Manual vs automatic What is desirable for MPG?

[freebeard]

I suggest either HTML or Python:

https://www.slant.co › versus › 110 › 130 › ~python_vs_visual-basic
Python vs Visual Basic detailed comparison as of 2022 - Slant
Python is ranked 1st while Visual Basic is ranked 66th. The most important reason people chose Python is: Python's popularity and beginner friendliness has led to a wealth of tutorials and example code on the internet. This means that when beginners have questions, they're very likely to be able to find an answer on their own just by searching.

https://sites.google.com › site › ev3basic › small-basic-ev3 › basic-or-python
Basic or Python? - ev3basic - Google
Python is a modern, very powerful programming language that is easier to learn than most others such as C++ or Java and is therefore very popular in schools and universities.Knowledge of Python is much more likely to help you get a career in computing than knowledge of Basic. One thing that helps to make Python easy to learn is that it creates very concise, easy-to-read code.

[SDMCF]

I used to think a manual transmission would always be more economical, but I am rapidly changing my mind.

3 Months ago we bought a 2017 BMW 420 diesel automatic and the gearbox is most impressive. When coasting, the engine is somehow disconnected from the drivetrain and drops back to idle speed regardless of road speed. There is no engine braking and the car will coast more easily and much further than any manual I have driven. I am still getting used to how early I can lift off and still easily coast up to junctions. In a manual car I often coast with the engine off, but the auto at idle speed seems to coast more easily than that. How it does so, I do not know. It is this improved coasting which I believe gives improved fuel economy.

I should perhaps point out that the car has 3 "modes", sport, normal and eco. The gearbox works as described above in eco mode, but I cannot say if it does so in the other modes as I always drive it in eco mode. The best economy I have achieved so far is 3.8 litres per 100 km.

[MetroMPG]

Originally Posted by Isaac Zachary

I find it funny that we compare the modern automatic to the not-so-modern manual. Manual transmissions haven't changed much since synchromesh was introduced. Automatics are totaly differnt animals than what they used to be.

I also find it funny that automakers almost never made a manual transmission (at least in the North American market) with a truly "tall" top gear (meaning: one that would satisfy an ecomodder). In other words, something analagous to the very tall top gears in some modern automatics for extra highway fuel savings.


I recently drove a Chrysler 9-speed automatic, and top gear didn't even engage until somewhere around 90 km/h (55 mph) on level ground.



Apparently a manual "economy" top gear that might require downshifting for any reason once at highway speeds is verboten by the product planners.

[MetroMPG]

Originally Posted by SDMCF

3 Months ago we bought a 2017 BMW 420 diesel automatic and the gearbox is most impressive. When coasting, the engine is somehow disconnected from the drivetrain and drops back to idle speed regardless of road speed. There is no engine braking and the car will coast more easily and much further than any manual I have driven.

I think either BMW or Mercedes marketed this at one time (recent history) by calling it "sailing" mode.

[SDMCF]

Originally Posted by MetroMPG

I think either BMW or Mercedes marketed this at one time (recent history) by calling it "sailing" mode.

I had not heard that before, but it is as good a description as any marketing slogan is likely to be.

[cRiPpLe_rOoStEr]

Originally Posted by MetroMPG

I also find it funny that automakers almost never made a manual transmission (at least in the North American market) with a truly "tall" top gear (meaning: one that would satisfy an ecomodder). In other words, something analagous to the very tall top gears in some modern automatics for extra highway fuel savings.

Nowadays, not even in Brazil I see such transmissions. I remember saying the 5-speed transmission of my mother's former car, a 2014 Toyota Etios, felt too short-geared.

[aerohead]

Originally Posted by MetroMPG

I also find it funny that automakers almost never made a manual transmission (at least in the North American market) with a truly "tall" top gear (meaning: one that would satisfy an ecomodder). In other words, something analagous to the very tall top gears in some modern automatics for extra highway fuel savings.


I recently drove a Chrysler 9-speed automatic, and top gear didn't even engage until somewhere around 90 km/h (55 mph) on level ground.



Apparently a manual "economy" top gear that might require downshifting for any reason once at highway speeds is verboten by the product planners.

The 1984- 1987 CRX HF had three overdrive gears. Top speed was achieved in 3rd-gear, as shifting to 4th dropped rpm so drastically that all power and torque was lost.
On the flat, the car could cruise effortlessly at 55-mph,in 5th, but throw a headwind or any grade at it, and you'd be back down in third-gear just to maintain speed.
According to Sergio Pininfarina, these 'tall' gears were a form of speed governor.
If allowed to accelerate to a horsepower-limited terminal velocity, the brakes would be inadequate, requiring a weight gain to brakes, suspension, and chassis, in order to beef everything up, safety wise; defeating mpg gains.
Robert Cumberford reported that engineers at a major European auto manufacturer had presented a producible Cd 0.15 design to their top brass in 1963. The CEO rejected it wholesale, on account of the top-speed implications and braking issues, etc.. The company chose to just keep making 750cc, softened 'bricks,' like always.

[Isaac Zachary]

Originally Posted by aerohead

The 1984- 1987 CRX HF had three overdrive gears...

Key word... 1987.

[jakobnev]

Best of both worlds(?), the automated Manuel transmission:



Of course it it's only good in a hybrid where EOC and regen without wasting energy spinning the engine is automated.

[serialk11r]

Originally Posted by SDMCF

3 Months ago we bought a 2017 BMW 420 diesel automatic and the gearbox is most impressive. When coasting, the engine is somehow disconnected from the drivetrain and drops back to idle speed regardless of road speed.

I noticed driving a loaner Cayenne that not only did it automatically coast in neutral, but the engine would stop before the car actually stopped. A rental Tiguan didn't have that feature.

I have yet to experience it but apparently Porsche 718s got a "virtual gear" feature where instead of using a low gear, the transmission slips the clutches in a higher gear to let the car creep along at low speed while the engine is at idle speed, instead of essentially idling at a substantially higher speed in 1st or 2nd. That is something you cannot replicate in a typical dry clutch manual transmission, but you can diligently pulse and glide to get the same effect.

I still like manual transmissions. If the cruising gear is too short, put on a taller tire or if possible use a taller final drive.