Gas needs to double in price..............

[mjstef]

Before anyone slows the heck down!! I ran the speed limit all day today (70) and the ONLY thing that didn't pass me were big trucks! I swear people were running 85-90 mph!! The big trucks have figured out slowing down saves fuel but 4 wheelers must not have a brain! You should not gripe one bit about fuel prices unless your running the speed limit or under.

FWIW i went 228.2 miles in my old explorer today and put 10.55 gallons in it. Filled up to the lip at the same pump both times. Thats 21.63 MPG on a 16 yr old 4X4 Explorer with 132K on it! Ran the speed limit all day which here is 65-70 on 2 lanes and 70 on the interstate. Also went over Boulder Pass, Homestake Pass & Mc Donald Pass so it wasn't all easy driving. The irony of this is Dad has a rental Chebby Trailblazer with 9K miles on it and can't get anything more than a low 22 mpg out of it and he drives slower than i do!! Seems like every time a new model year sport ute or pickup comes out the lower the mileage gets.

[drcampbell]

Originally Posted by mjstef

... FWIW i went 228.2 miles in my old explorer today and put 10.55 gallons in it. Filled up to the lip at the same pump both times. Thats 21.63 MPG on a 16 yr old 4X4 Explorer with 132K on it! Ran the speed limit all day which here is 65-70 on 2 lanes and 70 on the interstate. Also went over Boulder Pass, Homestake Pass & Mc Donald Pass ...

Does your dad live in the flatlands? At 6000-7000 feet elevation, air density and aerodynamic drag are 20% less (3-4 mi/gal) than at sea level.

[mjstef]

Originally Posted by drcampbell

Does your dad live in the flatlands? At 6000-7000 feet elevation, air density and aerodynamic drag are 20% less than at sea level.

Currently outside of Denver on vacation.......................

[lone_star_dsl]

I just made my trip to Odessa, TX. Went down empty at about 8200 lbs. Got a hand calculated average of 18.2. I had a pretty heavy headwind but thought that I did surprisingly well.

On the way back, I was hauling a bunch of stuff out of dads storage unit and was pretty deep into the overload springs. Got an average of 15.9 headed back.

All was fine and I ran 70-75 coming home. That was until I hit Colorado Springs. I put it in the hammer lane and kicked it to 80 mph. The turbo was screaming and I was loving it, that was until I saw the Toyota Tundra driving into the bed of my truck. I had open highway in front of me so I kicked it to 90 mph. My mpg dropped to 12.8 on the overhead and the Yota was still glued to my tail.

I moved over to the granny lane to let him by. Of course he pulled up right next to me and decided to stay there. He got right behind a car in front of him, then got behind me, then moved over to the on ramp and went around another car on the shoulder. I had 5 miles to go and I watched his backside pull farther away every minute.

While I was driving, the other cars were going around me by 10-20 mph. Colorado drivers are totally INSANE!

I made it to the off ramp and pulled up next to the Tundra. After all the danger he caused to other drivers, he beat me there by 30 seconds and was waiting on the light. I let him know his IQ number and turned right.

I just cant believe that Texas has upped the speed limit to 80 mph on most of the interstates.

[Hook'em Horns!]

Originally Posted by lone_star_dsl

...After all the danger he caused to other drivers, he beat me there by 30 seconds and was waiting on the light...

I just cant believe that Texas has upped the speed limit to 80 mph on most of the interstates.

Just out in West Texas with miles and miles of nothing, otherwise it’s mostly 70 but, even then you need to drive right (to the), or get ran over.

I drive the much busier interstates to the east of there, and it’s getting to be a little more treacherous than in the past. Because so many are starting to conserve by driving slower, they are creating a greater differential in speed to other traffic, and slow driving left (to the) just complicates things more.

Add to that, TxDOT has limited Truck traffic from the inside left lane for long stretches in heavier congested areas so they are stuck in the right two lanes trying to maneuver amongst themselves and smaller vehicles not realizing it’s legal to pass in the left lane.

Mix in the “I refuse to wait” crowd constantly changing lanes for a perceived gain in time, and it’s starting to get quite nasty out here.

All of my miles are spent hauling and I’ve tried lowering cruising speed to conserve but at times it just causes more consumption, time wasted and more wear. More shifting, and higher RPMs as you cannot maintain a constant speed maneuvering in the slower mix of traffic.

Under load with 18-25k gcw, the sweet spot is 68mph and 2000rpm for the best mileage and performance in my case. Traffic to the left wants 75+ and traffic to the right has a mix of 55-er’s. Add in the varying truck traffic in the center and it’s a mess with more volatile accidents.

I see insurance rates going up like they did here years ago when Truck traffic was limited to 60mph mixed in with 70+ cars.

[Greenie]

The right lane is the lane folks should stay in unless they're passing. It's amazing how many folks stay stuck in the passing lane - they'll slow when passing, then accelerate when they're cruising in the passing lane so you can't even get by them on the right.

