So if shortfalls of diesel drive up prices, then gasoline is partially to blame due to its influence on the refining process. So in essence it’s kind of the chicken or the egg thing. If diesel became popular, then less gas would be extracted from diesel which would keep the price competitive.

A couple related links with purdy pictures:

http://science.howstuffworks.com/oil-refining2.htm
http://science.howstuffworks.com/oil-refining4.htm

You guys are all way too serious, and taking me way too seriously.

I love my Diesel. I like making my own fuel (I have a batch drying as we speak, and another load of WVO going into the processor.) I get 50 MPG routinely without having to watch a star trek-like dash console telling me to annoy traffic behind me of the freeway. I haven’t spent a dime with a VW dealer service dept, as my TDI seems to have been built before siesta time, or maybe after, who knows?

Bottom line: I’d like to see greater choice of diesel powered cars in the USA, period. Right now you can count them on one hand and have most of your fingers left. That is not enough of a choice, or enough of a market to make judgements about.

–chuck

Thanks for that, well said.

Talking about burning diesel instead of gasoline is like arguing that we should eat chicken breasts and throw away the thighs.

Oil includes gasoline, diesel, jet fuel, asphalt, etc, and the smart thing to do would be to use oil efficiently, not to have an irrational consumption ratio based upon some fanboy love of a preferred fuel.

Most of a diesel’s superior fuel mileage, when measured on an mpg basis, is due to the specific gravity (BTU content) of the fuel. But if you look at a barrel of oil in the big picture, diesel is not more efficient than gasoline, it’s just different.

Diesel may have more energy per gallon, but it also has higher oil content per gallon, which explains most of the gain. Produce another gallon of diesel, and you lose more than a gallon of gas. It’s not an even tradeoff.

A German study showed that rapeseed (canola oil) burned in a diesel engine had more cancerous agents than straight diesel.
http://www.greencarcongress.com/2007/04/german_research.html
Despite the various pros (and cons) of using bio-diesel and vegie oil, it should not be assumed that the burning of them is intrinsically cleaner or safer than non-bio fuels.

If somebody with a gasoline engine took my bet I would. What’s the PPM of CO of canola oil compared to gasoline?

–chuck

Modern diesels are certified to start at 25 degrees below zero.

http://tdi.vw.com/a-vw-golf-tdi-gets-frozen-in-ice/

We recently test drove the 3 cars on her short list;

2009 Honda Insight EX, too focused on fuel economy, room, handling, braking and acceleration are no more then acceptable. Fun to drive ranking – poor.

2009 Honda Fit Sport with 5spd man. Amazing amount of room – and very usable with magic seats. Low beltline, like Hondas of old. Good handling and performance around town, but runs out of steam on the freeway at speeds over 60mph. Fun to drive ranking – good.

2009 Jetta TDI sedan with 6 spd man. and opt. 17″ wheels. Very comfortable, good stereo. Good ride and handling. Quick revving diesel and 6 speed makes for really good performance. Plenty of power for high speed merging and passing. Fun to drive ranking – two thumbs up!

We were both impressed the most by the VW, but the Fit is still a great alternative for people who like small hatchbacks with manual trannies, as my wife does! The key issues left to ponder are the issues discussed in this thread, diesel vs gas prices, maintenance costs, plus the $1300 federal tax refund. Issue #1 though – can someone spoiled by rock solid Honda reliability find happiness with a VW?

I doubt that’s going to happen. Our new and wonderful CO2 based taxation systems have caused many diesel cars to be much cheaper to buy and use than their gasoline counterparts, and diesel fuel is also cheaper in most places nowadays.

Thanks for that, I was hoping someone would post something based on engineering experience. The diesel truck engine programs I have worked on did indeed have longer life requirements for components (like for DV testing) than the gas engines for the same vehicle.

