Improving gas milage

Is there any way to improve gas milage on a car?
And are there performance parts that don't cause you to use more fuel?
Since I'm a poor high-school guy I can't affort much.
Prices here are around 1,45 euro for 1 litre fuel (about 7 dollars for a gallon if I'm correct).

keep the rpms low and driving habit affects your mileage more than you think. if you, like some people always tailgate others, you'll be constantly using gas and brake and that'll give you bad mileage. Be consistent on the gas.

I rode in a friend's car once, auto, where it seems like they only know how to either floor it, or apply no gas at all, so during cruising on the freeway, your head would tilt forward and back because they are constantly adjusting the gas instead of holding it constant.

Using too thick of motor oil will give you bad gas mileage too. Too much resistant force, oil is too gooey.

Using a thinner oil will give a better mileage, so will a good synthetic oil.

When accelerating accelerate fast up to speed (the best efficiency of an engine is close to full throttle) and then use the highest gear possible for your speed (this will increase load and reduce friction) and keep the speed constant.

Don't use the brakes if you can, let the engine slow you down instead without you touching the throttle (electrnic fuel injected cars shut off the fuel then).

Advance the ignition timing might also help to reduce the fuel consumption.

It might seem strange but you can get the lowest fuel consumption if you give almost full throttle up to speed, then shut off your engine and roll until the car almost stops, then you start your engine and accelerate once again.

It's my personal opinion that anything that helps your car work less and perform more is always a good thing. And if more HP is delivered to your engine then it works less and performs more. So with this given I think it helps your get better MPG but not a whole lot I bet. You will probably get like a 2-3% improvement in mileage for more power output that your car burns less fuel.

First of all the car you drive is most important. The things that impact a car are...

1)How heavy the car is...

2)How many cylinders the engine has

3)If it is V-Tec it usually tends to use a little more gas because higher torque demands more gas.

4)If you have a DOHC, you will burn gas faster then when comparing to SOHC.

5)Buy a 4 cylinder for commuting and for weekend street races save up for a Z06 C5 Vette from all the gas you saved.

AFTERMARKET PARTS AND MODIFICATIONS
IF you want to optimize your MPG to the FULLEST here is what you will need...

1) Superlight Racing Wheels that weigh less than 10 Lbs.

2) Superlight Ultra High Performance Racing Tires

(If your wheels roll easier it's less stressful on your engine giving you better mileage. Imagine a Boulder to a marble...)

3) Injen or AEM Cold Air Intake (Clean filter every 3 months replace every 1 year.)

4) 4-1 High Flow Heat Resistant Headers

5) High Flow Catalytic Converter (Magnaflow or Dynomax Preferably)

6) Full Cat-Back Racing Exhaust System (Good ones: GReddy, Magnaflow, Borla)

7) Remove Spare Tire + Jack (Weight Reduction 40 Lbs+)

8) If you drive alone remove passenger airbag if possible (Weight Reduction 15+ Lbs)

9) If you dont listen to music alot... remove the stereo system (Weight Reduction 50-100 Lbs+) Get a CD Player and listen to your CD's.

10) Remove Undesired Panels from your car + any junk from engine compartment (Weight Reduction 20+ Lbs.)

11) Switch to Amsoil 2000 0W-30 Racing oil (GET THEIR ENGINE FLUSH FIRST) It's Nascar's Racing Oil and if Nascar pros use it, your should too.

12) Get NGK Iridium IX sparkplugs + Magnecor Racing Ignition Wires. Better ignition means better engine efficiency.

13) Buy Chevron Techron Fuel Injection Cleaner and add it to your tank every month. This fill free up lost power in your engine to contaminants.

14) If you can always buy Shell Gas. It's cleaner and lasts longer.

15) If your car only takes regular unleaded gas NEVER buy premium gas! The higher the octane the more less of a liquid and more of a gaseous for gas is. So in the summer it will evaporate up to 2 times faster than unleaded!

16) If you know how or if you know a speedshop, buy an overhaul kit and install it every 100K miles on your car to keep your engine running smooth, or just get stage 2 or 3 internals (The parts in your engine going High Performance).

17) If not needed, remove your AC for less weight and better MPG.

18) And of course get an AEM Tru Pulley Kit for your car if available.

DRIVING HABITS

1) If you drive a stick always start it in 2nd gear and keep RPM'S below 3K whenever possible. Shift up early if you have time to drive and down shift earlier when you need to stop.

2) When going down a hill at more than a 33* Degree angle switch to neutral for as long as the downhill lasts and let the car roll on it's own weight.

3) Dont be a lead foot and pound the gas all the way... especially if there is a stop sign in front of you.

4)Drive at the speed limit or below the speed limit. If you constantly drive around 80-100 MPH you will lose gas faster due to the torque the engine needs to maintain that speed.

5)Avoid unecessary stops like stop signs and traffic lights. Try going the shortests distances with downhills and less stops.

6) Turn off your AC when driving. Open up your windows half way when driving but not all the way as this will make your car less aerodynamic. Acting as a parachute which will stress out your engine more.

7) Dont carry luggage with you on your car. Anything you dont need in a car should be removed.

NOTES:
Some people just get an Intake and an Exhaust and think that they will get better mileage right away. But that is only part of the breathing aspect of an engine. In order to get better MPH through natural asperated engines you need the whole spectrum of upgrades.

The intake is the first part and then the engine does the work. Afterwards it needs to expel the waste through the exhaust.

Which first needs to go out of the headers or extractors, and if you got stock headers and a high performance muffler... You are being restricted at the front by your stock low flow headers. Not giving you the full efficiency of your rear exhaust.

