Go Back   iRV2 Forums > MOTORHOME FORUMS > Class A Motorhome Discussions
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
 
Thread Tools Search this Thread Display Modes
 
Old 08-04-2016, 02:24 PM   #43
Senior Member
 
Cat320's Avatar
 
Fleetwood Owners Club
American Coach Owners Club
Join Date: Mar 2011
Posts: 4,280
Quote:
Originally Posted by chuckftboy View Post
I normally travel between 67 and 70 MPH but on my last 500 mile trip, I cruised at 63 to 65 MPH and my mileage increased a little e over 10 percent.
That's the bottom line. Once you go over 60...the MPG heads south.
__________________

__________________
2014 American Eagle 45T
DD 500
Pulling a Honda CRV
Cat320 is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 08-04-2016, 03:56 PM   #44
Senior Member
 
Join Date: Dec 2013
Location: Lake Havasu City, AZ & Plover, WI
Posts: 1,015
Quote:
Originally Posted by Cat320 View Post
That's the bottom line. Once you go over 60...the MPG heads south.
That's true to some extent. Each engine has it's own torque curve that will affect what that magic speed is. I've been told it is 200 rpm above the peak torque in sixth gear (allison transmission). That may coincide with 60 mph give or take a few mph. That gives a compromise of time to get to a destination vs fuel used to get there. Load is one factor, but wind resistance is the biggest factor in reducing mpg. If that is true, then 200 rpm above peak torque in 5th gear might yield 55 mph. Will mpg be even better there due to less wind resistance?? Probably. I used to spend a lot of effort and thought in trying to get the best economy that I could. Then one day a light bulb went on. A 40,000# motor home towing a 13,000# trailer is not a vehicle that will ever get good milage. So now, I still drive 62-63 mph because that's the most relaxing speed for me and finally stopped thinking about something I was never going to attain. When the gauge gets down to 1/4, I look for a truck stop.
__________________

__________________
2013 43 QGP Allegro Bus
26' Enclosed trailer for toys
Crasher is offline   Reply With Quote
Old 08-04-2016, 04:30 PM   #45
Senior Member
 
sdennislee's Avatar


 
Monaco Owners Club
Winnebago Owners Club
Join Date: Sep 2011
Posts: 6,404
Quote:
Originally Posted by Crasher View Post
I used to spend a lot of effort and thought in trying to get the best economy that I could. Then one day a light bulb went on. A 40,000# motor home towing a 13,000# trailer is not a vehicle that will ever get good milage. So now, I still drive 62-63 mph because that's the most relaxing speed for me and finally stopped thinking about something I was never going to attain. When the gauge gets down to 1/4, I look for a truck stop.
Yep, that's how I see it too.
__________________
US Navy Vet, Liberty Tree Member of Oath Keepers, NRA & VFW Life Member, Alaska EMT.
2009 Safari Cheetah 40 SKQ
2009 Winnebago Chalet 231CR
sdennislee is offline   Reply With Quote
Old 09-05-2016, 07:37 AM   #46
Senior Member
 
Join Date: Jul 2012
Location: Brooklyn, MI. 49230
Posts: 151
Look in MH-General Discussions

Quote:
Originally Posted by Crossingover View Post
Above about 50 mph overcoming aerodynamic drag consumes more engine power to push forward so I'm waiting to see someone market an RV air tab kit similar to the air tabs you see on some tractor trailers (e.g., beneath the trailer and around the rear doors). I'm sure some of the aero research and devices for tractor trailers would apply to MHs with the corresponding savings in fuel.
There is quite the discussion going on re: air tabs. I've not seen anything about V-Spoilers, although their website claims they do the same sort of thing, are easier to install and cheaper. I'm still evaluating this idea/option. My interest is 80% about minimizing the push from passing trucks, but improved mpg would be an added bonus.
__________________
TomMiller is offline   Reply With Quote
Old 09-05-2016, 08:53 AM   #47
Senior Member
 
Join Date: Jan 2011
Posts: 264
Haven't used the tabs yet, but going to try a few to see if reduces wind noise around my drivers window, and mirror
gbstewart
__________________
gbstewart is offline   Reply With Quote
Old 09-05-2016, 09:30 AM   #48
RVM1
 
