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Nope, I didn't miss either point; at 2,500 RPMs it is impossible to lug my engine (or pretty much any modern engine for that matter) even at WOT.
Fact, if I want a lower gear for better acceleration, I'll simply choose a lower gear.
1: there is far more friction and mass involved with the automatic as opposed to the manual. The same physics apply as they always have. Automatics have 5-10% power and MPG loss over manuals at the same RPMs.
2: Most manufacturers set their rpms as low as absolutely possible to get the same MPG ratings for their automatics as manuals. (!) The final gearing on most automatics is there just to make the EPA happy and has no correlation to real world driving patterns. If you so much as touch the pedal with one toe it will unlock the torque converter and drop down a gear. It's good for level ground only and is essentially coasting or close to neutral RPMs as it can get away with. Because of the higher masses involved and more friction/drag on the driveline, the automatic transmission acts like a very large flywheel so it won't actually stall out or lug as easily. The transmission will almost always shift as soon as it physically can as well, which would nearly stall most manuals. All to get better MPG.
The manual? No such gimmicks or problems. Better speed and driving dynamics at all times. And the same MPG. (and a slew of other benefits, not the least being $600 for a clutch vs $4000+)
To simply "hold" a set speed "peak torque" as you're using it has no meaning.
You fail to understand that these 2 tasks are not mutually exclusive. What do you think happens when you start climbing and incline and want to maintain a steady speed? Well, I'll tell you, you open the throttle more. So maintaining a set speed is completely dependent on the power available.
"Lugging" an engine means trying to maintain or attain a speed without the necessary power available so that it is struggling.
'11 GMC Sierra 1500; '98 Alfa 156 2.0TS; '08 Maser QP; '67 Coronet R/T; '13 Fiat 500c; '20 S90 T6; '22 MB Sprinter 2500 4x4 diesel; '97 Suzuki R Wagon; '96 Opel Astra; '11 Mini Cooper S
with 'underpowered' slushbox or other automatic-transmission cars, yes, the slightest throttle blip might unlock torque converter or otherwise downshift at highway or any other speed.
regarding torque peak and road hp - it is very relevant to have torque peak be near the rpm which provides the optimal rpm & necessary road horsepower to keep the car moving at highway speeds. diesels & v8s tend to have lower torque peaks ideal for this, providing ideal highway mpg 30 mpg or more, with big and/or sporty cars.
a real world side effect of these vehicular/engine differences is that the speed for peak mpg can vary widely between various vehicles. the speed vs mpg curve can similarly vary. one can select a vehicle optimized for mpg depending on the highway speed one prefers to drive, whether it's 80 mph or 45 mph, in right lane either way
And therein lies the problem with your understanding. To maintain a constant roadspeed of, say, 70 MPH, requires nothing close to WOT, far from it for most engines.
70MPH and 2500 RPM can result in lugging for LOTS of engines. At partial throttle, only enough A/F mixture charge in the cylinder to maintain that speed, there often is not enough energy in that charge to push the piston downward as fast as need be, so you get knock/e to engine lugging.
There is no way, ABSOLUTELY NO WAY, that I ever wish to be burdened with continuously shifting my manual transmission up and down the way most automatics do these days in order to obtain the absolute best FE for ANY road conditions.
1. Lossy torque converters are being bypassed in as many as 4 of the 6 gears. ATF gear type fluid pressure pumps are now under real time ECU control (linear solenoid) and only pump against a pressure head during actual shifts. FULL coastdown fuel cut techniques can be used with automatics whereas manual transmission engine MUST always be "fed" idle level fuel.
2. As you may note above most modern day automatics are geared sunstantially TALLER that their manual brotheren. With an automatic the ECU is available to INSTANTLY switch gears, downshift, if the need arrises. Also be aware that the ECU already KNOWS the engine is entering a parametric zone prone to knock/ping BEFORE it actually happens.
"...just to make the EPA happy.."
Along with 99% of the public now paying north of $4.00 for gas.