New gas motors are also common rail direct injected and many of them have VGT or twin-scroll turbos. GM, Volkswagen, BMW, Mercedes, Ford, Renault, PSA… they all seem to walk that route for gassers too.
Volkswagen’s gas-engine lineup for the European Golf includes 3 DI engines (1.4L turbo 125hp, 1.4L twincharged 160hp, 2.0L turbo 210 hp) and 2 IDI engines (1.4L NA 80hp, 1.6L NA 105hp)
The 1.6L NA engine will be replaced by a 1.2L DI turbo (105hp) later this year.
So it becomes pretty clear – NA IDI engines are becoming rare, even in economy cars.

so in summary, i’d have no problem with a diesel Hyundai with a 5 year warranty

Hyundai makes pretty good diesels these days.

this is all very modern and expensive technology

now some companies can contain this to some extent like Hyundai (and they have long warranties anyway) but I can detail some stuff like Nissan trucks that do need those $500 (you need six) injectors and $1,000 fuel pumps… i would be hesitant to keep these after warranty runs out

as far as i’ve seen most of the gasoline motors are not direct injection yet except for high end BMWs/Audis

so in summary, i’d have no problem with a diesel Hyundai with a 5 year warranty

i’d think again in say a medium sized truck with a 3 yr warranty

anything to do with the fueling system in diesels is often multiples of gasoline… eg. thousand dollar fuel pumps etc

If you compare high-tech diesels with low-tech gassers maybe… but modern gassers are direct injected and often turbocharged and/or supercharged… so they need exactly the same kind of kit (common rail fuel system with all the pumps and high-pressure piping, advanced injectors, turbochargers, intercoolers…)

@chuckgoolsbee :
I love my Jetta, but I’d kill a few folks here to get some of the choices available across the pond.. say an Alfa Romeo Spider JTDM?

Overweight bloatmobile on a GM Epsilon platform – but hell does it look fine.

@Kyle Schellenberg :
The concept of total cost of ownership is difficult for most people to address.

I own a calculator. Recommended.

In my case it was like that: (car purchase decision one year ago, BMW 1-series)
•MSRP of the diesel was 1550€ higher than that of the gas version
•Diesel was fun. Gasser was meh.
•Diesel on my test drive (lead footed) 5.8 l/100km (41 mpg), Gasser 9.0 l/100km (26 mpg).
•Diesel was actually a bit cheaper to lease, because used car buyers love them -> hold their value
•Diesel road tax: 308€/year. Gasser road tax: 135€/year
•Gas/diesel price roughly the same (+/- 10%)

Summary: Fixed cost about the same, (higher taxes for the diesel, higher depriciation for the gasser), diesel more fun, 55% higher fuel cost for the gasser with my driving style.

What do you think I drive now?

Diesel haters said it was stupid to buy a diesel due to price of fuel, and now they change their tune to maintenance. Well, they may be correct about that, I don’t know, but I did know the price difference would go away because I asked some folks who would know, while using my brain to judge their case. (That last part is where journalists and politicians usually fail).

Wouldn’t you all like to know what the NY financial advisor we had over for brunch had to say about the chrysler BK?

I bet you would.

Everything else being equal, that means they probably have about the same theoretical lifespan, and driving differences probably determine the rest.

As another example; the VW Golf TDi has the same driveshafts as the GTI because the torque is similar.

In terms of complexity, the singular advantage of diesel over petrol/gas was the largely absent electrical system. The electronics assisted diesels of today are just as, if not more complex, than their petrol/gas cousins.

The bad stuff in diesel fumes are the cancer-causing chemicals in the soot, not the carbon monoxide. That’s been all-too well documented, and the reason for particulate filters.

Carbon Monoxide from internal combustion engines becomes a problem in enclosed spaces, not outdoors. So your challenge is irrelevant regarding the tens of thousands of deaths scientifically attributed by many studies to diesel fumes in so many large cities around the globe. They’re dying from cancer and other problems caused by soot, not CO.

And even though diesels emit less of it, please Chuck, don’t go sit in the garage with your TDI running and the door closed – it might still well kill you. Diesel engines can emit up to 1200 ppm of CO, and even 667 ppm will cause half of your blood cells to…do things that won’t sustain life. OSHA’s limit for prolonged exposure to CO is 50 ppm. Would you want to gamble on beating that in your garage?

