Gas Milage - Page 3

Acableguy06 · 10-01-2013, 03:23 PM

Quote:

Originally Posted by Brother Les

Hello Oakman,

I see that you drive a Diesel. From what I understand of the AC on, it would have an effect on a gasser, but with a Diesel there is no effect in mpg......

Diesel or gas the compressor uses power, It does effect MPG's. My truck has a slow leak somewhere in the A/C so when its low the compressor will cycle more often, I can feel it kick in and out.

Also, the A/C compressor in some vehicles will cycle with defrosters on, this is also a power/mpg consumer.

ng2951 · 10-02-2013, 08:42 AM

Get a ScanGauge, use the cruise control. After a while the ScanGauge will probably reveal a sweet spot in the 60-65 range (mine is about 63 MPH).

Cruise maintains tighter speed control than the average Mark I foot/brain speed controller can perform. However, its hard to beat Mark I when you are traveling in the mountains or on rapidly changing grades.

Brother Les · 10-02-2013, 08:42 AM

Quote:

Originally Posted by RV PDI Guy

Diesel or gas the compressor uses power, It does effect MPG's. My truck has a slow leak somewhere in the A/C so when its low the compressor will cycle more often, I can feel it kick in and out.

Also, the A/C compressor in some vehicles will cycle with defrosters on, this is also a power/mpg consumer.

Hi Andrew, I see that you have a '99. Is it an early or late?

You said that you have a slow leak? Why not get it fixed? You are running the compressor to death. imo, on the 7.3, the engines does not give a hoot about the AC compressor turning round and round, unless the compressor is screwed up and dragging the serpentine belt because of bad bearings or clutches, or internal failure of the compressor. If your engine (7.3) is dragging when you turn the AC on and the AC is alright, you may need some kind of tune up (injectors?) or new sensors (ICP?)

Some ideas to look at.

AIR CONDITIONER - Ford Truck Enthusiasts Forums

AC problems - Ford Truck Enthusiasts Forums

ironj · 10-02-2013, 09:51 AM

didn't mythbusters do a episode on ac usage and determine that at highway speed it there was no impact on mpg with the ac compressor running due to rotating mass velocity??

if it wasn't mythbusters it was another show...but I do recall watching it....

I dunno, but in my 6.7 diesel ac usage makes not one iota of difference nor can I ever tell if the compressor is on or not, other than the ac light comes on when in auto climate mode....

I will say that WIND is always gonna be the nemesis when hauling a 60+ sq ft frontal area trailer with a 8000lb truck with the aerodynamics of rosie odonnel on an flag pole....gimmie a 5-10 tail wind on flats and ill show you 12+mpg with a 10k trailer....

gimmie a 5+ headwind in Colorado and ill show you 9...truck pulls same either way just visits more diesel stops in winds. and it got WORSE after the lift and 35" trail tires (but I tow with the stockers normally)

johndeerefarmer · 10-02-2013, 10:00 AM

I think the a/c uses about 7.5 hp so yes it would make some difference with any vehicle.

EricInColorado · 10-02-2013, 10:01 AM

I'm just guessing: I think we're all trained to think that the AC compressor sucks some power and thus MPG. And it certainly does. But it makes less of a difference now that engines make ~300hp instead of ~150hp. Thoughts?

**dcheatwood** · 10-02-2013, 10:03 AM

Quote:

Originally Posted by jevanb

buy a diesel that should fix your problem with fuel milage towing...

But will cost you more per liter. @ 50¢ per gal. Slow down.

**dcheatwood** · 10-02-2013, 10:04 AM

Quote:

Originally Posted by bikendan

slowing down, especially since the trailer tires are only rated for a max of 65mph, will help. 60 is the sweet spot for me and my Roo.

not sure what you expected going from a popup to pulling a 4000lbs. barn door behind you.
the average mpg for towing a full height trailer, is 8-10mpg, for a gas engine tow vehicle.

X2

jevanb · 10-02-2013, 10:36 AM

Quote:

Originally Posted by ironj

I dunno, but in my 6.7 diesel ac usage makes not one iota of difference nor can I ever tell if the compressor is on or not, other than the ac light comes on when in auto climate mode....

