Improving Fuel Mileage

[olds]

Other than driving like an old lady and keeping my tires to sidewall pressure (joke), how can I improve my fuel mileage?

Do things like hotter plugs, coils, etc. work?

I looked at the chips but at $350 I doubt it would ever pay for itself in fuel savings.

 

[jlee]

http://forums.anandtech.com/showthread.php?t=321054

 

[olds]

http://forums.anandtech.com/showthread.php?t=321054

There's a lot of drivel in that thread. Anything about electronics?

 

[Draftee]

This is well worth a read:

http://www.volkswagen.de/etc/medial...pps.Par.0008.File.pdf/effizient_unterwegs.pdf

 

[Vette73]

Yep the big ones are good tire pressure (NOT sidewall), use thinner oil (5w30), keep car up to spec (air filter, fuel filter, PCV, etc...), and if you have a diff many use to call for 80w80 and many switched over to a Syn 75w90. Not a high differance but if its time to change and you are trying to squeeze everybit out.

Also spraying out the throttle body with cleaner every 30k helps a decent amount as well.

 

[TraumaRN]

A really simple one.

Use your cruise control. Like everywhere. I know it sounds silly but most people can't modulate the pedal/throttle anywhere near as good a computer can.

If you aren't comfortable using cruise control in city driving then take the time to figure out exactly how much pressure is needed on the pedal to maintain common speeds and nothing more. Basically looking for the lowest RPMs possible that keeps you at a steady speed.

Coast up to stop signs/red lights instead of just slamming on your brakes. And at the same time try and time the light so that you never quite stop if possible. Takes alot more energy(aka gas) to move a car from a dead stop then if you are going 5 or 10 mph.

 

[Bignate603]

The cheapest is to just changes your fluids, your filters, and check your ignition (plugs, wires, distributor cap if you've got one). Take out any weight in the car you don't need, dragging around an extra 100 lb in your trunk won't do you any favors for fuel economy.

If you've got a truck or SUV and it is only used on the road you can get tires with a less aggressive tread the next time you replace your tires. Tires with more aggressive treads have higher rolling resistance.

 

[superccs]

Don't drive in traffic, as in find something to do wafter work while traffic dies down (just not drinking at the bar I hope).

 

[XZeroII]

Put up a mast and sail. Only drive with the wind.

 

[Kirby]

Remove your spare tire, air conditioner, and seats. you can sit on a 5 gallon bucket.

 

[archetypaul]

A really simple one.

Use your cruise control. Like everywhere. I know it sounds silly but most people can't modulate the pedal/throttle anywhere near as good a computer can.

Unless there are any sorts of hills, cruise does the exact opposite of what's right in any sort of elevation change. Accelerate about 10 mph faster before a hill so you can coast up it. Never fight the gravity down a hill, cruise will hold you at the speed you told it to.

 

[Zap]

Other than driving like an old lady

Actually some old ladies drive pretty fast. You mean "driving like a hypermiler." :twisted:

You can drive in ways which saves gas without being that "old lady." Let off the gas in anticipation of stops. Never going above the speed limit. No "jackrabbit" starts.

Heck, if I practiced what I preached, I'd probably get an easy 2-4MPG gain. :awe:

 

[Kirby]

Actually some old ladies drive pretty fast. You mean "driving like a hypermiler." :twisted:

You can drive in ways which saves gas without being that "old lady." Let off the gas in anticipation of stops. Never going above the speed limit. No "jackrabbit" starts.

Heck, if I practiced what I preached, I'd probably get an easy 2-4MPG gain. :awe:

I actually heard* you get better mpg from a quicker start and short shifts because you get into a higher gear more quickly.




*Could be utter bullshit and/or a figment of my imagination

 

[CraigRT]

Use your cruise control. Like everywhere. I know it sounds silly but most people can't modulate the pedal/throttle anywhere near as good a computer can.

Cruise control is not good for fuel economy unless you live in the salt flats.
As soon as you hit a hill, the car uses more and more throttle to try and keep the car at the same speed. if the person behind the wheel is fuel conscious they will just keep their foot at the same position on the gas and lose some speed climbing the hill.

The best way possible to improve fuel economy of any given vehicle is how it's driven. Period.

I get great fuel range out of my Maxima but its because I cruise in 6th gear on the highway and even around town when I'm moving well enough.

 

[Jumpem]

Always use cruise control, and stay within 1-2mph of the speed limit.

 

[LTC8K6]

If you have a poor cruise control, then it can waste fuel. Modern vehicles should have excellent cruise controls that will save you fuel. The last couple of cars I have owned have had nearly perfect cruise controls that kept the speed right on, even going up and down hills.

Modern cars with autos will downshift to maintain the cruise speed downhill, this downshift shuts off the fuel, saving you even more fuel than coasting.

 

[TraumaRN]

Cruise control is not good for fuel economy unless you live in the salt flats.
As soon as you hit a hill, the car uses more and more throttle to try and keep the car at the same speed. if the person behind the wheel is fuel conscious they will just keep their foot at the same position on the gas and lose some speed climbing the hill.