CampDaven's Avatar


 
Join Date: Jul 2012
Location: Fulltime, USA
Posts: 13,131
Blog Entries: 1
The MH goes from one spot to another. Fuel savings is from the toad.
Don't sweat the small stuff
__________________
Dave and Nola, RVM1
The Journey is Our Destination!

http://davenola.blogspot.com/
CampDaven is offline   Reply With Quote
Old 09-05-2016, 10:40 AM   #49
Senior Member
 
jimmy braden's Avatar
 
Texas Boomers Club
Holiday Rambler Owners Club
Join Date: Jun 2002
Location: What? Like right now? ;-)
Posts: 310
Quote:
Originally Posted by DD788Snipe View Post
The sweet spot on your rig is 62 mph @ 1800 rpm. I get around 8.5 to 9 mpg in that range and drive with my cruise control except when I'm in city traffic. I did have my ECM reflashed to increase the HP and torque. That helped pull the grades better but I still get about the same mpg as when I had 350 HP. My torque went from 1050 ft/lbs to 1200ft/lbs. that was the difference.
Interesting, at 62, im sitting right about 1550 rpm.
__________________
2003 Scepter 40PDBB - Roadmaster rr8s - Cummins ISC350 - suspension mods to come.
jimmy braden is offline   Reply With Quote
Old 09-05-2016, 10:52 AM   #50
Senior Member
 
DD788Snipe's Avatar


 
Newmar Owners Club
Spartan Chassis
Join Date: Jun 2013
Location: Apple Valley CA
Posts: 810
That's even better Jimmy.
__________________

Craig & Carolyn Roberts Apple Valley, CA
2006 Newmar 3910 KSDP 400 ISL Cummins Spartan Mountian Master Chassis
Toad: 2010 Chevy Colorado 4X4
DD788Snipe is online now   Reply With Quote
Old 09-05-2016, 03:16 PM   #51
Junior Member
 
Monaco Owners Club
Join Date: Sep 2014
Posts: 3
I drive a Dynasty 34ft with ISL400 since 3.600 miles in Germany.
The speed limit in Germany and in most other countrys in europe for this type of RV is 50 MPH.
I drive mostly 55 MPH due to the fact that the Allison shifts only in the 6th gear with speed > 54 MPH.
With this speed limit and most of the trip with cruise control (except grades hill) i drive this rig with 9.6 MPG.

I'm convinced that the brake pedal affected more the MPG than the accelerator.

Roland
__________________
Georgie-Boy is offline   Reply With Quote
Old 09-05-2016, 03:30 PM   #52
Senior Member
 
jimmy braden's Avatar
 
Texas Boomers Club
Holiday Rambler Owners Club
Join Date: Jun 2002
Location: What? Like right now? ;-)
Posts: 310
Quote:
Originally Posted by Crasher View Post
So now, I still drive 62-63 mph :
I kind of like that speed because its not to slow to worry about folks (except maybe on some two lane interstates) having to do much to get around you and still keeps the Alison in 6th as you pull a hill. If all pretty much works as planned and you are well optimized for load boost should come up and the thing make torque and you never notice a thing. And on the downhill side you still keep to some sane speed.
__________________
2003 Scepter 40PDBB - Roadmaster rr8s - Cummins ISC350 - suspension mods to come.
jimmy braden is offline   Reply With Quote
Old 09-05-2016, 03:34 PM   #53
Senior Member
 
