Hi Toot,
I beg to differ on the cruise control. In the mid to late 70's I was head research technician on the "electronic cruise control project" working for Eaton corporation in Battle Creek Michigan, I was working with Cadillac, Buick, Chevy, Ford and all of the big manufacturers in Detroit, as a matter of course we data logged many different performance characteristics on a set route on the I94, not just the cruise control, and also on a rolling road in the lab and at the Ford test track, which as I remember was in Dearborn?. We had a simulation program which was rigged to the accelerator pedal of the car being tested on the rolling road, and on the highway we had test drivers from all of the big companies driving for economy , we averaged out the manual input from the drivers on those particular vehicles, and also had a "standard" of all of the manual input from every car, regardless of the make, we always recorded a 3% to 5% better fuel consumption on every car tested using the cruise control, apart from the AMC pacers we had, they recorded only 2% to 3%, not the most efficient straight 6 motor. probably 80% or so of the cars were automatic, but we had a representative cross section of Auto V Manual based on sales. We data logged in every season, as the weather was so variable. All of the road tests and simulated tests observed the speed limits of the time. Nowadays I notice increased response times and almost no hysteresis to speak of, they are certainly more responsive, practically zero hunting. I realise it's difficult to equate a 1.6 diesel performance with a 6 litre V8, but we also used chevy vega's and ford pinto's (petrol) a lot as things were changing rapidly thanks to Ralph Nader and the oil crisis, they also were logged as being more efficient using the cruise, auto or manual.
I had as a company car a Chevy Vega manual and travelled well over 100 miles a day commuting from Three Rivers, I would always get a better fuel consumption using the cruise, I put over 140,000 miles on that car.
I also moonlighted on the Valve disabler project for Cadillac, and I can definitely say that was a disaster, and used more fuel, when it was working!. Which wasn't often. I believe the modern version doesn't have much success either?
I can almost match the fuel consumption not using the cruise on the Yeti, but I'm usually at least 2mpg worse, and yes I know it's very sad recording all of these numbers, but hey, I enjoy doing it. We found that driver fatigue was a major factor however, because if it were possible to manually get a better fuel consumption than using the cruise control, over miles and time, tiredness would take it's toll and speed and smoothness would be much more variable, using more fuel, and of course the cruise control isn't subject to those variables
Alan.