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One of the biggest reasons people consider buying a diesel car is the fuel economy. Diesel engines are much more efficient than gasoline engines. Diesel fuel economy compared to gasoline is about 33 percent better. <Snipped irrelevant stuff> Still, the price of diesel is not 33 percent higher than gasoline, so the cost benefits to diesel outweigh gasoline.
Not read my post on real-world numbers earlier in the thread?
There is a 13% difference in economy between the different 2012 Jettas based on REAL WORLD averages. For the same miles per year (15k), that's $181 difference. Not much. It'd take nearly 40 YEARS to break even on the cost difference between the cheapest gas Jetta and cheapest diesel Jetta. Where's that cost benefit again?
I've never seen 33% as the number for economy increase with diesel, 20% is more normal (and real world results show 23% on those 2 Jettas ~ I posted links to the data before, go look).
I'm a Jetta TDI owner, I love the car to death, happily get my 50mpg... but also bought it used Before the current fuel rise (bought 2005) for a price that was the same as any other Jetta with the same package level and in the current model production, gas or diesel. I don't think anyone could buy a 3 year old TDI for less than half the invoice price today.
Re: gas vs diesel prices in the last week or so (in CA).......
In my neighborhood (San Diego North County), 87 octane has been $4.50-$4.80/gallon. I've seen 91 octane as high as $5.10/gal. To contrast, I filled my old Ford IDI with Diesel #2 for $4.33/gal just the other day. So, right now, diesel is the way to go and gives me an excuse to drive the truck, so win-win for me. But, before the gas price spike, the same stations were selling 87 octane as cheap as $3.89/gal while Diesel #2 was $4.10-$4.30 depending on where you shop. And now that Brown has (finally) allowed CA to flip over to winter blend a bit early, I expect gas prices to come back down to what we normally expect any day now.
My reason for diesel? No smog (well, not for a '91 anyway), and ridiculous longevity. Take that, CARB!
Both snofarmer and Brian_M are right--and wrong. There are plenty of diesels that get 33% (or higher) fuel economy than similar gasoline-powered vehicles in real world use. That is not an unusual figure at all--especially for larger vehicles like pickup trucks. In smaller automotive diesels, the difference can be less, but it is still sufficient to achieve lower fuel cost per mile numbers, even with the rather dramatic "inversion" of gasoline and diesel fuel prices that is found currently in much of the US. As Brian_M notes, however, it may take a long time to offset the higher cost of the diesel option on many vehicles.
In the last few years, the gap between diesel and gasoline fuel economy has narrowed somewhat, but one has to look behind the numbers to see how many auto manufacturers are achieving it. In many cases, the manufacturers achieve it by equipping vehicles with small displacement turbocharged gasoline engines, more and more commonly with direct fuel injection. The rub is that, typically, small turbocharged gasoline engines sacrifice some engine longevity compared to a normally aspirated gasoline engine. That is not true of most automotive and light truck diesel engines--they seem to do a much better job withstanding the stresses of turbocharging--likely because the diesel engine is already designed to withstand the stresses of very high compression ratios and compression ignition of fuel.
Now, few people keep a vehicle long enough--200K-300K miles--to see that difference, but the increasing acquisition and ownership costs of vehicles, combined with the disintegration of disposable income in the middle class, may change that going forward. I personally consider vehicle longevity as a major component of my vehicle buying decisions because I almost always keep any vehicle that I buy for at least 10 to 15 years--sometimes more. I find today's small displacement turbocharged gasoline engines intriguing, but I seriously wonder what their longevity will be.
Yes ,I did.
I see you read mine.
I even cited my source.
My #'s are based in the real world and do not come from the MFG's
33%.
A side to side comparison I did myself.
Apples to Apples.
I own a few trucks lets, use these two as other than the diesel and some drive line components they are quipped the same
Lets take my dodge, 360ci ,3/4 ton, 4x4, auto, long box, extra-cab,
it gets 10-12mpg highway,on a good day
My dodge cummins diesel, 3/4 ton,4x4, auto, long box, extra-cab
gets 19-22mpg highway,everyday and all day long.
I also have the fuel, millage and maintenance logs for both.
It's a no brainer.
Quote:
Originally Posted by Brian_M
Not read my post on real-world numbers earlier in the thread?
Last edited by snofarmer; 10-08-2012 at 12:38 PM..
You can ru vegetable oil but it needs to be processed, kits like the one stacy did in tbat old trucks episode processes the stuff adding what the truck needs ect. See diesel is thinner than gas and the engine runs at a much higher compression. Its not a Hercules engine like the old dueces had. It wont run on anything. They will tun on propane and that also will give a nitrous effect if you hook it up that way.
Under ideal situations, you know driving 10 mph below the speed limit downhill with a tail wind.
My GTI frequently gets 34 mpg on the highway driving not very conservatively...I have no doubt many of these new compacts rated at 40mpg highway can do it. If you're looking at diesel cars for fuel economy you are probably better off getting a compact gasser.
Quote:
Originally Posted by scarabchuck
I drive very agressive and still get 46-48mpg in my Jetta, I don't think I'd get the 40mpg that the Ford Fiesta advertises (just using this as an example) with me behind the wheel.
Diesel engines were great, until 08 when they too were required to have full smog. Now that we have EGR and DFR, they are being choked. My 6.4 dual turbo power stroke is getting about 10MPG when it should be getting 20+. It put's out about 350BHP even though the design will deliver more than 500BHP easily.
I love diesels because nothing has torque (or smells) like them. They will run 300k miles and barely qualify as broken in.
To me, for newer cars, with the urea additive needed and etc. I don't see much advantage in Diesel - older Grease car makes a lot of sense if you are able to do that - not everyone is mechanical enough to cope.
Now, for a 3/4 ton or bigger truck, different ball game, here the Diesel comes into it's own.
Several guys posting from Europe - yeah, *there* a Diesel car makes a lot of sense, you get different engines and mostly stickshift cars, while here we get the EPA version of the motor, and a slushbox to go with it.
My old Scirocco I have personally put on 200K miles, still runs great, little/no oil use, 36-40 MPG, I paid $1000 for that car, although with the repairs and upgrades I have done, probably have like $3K in it. From a standpoint of having a car that's not a chore to drive, not a true "penalty box" sort of car, yet cheap to buy, cheap to run, and cheap to work on - you ain't gonna beat it with anything from the last few years of manufacture.
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