Hacker News Reader

Comment by quantified | Hacker News Reader

I have always seemed to get better mileage out of a stick than a CV or automatic and definitely performance that matches my desires, like engine braking on a downhill. But it really only pertains to a combustion engine. A stick on a EV seems like a rotary dial on my smart phone.

View on HN

That really depends on the brand of car / transmission.

Modern cars with the ZF-8 (which is like the number 1 automatic sold currently) are more efficient than their manual counterparts.

Extremely recent example in the USA: https://www.toyota.com/grsupra/2023/features/mpg/2385/2374

Toyota 3.0 Premium MT (6-speed Manual): 19/27/21 Toyota 3.0 Premium AT (8-speed Automatic): 23/31/26

And if you're like: Oh, the EPA's measurement sucks, here's the WLTP counterpart:

3.0 Petrol Twin-scroll turbocharger (335 BHP), 6-speed Manual: 32mpg / 198 g/km CO2 3.0 Petrol Twin-scroll turbocharger (335 BHP), 8-speed Automatic: 34.8mpg / 183 g/km CO2

Automatic has better mpg and less CO2 per distance travelled.

some of that (the highway rating especially) is gearing, the final drive is shorter and the 6th gear in the ZF manual is not nearly as tall as the 8th in the 8HP. This is a common issue in auto vs manual MPG comparisons these days

Well, I should test drive each. EPA standard and reality don't match. For my stick shift cars, I always beat the EPA mileage.

Yes?

EPA is a standardised regime so cars can be compared. You can drive better than the EPA (or WLTP) test, especially if you're in better conditions.

From what I have seen, VAG DCT models tend to be invariably less efficient than their MT counterparts (and I don't know why ZF-8 would be more efficient than a DCT).

I do wonder how much of this depends on the driving style, though.

In a manual I think you're much more likely to rev out the engine more, shift higher in the rev range, etc.

In an automatic unless you're in full "manual" mode and using the paddles/shifter to emulate that same style, then you're more likely to have the automatic's efficiency.

It's the difference in 8 speed and 5-6. Though the automatic still has some loss in a torque converter.

Historical higher mpg in a manual 5 and 6 speeds is due to driving style, 1st, the driver is more likely to drive based on what's ahead; 2nd (and related) the manual driver is likely more conservative in everyday driving.

The ZF-8 has a lock up clutch. That's why it's so efficient. It uses the torque converter as a pump to match the speeds but then engages that clutch to have a 1-1 connection. No losses.

There is absolutely a good reason for transmissions in an electric vehicle, it's just that most EVs elect to remove them for simplicity instead.

I will leave the interpretation of this graph as an exercise for the reader.

https://i.stack.imgur.com/HRUva.gif

I predict we'll end up with AWD vehicles with two motors. The front wheels will have a motor tuned for the low end, the rear wheels a motor that is tuned for higher speeds, and the controllers will adjust how much power goes front or rear depending on the need for torque, traction and mph.

Right now AWD EVs seem to get slightly lower range, and I would expect that to eventually to even out or reverse, even with the weight of extra equipment.

Some (not all) non-performance AWD Teslas do exactly this. As early as 2014, when they intro'd the S 85D, the front and rear motors were set up so one would be more used at low speeds, for better acceleration, and one at high speeds, for more efficient cruising.

This is how my Model S 70D is setup. The front motor is a somewhat smaller than the rear.

Most EVs don't use permanent magnet motors. Try again. The curve you linked is seriously misleading.

Like just look at any EV dyno curve, it is not "torque starts at top and immediately starts falling"

Transmission means extra losses and extra weight tho. It's not just "free" increase in efficiency.

It does make sense but in typical city/reasonable highway speed it's just not worth it

That is a strangely aggressive response - I'm not claiming every single ev is pmac but many are. What sort of motor do you think a Tesla model 3 uses, for example?

