Slower trucks don't always mean better mpg
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#21
07-30-2008Okay, I am not an expert or mechanical engineer. I do a lot of research and I found this in "The Trucker" May 15-31 2008 vol.21 no.10.
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On page 55 they had an article entitled "When buying used or new truck, fuel efficiency name of game now". Within that article it stated "A truck spec'ed for optimum fuel economy "will typically be geared to run at a very low engine rpm while at cruise speed, [the] so-called 'Gear Fast Run Slow' (GFRS) concept" says a Caterpillar news release. Driven correctly, trucks with drivetrains set up for GFRS will deliver good fuel economy and good performance as long as they aren't geared too fast and running at too low of an rpm at cruise speed. (More information is available at http://ohe.cat.com/drivingtips)".
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At http://ohe.cat.com/drivingtips you can download "Leht7296.pdf " which states among other things maximum torque is at 1300-1350 rpm. It also suggests that you wait until 1100-1200 rpm to downshift. I suggest that you download the driving tips to your computer.
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Check out "Big Rig Owner" June 2008 Volume 7 Issue 6 currently at the truck stops. While most people do not read these free truck magazines unless they are looking for another job, on page 18 there is an article "Getting The Most For Your Fuel Dollar". You might pick up some tips for better fuel economy.
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Just a thought. I hope this is useful to someone.
.
On page 55 they had an article entitled "When buying used or new truck, fuel efficiency name of game now". Within that article it stated "A truck spec'ed for optimum fuel economy "will typically be geared to run at a very low engine rpm while at cruise speed, [the] so-called 'Gear Fast Run Slow' (GFRS) concept" says a Caterpillar news release. Driven correctly, trucks with drivetrains set up for GFRS will deliver good fuel economy and good performance as long as they aren't geared too fast and running at too low of an rpm at cruise speed. (More information is available at http://ohe.cat.com/drivingtips)".
.
At http://ohe.cat.com/drivingtips you can download "Leht7296.pdf " which states among other things maximum torque is at 1300-1350 rpm. It also suggests that you wait until 1100-1200 rpm to downshift. I suggest that you download the driving tips to your computer.
.
Check out "Big Rig Owner" June 2008 Volume 7 Issue 6 currently at the truck stops. While most people do not read these free truck magazines unless they are looking for another job, on page 18 there is an article "Getting The Most For Your Fuel Dollar". You might pick up some tips for better fuel economy.
.
Just a thought. I hope this is useful to someone.
#22
Windwalker , 06-15-2008 04:44 AM
Quote:
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On page 55 they had an article entitled "When buying used or new truck, fuel efficiency name of game now". Within that article it stated "A truck spec'ed for optimum fuel economy "will typically be geared to run at a very low engine rpm while at cruise speed, [the] so-called 'Gear Fast Run Slow' (GFRS) concept" says a Caterpillar news release. Driven correctly, trucks with drivetrains set up for GFRS will deliver good fuel economy and good performance as long as they aren't geared too fast and running at too low of an rpm at cruise speed. (More information is available at http://ohe.cat.com/drivingtips)".
.
At http://ohe.cat.com/drivingtips you can download "Leht7296.pdf " which states among other things maximum torque is at 1300-1350 rpm. It also suggests that you wait until 1100-1200 rpm to downshift. I suggest that you download the driving tips to your computer.
.
Check out "Big Rig Owner" June 2008 Volume 7 Issue 6 currently at the truck stops. While most people do not read these free truck magazines unless they are looking for another job, on page 18 there is an article "Getting The Most For Your Fuel Dollar". You might pick up some tips for better fuel economy.
.
Just a thought. I hope this is useful to someone.
And, tire size also changes your optimum gear ratio.Originally Posted by Xcis2
Okay, I am not an expert or mechanical engineer. I do a lot of research and I found this in "The Trucker" May 15-31 2008 vol.21 no.10..
On page 55 they had an article entitled "When buying used or new truck, fuel efficiency name of game now". Within that article it stated "A truck spec'ed for optimum fuel economy "will typically be geared to run at a very low engine rpm while at cruise speed, [the] so-called 'Gear Fast Run Slow' (GFRS) concept" says a Caterpillar news release. Driven correctly, trucks with drivetrains set up for GFRS will deliver good fuel economy and good performance as long as they aren't geared too fast and running at too low of an rpm at cruise speed. (More information is available at http://ohe.cat.com/drivingtips)".
.
At http://ohe.cat.com/drivingtips you can download "Leht7296.pdf " which states among other things maximum torque is at 1300-1350 rpm. It also suggests that you wait until 1100-1200 rpm to downshift. I suggest that you download the driving tips to your computer.
.
Check out "Big Rig Owner" June 2008 Volume 7 Issue 6 currently at the truck stops. While most people do not read these free truck magazines unless they are looking for another job, on page 18 there is an article "Getting The Most For Your Fuel Dollar". You might pick up some tips for better fuel economy.
.
Just a thought. I hope this is useful to someone.
#23
Quote:
Before they cut my speed, I had an average of 5.8mpg on the truck. It stayed almost identical no matter what freight (weight) I was hauling. Now, since the speed drop, my average is about 5.1mpg. If I haul a light load (10-15k lbs) I MIGHT get 5.5-5.6mpg.
My company has us fill out a paper each time we fill up. It shows the total miles since the last fillup and the total gallons of fuel we purchased. So, I know firsthand what the mileage on the truck is on a daily basis (I have to fill up daily).
Any clues to why the truck would lose mpg after slowing down? I'm not idling the truck whatsoever, except for maybe the first 15 minutes in the morning when I'm getting ready to start my day, so that's not an issue.
Like one guy said ... its the sweet spot , your r.p.m. is whats dropping your mileage the motors working too hard and labouring a bit more than it was before , same thing happened to me , and another driver mentioned about hydrogen it might be worth while looking into theres a cool site I come across www.google.com might be a worth while look , very informative they seem to know what their talking about, even if I have no clue and am just a lowly spammer.Originally Posted by Malaki86
Well, it's been 3 weeks now since they've cut my truck from 68mph to 64mph. The main thing I've noticed is that my fuel mileage hasn't gotten any better. In fact, it's dropped.Before they cut my speed, I had an average of 5.8mpg on the truck. It stayed almost identical no matter what freight (weight) I was hauling. Now, since the speed drop, my average is about 5.1mpg. If I haul a light load (10-15k lbs) I MIGHT get 5.5-5.6mpg.
My company has us fill out a paper each time we fill up. It shows the total miles since the last fillup and the total gallons of fuel we purchased. So, I know firsthand what the mileage on the truck is on a daily basis (I have to fill up daily).
Any clues to why the truck would lose mpg after slowing down? I'm not idling the truck whatsoever, except for maybe the first 15 minutes in the morning when I'm getting ready to start my day, so that's not an issue.
#24
ironeagle_2006 , 03-23-2009 01:31 AM
I know I have not driven since the turn of the Century and take alot of heat but we used to scream about this even then. I know that I proved the same feaking thing back then. I took a truck that the boss put in a test program he turned it up from the Company limit of 65 to 68 and got between .5 to 1 MPG better depending on load and weather. Called I could hang in the top gears longer and did not have to slowas much in the hill. This company ran west and my playground was I-80 I-84 I-90 I-70 I-40 and I-44 to get from the Midwest to the west coast so I saw nothing but the Rockies Blue Mountians Seirras. Put it to you this way I got to the point were the waitresses at Little America Knew me by name.
