:
To note: I've driven hundreds of new cars over the past few years, and have been able to get week-long tests in both manual and automatic variants of a dozen odd of them. It isn't even close. Unless the automatic is a CVT, the manual will always outdo the automatic in every situation. CVTs can be driven to economy numbers as good as manuals given certain conditions, but this is highly dependent on the CVT in question. The Honda CVT from the first-generation Insight and first-generation Fits (from outside America) seem to do very well, as does the Mirage CVT... but as MetroMPG showed, in real life, manual variants of the Mirage still do better (especially in traffic, where the extra losses of the CVT are still noticeable). |
That is key, any kind of transmission can be automated, even a manual with some servos(probably wouldn't even need synchros). What is needed is an efficient transmission of energy to the wheels. CVTs have some inherent losses in them, as do automatics (plus costs). This needs to be weighed against the operating efficiency parameters of the engine/motor, and I don't know of many/any cases where cvt would come out ahead.
If you want to automate acceleration for best efficiency, you basically replace the gas pedal with a footswitch, it simply becomes a command for "accelerate at best efficiency", and hopefully it freewheels when not accelerating. I think this is very doable, today. But "power" and "performance" still sells cars too... Just a caveat about extreme automation, will it allow some measure of "civil disobedience" when the situation calls for it, either to exceed the speed limit on a pulse for even greater efficiency, or in an "emergency"? |
Of course a manual speed transmission is better because it its not using fluids to make the gears turn and thats where the automatics lose out. Also not everyone can or wants to drive a manual transmission. Also Honda is now coming out with a dual clutch transmission that still utilizes a torque converter, interesting design.
|
I can feel my dual clutch 6 speed powershift in the Fiesta downshifting when I am coasting in neutral. I wonder if it even has a neutral or if it just keeps the clutches disengaged.
regards Mech |
Car companies are very good at designing and manufacturing things. They can build wonderful slushboxes that excel at being operated for the EPA testing. I don't work as an EPA test driver, so I use EPA ratings the same way I use 0-60 times: as a largely irrelevant number that only serves to give an idea of relative performance to other cars being operated exactly the same way under identical circumstances.
In real life if you can and care enough to do more than simply shift into Dumb, there's no comparing the two. An auto doesn't know what's going on outside the car or what you're trying to do. |
Metro, thank you very much for sharing that information! I have seen several discussions on here regarding the superiority of modern automatic transmissions, but it is great to have numbers showing that people get better mileage with manuals in the real world!
Old Mech, that kind of sounds like the high-mileage competition with astronomical MPG calculations, where college kids drive motorized enclosed recumbent bikes. I do not intend to disrespect the research, hard work, and achievement there, but until we have entire cars weighing less than single components in our current ones, not to mention impossible aerodynamics, and unrealistically-slow speeds, it does not seem relevant. A few weeks ago for my Energy in the Global Arena class, we were required to attend a lecture by Amory Lovins. He talked a lot, that was the point, but he discussed using modern fabricating techniques to craft car bodies straight out of carbon, and raved about how much energy it took, how much lighter the product was, and how much less energy it required to power it. It is exciting to think that projects like CarBEN could be far simpler. |
Quote:
|
Quote:
I drove a new 981 PDK Porsche Cayman and I was kind of excited to see how it would do when I saw the brochures talking about auto-coast. Well, it's basically no better than the automatic in any other car, though it shifts a hair faster when you press the "+" button and the auto blips are certainly better than the crappy cars that just select a lower gear and then use the clutch to drag the engine up to speed. The auto coast is totally useless because the computer sucks at deciding when to coast, and the shifting pattern is exactly like any other car in auto mode. Oh and on top of that, not having a clutch and gear shifter is incredibly boring once you're used to having it. I'll take my manual transmission with less gears and slower acceleration any day. With the 7 speed manuals coming out, I'm definitely not concerned about getting "less" fuel economy, and besides you don't have to lug around the solenoids and extra clutches, which saves ~2% curb weight. |
Dual clutch clutch packs cost something like two to three times as much as a regular clutch. And that's considering you can replace them. Early dual clutches claimed "lifetime" use... which meant that if you burned the clutch packs, you had to replace the entire transmission.
A dual clutch with a torque converter would be nice, but as you said... that extra-fast shift doesn't really matter all that much, in the grand scheme of things. I still like the Mazda torque converter automatic better than 99% of the dual clutches I've ever driven. The Toyota-Lexus planetary gear system is better yet, but probably not applicable without hybrid assist. |
Quote:
|
DSG, DCT, Dual clutch. Mentioned it in the post above yours.
Downsides: complex to build, rather expensive, and sort of heavy. Also, supposedly has fewer wear parts and less wear than a traditional manual. If you're lucky, this holds true, but oftentimes the clutch packs do wear down and need to be replaced. This costs more than in a regular manual. Some side-step the problem by using a torque converter... which adds weight, drag and fuel consumption. Me, I'm looking forward to the day that DSG/DCT clutch replacement jobs are as easy as ordinary manual clutch replacements... |
older cars are no doubt more efficient with a manual.
|
Every new technology means you have a certain amount of lag time before the repair industry becomes familiar then profeciant at repairing that technology. CVTs are just getting there and they have been out for over a decade in the US even longer with the early Subaru Justy.
Dual clutch automated 6 speeds are still mostly under warranty by manufacturers. When that time period runs it's course then they too will repaired by transmissions shops. Any human action in operating a car can be automated. The hydromatic came out in 1939. regards Mech |
Quote:
|
| All times are GMT -4. The time now is 10:36 AM. |
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2025, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com