Even considering that, induction motors also have an efficiency curve which is the point I'm making. If you care about efficiency motors have a sweet spot. Sometimes you care a lot about that, sometimes not.

> What sort of motor do you think a Tesla model 3 uses, for example?

IPM-SynRM https://www.youtube.com/watch?v=esUb7Zy5Oio

They went into a lot of effort to optimize it over RPM range.

If you want to make a point use real motor curves at least. Your graph suggests it goes to sub 20% efficiencies at low speed which is completely false and would suggests way higher gains from gearbox than in reality. Hell, it would suggest ICE like performance, it's THAT bad.

But was the rotary ever fun to use?

It definitely was.

Try saying that when using it in real life, making many calls daily, with an exchange such as 908-.

Then, the tone dialer appears.

I was not interested in interacting with my telephone. I just wanted it to place calls.

The question was about FUN, not about making many calls daily.

What a strange response. The point is, repetitive usage shows the difference between fun, or just novel.

A rotary phone could be novel. Yet it became tedious with common use, especially when compared to tone dialing.

My grandparents had a rotary phone and I always thought it was fun/neat to play around with (they'd unplug it first, obviously). I was about 8 years old when they got rid of it so no idea if it's still "fun" to an adult.

I can very much see it as fun, when it is unusual.

It isn't fun as a daily driver.

I've had a rotary phone for about 5 years, but always a voip line and most ATAs don't handle pulse dialing well (some of mine say they can, but it doesn't work with my particular phone anyway), but I recently setup a real POTS line and it works there. It's kind of fun, but mandatory 1+ ten digit dialing makes it a lot more tedious. Even if you were somewhere without ten digit dialing, there's a lot more cross area code dialing these days.

When 1-800- numbers were introduced, they were tedious to dial. You could see why NYC was 212, Chicago 312, LA 213, and so on. Yes, I was around for all that. I envied the houses with touch-tone.

That's interesting. I'd assumed the USA would use the letters on the phone dial, since those are still used in advertising today but have fallen out of use in many other countries.

In Britain, the area codes were originally allocated based on the letter corresponding to the number, except for London.

  01_ London
  021 Birmingham (B=2)
  031 Edinburgh (E=3)
  041 Glasgow (G=4)
  051 Liverpool (L=5)
  061 Manchester (M=6)

with other cities taking two-letter codes:

  0532 Leeds (LE = 53)
  0742 Sheffield (SH = 74)
  ...

https://en.wikipedia.org/wiki/History_of_telephone_numbers_i... (impressively long article)

US area codes are a fixed three digits and initially had a rule that states which fit in a single area code would be X0Y, and those with multiple would be X1Y.

When the area codes were made, AT&T already had usage data from operator connected long distance calling, so they chose the numbers to minimize dialing time.

Within area codes, the first three digits indicate the telephone exchange, those used to be named based on the first two digits ex 555 KLondike-5 or 736 PEnnsylvania 6 [1]; these exchange names historically tended to have geographic meaning on a local level, but that wasn't always practical and when customer dialing happened, exchange names mostly disappeared, only to be heard from in older media.

[1] you might know of this one from the Glenn Miller song, PEnnsylvania 6-5000, which was the number of a the Hotel Pennsylvania in New York; it's exchange was named for PEnn station, the area the exchange serves

RX-7, RX-8... oh, wait

It was great for scrolling.

Its basically petrol heads who prefer manual transmissions, I doubt any of them have economy in mind, I have a manual transmission on my hilux EV conversion unless I'm going uphill or have a big load it stays in 3rd from start to finish

Yep. I love my manual 90s Skyline, but I am really hoping to get a pragmatic commuter EV after driving a couple. I will not miss the gearbox for that task.

I also think EVs tick a couple of boxes that manual gearboxes also do for enthusiasts, which slushbox autos didn't. Always being in a good powerband and engine braking are both features of EVs and manual gearbox ICE cars that I miss if I am in an auto ICE car.

