350 MPG cars

[luchog]

A critique of your critique :
it's one thing to *say* that it's easy to change factory farming.
it's another thing entirely to actually change it, particularly with the current land use patterns of the US. Monoculture does not lend itself to organic cropping, and low-till/no-till can only go so far. In fact, Low-till might use more oil, not less, since in some versions it relies on repeated harrowing rather than pesticide sprays/fertilizers.

Not advocating labor-intensive organic farming, merely sustainable farming techniques. There's a big difference. The only real changes needed are less reliance on petrol-derived fertilizers, and crop rotation. The alternatives are a bit more costly in the short term, but considerably less so long-term; particularly when soil depletion is factored in.

And again, it depends greatly on the crop. Some are much easier to farm than others, and do very well in marginal land and with less intensive techniques.

And I should have said "simple" instead of "easy"; because convincing anyone to change long-established practices is never easy.

I'm talking about energy inputs into raising and processing the soybeans, not the pollution released.
Between the herbicide/pesticide/fertilizer production costs, transport, application, tilling, harvest, transport, & processing, I have yet to see anything that even aproaches break even with energy inputs.

The energy input is still considerably below that recovered; or it would simply not be used. The majority of the energy in the system is solar; just like with fossil fuels. Fossil fuels also require a good deal of energy to extract, process, refine, and transport as well. Many large fields of crude oil remain untapped simply because they are of such low quality that it would require more energy to extract than could be obtained from the fuel.

According to the US DOE and USDA 1998 Biodiesel Lifecycle Inventory Study, cradle-to-grave inventory of energy and materials used in the developement, processing, transportation, and utilization of biodiesel vs. petrol diesel; the overall energy efficiencies did not vary significantly -- 80.55% for biodiesel, 83.28% for petrol diesel.

Fuel efficiency tends to be 2-3% lower for biodiesel. Greenhouse gas (Carbon Dioxide) emissions over the complete lifecycle of the product are 78% lower for biodiesel (and all of that is part of the current CO2 cycle).

Links to various studies and stat sheets are available on the Biodiesel.org Factsheep Page.

 

[_Q_]

Re: Re: Re: reply to a couple of recent posts

This is interesting news to me. I've read a little bit about diesels, but never come across a reference that suggests such a short oil change interval.

Could you direct me to some sources where I could read more about this?

Originally posted by _Q_
Bumpity-bump. I really am curious about the 2,000 mile oil change intervals.

Bumpity-bumpity-bump.

Unless I see some additional information, I'm going to dismiss casebro's original statement as inaccurate.

I've seen fairly old (20+ years), fairly high-mileage (200k-400k miles) passenger diesels run on conventional (as opposed to synthetic) oil with 3,000 mile oil change intervals. These have engines noted for fairly substantial soot production compared to more modern passenger diesels.

I've seen reports from owners of such cars and of slightly newer (18 years), more modern passenger diesels who are running on synthetic oil and have the occasional oil analysis performed to determine suitable oil change intervals (and also to keep tabs in general on the condition of the engine). Depending on the driving performed and on the condition of the engine, even some of the "old guys" can run out to 5k miles or more, soot loading often being the limiting factor. The "not quite so old guys" can, again depending on the particulars, run out to 10k miles or more.

I suspect it's the case, as suggested by ceptimus, that modern passenger diesels can do all that and then some.

 

[bruto]

Re: Re: Re: Re: reply to a couple of recent posts

Bumpity-bumpity-bump.

Unless I see some additional information, I'm going to dismiss casebro's original statement as inaccurate.

I've seen fairly old (20+ years), fairly high-mileage (200k-400k miles) passenger diesels run on conventional (as opposed to synthetic) oil with 3,000 mile oil change intervals. These have engines noted for fairly substantial soot production compared to more modern passenger diesels.

I've seen reports from owners of such cars and of slightly newer (18 years), more modern passenger diesels who are running on synthetic oil and have the occasional oil analysis performed to determine suitable oil change intervals (and also to keep tabs in general on the condition of the engine). Depending on the driving performed and on the condition of the engine, even some of the "old guys" can run out to 5k miles or more, soot loading often being the limiting factor. The "not quite so old guys" can, again depending on the particulars, run out to 10k miles or more.

I suspect it's the case, as suggested by ceptimus, that modern passenger diesels can do all that and then some.

The factory recommended oil change interval for my '72 Mercedes 220D is 3000 miles, and for the 78 240D it is 5000 miles. I think they can safely be counted as "old guys." As noted above, it's soot, not dilution, that eventually kills the oil.