Gasoline usage for BM

[dj_john69]

So, just curious to see how much money you are budgeting for the burn this year. With the gas prices climbing each day, are you trying or planning to conserve gas or do you just save extra money to and deal with it.

What do you think about if gas hits the $6.00 mark before BM ?? Instead of taking an rv...would you go with a tent ?? Would you consider NOT going to BM ??

[ibdave]

65 gals today in my RV, Betting that it won't go down b-4 I leave for the Playa.. cost$ 265.00 and I'll have to do that 1.5 times more...
I would had filled a long time ago, but had to drop the tank last week for a new fuel pump...
1st year I went gas was below 2 bucks....

can't stop going over a few $$$

[Captain Goddammit]

This same topic gets brought up every week or two it seems... Yeah gas is expensive this year, but it's still not the biggest expense for the whole trip.
Would I give up my RV to save a few hundred bucks on fuel this year? Hell no. And if I don't drive either the motorhome or the truck I also give up bringing the Land Yacht, it's heavy and can't tow it with anything smaller.
So it's a few hundred more this year, I'm not gonna drop my plans for that.

[skeetsh00ter]

Yeah, gas is going to rape me. ATL to BRC and back will cost around $1300 assuming gas stays around $4.50. Suck. But that will be split between 7 people (hopefully, if you need a ride let me know) so it will be manageable.

[Dark Star]

Gas is the biggest expense for me.

Alas, I'm hauling more weight even further this year in my ever thirsty Ford Explorer.

Hey, at least I got new tires. Oh, wait, that probably doesn't help besides adding more weight.

I plan on drafting behind more vehicles during the trip and driving slower. On a recent multi state drive I never went above about 57 MPH. Low and behold I did get much better gas mileage.

[skeetsh00ter]

I'll be using the same strategy. Going slower and following close behind semis as much as I can. Should give me an extra few mpgs.

[AntiM]

Careful drafting the semis, there's a sweet spot, but if you'[re in the turbulent zone, it won't help and may decrease your fuel efficiency. Practically useless practice if you're towing anything yourself. I've also heard that staying too close prevents the engine from cooling properly, but I don't know enough about how this works to say. Anyone?


We have plastic, we have a savings account. We may be bringing two vehicles and a trailer even though we are only transporting four people. Bringing lots of infrastructure for co-campers, and all that art.

[ragabashpup]

Mythbusters debunked drafting. Its dangerous and almost impossible to find the sweet spot.

[Token]

Mythbusters proved that drafting does work. They were able to boost economy by ~40%. The problem was that to get that you had to be 10 feet behind the big rig, which is rather unsafe.

But even at 100 feet you do get some benefit.

Here is the data from the episode:

http://mythbusters-wiki.discovery.com/p ... g+Drafting

Results: The team measured fuel efficiency at 5 different distances from the big rig.

(ft) mph) FUEL CONSUMPTION DECREASE
100 55 11%
50 55 20%
20 55 27%
10 55 39%
2 55 28%

[Kinetik V]

Drafting does work. For example I had to move our 10,000 lb 73 Winnebago (think super heavy brick on wheels) from Denver to Lincoln, NE along I-76 and I-80. I used the 2-3 second rule of getting in behind the trucks and the difference was huge. With that vehicle I run it by the tach and the vacuum gauge...and drafting gave me almost 5 hg difference on the vacuum gauge and an almost 3 mpg difference once I got it out on the flat stretches of I-80 past Big Springs.

And along with the Mythbusters research there's about 25 years of NASCAR research at Daytona and Talladega on the effects and benefits of drafting that has been highly scrutinized....in short it does work.

That being said don't be stupid with it...nobody likes tailgaters so follow the 2-3 second rule. That way when I hit the brakes you don't rear end me and you don't draw the attention of the State Troopers.....along I-80 in Nebraska tailgating is a surefire way to get them to flip around in the median strip and reel your ass in for a chat and an autograph.

[dr.placebo]

Personally I use abut 40 gallons for a round-trip to the playa for 2 people. At $5 a gallon this is $200, which is not pleasant but well within reach, and is less than $100 more than last year.

But for those who burn that much getting out of town the situation is painful. May I suggest

http://en.wikipedia.org/wiki/Hypermiler

as a place to start? It's not a panacea, but it could save some money.

[Bluelatinsurfer]

Instead of renting a Minivan, I'm renting a Priest.
That means I won't be able to pack it up with most of my BM toys.
It's all good! as long as I get there.

[skeetsh00ter]

Mythbusters proved that drafting does work. They were able to boost economy by ~40%. The problem was that to get that you had to be 10 feet behind the big rig, which is rather unsafe.

But even at 100 feet you do get some benefit.