"...Better speed and driving dynamics at all times.."
Dynamics, yes...YES, speed...NOT.
"...same MPG.."
Sorry, just no way, yesteryear, sure, but no more.
Exactly, which is why a 6th gear in my car netting 2,500 RPMs at 70 would be perfect; thank you for finally admitting that.
70MPH and 2500 RPM can result in lugging for LOTS of engines. At partial throttle, only enough A/F mixture charge in the cylinder to maintain that speed, there often is not enough energy in that charge to push the piston downward as fast as need be, so you get knock/e to engine lugging.
I've driven well over 100 cars with small engines and I have never once driven a car which can be lugged at 2,500 RPMs (although it wouldn't surprise me to hear that two and three cylinder engines can be lugged at that speed). For the 2.0 liter Mazda3, 2,500 RPMs at WOT isn't even close to lugging the engine.
That comment has zero relevance to the discussion at hand, namely gearing the top gear of a Mazda3 or an Audi A3 (both have been discussed in this thread) tall enough to achieve a few hundred RPM reduction at highway speeds.
There is no way, ABSOLUTELY NO WAY, that I ever wish to be burdened with continuously shifting my manual transmission up and down the way most automatics do these days in order to obtain the absolute best FE for ANY road conditions.
Nothing in what's been discussed here would suggest constantly shifting when running down the interstate. If my car had the theoretical 6th gear we've been discussing, it would probably be necessary to downshift from 6th to 5th when climbing a steep grade of say over 5% at 70 mph, but hey, I can live with that no problem. In the case of an Audi A3, even that downshift wouldn't be necessary.
Please name me even one car where the field reports indicate better fuel economy from the automatic models versus the manual models. I've read numerous test reports and anecdotal fuel economy reports for cars which the EPA tests indicate the automatic returns better fuel economy, and as of yet, not one field report confirms the EPA findings of superior automatic fuel economy.
And just how many "valid"(***) field reports would you expect to see..."
*** Same, same, same, except manual transmission vs automatic. Anyone out there have those vehicles, two otherwise EQUAL vehicles, at hand to provide that field report....??
I thought not....
"You may wish to take note that modern day automatics are attaining better FE than their manual brotheren, even with a driver trying the utmost otherwise."
Please provide us with support for such a claim; by all indications no such a car exists (at least not yet).
No, just adequately powered, no need for a gas-guzzling V8, or EcoBoost V6, such as today is found in the new fleet of muscle cars/trucks.
http://www.mazdausa.com/MusaWeb/displayPage.action?pageParameter=modelsSpecs&veh- icleCode=MZ5
21/28
The EPA esitmates are not real world.
Or, if it's from the owners, then their log books for say 6 months of driving.
Regarding the Mazda3 and Mazda5 fuel economy comparisons (the two cars share their platform and their drivetrains); I currently drive a Mazda3 and spend quite a bit of time on several Mazda related boards. Choosing my words very carefully here; the indications of the literally hundreds of mileage related reports I've read suggest that automatic equipped Mazda3s and Mazda5 are unable to (or are barely able to) achieve EPA figures even when driven extremely carefully. On the manual transmission side of the house, reports of drivers easily besting the EPA numbers are a dime a dozen.
Does the above constitute hard and fast evidence? No. Does the above indicate a trend which might be worth further analysis? I think so.
Boards that post MPG only sample a sliver of owners. The ones who post that they beat the EPA stats are undoubtedly proud, or at least pleased, so they post. The ones that don't beat EPA would only be those that get miserable mileage. I mean, who comes online to boast "Hey, I'm getting the mean average MPG with my Mazda!"
So those anecdotes are dangling out there in space. Logic suggests (well, MY logic) that if one bought that model of Mazda, one is more likely, statistically to get EPA or less than to beat it.
Longer story even shorter, the FULL mpg RANGE is actually published on the new car sticker, pretty close to the stated EPA ratings. They are normally in MUCH smaller print.