Not only that... but if you got a stock catalytic converter it is also restricting both the headers and the exhaust. The cat converter connects the headers to the muffler exhaust. It's right in the middle and acts as a link that hooks up headers + exhaust so it's also in the way of the entire asperation system.

So basically...
Intake and Catback Exhaust is NOT ENOUGH
The restrictions are stock headers and cat converter.

What you need:
1)Cold Air Intake either AEM or Injen
2)Race Design 4-1 Headers w/ heat resistance
3)High Flow Catalytic Converter
4)Racing Cat-Back Exhaust.

ZERO restrictions to airflow.

I may be wrong in a few things but I hope this helps...
-Nexagen

1) If you drive a stick always start it in 2nd gear...

Why would they put a first gear if it's not efficient to use it? According to your theory, we should just have one big gear for all speeds.

5)Avoid unecessary stops like stop signs and traffic lights.


Avoid stop signs or avoid stopping at stop signs?

What I mean by that is if you can go down a road that has little or no stop signs take it. I dont mean for anyone to break the law and I do value other people's lives when I am behind the wheel always.

Just choose and find roads that have less stops. If you do need to stop by law you should and you should do so unquestionably.

-Nexagen

First off, note that an engine have better efficiency when the load is high, that means when it works near wide open throttle. Many people tends to believe it's the other way around, which is, of course not true.

Because of this reason a smaller less powerful engine will in general give the lowest fuel consumption.

Never put the gear in neutral and let the car roll. Use the engine as a brake, almost all cars with electronic fuel injection shuts off the fuel when you don't give any gas, unless the gear is in neutral and the engine is running on idle.

The octane rating of a fuel is NOTHING more than a practical value on how the fuel can resist engine knock. Buy the fuel that is recommended in you instruction manual, nothing else. Don't use any addetives, not in the fuel and not in the oil.

Your car has a system that prevents the fuel to evaporate from the tank. The fuel companys also match the fuel for the season, this means that in the summer it takes more to evaporate it than in the winter, there is also no difference between octane ratings.

Mobil 1 is what most NASCAR Nextel Cup teams use (over 70%), it's also the official NASCAR oil. Buy a good oil, I won't say buy that or that brand, just buy a good synthetic oil that fulfills the requirements listed in the cars manual. Some oils also improve fuel consumption, in that case they will be marked with API EC and/or ILSAC GF-2.

DOHC engines offer better fuel consumption, power and lower exhaust emissions.

Don't buy any special spark plugs or ignition wires, use what the manufacturer recommends. Something that do decrease fuel consumption is a more advanced ignition.

Remove unnessecary weight from the car like spare wheels, use a lighter battery but you don't need to do that much more than that, any improvements won't be worth it.

Run the car without the AC, but note that it must be used sometimes to stay in condition.

Cold air intakes, filters and so on, they won't make any difference that you will notice.

The best way to improve milage is to remove unnessecary weight like the spare wheel, keep the car in good condition, use a good synthetic oil, use the right fuel, use the correct tire pressure and drive correctly without the AC.

With drive correctly I mean accelerate fast with a close to wide open throttle, then use the highest gear possible and drive at a constant speed. Use the engine to slow down. Plan your driving, don't stop unless it's needed.

two words...cruise control.
use it when you can...it makes a difference while driving on an open freeway or highway

Thank you all for your information, it was very helpfull.

So if I'm right, gas milage is very dependant of your driving habits.
But if you have to buy all the things you listed, wouldn't that cost me a large amount of money?
For example, If those modifications cost abou 1k I could buy a lot of fuel woth that.

I think proper maintenance of the car and driving habits will give you the best mileage. The cars we get in the US were designed to minimize emissions, not maximize mileage, but I'm sure the companies try to maximize efficiency in terms of more power per fuel used, that's unless you buy an American made car, Ford, Chevy where everything is v8, then you'll have low mileage no matter what. But they compensate for the huge fuel consumption by having bigger gas tanks. :)

Then you have drag racing cars in which the primary goal is get as much power as you can by dumping as much fuel in the engine possible.

First off, note that an engine have better efficiency when the load is high, that means when it works near wide open throttle. Many people tends to believe it's the other way around, which is, of course not true.


When driving at WOT though, wouldn't engine revs be higher? And so use more fuel? I understand that by using WOT, you would be able to get to higher gears faster so you save gas, but would you not also waste more through the high revs?

When driving at WOT though, wouldn't engine revs be higher? And so use more fuel? I understand that by using WOT, you would be able to get to higher gears faster so you save gas, but would you not also waste more through the high revs?

Load is a separate issue from engine speed, wide open throttle is 100% load.

http://hem.bredband.net/b132378/annat/bransleforbrukning.jpg

Specific fuel consumption plotted against rpm and load for an Opel engine.

Note that engine speed doesn't affect specific fuel consumption much but that load do. The lowest specific fuel consumption is achieved at close to full throttle, especially in the usuable power range of about 2000 to 4000 rpm but that doesn't affect that much.

So when running the car energy is needed, we will need the same energy even if we accelerate fast or slow and at constant speed the same amount of power will be needed independant on the engine speed, so this means that the mean power consumed is the same (as long we don't compare driving at different speeds).

Of these reasons it's best to use the engine with a high load, that means to acclelerate fast with close to full throttle and at constant speed use the highest gear so the engine speed is low and load is high (compared with higher engine speed and lower load).
At higher load less fuel is consumed per power delivered by the engine.

Note that a turbocharged engine for road use is usually designed to give it's lowest fuel consumption with a little less load, this has to do with the high compression ratios while boosted and the smaller displacement for the same power.

Thanks for explaining.

Cheapest modification for improved gas mileage: Have your high school friends give you money for gasoline! They only add to the dead weight of the automobile. You won't have to modify anything other than the spending habits of your friends!