I watched this episode over the weekend. I was amazed that even at 100ft it still helped to improve fuel efficiency that much.

That being said don't be stupid with it...nobody likes tailgaters so follow the 2-3 second rule. That way when I hit the brakes you don't rear end me and you don't draw the attention of the State Troopers.....along I-80 in Nebraska tailgating is a surefire way to get them to flip around in the median strip and reel your ass in for a chat and an autograph.

I certainly won't be nosing up to any semis. I'm a big fan of the two second rule.

[dj_john69]

Just a heads up while we are talking about gasoline, don't forget to buy (if you don't have one already) a locking gas cap for your vehicle while on the Playa and you might want to consider locking up your spare gas cans as well.

Over the past couple years, we have caught people trying to steal gas from our camp and our vehicles. I can only imagine how much this will happen this year with gas prices at the highest ever here in the states.

[Captain Goddammit]

Instead of renting a Minivan, I'm renting a Priest.

?????

He's gonna pray that you find cheap gas?

[skeetsh00ter]

Just a heads up while we are talking about gasoline, don't forget to buy (if you don't have one already) a locking gas cap for your vehicle while on the Playa and you might want to consider locking up your spare gas cans as well.

Over the past couple years, we have caught people trying to steal gas from our camp and our vehicles. I can only imagine how much this will happen this year with gas prices at the highest ever here in the states.

I hadn't even though of getting a locking gas cap. Great idea! That would suck to find yourself with not enough gas to make it back to Reno after someone siphoned it all away.

[gyre]

The locking gas cap is probably more helpful off the playa than on.
Every time gas goes up, theft spikes.

The hypermiler thing is interesting.
I haven't read all of it yet, but most of it seems pretty good.
Some things are dead wrong though.
Engine efficiency peaks at different points on each engine.
The best car for mileage I've had peaked at 5000 rpm.
It is the same for air drag and speeds.
I imagine very few cars peak at slow speeds these days.
Cars are usually designed for 70 mph.
I imagine my ford peaks at 100 mph due to low drag and high power.
The Lotus Europa peaked at 80-85 mph with a 4 cylinder.
It all depends.

Improving aero will help on the highway for anything.
I am planning some tweaks this year that will be so low as to be hard to use in a city, but worth it on the highway.

There are low drag tires, but weigh grip in an emergency against it.
The prius uses this trick.
Unsafe in my opinion.

An adjustable ignition advance is one of the best things you can do.
If your car is older or just backwards, a new management computer can pay off big.

The hypermiler info on octane is misleading at best.
A car tuned for high octane will always perform better on it.
Knock is not the issue.

Octane enhancing can be artificial or with more potent fuel.
Avoid alcohol.
It never goes in my tank.
It is easy to test your car but it takes a lot of miles to get an accurate idea.
It does not take a big difference for premium to pay off.
Do the math.

If you check it for a long time, many tanks, and there is no difference, then stick to low octane.


On drafting, I have done this and it works.
I think it is usually not worth the trouble, except perhaps in a big vehicle at a safe distance.
Turbulence is not necessarily a bad thing.
Depends.
I have heard of bikes shutting the engine down and being pulled.
I was in a 2000 pound coupe with low drag but high turbulence.
The spot for me was 100-150 feet back.
It was easy to spot.
I think the difference was the reduction in drag at the front of the car, in that case.
I gained 5-10 mph at 60 mph.
Note that this was a car with superb brakes.
Don't even think about it without that.
WARNING Semi-trailers due to size can be hard to perceive when slowing dramatically on the freeway without perspective near them.
I think this is the cause of many big pileups on the freeway.

It may be safer to draft a big rv at a safe distance.
It's not hard to outbrake them.

It's not usually worth the effort and don't take a risk.

WARNING The advice on short shifting is very risky and should NEVER be done at hard throttle.
I do it at VERY light throttle sometimes, but I know what I am doing.
Hard throttle is most efficient at reaching speed.
They were getting 50 mpg in the fifties in big cars using the full power and coast approach.

Get your car in tune.
Make sure the brakes don't drag.
Do what aero improvements you can, especially on trucks.
I expect my air dam will hit the ground on bumps until it wears.

[Kinetik V]

Another option for increasing gas mileage is to consider NOT using E10 gasoline. It is an established fact that E10 gas has slightly less energy per gallon than traditional unleaded gas....

Cite: http://www.ext.vt.edu/pubs/bse/442-884/442-884.html

Anyone can spout off scientific mumbo-jumbo but I value real world experiences and having spent almost a year out here in Cornland with ethanol gas....I've learned a few things....such as:

1: Some riding lawn mowers and small engines do not have as much power when running E-10 fuels. If you run E10 one week...and I run it until the tank is dry, then pour in regular unleaded and go at it.. I notice a difference in seat of the pants power and performance from the mowers.