But then on the other hand, that really negates the whole concept of reading the owners manual: specifically, the performance characteristics of one's specfic engine and transmission combination. Really unless there is something technically wrong with the specific car, driving for mpg (or lack thereof) is between the headsets, (given, given, given, etc., etc.etc.) Nowadays because of the "appliance mentality", most folks don't even have a clue as to the performance characteristics of their vehicles.
Post 01: The EPA numbers for my Mazda5 Automatic are 21/28 and yet the best I've gotten is 19 on 300 mile trip at a pretty steady 65 mph; it's more like 14 when I drive around town.
Post 02: Wow that's bad, our Mazda5 Automatic typically gets about 25 on the highway and 19 in the city.
Post 03 - Post 05: Similar in nature to Post 02.
Post 06: Geez, I'm so glad I got my Mazda5 with a stick, we just got back from a 1,700 mile trip with the family and we averaged 30 miles per gallon for the entire trip. We had two tanks which were almost all highway which got more like 33 miles per gallon.
So there you have it, kind of a cross section of posts, those with terrible mileage, those with exceptional, and those in between.
Like I said, none of the above makes hard and fast evidence, but I do think after reading thread after thread after thread like the above, that there are at least a few compelling indicators which could justify further controlled analysis.
I just drove 300+ miles over the weekend in our '01 Porsche C4 6 speed manual, 300HP. Seattle, I90, to Ellensburg, then to Yakima, and back over Chinook pass. Initial leg was mostly at 70-75MPH and mostly in top gear, 26.7MPG. Yakima back to Seattle, 55-65MPH, mostly 6th gear but some 5th for climbing, 24.7MPG.
What I came to realize was that in 6th gear I had a lot of leeway, I could drop down all the way to 2,000RPM and still have enough torque to regain speed provided I was on relatively flat terrain and was "graceful" with the gas pedal.
What I came to realize was that while the engine control system could not command a downshift as it might well do with an automatic, it could still switch, and undoubtedly DID switch, the A/F mixture control loop from idle/cruise mode (oxygen sensor[s]) to air/fuel mixture enrichment mode (MAF/IAT) if/when I depressed the gas pedal enough to attain that result.
So, would I like my 6th gear taller, tall enough to drive 70MPH at the minimum RPM that produced only enough torque to move the car along at that speed...?
No, absolutely NOT.
On the other hand would I give a hoot if my automatic did exactly that...?
Same answer....
No, absolutely NOT.
That's exactly what CVT's are all about. Take your choice, enrich the mixture whenever you wish to accelerate with a stick shift remaining in the same gear....sacrifice FE...
Or...
Have an ECU in charge of BOTH engine A/F mixture and gear ratio selection thereby allowing the ECU to always judge the best, OPTIMAL, action for ANY level of acceleration required...enrich the mixture, downshift, or even a combination of both.
On my just completed drive I'm fairly sure I could have gained at least another 2 MPG had my Porsche come with an indication of entering A/F enrichment mode AND had I religiously downshifted whenever that indication came on.
Long story short, I'm thinking you need a refresher physics class.
Refresher? Wouldn't one have needed to have taken physics in the first place?
No, my position on that is you have to be an extremely inexperienced driver, or a foolhardy one, to have rear braking, rear braking ONLY, result in a spin.
Like it or don't, believe it or not, the above will happen; contrary to your tossing out an anchor behind your proverbial row-boat.
As for manual transmissions, I still love them. When I reached driving age long ago, cars usually had a choice between a slick 5 speed manual or a lumpy 3 speed automatic. You'd usually end up losing 10-20% of your economy and acceleration to a manual. That gap is gone. I still like to have a manual simply to have more control of the car, but I am pretty sure I am a dying breed.
Now the Crossfire? That would be a LAME automatic. We will probably always have one little 2-person coupe, and that will always be manual.
