I have a few questions about Fuel Economy (and the new low emission engines). If you can answer any/all of the below questions I'd really appreciate it!

What's your current average fuel economy (mpg)? (i.e. 6.1 mpg, 5.4 mpg on average?)

What class (5, 6, 7, of truck do you drive?
What engine (Caterpillar C13, Cummins ISX) would be helpful too.

Generally how do you use your truck?
--On Highway[Long Haul],
--Pickup & Delivery [Short Haul] or
--Vocational [Concrete Mixer, Dump Truck, etc]

For a Vocational truck, does 3 mpg (on average) seem low?

Has fuel economy (mpg) dropped because of the new low emission engines? (first of these engines came out in 2004 Model Year.. with the second phase this year).

Thanks!

Very interesting questions!

I'm anxious to hear the answers.

I, personally don't have enough experience with the engines you've specified, but I'm betting SOMEone here does.

W E L C O M E to the Forums!

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Pontificating Dogmatist

I should clarify that I'm looking for anyone with experience in any new emission engines... not just the 2007 ones but also the ones that were introduced in 2004/2005 model year trucks to meet the 2004 emission standards.

I'm also interested in any engine model/manufacturer (the ones I listed were just examples).

Thanks in advance! Great forum!

Basically, I noticed no apprciable fuel economy drop in the engines prior to the 2007. I've driven Cat, Detriot, and the Cummins.

Detroit has always been the worse of the lot for me, regardless of year. Cummins the best in fuel economy, until you put it in the hills, then the Cat comes in as the best.

Average fuel economy on the Detriots I have driven. Around 6.3 per gallon.

Cummins 6.7
Cat 6.5

I was really impressed with the new High Torque Low RPM engines, CAT and Cummins.

The only input I can offer you regarding the new engines that meet the 2007 specs. Companies are reporting about a 7-10% reduction in fuel economy.

3 MPG you were asking about....not good for any engine. Unless you are talking about a Industrial/Mechanical Cat pulling 100K plus loads at all times.

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I'm gonna kill the next SOB who tells me I look stressed out.

--Unknown

2005 KW T-600 C-15 475hp averaged 6.2mpg [longhaul]

2002 Peterbilt 379X C-15 550hp average depended on my right foot.. best was 6.5 worst month was 4.2 [longhaul]

1998 Peterbilt 379 C-12 450hp so far averages 6.8mpg. [shorthaul but I run it hard]

Threw in the 2 pre emission trucks just because they got better than the emission truck I drove.

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2008 Pete 387 with a Cat C-13, i haul 35-40,000 lbs, 60,000 Km's............... 6.1 mpg
Restricted to 70mph and thats where it spends most of it's time, S#*T uphill, lacks power (435) I hate cats ....................give ma a Cummins
(getting the heavy haul pack before my next trip.)

Thanks everyone for the responses--its very informative!

Sort of a follow up... how much does idling lower your fuel economy?
For a Vocational truck like a concrete mixer that might be at a jobsite for a while idling to run the mixer... could that drop its fuel economy down to 3mpg on average? Or would it not have that big of an impact?

Thanks again everyone!

When you look at the mpg numbers for a vehicle doing construction work, vice that of a road tractor, you are comparing apples to oranges. The construction trucks working on a job site like highway construction may run their engines all day long, but pile up hardly any mileage because of the low speeds and limited distances of the work area. So they do not compare to the miles per gallon of a truck operating at higher speeds where more distance will be covered. You have to look at construction vehicles on the basis of fuel used per tons hauled, or fuel used per operating hour, or some other standard to get any kind of accurate numbers. Even operating on the road, the construction truck is at a disadvantage, since the lower gearing means it needs to turn more rpm and higher fuel use to run at the same speeds.

I used to operate a large piece of heavy equipment, a Terragator 2500, injecting waste underground as fertilizer on farm fields. And I knew that on a daily basis, I could take the number of gallons of product I ran through the machine, and figure that I would use 1 gallon of diesel fuel for each 2000 galllons I hauled. I used that number for financial planning and it always worked out that way, and at the end of a day of running, I knew exactly how much fuel i needed to fill the machine back up again. That was the standard I applied for that specific job and machine.

Even among road tractors, there is a big difference attributable to different trailers. The industry standard is a van trailer, set within 24-30 inches of the back of the cab for maximum aerodynamic benefits. But there are people pulling other types of trailer and that affects their fuel mileage. I pull tank trailers and never get my truck about 6 mpg, no matter how I drive it. But I hook up to a van, and I immediately go up to over 7 mpg because of the better airflow around the van trailer. people pulling car trailers, or tanks or ribbed side dump trailers see a big effect on their fuel mileage based on what is hanging on to the back of the truck.

concrete trucks with 350 hp, cummins about 5 on average.