2: 2 stroke engines at least the ones I have for weedeaters and scooters don't operate with quite as much power on E-10 fuel.

3: With a 2001 Ford Focus commuting 750 miles per week over a 2 1/2 month span, a switch from E10 to regular unleaded cost us about $1.20 more to fill up, but we gained an additional 40 to 50 miles per tank of gas.

YMMV certainly applies here. In short, I would encourage everyone to experiment and see what your car or truck likes the best. For us E-10 fuels might be great if you're looking at having to take an emissions test but otherwise...we steer away from them if possible.

[twinwitin]

I was watching the news the other night and heard that E-10 can be hard on small engines (lawn mowers, weedeaters, chainsaws etc...) that have plastic parts it gums them up and the oil can't lubricate the machine causing it to seize up. The small engine repair guys have seen an increase in repair buisness due to the E-10. They suggest the traditional unleaded also, but it is getting harder to find. There is only one place in the Eugene Oregon area that sells non E-10 gas. the repair guy also(as Kinetic V did) made the suggestion of running all the gas out of the engine and said don't store them over winter with gas in them. (I'll have to remind my teenage lawn mowing son of that one, ha ha)
We also heard that a slower acceleration and deceleration(?) would save gas. I have always been a quick accelerator, so I have had to remind myself to start slow.

[gyre]

We also heard that a slower acceleration would save gas.

This is not true.
I doubt it ever was.
It may or may not be easier on your car.

Coasting as far as possible and avoiding braking does help.
Slow acceleration is the least efficient.
Cars work well at steady speeds and full throttle.
Remapping a car for less fuel on throttle will save gas and drastically affect response, so may not be a good idea without being easy to change.
Cities aren't designed for efficiency.

Accelerating slowly is one of those things people say because it sounds good.
Like 'Hot water freezes faster than cold water'.

[Kinetik V]

A few ounces of extra fuel burned to get on the Interstate quickly and safely vs. poking up the ramp and having a hard time getting into traffic seems like a reasonable tradeoff to me.

I'm also a believer in tire pressure checking, using synthetic oils like Mobil1 or Castrol Syntec and not changing said oil until 7500 miles.

Edit: One other thing about E10 and using it on the playa. Remember the old rule that you lose 3% of your engine's rated power for each 1000 ft of altitude you go up. With the playa sitting pretty close to 4000 ft and generously rounding the numbers you're going to be losing essentially 12% of your power. Then add on the loss from burning E10 and it makes for a more compelling case to burn traditional fuel out there.

[Dark Star]

[quote="gyre"]Accelerating slowly is one of those things people say because it sounds good. Like 'Hot water freezes faster than cold water'.[/quote]

Hot water does, in fact, freeze faster than cold in many situations. You'll find many pages about this phenomena in a google search. Here's one example.
http://math.ucr.edu/home/baez/physics/G ... water.html

To put it generally: warm water benefits from a faster rate of evaporative cooling than does colder water.

[gyre]

The import of the common saying is better stated as "Hot water always freezes faster than cold water".
Monwhea Jeng assures me this is not the case.
When the experiment is restated as "Will hot water reach a specific lower temperature faster than cold water?", he assures me that this does not occur.
He has not performed these experiments himself, but collected the information.
He says the conditions for the effect are very specific and difficult to reproduce.
We discussed convection, turbulence and superheating.
Nice guy, very interesting.
My grasp of physics is weak, so someone with more background should chime in.
I remain unconvinced of the effect, but, as always, intrigued.

His latest paper
http://arxiv.org/abs/physics/0512262v1

A recent paper from the March meeting
They claim to be able to reproduce the effect by heat cycling the water.
It appears they are freezing room temperature water faster than room temperature water!!! Is this even the mpemba effect at all?
The effect of nucleation around bubbles may be a factor. I can reproduce superheated water in a microwave and nucleation appears to be the factor there, though I think it has to do with motion of the water. Bubbles boiled out may be a factor though. I think the consensus is on motion.
http://meetings.aps.org/Meeting/MAR08/Event/77535
http://absimage.aps.org/image/MWS_MAR08-2007-006331.pdf

[mdmf007]

cold water freezes faster than hot water

[gyre]

Accelerating slowly is one of those things people say because it sounds good. Like 'Hot water freezes faster than cold water'.

Hot water does, in fact, freeze faster than cold in many situations. You'll find many pages about this phenomena in a google search. Here's one example.
http://math.ucr.edu/home/baez/physics/G ... water.html

To put it generally: warm water benefits from a faster rate of evaporative cooling than does colder water.