[roofeditor]

Originally Posted by Hook'em Horns!

Just out in West Texas with miles and miles of nothing, otherwise it’s mostly 70 but, even then you need to drive right (to the), or get ran over.

I drive the much busier interstates to the east of there, and it’s getting to be a little more treacherous than in the past. Because so many are starting to conserve by driving slower, they are creating a greater differential in speed to other traffic, and slow driving left (to the) just complicates things more.

Add to that, TxDOT has limited Truck traffic from the inside left lane for long stretches in heavier congested areas so they are stuck in the right two lanes trying to maneuver amongst themselves and smaller vehicles not realizing it’s legal to pass in the left lane.

Mix in the “I refuse to wait” crowd constantly changing lanes for a perceived gain in time, and it’s starting to get quite nasty out here.

All of my miles are spent hauling and I’ve tried lowering cruising speed to conserve but at times it just causes more consumption, time wasted and more wear. More shifting, and higher RPMs as you cannot maintain a constant speed maneuvering in the slower mix of traffic.

Under load with 18-25k gcw, the sweet spot is 68mph and 2000rpm for the best mileage and performance in my case. Traffic to the left wants 75+ and traffic to the right has a mix of 55-er’s. Add in the varying truck traffic in the center and it’s a mess with more volatile accidents.

I see insurance rates going up like they did here years ago when Truck traffic was limited to 60mph mixed in with 70+ cars.

Technically 55 IS your sweet spot. You can't go against aerodynamic drag and win. Now you point that 55-60 you are constantly shifting and speeding up and down because of traffic> This I would concede is a major factor.

Also your point of 55 traffic trying to mix with 75 traffic is also a good point.

[roofeditor]

Originally Posted by drcampbell

Does your dad live in the flatlands? At 6000-7000 feet elevation, air density and aerodynamic drag are 20% less (3-4 mi/gal) than at sea level.

Generally so is power because of reduced Effective compression. Turbos can overcome this obviously.

You should see the fuel consumption of a Boeing Jet at 20,000 feet VS 40,000 feet. Down at 10,000 feet it's a real hog.

Here is a conundrum for ya. If you are at full gross at 40,000 feet and you are over the ocean and you lose an engine (now you got only one left) you no longer have the power to maintain 40,000 feet. OK? now down at say 28,000 feet the drag is tremendous and even though you are running on only one engine that engine is at MCT (Max continuous power) . Your range is now seriously reduced. We have to figure flying 1/2 way and losing an engine right there and then what is your range. Worse case scenario.

[Hook'em Horns!]

Originally Posted by roofeditor

Technically 55 IS your sweet spot. You can't go against aerodynamic drag and win. Now you point that 55-60 you are constantly shifting and speeding up and down because of traffic> This I would concede is a major factor.

Also your point of 55 traffic trying to mix with 75 traffic is also a good point.

The problem is at 55-60 under load and in Tow/Haul mode; the Allison will run the next gear down and have you at the same or higher RPM as at 68. Also, traffic aside, under load and climbing hills at the slower speed results in more gear change and RPM by itself.

Today, I had a chance to run trailer-less and check on savings in reduced speed. Since Diesel jumped .13 - .35 cents over the weekend and time was not an issue, what’s to lose?

Previously, I had seen 17.34mpg at 72mph and today, 18.1mpg at 68mph. I wanted to drop further to 65 and see how close to 19 I could get but, at 68mph I was over the edge of being an obstacle with traffic passing left and right and occasionally on the shoulder.

Without a load on and the absence of traffic, I would like to pursue the lower speeds and see if my figures are representative of the drag issues that were charted earlier. Never having seen 18 before felt good, since hauling gives me 9.8 to 10.5 on a regular basis. ($100+/day, and not counting anymore)

[roofeditor]

Originally Posted by drcampbell

Tell you what: The very next time I'm the pilot in command of a trans-oceanic multi-engine turbine-powered airplane, (with my single-engine, non-turbine, non-type-rated, limited-to-12,499-pounds license) I'll worry about it. (assuming it hasn't already been calculated and published in the performance chapter of the pilot's operating handbook)

Of course, I do wonder how you managed to burn enough fuel to climb to 40kft, get halfway across the pond and then be at maximum gross weight - what was your takeoff weight, anyway? A smidgen over the maximum legal gross weight?

Fuel burn to altitude and fuel burned is calculated but STILL you won't be able to hold altitude @ 40K on one engine. Ya got to come down in thick air. Yes I guess it's in the manual sort of.....we have a computer for that sort of thing now but YES in the old days we did do it by hand. Hey we navigated by celestial navigation which was a trip.

You get my point, air is thin at 40K and very thick at 10K.

BTW we do taxi overweight and on a long one hour wait and taxi we do burn off some weight. At roll out we are on the numbers. Here is how you get stuck. coming out of Boston in the late afternoon you can count on a one hour f-around with ATC and ground control, BUT every once in a while they fool you and move your number up and if you calculated heavy fuel for taxi, you are now heavy.

