A hypermiling intro...
 

I put this little thing together, critique it!

www.crxmpg.com/hypermiling.html

Also, I know my pictures are all down, I'm working on it!

Nice Job. I good intro indeed!!

Although, I do have to say something about this...

This doesn't really make much sense. If a vehicle has true 4 wheel drive, you CAN'T use it on dry pavement, and vehicles with "real time" 4 wheel drive cant turn the 4 wheel drive feature off.



BTW, Ive never heard of a "Hot Air Intake" before. Very interesting. What makes Saturns like them?

Also, you may want to mention a "Cold Air Intake". You know, for normal vehicles. LOL :D


EDIT:

One more thing, about removing the alternator belt. About how long can an average vehicle go without an alternator?

For 4wd, I am refering to unlocking the wheels.

Iono why saturns like hot air, but they take to it very well. I, for my part, think cold air results in worse mileage for various reasons.

*shrug* on how long a car can go...depends on how much power you're sucking, how large the battery is, la la la. Just have to try it I guess.

This is based on what I learned in my Thermodynamics course I took for Engineering.

Basically, the power of an engine is dependent on the overall temperature difference between hot and cold. The cold temperature is based basically on the outside air temperature. The hot temperature is the engine temperature after the combustion of the air and fuel in the cylinder. So power is related to the hot temperature minus the cold temperature.

To illustrate this, let's compare temperature with height. Let's say you're standing on the sidewalk. Let's say the sidewalk represents the cold temperature, whatever it may be. Let's say the top of your head represents the hot temperature. So your overall height is the same as the "temperature difference between hot and cold temperature." Now, imagine standing on a strong box. Now, the top of your head is now higher after standing on the box than before you were standing on the box. Since the top of your head is now higher compared to the sidewalk, that height increase has made you "taller." So thermodynamically, by using warm air intake instead of cold air intake, just like the strong box make you feel "taller", you have given the engine combustion a thermal "boost" in order to reach higher temperatures. So that increases the overall temperature difference which also increases power. Remember, that the cold temperature point is the temperature of the radiator and not the temperature of the air intake. However, it may not be safe to simply raise your engine temperature indefinitely to increase the temperature difference to increase power because even your engine block is made of a material with a melting point like ice cream. :)

At a relatively more advanced level, I read somewhere that one mod is to replace the thermostat so that the engine runs hotter because the fuel/air mixture is leaner therefore saving fuel. I'm guessing this trick works by tricking the mixture control computer into using less fuel. However, relatively warm air is less dense than cold air. That means cold air has more air molecules per volume than warm air. So using warm air intake, in order to maintain the same fuel/air mixture ratio, the fuel control system would reduce the fuel flow because the warmer air has less air compared to cold air.

I hope this helps.

Indeed. I did not mention the IAT trick because I do not like the fact that it lies to the ECU and creates a lean condition (that would result in more NOx pollution).

I also understand why the WAI works, in theory, but the reason I qualified what I said for Saturns was because it does not work on my car and has been reported to not work with many other cars. However, it seems that Saturns almost always benefit from it. It seems to be in the ECU programming of many vehicles to retard ignition based on increasing IATs in order to prevent knock, but the Saturns may not have this safety valve or it may work differently. Or it could be something different entirely.

Iono, *shrug*

I see. Since I'm a newbie to GS with a gasoline car, how about reorganizing the introduction by starting with hypermiling techniques that can be done with an unmodified gasoline car, then hypermiling techniques for an unmodified hybrids, then maybe advanced techniques/mods for gas and hybrid?

clear me up on Item 5
 

First of all great job and very informative.


5 - Avoid rapid acceleration and hard braking
These sort of actions waste gas. Instead of braking hard, coast from as distance. Use your brakes as sparingly as possible. Also, be aware the slamming the gas will only dump more fuel on than is necessary. Conservative acceleration will generally return the best fuel economy.


The braking part is what confuses me. How does hard braking hurt mpg.

Maybe I just read it wrong.

retrorocket

Why does braking hurt FE? Because you used gas to build speed/kinetic energy in the car. Allowing the car to coast to a stop uses it all up.

If your braking hard your wasting fuel you already burned.

In my old automatic saturn WAI really helped the car shift into the next gear better at low rpm with a lite throttle (1,300rpm shifts rather than 1,600rpm shifts). I never had it scangauge tested, but I believed it helped.

It's mainly meant to be an introduction. I have another article that's a little more in depth on such things.

And lovemysan is correct with the braking issue. I should clear that up too. You just need to be careful where all your momentum goes, so rather than racing up to a stop, realize you'll have to stop and use your momentum to coast.