Thoughts on Fuel Economy:How to Stretch a Gallon of Gasoline

So Cops are tire experts now ? I thought Cops were experts on Tazing people

He was discussing OVER inflating the tire. Tire pressure can make quite a difference in vehicle handling. There is an ideal and that changes w weight and temperature.

You cant get better mpg AND better handling and braking all at the same time. A tire can only do a few things and it cant do them all simultaneously

This is why there are tires for mpg, for motorcycles, for airplanes, tractors, race cars etc. Each tire does what its meant to do best

To say that 1 magic tire can give you ideal mpg, handling & braking simultaneously is not accurate

 

Do you know why diesel Jettas' are not sold in the US any more? Besides, you are hijacking the thread - the way you drive can make more of a difference as trading a current vehicle with a similar hybrid or diesel one.

When I've seen the results from economical driving, higher tire pressure on my own car and others, I give them a lot more weight than an all-knowing newbie. This kind of driving would be foreign for a racer, but hopefully you will occasionally listen while you are here.

 

No, I'm not hijacking, I'm trying to keep people from having accidents while chasing mpg w overinflated tires

as a racer I know plenty about what makes tires handle, brake, & accelerate

The mpg I'll leave to you guys

 

"How to Stretch a Gallon of Gasoline"

Plan ahead. Drive less! Live life someplace else besides behind the wheel.

 

underinflated tires are the ones that heat up and blow up. this phenomenon on SUVs is why all new cars get federally mandated TPMS.

 

its not a good idea to either underinflate or overinflate

Both are asking for trouble

in the Ford Explorer case, Firestone had the proper pressure on the tires but Ford wrote a different pressure on the visor which caused the tires to fail

 

well, overinflation decreases the contact patch with the road so you lose traction. but hypermilers (the ones who are gonna be doing this overinflation stuff) are really slow, careful drivers. not the type to break into a skid. no, i'm not one of em- i'm not that patient.

 

As a racer you should be well aware of when it is appropriate to overinflate and underinflate a tire. Depending on the circumstances and the tire either is ok.

 

Maybe but is the 21 yr old on crack driving an 18 wheeler next to you also a careful driver ?

 

I smell a Troll

I smell a troll. 56 posts since joining yesterday? No Prius?

 

Better Mileage in ANY car - Best in a Prius

Here's the thing about fuel mileage. You get the most from each gallon when you use it to propel your vehicle forward. What else might I do with it you may ask? Well it's not so much what you do with the fuel it's what you do to the car once you've spent the fuel getting it rolling.

#1) Slow down. Anyone who disputes the fact that driving slower saves fuel should be sentenced to two weeks of hard math with an aeronautical engineer! Each additional MPH adds more friction than the last. So go slow(er) and save fuel.

#2) Don't slow down. (Huh?) Right. Every time you touch the brakes (Yes even in a Hybrid) you are losing energy already spent to put your car in motion. Ways to do this are many but a couple key ones are:

2a) Don't tailgate. When you do you must brake EVERY time the guy ahead of you does because otherwise you'll HIT HIM! Leave a nice margin allowing yourself to coast (or glide) while he brakes. Use the cushion to your advantage. As a bonus you'll be more easily able to see over and around the guy. (AND you'll be less stressed)

2b) Look ahead. When you see a light change lift your foot immediately. When you know a stop sign is ahead glide to it! Don't burn another drop of Fuel getting to a red light while it's still Red. Don't get to a stop sign before the guy ahead of you has begun to move. Both of these things lower your peak speeds while doing absolutely nothing to your average speed. They don't cost you a second!

3) Accelerate less mass. Clean out your car! Everything additional in there needs to be accelerated and eventually the energy imparted to it gets burned up in the brakes. The additional weight also puts more heat into the tires and the shocks. ANY heat created is lost energy and must be replaced by burning more fuel.