Have you ever done this yourself, and if so, how?
I can only picture evaporative cooling being adequate in an extremely dry environment when there is a great ratio of surface to volume, such as the example of fishermen splashing hot water on their poles.
I have used boiling water to thaw things out in cold weather and this was not my experience.
There may be some empirical evidence of greater expansion or force from hot water frozen in tubes, but even that is statistical and I am unsure what it means if true.
_______________________________________________________
It would be a shame if I had to resort to self-deception to preserve my faith in objective reality.

[Captain Goddammit]

OK, I can't take it!
First of all, octane. Knock is the ONLY issue... "octane" refers to a fuel's ability to resist "knocking" or preignition. That's what octane rating means. There is NO more power or energy in it. Higher compression ratios require higher octane fuel to resist knocking... the extra efficiency and/or power comes from the higher compression ratio. Not the gas.

It doesn't matter what rpm your engine's efficiency peak is, going faster than around 40 or 50 will NOT result in better mileage. Aerodynamic drag increases exponentially with speed. Faster speeds require more energy per mile, and the savings of operating your engine in it's "sweet spot" are more than eliminated by the extra drag.

Full-throttle starts will not get you better gas mileage. This is another example of a tradeoff that isn't positive. Even if your engine operates most efficiently at full throttle, it requires so much more energy to quickly get all that mass moving that there is still a net loss. The only time this works is on ultra-lightweight vehicles with small engines tuned for peak power at a specific throttle setting... I know, the high-mileage competitors use the "burn and coast" method to achieve the greatest MPG, but in a standard car designed for efficient operation over a broad range of operating parameters, it doesn't work the same.

Stomping hard on the gas and avoiding getting crunched into road pizza by a semi is certainly the most efficient option at the time.

[gyre]

What I said about octane was a specific reference to the hypermiler link.
They said you only need high octane to prevent knock.
This is wrong.
Even when my advance was set low enough that knock never occurred, I have seen a mileage loss in some cars using low octane fuel.
I'm not qualified to argue compression or energy density as an efficiency factor.

More energy dense fuels tend to have higher ignition resistance but technical cheats that achieve resistance are common.
Some fuel is simply better than others.
Octane measurement is a complicated issue.
The race gas I use doesn't even have an octane measurement as the number is misleading, but it is over 112.
I stand by what I said.
Some people will save money with high octane, some won't, regardless of knock issues.
Some cars have adequate knock sensors and adapt but lose mileage.
Tuning the car to the edge of preignition is the ideal.
I once had my car tuned to the point where it would not run on exxon premium, but shell or mobil of the exact same octane measurement ran perfectly.
There was a difference.

Drag does increase with speed.
I presume you will be driving to the burn at 15 mph?

There is no magic number.
Most efficiency records are set at speeds over 100 mph, admittedly with ultra low drag designs.
Aerodynamic factors vary from one car to another.
Excess power is wasted at lower speeds.
Many big engines get poor gas mileage due to overly low gearing, not due to bad engine design.

75% to full throttle is more efficient in almost all cars due to many factors such as less time spent out of cruising mode, heavier (and more efficient ) load on engine and others.
There may be some exceptions that are artificially modified for better performance at part throttle.
The prius may be one of those.
I can't recall offhand.

Research this and you will see universal agreement.
BMW has done extensive research in this area in particular.
SAE.org is a useful source, as is Road and Track's technical info online.

You may not wish to drive this way.
Just don't kid yourself about it.
It may be very unwise to use throttle for other reasons, especially when towing, but saving gas isn't one.
Steady speed once at cruising speed is the target, of course.
I didn't come up with all this on my own.

[gyre]

CG, if you're driving a diesel, the throttle efficiency may be different.
Diesels vary and the technology is evolving rapidly.
Did you catch the recent article in R&T about the new advanced diesels in europe?
I have heard of some diesels tuned for delivery that had maximum mileage at extremely slow speeds.
I passed on an Izusu coupe a while back and I really wish I hadn't now.
Too small for burning man, of course, but a great deal.
The ugliest car I've ever seen, but it had the pickup diesel in it.

[thirt33n]

damn...you guys are smart.
i'm glad you're my friends.

[mdmf007]

Octane rating only refers to the ability to spontaneously detonate. It gives no more power over lower octane ratings.

Where you do get more power in higher octane ratings is in engines that need it, these engines run at a higher compression rate. A lower octane rating run in a higher compresion engine, will knock, or pop the heads off. The fuel is detonating on its own before the piston is at TDC (Top Dead Center) in effect trying to shove it back down, before its all the way up. Higher octane resists this urge and allows the spark to blow it off.

a higher octane rating in an average engine makes no difference in power or efficiency

Wind resistance is a function of the square. resistance at 100 MPH isnt simply twice that of 50MPH. So i would have to believe that there is a happy medium.

later