[clamgulch]

And then? Throttles to the wall? I suspect all that runway is for landing without brakes...except for taking off on a 90* day in Denver.

Staying within ETOPS ratings should keep you from running out of the juice over the big pond on one engine. yes, whatever happened to amelia earheart?

[mjstef]

Originally Posted by Hook'em Horns!

Today, I had a chance to run trailer-less and check on savings in reduced speed. Since Diesel jumped .13 - .35 cents over the weekend and time was not an issue, what’s to lose?

Previously, I had seen 17.34mpg at 72mph and today, 18.1mpg at 68mph. I wanted to drop further to 65 and see how close to 19 I could get but, at 68mph I was over the edge of being an obstacle with traffic passing left and right and occasionally on the shoulder.

Without a load on and the absence of traffic, I would like to pursue the lower speeds and see if my figures are representative of the drag issues that were charted earlier. Never having seen 18 before felt good, since hauling gives me 9.8 to 10.5 on a regular basis. ($100+/day, and not counting anymore)

Amazing what a little reduction in speed will do for mileage huh? The funny thing is these idiots running 80-90 mph are burning more fuel than they are saving time. I am only 37 years old but have not had a ticket in over 14 years. I drive AT the speed limit and sometimes a few mph over. I have better things to spend my $$ on than pouring it through the engine to save 5 minutes. Just leave 5 minutes earlier and all is good!!

[eagleeye]

Interesting thread. I took a trip on the interstate last Saturday. First one in a while. I set my cruise at 65 mph where I knew I would get my 19-20 mpg. I could not believe how many people passed me, virtually everybody. From the time I would see a vehicle in my rear view mirror to the time I would loose sight of them I would say was less than 90 seconds. Every type of vehicle too, from 4 cylinder economy cars to 1 ton diesel duallies, everything but semis. I know from experience that the difference between me driving 65 mph and 75 mph is 3 mpg. I would agree that fuel will have to get a lot higher before people start changing their driving habits to improve fuel economy. Maybe $200 a barrel for oil will change people, maybe I'm just too much of a tight a$$ that values his money too much. I guess time will tell.

[roofeditor]

Originally Posted by clamgulch

And then? Throttles to the wall? I suspect all that runway is for landing without brakes...except for taking off on a 90* day in Denver.

Staying within ETOPS ratings should keep you from running out of the juice over the big pond on one engine. yes, whatever happened to amelia earheart?

Auto throttles are pretty much standard now.

[Hook'em Horns!]

Originally Posted by mjstef

Amazing what a little reduction in speed will do for mileage huh? The funny thing is these idiots running 80-90 mph are burning more fuel than they are saving time. I am only 37 years old but have not had a ticket in over 14 years. I drive AT the speed limit and sometimes a few mph over. I have better things to spend my $$ on than pouring it through the engine to save 5 minutes. Just leave 5 minutes earlier and all is good!!

I have tried to teach this point in the past as an instructor. Trying to show the math was always a hit or miss. Most destination driving is for an hour or less from one’s home base and an even larger portion of these trips are less than 30 minutes in most cases.

The difference between driving 65mph for an hour versus 80mph with no interruptions and maintaining a constant speed is just 11 minutes. Now, let’s say over the course of that 49 minutes of travel you encounter just 7 vehicles forcing you to reduce to 65mph for only 25 seconds until you return back to speed at 80mph. Now we’re down to 8 minutes gained.

Come off the freeway into urban traffic and catch a few lights and the odds are that 65-er will pull up right behind you, or just ahead in another lane. Mix in a few more vehicles along the highway to slow down for and the 65-er will most likely catch you at the first light.

Equate these facts to a shorter trip of 30-40 minutes mixed with various lane changes and the 65-er could very well end up in front of you at the first light.

At the time, my goal in teaching this was not to encourage saving/conserving fuel, but to the dangers of driving at greater differential speeds than the flow of traffic for little or no time gain achieved.

As for tickets, most enforcement observation is for highly differential speed to the average flow of traffic. Drive to the right. If you’re in the left lane you should at least be gradually passing vehicles to your right, even if you must exceed the posted limits to do so. Complete your pass, move over, and carry on.

On a different note, while traveling longer distances, the two most annoying types of drivers are what we call the “I think I cans” and the “Lonely Souls”.

The ‘I think I can’ will refuse to move right and just keep upping their speed to try to satisfy you on their rear. “Wait, wait, I can do better, see?”

The ‘Lonely Soul’ is one that you passed 20 miles back and they latched on to you for company along the way. They’ll usually stay 1 car length behind or just behind and in the next lane. Speed up, and they speed up…slow down, and they slow down. Head up 30mph over the limit, they're right there…Slam on the brakes and drop 30mph below the limit and there they are.

The only way to get rid of this Suckerfish is to wait for some unsuspecting soul to pass you and let ‘em leech on to them for awhile!