The best way possible to improve fuel economy of any given vehicle is how it's driven. Period.

I get great fuel range out of my Maxima but its because I cruise in 6th gear on the highway and even around town when I'm moving well enough.

Oh I know about disabling cruise control on big hills however I live in an area that's generally flat as a board so generally I can set my cruise and forget it and my Fusion Hybrid has a pretty 'smart' Cruise and adjusts for the few small hills around here by letting the car bleed 2-4mph in speed so less throttle is needed, shuts the engine off on any steep downhill or goes into a advanced spark leaner burning state.

But anyways you are right I should have clarified my first post and said use cruise but in a smart way so to speak

 

[Howard]

I actually heard* you get better mpg from a quicker start and short shifts because you get into a higher gear more quickly.




*Could be utter bullshit and/or a figment of my imagination

I can believe it. My CTS reads 99L/100km for any sort of decent acceleration in 1st, and about 40-50L/100km for the same in 2nd. Starts getting better in 3rd, and 4th is pretty much ideal.

 

[exdeath]

I actually heard* you get better mpg from a quicker start and short shifts because you get into a higher gear more quickly.




*Could be utter bullshit and/or a figment of my imagination

That has to do with the throttle being a huge restriction.

If you accelerate hard, you have the throttle open and the engine is at it's best efficiency.

The idea is you use alot of fuel in a short time (20&#37 to get to cruise where you use the least amount of fuel for the remaining 80% of the time. You spend less time in load with a closed throttle.

VS. having a part open throttle under load 100% of the time and taking longer to get to cruise speed where the engine isn't operating efficiently having to suck air through the throttle restriction.

In laymans terms, the former uses high fuel consumption for 20% of the time and low fuel consumption for 80% of the time, and averages out to be less than the latter medium fuel consumption 100% of the time for the same distance. You're spending less time accelerating with the engine loaded and restricted.

 

[Howard]

That has to do with the throttle being a huge restriction.

If you accelerate hard, you have the throttle open and the engine is at it's best efficiency.

The idea is you use alot of fuel in a short time (20%) to get to cruise where you use the least amount of fuel for the remaining 80% of the time. You spend less time in load with a closed throttle.

VS. having a part open throttle under load 100% of the time and taking longer to get to cruise speed where the engine isn't operating efficiently having to suck air through the throttle restriction.

Which is why I'm not sure that using cruise control is ideal at highway speeds. Hypermiling procedure tends to be constantly speeding up and coasting down rather than the maintenance of any given speed.

 

[obamanation]

Which is why I'm not sure that using cruise control is ideal at highway speeds. Hypermiling procedure tends to be constantly speeding up and coasting down rather than the maintenance of any given speed.

It depends on the vehicle. Some vehicles have no torque so when you have cruise control engaged and you hit an incline, it downshifts a gear just to maintain speed, something that could have been avoided if you were manually modulating the throttle. I'd say use cruise control and see what kind of inclines get the vehicle to downshift, then when you're driving, use cruise control and disable it when approaching those inclines. One thing I like to do is gradually speed up in anticipation of inclines, maintaining a steady throttle position so that when I hit the incline, I lose speed. Better to gain momentum before the hill then to attempt to maintain it when you reach the hill.

 

[TraumaRN]

Howard- remember that alot of people that hypermile do so in hybrid cars where the coast literally uses no gas(uses electric motor) so in a sense that's infinite mpg. But alot of pulse and glide involves light throttle pressure during the glide phase basically depressing the throttle enough to lose speed but very slowly, imperceptible if you were riding as a passenger but for most modern cars and especially hybrids this light amount of throttle is very fuel efficient

 

[Howard]

Howard- remember that alot of people that hypermile do so in hybrid cars where the coast literally uses no gas(uses electric motor) so in a sense that's infinite mpg. But alot of pulse and glide involves light throttle pressure during the glide phase basically depressing the throttle enough to lose speed but very slowly, imperceptible if you were riding as a passenger but for most modern cars and especially hybrids this light amount of throttle is very fuel efficient

I don't believe any gas is used when coasting, even with conventional drivetrains.

Also, can you provide something to back up your latter statement?

 

[jlee]

Which is why I'm not sure that using cruise control is ideal at highway speeds. Hypermiling procedure tends to be constantly speeding up and coasting down rather than the maintenance of any given speed.

Ugh in a land with few highways and not many passing zones, it's so annoying to be stuck behind someone like that...

 

[TraumaRN]

I don't believe any gas is used when coasting, even with conventional drivetrains.

Also, can you provide something to back up your latter statement?

For that latter statement only my own driving and my wife's but taking my Fusion Hybrid for example I can apply that light throttle touch on flat straight road and my instant fuel economy will basically peg off scale(60+ mpg) I can replicate this in my wife's Focus as well. It's part of the reason my long term MPG on my Fusion is 48.4mpg. And in my wife's case her first fill up using this method with 50% city/50% highway driving she managed 38.1mpg. I'd post more but I'm posting from a cell phone I'll post more later tonight on our driving experiences and fuel saving techniques.