X2 other then the light and the cold air I do not know it is running. guess it has something to do with all our modern power we make compaired to the 99SD

Iwannacamp · 10-02-2013, 07:24 PM

Quote:

Originally Posted by johndeerefarmer

I think the a/c uses about 7.5 hp so yes it would make some difference with any vehicle.

.

I agree.

ironj · 10-03-2013, 11:40 AM

Quote:

Originally Posted by johndeerefarmer

I think the a/c uses about 7.5 hp so yes it would make some difference with any vehicle.

even at 7.5 hp that is but a mere .017% of my 435RWHP(closer to 500@engine).A numerical drag for sure but in the grand scheme a totally insignificant portion of diesel usage.....

I used to really fret when I had a bad day of pulling the trailer and only avg 10mpg....

anymore I don't care...I leave it running with ac and rear tv on for my daughter at all stops..its just a few bucks and we are supposed to be relaxing and enjoying yhis whole camping thing...lol

elind · 10-21-2013, 08:10 PM

Speed makes a big a differance in gas milage. I just made 400 mile trip to the twin cities. The first 250 miles I drove 62 mph and got 20.5 mpg. The next 150 miles I drove 77mph. That's when I found the milage dropped down to 17.5 mpg with the cruise control both times. So 3mpg adds up in the pocket book.

rbneron · 10-21-2013, 08:20 PM

Quote:

Originally Posted by ironj

even at 7.5 hp that is but a mere .017% of my 435RWHP(closer to 500@engine).A numerical drag for sure but in the grand scheme a totally insignificant portion of diesel usage..... I used to really fret when I had a bad day of pulling the trailer and only avg 10mpg.... anymore I don't care...I leave it running with ac and rear tv on for my daughter at all stops..its just a few bucks and we are supposed to be relaxing and enjoying yhis whole camping thing...lol

Check your math. From a practical perspective, agree that it won't make much if a difference, and your comfort is more important.

dwaynerz · 10-21-2013, 08:39 PM

i have to chuckle a bit. we buy these (sometimes) huge by large rolling palaces, homes on wheels whether they be towed or driven, and worry over fuel mileage. it is sometimes kinda oxymoronic.

ironj · 10-21-2013, 09:02 PM

Quote:

Originally Posted by rbneron

Check your math. From a practical perspective, agree that it won't make much if a difference, and your comfort is more important.

math was right..decimal in.. wrong place...lol..a technicality...

on another note made a trip to caprock canyon st park...ran into cold front just as I left...26mph headwind....got 6.2mpg avg going up....did have the 35" nittos on and not my normal stock tires I use for towing. ..ouch..!! had a good laugh with my camp neighbors (who work with my wife at hospital) as they netted the same or worse in their diesel pushers......I hate you wind. .!! lol

jbrostek · 10-22-2013, 08:08 AM

Headwinds are the worse. I had a DP and just moved to a 5th wheel. the DP pretty much averaged 9 weather a towed something behind it or not. But get into a head wind and I could drop down to 7. And thats on the east coast where steep long grades are limited.

jevanb · 10-22-2013, 09:23 AM

Quote:

Originally Posted by ironj

even at 7.5 hp that is but a mere .017% of my 435RWHP(closer to 500@engine).A numerical drag for sure but in the grand scheme a totally insignificant portion of diesel usage.....

nice, I guess my 540.44HP rear wheel is around .013hp to run mine, as i said cant tell it is even on

ironj · 10-22-2013, 10:17 AM

Quote:

Originally Posted by jevanb

nice, I guess my 540.44HP rear wheel is around .013hp to run mine, as i said cant tell it is even on

actually I mis typed mine..its 1.75%....lol...in any case no...I never know its on.... nice numbers btw. ..gotta love that tq #...can't wait till I get the new 450tow pig so I can delete my 250 and run a better tune and fuel mgmt......for now its all stock save for cold air and stock tune...honestly its more than enough as is tho....but that never stopped me before...

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