Mr_D's Avatar
 
iRV2 No Limits Club
Join Date: May 2011
Location: Vancouver, WA
Posts: 23,313
Quote:
Originally Posted by Crasher View Post
That's true to some extent. Each engine has it's own torque curve that will affect what that magic speed is. I've been told it is 200 rpm above the peak torque in sixth gear (allison transmission). That may coincide with 60 mph give or take a few mph. That gives a compromise of time to get to a destination vs fuel used to get there. Load is one factor, but wind resistance is the biggest factor in reducing mpg. If that is true, then 200 rpm above peak torque in 5th gear might yield 55 mph. Will mpg be even better there due to less wind resistance?? Probably. I used to spend a lot of effort and thought in trying to get the best economy that I could. Then one day a light bulb went on. A 40,000# motor home towing a 13,000# trailer is not a vehicle that will ever get good milage. So now, I still drive 62-63 mph because that's the most relaxing speed for me and finally stopped thinking about something I was never going to attain. When the gauge gets down to 1/4, I look for a truck stop.
Cummins also has an online calculator for figuring the best rpm for mileage. With our ISX it shows 1370 as best and 1350 is 60 mph so that's where I try to stay.
__________________
2009 45' Magna 630 w/Cummins ISX 650 HP/1950 Lbs Ft
Charter Good Sam Lifetime Member, FMCA, SKP
RV'ing since 1957, NRA Benefactor Life, towing '14 CR-V
Mr_D is online now   Reply With Quote
Old 09-06-2016, 10:47 PM   #54
Senior Member
 
Tiffin Owners Club
Join Date: Oct 2010
Posts: 181
1. Always drive with a tailwind.
2. Always drive at high altitude.
3. Always use pure, not bio diesel.
4. Don't fixate on the instant fuel economy gauge.
5. You bought your rig for comfort, not fuel efficiency. Fuel efficiency comes in the diesel Yugo. Enjoy the scenery!
__________________
Larrikin is offline   Reply With Quote
Old 09-07-2016, 08:00 AM   #55
RVM1
 
CampDaven's Avatar


 
Join Date: Jul 2012
Location: Fulltime, USA
Posts: 13,131
Blog Entries: 1
We are F/T. Our average move with the MH is about 200 miles, or about $65. I don't baby it.
The Wrangler toad takes us to magical places with sceneries and critters the average RVer may never see, except in plastic at Disney.
Twixed the 2 machines we average 15 mpg.
Damn the mpg, the Journey is the Destination!
__________________
Dave and Nola, RVM1
The Journey is Our Destination!

http://davenola.blogspot.com/
CampDaven is offline   Reply With Quote
Old 09-07-2016, 01:39 PM   #56
Senior Member
 
m.elliott63's Avatar
 
National RV Owners Club
Join Date: Nov 2015
Location: Monrovia, IN
Posts: 163
Quote:
Originally Posted by Rich-n-Linda View Post
If you have a 100 gallon tank and get 7.5 mpg, that's 750 miles per tank. If you improve that to 7.7 mpg, that's 770 miles. At $2.75 per gallon, that's a savings of $7.65 per tank. Big whoop.

I didn't buy a 42-foot long, 34,000 pound motor home so I could worry about fuel economy.

We travel where we want at the speeds we want and the MPG is what it is.
I didn't by a motor home so I could get from point A to point B as fast as possible.
__________________

__________________
1998 National Seabreeze 1330 Limited Chevrolet P37 chassis 7.4 Vortec 2014 Jeep JKU Sport Toad
Me, Beautiful DW, sometimes kids & grandkids
m.elliott63 is offline   Reply With Quote
Reply

Tags
fuel


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
A Good Experience w/Progressive Following Accident RickO iRV2.com General Discussion 22 12-13-2012 07:18 AM
Warning Code 278 following lift pump replacement Catch14me Cummins Engines 3 04-08-2011 12:05 AM
What 'should' I expect to pay for the following services in Oregon...: fkloster MH-General Discussions & Problems 1 08-20-2010 12:14 PM
Can a pill save you fuel or just another gimmick? Warpath iRV2.com General Discussion 4 03-22-2006 06:37 AM

» Virginia Campgrounds

Reviews provided by

Our Communities

Our communities encompass many different hobbies and interests, but each one is built on friendly, intelligent membership.

» More about our Communities

Automotive Communities

Our Automotive communities encompass many different makes and models. From U.S. domestics to European Saloons.

» More about our Automotive Communities

Marine Communities

Our Marine websites focus on Cruising and Sailing Vessels, including forums and the largest cruising Wiki project on the web today.

» More about our Marine Communities


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 04:18 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.