Video: Driving with a Steady Speed, or a Steady Accelerator?

[Gone4]

Hello guys. I am a brand new member who has been lurking for a few days now.

I have a lot of interest in this as a mechanical engineer graduating in May and going on to graduate school in fluids and heat transfer for more efficient machine designs.

Anyways, I go to school in the mountains of Vermont and drive through the NH mountains for various reasons as well, since I live at the foot of them in southern NH. I am really interested in which is best for these types of situations. I don't often see flat roads to drive on...

This summer I will invest in some equipment to do real testing, but for now does anyone have some resources on handling these mountains best?

[MetroMPG]

So, what are you driving? Automatic or 5-speed? By the "testing equipment" comment, I take it you don't have OEM fuel economy instrumentation or a ScanGauge?

[Gone4]

Originally Posted by MetroMPG

So, what are you driving? Automatic or 5-speed? By the "testing equipment" comment, I take it you don't have OEM fuel economy instrumentation or a ScanGauge?

I don't have any of that... yet. I drive a 2001 Ford focus, automatic. That will also be changing this summer because its a shared deal with my younger brother and he will be taking it permanently.

[DifferentPointofView]

I find that most cruise controls only get you better fuel economy if your a "regular" driver or are on really flat hills. If it's got even low hills, it seems that more throttle is put on going up hills. CC is more of SC, or speed control, it puts on gas while going up hills so that your speed is constant, and lets off going down hill. If your a real ecomodder then you're probably good with your feet while driving and can hold a constant throttle without realizing it, whereas normal drivers fluctuate with the pedal. And it seems they also have trouble with their feet stop working while talking on a cell phone.

Cruise control IS a savior tho on road trips :thumbsup:

[Gone4]

Originally Posted by DifferentPointofView

I find that most cruise controls only get you better fuel economy if your a "regular" driver or are on really flat hills. If it's got even low hills, it seems that more throttle is put on going up hills. CC is more of SC, or speed control, it puts on gas while going up hills so that your speed is constant, and lets off going down hill. If your a real ecomodder then you're probably good with your feet while driving and can hold a constant throttle without realizing it, whereas normal drivers fluctuate with the pedal. And it seems they also have trouble with their feet stop working while talking on a cell phone.

Cruise control IS a savior tho on road trips :thumbsup:

Cruise control on road trips down south is AMAZING. I can pull in really good mileage on the Focus. I'm not sure if I can do better simply because the distances are too great for me to have bothered trying, to be honest. However, in the mountains cruise control can drop me down to 26 MPG in a Focus, which is utter trash. Using my foot I can get back around 32 MPG but that's without any technique and driving way too quickly.

This sort of dedication to mileage is something I just never considered - maybe because I didn't think it would make sure a huge difference. Now I really want to start with the best habits that will boost me in the hills and work on physical modifications this summer on my own machine. CC isn't it for the mountains, though. I have a feeling peakster would have had some more interesting results on some good hills.

[MetroMPG]

Man, you know what? I have precious little experience driving automatics and even less driving in really mountainous country. I don't think I'm qualified to give out a lot of advice on that combination except the obvious:

- At highway speeds, keep the torque converter locked if at all possible. (Can you even do that in the mountains? Does the car even have a lock-up converter?)

- Your best constant speed efficiency with an attentive right foot (and traffic conditions that give you enough lattitude) is going to be whatever speed you're at just after the highest gear / torque converter engages.

- Hills.... if it's a short, steep climb, that could mean DWL (driving with load): actually releasing the accelerator as the vehicle speed drops, to keep the car from downshifting. Regain speed gradually on the other side.

- Obviously the above doesn't apply if it's a long climb.

- On the descents, neutral is your friend, provided it doesn't cause you to get into situations where you have to brake, otherwise just leave it in gear.

[DifferentPointofView]

Call me a noob, but wouldn't you stop quicker if you were in neutral in a sudden stop? or does it have to do with brakes and engine power?

[MetroMPG]

I was thinking more from the perspective of gathering too much speed on a descent in N that it forces you to ride the brake, or brake repeatedly to keep things under control. In that situation, might as well just stay in drive.

[Gone4]

Thanks for all the advice. Rt 89 is pretty barren when I travel it so I can vary my speed a lot assuming no statey latches onto me at the bottom of a big hill / small mountain. Super troopers may have been based off of VT cops but they aren't that bad in my experiences. I have always planned on making my next car a manual transmissions. And, I have no idea what a lock up converter is hehe.

[MetroMPG]

Manual transmission is definitely the way to go if you're going to develop ecodriving/hypermiling techniques. The EPA ratings comparing an auto vs. manual transmission for the same car may not be that far apart, but in the hands of a determined hypermiler, they'll be miles apart.

http://auto.howstuffworks.com/torque-converter4.htm

A lock up torque converter makes a direct connection between the engine & transmission, typically in the highest gear, once engine & transmission speeds are close. It improves efficiency by eliminating slip between the 2 sides of the fluid coupling.