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2015 Kia Soul, 2021 Subaru Forester (kirstie_h), 2024 GMC Sierra 1500 (mr. kirstie_h)
Review your vehicle
MODERATOR /ADMINISTRATOR
Find me at kirstie_h@edmunds.com - or send a private message by clicking on my name.
2015 Kia Soul, 2021 Subaru Forester (kirstie_h), 2024 GMC Sierra 1500 (mr. kirstie_h)
Review your vehicle
http://www.consumerreports.org/cro/cars/new-cars/news/2008/10/save-gas-and-money- - -with-a-stick-shift-10-08/overview/manual-vs-auto-ov.htm
Bottom line
A manual transmission can deliver better fuel economy and acceleration
A significant 2 to 5 mpg better and significantly quicker EVERY time, no exceptions to either.
This is true even in the case of the Forester, which had identical EPA mpg numbers, it still did about 10% better with the stick in the real world. And it's not like Consumer Reports drivers are the world's most skilled, either (a bigger factor with manuals).
Better automatics will slowly close the gap, but the gap still exists, never mind what the EPA says happened in a lab. Automakers perform those tests and EPA doesn't even verify most of them.
plenty of car magazines, and especailly consumers reports, still show the stick model to be quicker, especially on smaller engined "normal" cars. And I believe they also tend to get better overall RW MPG out of them too.
I know CR has its critics, but at least they test acceleration the way normal people drive (no brake loading the AT or high RPM clutch dumps!)
2020 Acura RDX tech SH-AWD, 2023 Maverick hybrid Lariat luxury package.
My opinion? The makers are good at programming an AT to do good on the test, but that does not always translate to the RW (such as going to top gear as soon as you hit 20 MPH!). a stick must be much harder to massage the test results with.
so, sticks do at least as well, while the AT suffers a bigger hit to actual drivers and conditions.
2020 Acura RDX tech SH-AWD, 2023 Maverick hybrid Lariat luxury package.
I wonder if the gap narrows when you are looking at midsized V6 cars.
So true, and you end up mashing the pedal to keep the trans from going to overdrive too soon. I remember hearing enough complaints about the GM Lambdas with the then-new 6 speed auto that GM had to recall them and reprogram the trans.
They claimed that mileage was not affected, and kept the same EPA numbers, but that sounds fishy to me.
To be fair, some sticks force 1-4 shifts, I remember some Vipers and Vettes did that. And to counter them you did the same thing - mash the throttle, then it would let you find 2nd.
So in both bases, and over-eager attempt to improve mileage in a lab might actually have hurt real-world mileage.
Or you ordered a little thingie from the Internet to take care of THAT problem on your Corvette!
re: manual shifts and MPG. It's a matter of degree of control. The human brain can still make better decisions than anything electronic, or at least anything that is affordable enough to put into a car.
re: have I become a politician? Fortunately for me, forums Hosts are not elected by the members. :P
It falls flat when I approach a speed bump, though.
Here's what happens, it's a 25mph speed limit, so I'm usually in 2nd or 3rd, I let off the gas to brake for the bump, and it inevitably shifts to 4th, the logic (can we call it that?) figuring I must not need any power, so let's save gas and find 4th gear at 25mph. Guess what happens next?
Then, after the speed bump, hit the gas, and it's stuck in the wrong gear. 4th has to shift to 3rd then 2nd, but it's lose vacuum pressure and it hesitates before shifting. By the time it shifts it gets TOO much throttle and wastes fuel accelerating away from the 1st speed bump on the way to the 2nd speed bump.
Rinse, repeat.
Rinse, repeat.
Rinse, repeat.
Rinse, repeat.
Yes, there are 5 speed bumps on my street.
So by the time I make my very first turn, the transmission has made 5 gas-wasting mistakes and hesitated enough for gas prices to go up. It's bad enough that I take another route out of my neighborhood, one without speed bumps!
With a stick I usually keep it in 2nd or 3rd, no shifting required. The throttle actually responds (go figure!) and I bet it uses less fuel in the process.