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Comment by olex | Hacker News Reader

> slow to accelerate

Have you driven a modern diesel? At lower speeds, they easily beat similar-displacement petrol cars off the line with superior torque. They are weaker at high speeds, but in normal (especially city) driving, a diesel is usually faster than a petrol.

But yeah, their main factor for popularity is the cost per km. They use less fuel than petrol engines, and the fuel is less expensive (in Germany). This is offset by higher road tax and insurance somewhat, but for commuters and others who drive a lot (>~20000km per year) diesels are a much more cost effective option in Germany than anything else.

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Diesel isn't that cost efficient actually, even if you drive a lot. Diesel are more expensive to maintain due to regulations, plus diesel cars tend to be more expensive their petrol counterparts. Moreover, there is depreciation, which tend to be worse for diesel cars, because they are valued less on the second hand market (fairly or unfairly).

On average, you should expect to drive at least 150.000+ km before you've broken even on a diesel car with its petrol counterpart.

People only look at fuel consumption and fuel prices, but maintenance and depreciation are actually one's biggest loss on a car purchase. And in general petrol comes out on top.

Different tax systems can affect the equation even if you disregard that you pay less at the pump for fuel that your car consumes less than a petrol equivalent – lower CO2 figures may also mean that you pay less yearly fees or less taxes on car registration as well. The break-even figure certainly varies by country (as does depreciation of different cars).

The premium of diesel engines over petrol is one of the key reasons that we don't get many in the USA (the other issue being emissions). Bob Lutz, former GM CEO, was a big proponent of diesel but repeatedly acknowledged that it doesn't make sense in the USA. The market for people willing to pay the $5,000 premium (in 2007 dollars, mind you) was very small. Americans don't appreciate just how cheap cars in their region are.

GM did manage to get a diesel Cruze into the USDM market, and keep it here, but it's low-margin and not a huge seller. A manual diesel Cruze starts at about $25,000 (compared to $17,000 for the base). So it is basically slotted as an "enthusiast" model, just not a high-performance one like Ford and Honda would offer.

Diesel has a higher maintenance cost too, especially if you only drive short distances. IIRC the main cost here is the catalysator, which basically clogs up if it can't properly heat up. That doesn't happen on short range.

No, that only applies to cars with the more fancy antiparticulate filter that also requires urea fluid.

No, this has nothing to do with urea fluid. This is just a quirk of some DPFs.

> Now Germany spews out about same carbon as before giant investments in solar, electricity is four times the price as in US, plus they now have to buy from France cause they don't produce enough.

Well, they require a more complex motor which handles higher pressures and supercharging. The picture would be different if you would compare motors with the same price.

It's an illusion that diesel vehicles are faster than gasoline. Gasoline engines have way more horsepower and are faster that the diesel options (unless Germans are getting neutered or smaller power plants than say, the USA)

That's a strange statement. More horsepower based on what? I think if you look around, you'll see that the largest and highest horsepower combustion engines all burn diesel. Semi-trailers are exclusively diesel.

Your statement on speed is also odd. Record setting cars may burn gas, but your typical car driving around a city or highway needn't ever go faster than 160km/h. Most cars can achieve this, and most modern cars, whether diesel or gas, can achieve this without much difficulty.

This leaves us with acceleration, where diesel vs gas is equally unclear. As small diesel engines often ship with turbos, you'd be perhaps comparing a turbocharged 2.0L diesel vs a normally aspirated 2.0L gas engine. Assuming roughly equivalent mass of the cars, with higher low-end torque, the diesel will win just about any street race.

If what you're comparing is purchase price to acceleration, then indeed the gas cars may win.

> the diesel will win just about any street race.

This is really wrong. It's a weird myth that gets perpetuated in America where people don't really drive diesels.

Let's compare a 2.0L diesel Golf TDI to a 2.0L petrol Golf GTI. Same car, same displacement, both turbo engines.

The Golf TDI does 0-60 in 9.0s and a quarter mile of 17.0s@84 mph.

The Golf GTI does 0-60 in 5.7s and a quarter mile of 14.2s@100 mph.

There's a staggering difference in performance there. The TDI is so slow that it's genuinely difficult to find a Motor Trend instrument test on a slower car, because at that point, it's too slow to really bother.

I found the 2018 Rav4: 0-60 in 9.3s and a quarter mile of 17.0@82.

If it were true, Formula-1 would use nothing but diesel engines.

This comment makes no sense. I'm saying diesel engines are bad for performance. It's not physically possible to make a diesel 1.6L engine that produces F1 levels of power, they just can't spin fast enough.

The comment make sense, since I'm saying "[i]f it were true [that diesels easily beat gasoline burners in a street race], Formula-1 would use nothing but diesel engines [which they don't at all]."

If you want to do this comparison please do it right: The Diesel equivalent to the Golf GTI is the Golf GTD. There's more than just displacement that makes up an engine and the fact that is some kind of turbocharger.

Their difference in 0-60 seems to be 6.4s vs 7.4s according to what I find. Guess the difference in higher regions might be even less, because of a different torque profile in turbocharged diesel engines.

The GTD is Euro-only, so it's harder to get performance comparisons. But it's still much slower than the GTI, I found a 15.6@93 in the quarter.

0-60 is an awful way to measure acceleration; most of what it measures in modern cars is traction, since a Mk7 GTI will shred the front tires with a hard launch. So high five second and low six second times are both accurate, it just depends how good the launch was.

That's why you compare quarter mile times when looking at acceleration. And the GTI is still so much faster than the GTD; a full second and a half and 7mph trap. Meaning, in a drag race, the GTD wouldn't be close enough to read the GTI's license plate.

I think the 0-40 profile would be much more favorable to the TDI, and much more useful to the typical driver. But we'll never really know as that's not the standard measurement.

The diesel golf is still a lot slower to 40 than the GTI. The TDI diesel has a lot of turbo lag, a narrow powerband, and poor gearing. What people who've never owned diesel cars fail to realize is, that peak torque number is hugely misleading. It sounds impressive, but it starts from like 2200RPMs and falls off a cliff past 3500. While a (modern) turbocharged petrol engine has full torque by ~1800rpms and that lasts until like 5000rpms.

I've owned a (Jetta) TDI before, I even tried to make it fast. Even with a tune and full exhaust it was slower than a stock turbo petrol.

It's always Americans that talk about how awesome diesels are. I never see posts from Europeans (who are the ones that actually have to drive them) talking up diesels. They are always complaining about how terrible they are.

Diesels are great for trucks, but not cars.

You need power for acceleration, not torque. (But I agree that modern diesel cars accelerate fast enough).

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