F.Y.I. Improving Gas Mileage - List
 

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Ok, I thought I'd make a huge list of things you can do to improve your gas mileage since everyone is always asking about this.
So go ahead and post your suggestions and I'll just keep editing the first post to include them all. Thanks!

External Factors

1. It goes without saying, don't race your car around. Drive conservatively.
2. Keep it under 110km/h. (wind resistance + high rpm in cruising are bad)
3. Drive with your windows closed. (wind resistance)
4. Stop using the A/C so much... or at least get it checked to make sure it's still efficient.


Lightened car

1. Remove all un needed weight if possible
2. Sound deadening = approx 25lbs
3. Huge heavy stereo system
4. Entire A/C system is approx 45 lbs
5. Convert to JDM CRX front and rear bumper rebars = approx 50 lbs savings


Suspension

1. Get an alignment! Anything that prevents your car from rolling straight will rob power and create resistance (from your tires wearing out prematurely).

2. Fix your bushings! This is my own belief and here's why... I had a bunch of crap in my back seat and trunk that was weighing my car down. Now you might think it was just the weight, but I think it's also why my rear tires have worn out prematurely. During this time I also had severely bad gas mileage (25-30 mpg). Somehow, my tires had negative camber with all the weight because all the wear was on the side walls on the outside. I since removed the boxes and crap and magically my gas mileage is improving (without fixing the bushings... yet).

3. Check your tire pressure to make sure it's correct. High pressures within tolerance = better gas mileage.

4. Make sure brakes are in good order and not sticking. This goes for the emergency brake too. Lift your car up and try to spin the wheels. If they have any resistance (they slow down too fast) then something is wrong.

Engine

1. Get a new o2 (oxyden) sensor. If they go bad, or are very old 10+ years, you will definitely have bad gas mileage. But if they're giving low voltages because its dirty, your ecu will think you are going lean and will dump more fuel to compensate. Check your muffler tip to see... it will be BLACK, not dark gray.

2. Change your PCV valve.

3. Check and correct your timing at the distributor with a timing light.

4. Get rid of that eBay chip. It's crap... go back to stock or get it professionally tuned.

5. Change/clean your air filter. Get a K&N to replace a stock air filter.

6. If you're turbo, get rid of the FMU and the piggyback. Get a professional tune using Crome/Uberdata/Hondata/Turboedit/Neptune. Or do it yourself with a wideband o2 sensor.

7. A clogged fuel filter will ruin your mileage.

8. Check valve lash when the manual says to.

9. Check/change spark plugs. All you need are NGK copper V-power plugs. Nothing fancy.

10. Don't wait forever to change your oil. Also watch oil level.

Forgot about over sized shopping cart spoilers :P.

Good write up.

Nice write up Robb! :thumbup:

Some very good/valid points.

I think you meant to say POSITIVE camber not negative camber. Excessive positive camber will wear the outsides of the treads. :wink:


Just to add: I can't stress enough, what makes a major difference is the driver! :nod: Change your bad driving habbits and you'll see an improvement. Instead of following closely behind someone and having to brake when they brake and accelerating as hard as they do will eat up the gas fast. Keep your distance and try to time it so you're not slowing down or accelerating as hard all the time. Something to remember: The more you slow down, the more fuel it will require to get back up to speed.

Lower rpm shifting isn't always a good idea. Especially with our little weed-wacker engines. They run more efficiently at higher rpms then most other larger engines. If you shift too soon, you'll be loading the engine up when it's not within it's efficiency range, meaning it can't make sufficient torque to accelerate the car as easily...this eats gas fast. With my b16 I typically shift between 3-4000rpm. 4000 may seem a little high to some, but the engine is making plently of power efficiently to move and accelerate the vehicle with minimal throttle input (seriously, I barely move the pedal), which means it's burning less fuel. My record is 705kms to a tank (45L) last summer, and that INCLUDED an autocross event on that tank!

Making a car lighter will help reduce fuel consumption, no doubt. Especially in city driving, or stop and go traffic. The less weight or mass a car has, the less energy is required to get it moving/up to speed and maintaining that speed.

However, on the highway there is a point at which a vehicle can be too light and require more throttle input or fuel consumption to maintain a specific speed. How so? Well, mass in motion has inertia. The more mass, the more inertia there is. The more inertia, the less effect wind resistance has on that vehicle because the inertia of that mass is overcoming that resistance more easily and therefore, less throttle input or energy is required to keep that vehicle at speed. A vehicle with less mass and less inertia will be effected more by wind resistance and that resistance will be able to more easily overcome the lower inertia, therefore requiring more throttle input or energy to keep the vehicle at speed.

This, of course would be more evident at higher speeds and in extreme conditions and circumstances...Also nothing really we'd have to worry about with our cars. Just something interesting to think about. :)

You are so right on all those points, i do this on my beater car except for som of them. Its a 91 sentra but it gets 600kms to the tank but if you see the condition of this bucket, you would see better beater cars at a scrap yard. Im so serious that i had a tow truck driver that offered me $200 to scrap it for me. lol

Nice write up. i just did my spark plugs the other day and my ac was taking out weight reduction ftw lol!

key info right here!!! good write up!

A big one to follow is don't hit vtec :pout: this is when those fuel sipping 4 cylinder engines become gas hogging, power shifting, tree freshener goes sideways, tire screeching, bwaaah crying screamers. Oh and one more thing, don't drive a v8 :p

I'd recommend putting Nitrogen in the tires.

Keeps a consistent tire pressure, less rolling resistance = better fuel mileage (about $300.00/year)... and saves on tire wear as well.

I have it in my summer tires, winter tires and I even put it in the Harley Davidson.

I sell it at my dealership for $89.95... well worth it.

The question is, if you have a 10+ year old car is it worth making all these changes in order to save on gas mileage? Not like you're going to get an extra 200km out of each tank.

The age of the car is not as important as the condition of the car.

:wink:

exactly. I own two 20 year old cars, that look better than some 2 year old cars Ive seen.
LoL

^And I bet they get WAY better fuel mileage as well. :nod:

hey robb how come you never come to meets? i dislike being the only ef man

Meets are boring... been to so many in the passed 10 years... also, Im not really a 'Honda fan', but just like the 88-91 crx-civic. :)

that's besides the point

If I still had a 10+ year old civic I wouldn't be dumping all this money into it to try to hang on to it regardless of its condition.

To each their own.

If you take care of your car, you shouldn't have to dump a ton of money into it.

There is a HUGE difference between a piece of junk, rusted out 20 year old civic with a ticking engine and a mint condition, well taken care of 20 year old civic that runs as smooth as the day it was made.

As I said before, the CONDITION of a car is more important than the age.

If it's not taken care of and runs like crap, doesn't matter how old it is. It's going to get crap fuel mileage.

The OP wasn't suggesting everyone go out and do all these things to our cars... it was just a few suggestions to help get better fuel mileage.