To CC, or not to CC?

[Zeta]

I put about 1000 miles on the rig this past week exploring Colorado with it's smooth roads, 13,000 foot passes and boiling hot SW corner. Filling up three times netted me a fuel mileage of 14.5-15mpg. It's never been this high. I would like to think it was all the cooling mods I did making the intercooler more efficient, but most likely it was because I have backed off using the Cruise Control.

Why? Because it's too eager to please. To get from 63mph to 65mph uphill, with the cruise engaged, it will downshift, rev the huge 6.0 engine to 3000rpm, shoot the EGT to 11-1200F, the boost to 23psi thus leaving me at 68mph. This must be wasting huge amounts of fuel. Now when going uphill, I control the throttle and downshifting which I is what I think made the solid 10% improvement.

Z

[86Scotty]

That's exactly what a lot of the tuners do as well, at least partially. They sort of trick the vehicle at highway speeds to keep it from kicking down so quickly. But you are right, the same thing can be accomplished by no CC and extra attention to the engine when you're on hills.

[Ford_6L_E350]

No doubt, the CC can waste a bunch of fuel in the hills/mountains. You do what I do, use the CC on level ground and use my foot in the hills.

CC has no concept of 'Speed is coming down, so more throttle is needed'. It just seems to wait until the speed has dropped 2-3 mph and then 'Full Throttle'. It really seems to irritate me when the speed picks up down one hill, and then has to drop below the set speed going up the next before accelerating again.

When I'm in control, I give it a little throttle downhill and pick up 5-10mph and give it a little more throttle to try and keep the speed from dropping too fast going up the next hill. At least it makes me feel better than listening to the engine screaming uphill.

Mike

[etbadger]

We did a few thousand miles religiously using CC, and found a significant (~2mgp) drop in mileage in that period (far more than our change from 32 to 37" tires). Since then it is rarely on and out mileage has returned to norm.

-e

[Chopperguy]

I just don't like cc. My boot is my cc for these very reasons.

[Ultrasport12]

One of my old vanning friends always used to say when ever he bought a new car or truck:

"Why in the world would I want Cruise Control? I like to Cruise out of Control"

Myself personally I like having it on my vehicles but I don't use it as much as I used to.
With my van I use it around my home as we have 25MPH speed limits and they will give you a ticket for 30MPH every time they can. My van does not like to go under 30MPH so I set the cruise at 28MPH on my GPS. I do use it on longer trips sometimes once I can get away from all the traffic around and can keep it on for a while. I cannot say if it helps or hurts my mileage. On trips I usually get 13-15 MPG but I am still 2wd.


...Jamie

[9pb9]

I use cc except on very hilly areas, in moderately heavy traffic, or on slick roads. It has saved me a few tickets. Plus I tend to slow down sometimes when taking in the views, so it keeps my speed up so I don't annoy the drivers behind me.

[dhally]

when I'm on the freeway I never use cruise control. I like to go about 5 mph below the prevailing speed. Then when somebody creeps up behind me from behind, I can subconciously, slowly speed up to match their speed. If they speed up to pass, I can keep pushing to keep them right beside me. If they do manage to pass, then I tailgate them for 50 miles.

Using cruise control would make me to keep the same speed and let people pass me.

[BIGVANS]

Originally Posted by dhally

when I'm on the freeway I never use cruise control. I like to go about 5 mph below the prevailing speed. Then when somebody creeps up behind me from behind, I can subconciously, slowly speed up to match their speed. If they speed up to pass, I can keep pushing to keep them right beside me. If they do manage to pass, then I tailgate them for 50 miles.

Don't you know that's the law in WA and ID!

[larrie]

CC is off when on city streets and going up hills. It is on for freeways and other roads between towns. It keeps me from exceeding the speed limit.


Larrie
89 Ford 2WD penthouse