Fuel Economy Using Cruise vs. Human

[chewy22]

I get better mileage both empty and towing running 91 vs 85. v4 holds longer and hits more often with 91. In our area 91 is more $$$ than diesel - just another add to the column of 'should have kept the oil burner'.

[thefishhawk]

I did notice it holding V4 better this week. I should have mentioned I had been running 85 before that too, it was just that Costco tank that killed it for some reason. There seems to be a lot of debate about altitude effect especially newer vs older cars. Apparently I found some info where Ford/Chevy/Dodge are saying to run recommended octane regardless of altitude being that's what the engines are tuned for. Add the altitude issue on top of the debates of which gas to run in the first place and it gets confusing in a hurry

 

back on topic, I don't know if I can do better than the cruise but I generally set it when I can just to keep me from speeding (too badly lol). I've still gotten really good mileage footing through the mountain passes not towing though so who knows. I bet the computer is smarter than me. I don't get to do much flat highway driving though.

[leviblue]

My best mpg with a 5.3, 3.42 setup was 25.4 with cruise going about 65 on back highways with hills and flats. The average for weekly driving is at 17.8 which matches my closely the fuelly calcs at 17.4. Cruise beats me every time.

[maxxman935]

I just finished a test of this with just over 1300 miles on the truck. A tank was burned using my foot, and a tank was burned using cruise. My foot won by .5 mpg. I am in East Texas, so there are some hills and such to maybe explain this. I use 89 octane gas.

 

I have a few road trips coming up, so i will try it again.

[johne]

I have always gotten better mpg's with cruise as long as it's flat highway driving. I'm just too impatient most times to allow cruise to do it's job efficiently.

I feel the same way. I always use mine on the highway until I run into jerks going slow in the passing lane and I step on the go pedal to get around negating any advantages I get on a trip using cruise control.

[Spurshot]

I run Costco 87 @ sea level pretty regularly. I'm going to run their premium for a while to see if it's worth switching.

[TopazBlue6.2]

On a 1700 mile trip from Wisconsin to Idaho my 6.2 got a around 18.5-20 mpg using cruise at 80mph. On the last fill up through Wyoming using just foot the truck got 23.42 mpg! Best 25 mile stretch on the DIC said 30.4 mpg during that trip. I think that on flat land cruise will probably be the same or a little better but in the mountains and hills foot is the way to go.

[Mike1220]

Yep unless you are in hilly terrain it's better to use cruise. On flat ground cruise will keep your engine on a consistent work load, your foot may increase the work load unintentionally and lower the mileage. If you are on hilly terrain you can let off when going downhill or you can speed up so you can let the engine relax more when going up hills.

[GearheadSS]

I read somewhere that premium fuel was recommended but not required. Maybe that was for the 6.2 engine. I'll keep this in mind the next time I fill up. The difference between regular and premium is about $.50 per gallon and I rather keep that in my pocket since I've been filling so about every 3-4 days.

It is for the 6.2 but not the 5.3.

[bboyce536]

Cruise always gets me 1-2.5 mpg worse then I can. Sometimes much more. I use cruise as little as possible. It constantly adjusts throttle position to keep a certain speed versus gaining speed downhill and loosing uphill. Honestly can't see how cruise would ever get better mpg unless you can't keep your foot still.

[milligan]

I live in a mostly flat area. Cruise does a better job than me. In hilly areas, I tend to not power up the hill like cruise wants to and I'll let the truck speed up going down the other side instead of holding steady.

[Luster]

Ok ... I tested the same route with and without cruise on my '14 Silverado.

 

Fairly level 2-lane road runs east/west. Speed posted 55. 50 mile round trip.

 

Manual speed control... 20.8 mpg. (with my best effort)

Using Cruise control.... 22.7 mpg. (same weather conditions next day)

 

No question about it in this case. 2014 cruise is almost 2 mpg better than my right foot.

[j-ten-ner]

Ok ... I tested the same route with and without cruise on my '14 Silverado.

 

Fairly level 2-lane road runs east/west. Speed posted 55. 50 mile round trip.

 

Manual speed control... 20.8 mpg. (with my best effort)

Using Cruise control.... 22.7 mpg. (same weather conditions next day)

 

No question about it in this case. 2014 cruise is almost 2 mpg better than my right foot.

 

I think it depends on the terrain. If you drive on a level highway the cruise control can handle it better.

But in more "hilly" regions you're better off with the 'manual speed control' .

 

I know there was a European truck manufacture (RENAULT ?) whose trucks have a different power output either in 'manual mode' or with the CC set. With the CC there were around 100-150hp more. Can't quite remember.

 

I'm wondering if it changes any engine or transmission parameters in our trucks too when the CC is set?

 

so long

j-ten-ner

[thefishhawk]

Cruise control aside, I think what there really needs to be is user selectable AFM modes. When you hit a 1% grade and it kicks back to V8 there's just no reason for that.