In the UK manuals are still significantly cheaper, so the bottom end of the market prefers them as well as the petrol heads

It's not really a preference if it's only what you can afford. People who only buy second-hand cars will naturally end up with whatever was new 5 years ago, which will gradually include more automatic ICE cars, hybrids and EVs.

not 100% disputing what you're saying and im sure more automatics/EVs etc will gradually filter in. BUT it's not just an affordability thing lots of people just prefer cheaper cars and would prefer to put their disposable income elsewhere.

Preferring to put your disposable income elsewhere sounds exactly like an affordability thing.

If I have £15,000 in the bank, spending £8,000 on the manual vs. £9,500 on the automatic (Renault Clio, 5 years, both on motors.co.uk) is significant. I'd choose the cheaper car.

If I have £50,000 in the bank it's much easier to justify.

(And if I have only £8,000 or less I don't have a choice, but I might tell my friends I "prefer" not to put a lot of money in the car.)

This idea is outdated by about ~5-8 years. You’re unlikely to match the efficiency of a CVT with a 5 or 6 speed manual.

Manual transmissions are more efficient than automatic because there is more energy lost to unproductive sloshing in the torque converter in the automatic, whereas the manual has a clutch that makes a near-lossless linkage. Nowadays, I'm sure we could software-automate a mechanically manual transmission to have the same driver experience as an automatic...

It’s already a thing, but was widely derided by both manual and automatic proponents (for different reasons): https://en.wikipedia.org/wiki/Automated_manual_transmission

I have one of those in my '06 Maserati. It's a pain in the ass in some ways, but it's still more fun than automatic.

> Nowadays, I'm sure we could software-automate a mechanically manual transmission to have the same driver experience as an automatic...

Paddle-shifters and CVTs, right?

This was true decades ago when the dominant automatic transmission was torque-converter junk. This hasn't been the case for some time now, though. The modern automatic transmission (e.g, Porsche's PDK, or any the DCTs, or even the ZF8) will win every time.

Driving a manual is pretty much only for feel or technique at this point, there's no real argument otherwise.

Can you clutch start a modern auto? I've clutch started a manual more often than I can count.

When I was young an dumb I drove a car with a dead starter to work and back for a week. I'd bump start it by pushing it up to the crown of the street.

I think a classic automatic transmission needs hydraulic pressure to engage the bands. And since the gear pump is on the input shaft side it doesn't run when the car is pushed or towed.

"The old Model A had a spark advance you could manipulate. I don't know why they got rid of it. Well, that's your Detroit smarties. The hand choke too. That's gone. Been gone." - Charles Portis, The Dog of the South, 1979

You can't even clutch start some modern manuals.

Maybe I'm wrong, but I thought "automatic transmission" refers to one with a torque converter, and DCT is its own thing.

They're lumped together under "automatic transmission" insofar as the industry goes, however yes - the DCT is very different under the hood.

In this case, though, an automatic transmission is - for all intents and purposes - a transmission that does not require the driver to handle shifting at all. The DCT fits in this category.

> Maybe I'm wrong, but I thought "automatic transmission" refers to one with a torque converter, and DCT is its own thing.

AT is "the car changes gears".

Sometimes a distinction is made between AMT and others because AMT is kinda shit, but both DCT and torque are AT.

Also modern torque converters have lock-up clutches, meaning once they've switched gear they've got the same direct-coupling efficiency as a DCT. The ZF8 mentioned by Klonoar is a torque converter.

>The ZF8 mentioned by Klonoar is a torque converter.

Ha, you're right! I don't have the energy to go edit my parent comment but hopefully it's clear (or at least, now) that I meant old school vs modern AT transmissions.

Thanks for the correction!

I don't drive any of those cars. Very few people do.

Well, no - when it comes to the modern manual transmission, we're now mostly discussing these kinds of cars. The manual is rare (and moreso by the year) in just about every other segment.

Reply on news.ycombinator.com