I generally am a self-reliant, DIY guy. I work on my own cars, I even drive them on my own home-made fuel. The only thing I’ve ever paid a mechanic to do on my TDI is change the timing belt, and that was only because the tools to do the job cost more than the job itself. So in seven years and 140,000 miles of usage, I’ve saved a lot of money on my choice of motive power.

I have nothing against gasoline. I own a lawn mower and an old Jaguar that run on the stuff. I just wish a lot of the myths about Diesel would die, if only so that I could choose something other than one model when it comes time to replace my current car. I love my Jetta, but I’d kill a few folks here to get some of the choices available across the pond.. say an Alfa Romeo Spider JTDM?

So here’s a myth about Diesel that comes up a lot: “The stuff that comes out of the tailpipe is REALLY bad for you.” In fact a commentator on the “London busses kill 3000 people a year” post from a few weeks back used the phrase ‘Diesel Kills”, I asked it then, and I’ll ask it now (because I never get a volunteer when I pose this challenge!)

You close your garage and sit inside your idling gasoline powered car. I’ll close my garage and sit in my idling Diesel. Let’s see who dies first.

I promise you it won’t be me. I might cough. My challenger on the other hand will pass out, and then die.

–chuck

I love VW’s diesel engines and I accept that it might cost a bit more to run than a gas engine. However, I only change oil every 10000 miles (costs about $32 for oil/filter), then there’s a new $25 fuel filter every 20000 miles, and a $12 air filter every 40000 miles. The timing belt interval is every 100K, and that runs about $600 for parts and labor from my local TDI guru.

My injection pump did fail recently at 107000 miles and it did cost $1000 for a new pump and labor, but there are stories of expensive premature component failures with any brand of car. Plus Bosch made the IP, not VW.

I think the US will always be afraid of diesel engines. A lot of people don’t even know about them to begin with, and the people that might know about them still think of them as dirty dump truck engines. But as long as VW keeps importing them, I’ll be happy. I enjoy having my own private pump to fuel up at once a month.

An excellent point. It is hard to believe, but government intervention to make prices more predictable might be just what the “free market” needs.

BTW, China’s government directly controls the pump price of gasoline there. Last year China was subsidizing gasoline heavily. Note to the those who float the idea that modern China is more capitalist than the US, it isn’t.

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See: http://www.youtube.com/watch?v=mSQh4zQcThc

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God Bless America

I’ve absorbed all the arguments and assumptions over the decades. I’m not anti-diesel. But these observations and arguments are just the self-reinforcement that diesel owners use to justify their not-always economic decision to buy or own a diesel.

Modern automotive engines are now both designed and capable of attaining and exceeding 200-300k miles. Lots of gas (and diesels) surpass that with 400-600k miles. How many owners are going to actually run their cars that long? There is no difference in longevity anymore, like there once was. But diesel owners understandably want to hang on to the old myths, that are reluctant to die.

I did a quick search and found some discussion on a tractor forum and this is definitely one of those age old questions that probably can’t be answered with 100% certainty.

One opinion (there’s that word again) I got was that although gas engines have the potential to have a long lifespan, they may be designed to meet ‘acceptable levels of engineering’ to match the production price and maintain profitability. Because gas cars are cheaper to buy and more common then they are treated more like a disposable commodity to be replaced when the owner is drawn to a newer model.

Diesel engines on the other hand have to be built to handle higher compression but designing them to be ‘just acceptable’ could have a more detrimental outcome on a failure so perhaps they are built up more than they need to be. They cite an example where in the 80s GM just modified a gas engine into a diesel and they immediately received a terrible reputation for reliability. Do diesel owners hang on to their cars for longer? I don’t know but if they spent more up front to get one they might. There’s also the underdog factor (I’ll show you that diesels rule!).

Another unrelated thought is that it’s the lower rpm that diesels tend to run at that saves the engine’s life.

That’s opinion, not the “shred of evidence” I was looking for. The reality is, in modern gas cars the fuel injection is so accurate that there is no extra unburned gas to wash down the cylinder walls. That might have been the case thirty years ago with chokes on carbs, but no longer.