4) Keep your vehicle maintained. Good oil. Good Shocks, Good tires properly inflated. Tires aligned. Brakes clean and properly adjust so as not to drag. Don't let things hang out, drag, or flap in the wind.

5) Learn your routes and know when going 5 over is going to keep you rolling through lights without stopping and when 5 under will do the same. Even speeds are so much better than up and down. If you drive a Hybrid find those routes with the 1/2 mile or more downhill runs in 35 or 40MPH zones and glide them for all they are worth!

6) Keep the engine warm. Four trips a day with 2 hours between them burns more fuel than the same four trips back to back. All us Prius drivers know a warm engine gets the best mileage so why warm it up more often than needed.

7) Remote car starters? YouGottaBeKidding...

I can't even imagine that these things haven't been touched on before but they are the biggies I'm attempting to impart to my 18Yr old who drives my 2001 Prius.

 

They have, ad nauseum in fact.

There are a number of threads and stickies detailing these things as well as hypermiling and even .pdfs by companies like Cummins detailing efficiency on the road. Good list though.

 

How best to stretch a gallon of gas? Don't use a car that burns it, and it lasts a long, long time.

Stay home. Walk. Bike. Drive an EV.

Fun tire pressure tidbit: I run 140 PSI in my road bike tires. And the middle ALWAYS wears out. Of course there is nothing but middle. And it is only 3/4" wide.

 

EV only works as advertised if your local electricity comes from a nuke, geothermal, or solar plant

if your electricity is from a coal or oil fired plant then you are just relocating your exhaust gases

 

I might add: 8) Tailgate semis on the freeway, very carefully. Drafting will dramatically increase gas mileage, even at a relatively safe two car lengths. (Emphasis on "relatively" -- yes, I realize the risks here, as should anyone who attempts it.)

 

Actually it is still less of an impact than burning fuel in a normal engine.

 

Drafting

Yes Yes but some are better than others. This time of year in Michigan is great for some research. When snow is falling lightly you can watch the snow patterns off the back of trucks to 'see' where to be for best drafting. For example I have found the following:

1) Your basic 18 wheeler isn't so good unless you get inside that 2 or 3 car lengths. Too much air comes from between the trailers rear wheels and the long flat trailer roof sets the air up to crash down quickly. And as you mention it's not terribly safe because you can't see at all.

2) Moving trucks or other trailers with 'possum bellies' are better. The low belly of the truck keeps the air out from beneath the trailer causing a much better 'pull' and from a longer distance. Of course visibility isn't any better.

3) Heavy trucks with lots of axles are better too as all though axles also keep the air out from under the truck. BUt be careful what you follow, lots of those heavy trucks haul gravel and such and may be bouncing things from time to time

4) Tankers. This is very interesting to me, the long 'tube like' silver tankers that are not so tall or wide seem to be incredibly good. I have averaged 70+MPG behind these guys at 70MPH and not to close either. And the bonus is that you can see over the rear trailer wheels improving safety somewhat.

5) 'Low Boys' or heavy equipment trailers that are empty. It doesn't get any better than these guys. The very low trailer (often only 6 or 8 inches off the road) moves all the air out of the way and the rear axle set then kicks the air from the top of the trailer up in the air. Since those axles are right in front of you it's not hard be inside that 'bubble'. And as these often have smaller rear wheels you can easily see over the entire trailer. I followed one of these guys for about 15 miles at 65 to 70 MPH and was seeing 90MPG! There was simply no wind to deal with behind that guy.

5) Anything short but tall that's kicking the air up but not long enough for it to get back down right behind it.

And of course spooky good mileage comes from being boxed in with trucks ahead and on both sides. Roll I94 south of Chicago or the Tri-State and you get this fairly often. I've averaged 75MPG for over a half hour at better than 60MPH in such a box.

As always it's your life so know when you can try this and when conditions make it just plain crazy to try.

One additional thought. If there is any significant side wind then drafting often is ruined.

-DrFranken