Re: Fuel Usage When Idling

"David" wrote in message news:urkc64puscjf1rgd8qmiqg8n1jjtg7un06@[EMAIL PROTECTED]
> On Fri, 27 Jun 2008 10:32:11 -0700, PerfectReign
> <theperfectreign@[EMAIL PROTECTED]
> wrote:
>
>>David turned on the Etch-A-Sketch and wrote:
>>
>>
>>>>Your 6.0 Vortec will use slightly less fuel at idle than your 6.6 L
>>>>Duramax, obviously.
>>>
>>> You've never seen someone drive two vehicles at once?  Its astounding!
>>
>>Need to watch bullit again...
>>
>>
>>>
>>> I know the Duramax has a larger displacement, but I thought the
>>> Duramax would have less fuel usage at idle because its a diesel & the
>>> Vortec is a gas engine.  The Duramax does get nearly twice the
>>> miles/gallon that the Vortec does under similar conditions when being
>>> driven.
>>
>>
>>Having done a ton of research on diesels - and wanting a duramax (or
even
>>the future mini-duramax 4.5L) in my Avalanche - I know that the
difference
>>comes from a few factors.  (I'm seriously considering buying a used
>>Mercedes 300d or 300sd for commuting purposes.)
>>
>>First, diesel fuel has more energy per volume than does gas. (At least
it
>>did before ULSD fuel.)  Therefore you need less of it to create the same
>>amount of torque to push your cylinders up and down.
>>
>>Second, because the torque curve is lower, you need less RPMs to move
the
>>vehicle forward than you would with gas.
>>
>>However, at idle, I don't know if there is any difference.
>
> I have not noticed a significant drop in mpg since ULSD fuel appeared
> on the market.
>
> I don't know for sure what idle fuel usage is.  I have heard rumors
> that Class 8 trucks (big over the road rigs) will burn a couple of
> gallons idling overnight.  I have no idea if this is true or not.
>
> The original reason for my post was to find out if there are any
> reasearch studies, surveys, etc. that do***ent idling fuel usage. This
> information might come from the feds, from vehicle manufacturers,
> private individuals, etc.
>
> I would like to know if anyone has any verifiable idling uysage info
> or knows where I might find it?

 I have ***mins and have had a Cat.  The small "B" series (5.9l) ***mins
and 
the Cat 3126 (7.2l) each used around 3 gallons per night of idling, 
confirmed by evening and morning fillups.  Diesels idle at about an 80:1 
air/fuel ratio.  Gas engines 12:1?  I did idle a 350 Chevy van overnight
and 
noticed the gauge dropped from 1/4 tank to below empty, never tried that 
again.