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Comment by mordechai9000 | Hacker News Reader

I love driving my manual, although I recognize in this day and age that is probably kind of silly on my part. Are the new automatic transmissions really as much an improvement in fuel efficiency as the manufacturers claim? I'd like to justify buying another manual, but I can't ignore a 4 mpg gain in fuel efficiency.

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I think the reason automatic is more efficient is you'll often get more gears, maybe like 12, so it stays closer to the most efficient RPM. And it'll shift way up just cause you let off the gas for a second, so engine-braking is minimal. Stickshift drivers can maaybe do that, probably not. I can see those two things saving 4 MPG. Also have no idea if the EPA tests account for average stickshift driving habits.

And all that is without considering hybrid tech.

Dry Clutch DCT technology is nearly equivalent efficiency to a manual transmission. Its the same dry-clutch to connect the engine to the wheels after all, though there's additional weight required as Gear1/3/5/7 are on Clutch#1 and Gear2/4/6/8 are on Clutch#2.

ZF-8 apparently removed a lot of the "slushbox" / wet-clutch problems with efficiency. Its apparently the best / peak automatic transmission technology with exceptionally good reviews and specifications, though the main problem seems to be downshifts. But upshifts (1->2->3->4...) are basically solved with ZF-8 and operate at high efficiency.

CVTs are manual-transmission/clutch-like levels of efficiency, though there's so much diversity in CVT implementations I feel like its hard to discuss.

Hybrid Vehicles are either directly-connected / 1-gear systems (ex: Honda: ICE Engine gets a gear and EV engine gets a 2nd gear, no transmission otherwise required), or the Toyota Power-split device (aka: Prius) that has exceptionally good efficiency as you're probably aware.

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Manual Transmission's main benefit is economy. Its just a bit of hydraulics controlling a drum-brake like system (aka: the Clutch) with a human controlling the gears, so no need for any complex logic.

I think economy cars / low-cost cars need to go back to manual transmissions. But maybe USA is just too rich and that the $20,000+ price point is high enough to just default to automatic transmissions.

There's a lot of "machine empathy" in manual transmissions, they're exceptionally simple, cheap, and reliable (when used properly).

With the wrong driver, "machine empathy" turns to "machine torture".

I love driving my manual too and would like to beg you to keep buying them -- the few of us that still appreciate them are the only shred of remaining market

if you use fuel consumption instead fuel economy to look at it the differences can be small. I have both auto and manual transmission vehicles, and for me personally, I almost always beat the rated consumption numbers in manual and rarely beat it in the auto. This just boils down to how I drive; I end up going much slower when driving manual (in a small Ford Ranger pickup) than I do in either auto.

I've had a couple of hybrids and I've always been able to hit the EPA numbers as long as I'm not driving in the mountains. And on state highways I can usually beat them. Some of the numbers hybrids are putting down are damn good these days. The base Camry hybrid starts under $30K and gets >50mpg.

I'll only own manual cars. On a long highway ride and consciously want to conserve fuel, I often get better mileage (+3-4 mpg) than my car is rated. If I'm low on fuel I can drive in a way that will eak out extra miles just by keeping it in high gear, driving at the lowest RPMs possible for the terrain, coasting long distances in neutral...

My car is a dual-clutch automatic. On a long highway ride, where I'm doing nothing special besides just driving at a steady speed or using cruise control, I'll often get +6 or more MPG over my car's highway rating.

Often manuals are whatever they have instead of desinging one with optional gear ratios.

I was shocked at the gearing of my friend's stickshift 5-gear Nissan Versa. The revs are so high at freeway speeds in 5th. Doesn't get very good highway MPG.

I wonder if that's an artifact of it being a parts-bin transmission meant for countries with slower highway speeds. Nissans larger cars in the US are North America specific models.

That would be my guess. The small wheels make it look like the cars from Mexico, technically also North America but their car models are different.

Automatic transmissions also have gears and no one is designing a bespoke unit to install on a mass produced car, also because the same car has many trims levels with different weights and different engines.

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