Using Cruise Control

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wow

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Apr 29, 2012
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I am curious to know how many out there use cruise control regularly. I find, on my rig, that if I use the cruise, it down-shifts on almost every hill. That seems to be a negative as far as gas mileage goes. However, on my trip last week, I tried to use it only on flat straight-a-ways and did not allow it to down-shift. I still got poor gas mileage. Opinions?

Will Walker
 
Personally, I find that an engine loaded down enough to trigger a downshift is using about the same amount of gas as when downshifted.  It's not so much the RPM as it is the throttle position.  That said, I use my cruise a lot and often force a downshift (kick out the OD) before the system kicks it out automatically.  This keeps the RPM up without forcing so many immediate shifts from OD to OD out to 2nd gear.  That said, if gas mileage were my only consideration, I probably wouldn't use cruise at all.  Trying to maintain a constant speed (as cruise does) uses more gas than paying attention to the road and load and adjusting your throttle accordingly.
 
I too use it a lot, especially on the interstates. However if I notice it constantly changing gears a lot, then I disable it. In hilly country I like to get up a little extra speed going down hill to help with the next rise.

Don't see much difference in MPG either way.

Jerry
 
Will

We do need a little more information; do you have a gas or diesel engine and how big are they both?

I have driven cross country just using cruise but I have a large, high torque diesel engine. With my car I normally turn it off when there are any hills. With the diesel, turn on economy mode, that will reduce shifting a bit, and you might also need to manually downshift to 5th and leave it there while climbing.
 
What Wizard46 says. Only thing that affects my mileage are terrain, wind, speed that I set and probably altitude but am not sure about the last because I never drive while high  ::)
Bob
I live with cruise control using it for accelerating and slowing.
 
We use cruise control most of the time but often take it off in mountains because it works too hard to keep a higher speed.  If it starts to "hunt" (e.g. shift between two gears frequently) then it's time to turn it off and maybe downshift manually.  Also, if your temperatures start to rise when climbing, back it off maybe 10 miles per hour.  In some states with high speed limits such as 70 mph, we don't go the speed limit, again because it works too hard to keep a high speed and uses more fuel.  Most of us prefer the 55-62 mph range and in some states large vehicles such as motorhomes that tow should abide by the lower truck speed limits.  As Bernie mentioned, use of the Economy feature might help.

Your question reminded me of my dear departed sister who learned to drive when middle aged and really understood nothing about automobile engines and transmissions, especially that part about downshifting on hills.  She refused to use cruise control.  When I drove her car and used cruise control she had fits because that "devil car" just took off and she had no control over it!  We tried to explain downshifting to no avail.  As far as she was concerned the car had a mind of its own.  :eek:

ArdraF
 
I like to use the cruise control for increasing mileage and staying at the correct speed. In my coach 70 feels a whole lot like 55 so the seat of the pants speed control doesn't work so well. Unlike Ardra's group, my coach won't shift into 6th gear unless I'm going 63 so I guess I'm not in the majority. 63 or 64 works well for my rig and with the "loose" cruise setting that Cat offers, where it will allow a couple or three miles above or below the set speed before it floors the pedal, or activates the engine brake, I get acceptable mileage from every gallon of fuel.

Ken
 
Unless I am on a road that won't let me maintain a constant speed, I almost always use the cruise control. I remember reading that one way to maximize mileage was to maintain a constant speed. Continually decelerating and accelerating hurt mileage. When the transmission needs to downshift, I let it. I haven't done it in this coach, but in my last one, the best mileage I got was on cruise control.
 
Thanks for all the replies. I am learning a lot. My rig is a 97 Fleetwood Pace Arrow with a Ford f53 chassis. The engine is a 460. Any other thoughts appreciated.

Will
 
wow said:
Thanks for all the replies. I am learning a lot. My rig is a 97 Fleetwood Pace Arrow with a Ford f53 chassis. The engine is a 460. Any other thoughts appreciated.

Will
Since your MH is a gas unit and not diesel, I stand by my original posting.  You can get better gas mileage by not using the cruise if you are aware of road and load conditions and adjust the throttle and OD accordingly.  Cruise is a lazy man's gizzmo, which is okay.  We are all lazy one way or another.  But, on a flatter open stretch of road, cruise is good.  Also, if bucking a stiff headwind, back off and maybe even kick it out of OD.
 
Will:
  Like almost everything else in life, there is no one good answer that is right all the time.  Over time, you will gain a sense of when it is a good time to use cruise and when it's not.  I would say that most of us use it when the conditions seem right for using it, and we don't when it's not. As for the mileage thing, motorhomes get poor mileage period. :(

Steve
 
My old Dolphin has the Allison 4sp slush pump. The cruise was broken when I bought it and this trip will be my first trip where it actually works. I'm not expecting any big mileage changes but it will be nice to not have to pay as close attention the the speedometer because I often find I'm either under or over by enough to irritate other drivers or attract attention of a bored cop. I usually run about 60 and just because it will do 75 flat out I don't like to push it. The coach is not young and neither am I. When I get there is always the right time for me. I've been getting around 8 to 8.5 with the old girl towing my CRV. It shouldn't lower my mileage and any increase would be a plus.

George
 
I use Cruise almost constantly, whenever I can.  I put the tranny in econ. mode with engine brake off.  I find this kitty Cat. can drive itself better then I can. 
 
Steve hit it on the head..I set the cruise 63mpg. Watch my mirrors..come to a hill, give it some gas maybe 68mpg keep speed up hill.. Going down, watch mirrors that 18 wheeler that I passed going up will be coming down.

Truckers I spoke to hate RV 's with cruise because they impare there momentum. 

About fuel economy sort of like a oximoram.

Use a lot if kinetic energy to move the beast.

 
Using cruise control is not the best way to get the best mileage from your vehicle, especially is hilly or mountainous country.  Hypermiling is the best way to get maximum mileage, but it not always possible, practical, or safe.

Paul
 
Paul & Ann said:
Using cruise control is not the best way to get the best mileage from your vehicle, especially is hilly or mountainous country.  Hypermiling is the best way to get maximum mileage, but it not always possible, practical, or safe.

Paul

What the heck is hypermilling?
 
You accelerate slowly, slow down without using a lot of brake, accelerate slowly going down hill, and slowly decelerate going up hill, among other things.  do a search, it will give you a better idea.  Back in the 80s alot of cars had vacuum gauges in them, if you could keep the vacuum up as high as possible, you generally got better mileage.

Paul
 
Paul & Ann said:
Using cruise control is not the best way to get the best mileage from your vehicle, especially is hilly or mountainous country.

Can't agree with you Paul. I've been using cruise since my first DP. What really got me hooked was a seminar where the presenter (can't remember if it was CAT or Freightliner) said that no driver can be as accurate as the Allison transmission in minimizing fuel usage. Next time you climb a hill, back off the accelerator a little bit and you won't slow down. The tranny will save you that little bit of fuel. I have a 30,000# coach with 117,000 miles on it and have averaged 8.79mpg (and getting better) since new. I use cruise religiously, I don't think you can do better with your right foot and hypermiling.

What helps the Allison is, if you have the cruise set at 62 like I normally do, and you are climbing, the Allison won't maxi downshift like a gas engine to keep your speed up and will let you slow down even 10-15mph while still feeding just enough fuel to keep you going. And after I crest the hill I'm told I am getting 256 mpg. :)
 

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