What method do you use when driving at constant speed?

[surfstar]

First off Dave:

Sometimes it even helps if you can rest your upper leg against the interior panels - keeps some of the weight off your lower leg. Won't work in trucks or cars with center consoles that don't go to the floor, though.

 

[Benzadmiral]

PandaBear wrote:

>> I tailgate a big SUV within 10 feet so I can take advantage of their air drag. Annoy the heck out of them but hey, I am taking advantage of their waste anyways.
You'll be taking advantage of your auto and/or medical insurance if you keep that up, and he slams on his brakes. . . .

-- Paul W.

 

[DaveInLA]

LOL, you guys must think that I slow down dramatically before I add throttle again. Far from it. Like Jimbo said, it's only a couple of seconds. If I'm going 65, I'll blip the throttle again when it's down to 63, go up to 66 to "catch up" to the car ahead of me, and then repeat. I've never had any complaints. I didn't even know that people noticed.

I have been trying the constant speed thing. I find myself constantly looking at the speedo, which is a bit uncomfortable.

 

[GROUCHO MARX]

Keep it in 5th.

 

[pitzel]

I leave it locked on cruise unless the tailwinds are such that I get a significant oscillation in engine power settings due to some instability in the PID control loop that my cruise control unit uses.

I wish there was a way to optimize for efficiency at load, rather than for power setting versus speed, in modern auto autothrottles. But ultimately cops care about (and measure and ticket you for) speed, not the specific power setting of your engine at a given load.

Anyone else get oscillations with their autothrottle (cruise control) under certain conditions?

(for those who don't know what I'm talking about....go fly on a fly-by-wire Airbus 319/320/321 during turbulence. the engines spin up and down every 2 or 3 seconds, but because of the phase lag and delayed reaction of jet engines, one actually can feel the accelerations and the decelerations, as the nature of the engines' automated control leads to frequent power changes to maintain a set airspeed.)

 

[PandaBear]

quote:

---

PandaBear wrote:

>> I tailgate a big SUV within 10 feet so I can take advantage of their air drag. Annoy the heck out of them but hey, I am taking advantage of their waste anyways.
You'll be taking advantage of your auto and/or medical insurance if you keep that up, and he slams on his brakes. . . .

-- Paul W.

---

I was just kidding, I stay with the same space and speed with the rest of the traffic as the 2nd car on the fast lane, so I am safe from cops catching speeder.

10 ft happens to be the following distance in 35mph traffic, about 20 ft in 70mph traffic here.

 

[TheTanSedan]

Cruise control in the 1960/1970's was good if it kept car within 4-5 mph. Easy to beat with a steady foot . . but lot's of attention.

Use a vacuum gauge to teach yourself. Anticipate hills, traffic.

So,

Put on yer boots

http://www.pintoranch.com/g9338.html

yer hat

http://www.petersbros.com/S_WEST_FELT/Default.htm

light one up

http://www.ecigardepot.com/Anejo.htm

start the car (a real car, with a 440 and a Holley)

http://www.imperialclub.com/Yr/1967/Ads/Bronze.jpg

and, with more torque than you'll ever need at 75-90 mph you'll barely move that right boot all the way from Denver to Salt Lake City across the Rockies.

On yer modern car it ain't got no feedback worth a hoot throttle, just stick the cruise on.

Or plant yer boot heel.

[ March 25, 2006, 03:36 AM: Message edited by: TheTanSedan ]

 

[T-Keith]

Correct me if my math is wrong, but at 70mpg you move 100 feet/second, 20 feet would give you about 1/5 of a second to react to problems, doesn't sound very safe to me. In addition you'll be catching every rock and sand particle that the SUV is throwing up with their big tires.

Also, Dave, even if your only changing your speed two mph, the guy using his cruise control behind or beside you is still getting annoyed. Drive a constant speed in the right lane, use the left lane for passing only. Nothing more annoying then trying to pass someone and they speed up.

 

[PandaBear]

Yeah, I remember the 4 second rule back in high school. Wouldn't work here. If you have 100 ft people will squeeze in between you and the car in front. You have to make sure the space is barely not enough for them to comfortably squeeze in, but not too close that you cannot see their tire.

 

[GROUCHO MARX]

"You have to make sure the space is barely not enough for them to comfortably squeeze in, but not too close that you cannot see their tire. "
------------------------------------------------------

You gotta love it.

 

[T-Keith]

4 seconds might be too much, but 1 or 2 isn't unreasonable. It's the just the braking you have to worry about. I've seen many cars swerve at the last minute to avoid something in the road, if your right behind them your going to hit it.

 

[Racerjk]

I keep a steady speed.

 

[obbop]

Drive like yer' drunk and they usually get outta' yer' way.....

except for the drunks.

 

[brianl703]

quote:

---

Anyone else get oscillations with their autothrottle (cruise control) under certain conditions?

---

When idling along in 1st gear, my 1988 Mustang GT will sometimes start bucking (oscillating). If I don't do anything, it will get worse. If I give it some gas or hit the brakes, it stops. It also does not happen when idling up hills.

I believe this is due to a combination of slow response from a likely dirty idle air control valve (iac) and tall gearing and ECU software that isn't tolerant of slow response (ie, it wants to see engine change speed NOW! so it commands the iac open, which causes the engine to speed up past what the ECU wants so the ECU commands the iac closed which causes the engine to slow down to below what the ECU wants so the ECU commands the iac open...)

I've been meaning to try cleaning the idle air control valve to see if that will help..

 

[k1xv]

Most of the places I drive in within the northeast, either rural, suburban or urban, afford few opportunities for long distance constant speed driving for any length of time. However, when they exist, I try to use constant, light throttle application. Having a truck and a previous car that included a fuel economy digital display, it was easy to develop such a habit and develop techniques.

If I am out on an Interstate and conditions allow constant speed, I tend to use cruise control.

 

[Benzadmiral]

PandaBear writes:

>>Yeah, I remember the 4 second rule back in high school. Wouldn't work here. If you have 100 ft people will squeeze in between you and the car in front. You have to make sure the space is barely not enough for them to comfortably squeeze in, but not too close that you cannot see their tire.
Then you fall back and maintain your space. The laws of physics can't be argued with or bargained with.

If traffic is that bad, it's time to move.

-- Paul W.

 

[GROUCHO MARX]

I save a lot of fuel when the car remains parked.

 

[OriginHacker21]

When I worked in Iowa I had an hour drive to and from work. Now out in California I have a 2 hour drive to and from work. My car doesn't have cruise control yet I can keep the speed within a few mph of speed limit.

What helps is, the side of the middle console allows me to rest my foot on it while keeping the gas constant.

In my opinion - coasting, gassing combination would ultimately be more of a waste of gas - though not by much. Plus, wouldn't it be easier on the engine to maintain a constant speed? You never see semi-trucks doing that and they last forever.