I know there are some obvious ways of cutting down on gas consumption: drive slower, don't use AC, etc...

But I have heard that there things you could do to your car that save gas, something to do with air filters perhaps?

Anyone know what those things are?

Thanks

Automobile Maintenance:
Keeping your car tuned can increase fuel efficiency by up to 4%. Replacing clogged air filters improves gas mileage by up to 10%. Air filters also protect your engines by keeping impurities from damaging the engine

http://www.fueleconomy.gov/feg/maintain.shtml

Properly Inflated Tires:
Under-inflated tires causes car engines to work harder, using more gas.This can improve gas mileage by up to 3%. You can find the recommended tire pressure on a tag in your car or in the owner’s manual

Reduce the Weight in Your Car:
Although there are certain items you should carry in your car, such as a spare tire, any extra weight in your car decreases your fuel efficiency. An extra 100 pounds in your car could increase your fuel needs by 2%. Keep in mind this affects smaller cars more than larger ones and the percentage of extra weight is relative to your vehicle’s weight.

well the tricks i have learned to safe fuel are:
- well keep the total weight down, so keep your truck as emty as possible. Toss the junk.
- don't stick and flags and stuff on the outside. It adds drag.
- change gears in time (well if you have a stickshift).
- Keep your tires on the right pressure. low pressure means more drag.
- keep your car well maintained and well oiled.

No idea what the airfilter will do to safe fuel. But having a clean filter will let the enige "breath" more easily.

Ofcorse not driving the most fuel economical methode.

hmm... i just converted the cost of regular unleaded gasoline in the netherlands, to gallons and dollars. It's 9,86 dollars a gallon now.

us gallon is 3.78 litres making it $8.82 a gallon at UK prices

I think its time for a mythbusters episode on this idea that clogged air filter reduces efficiency on a gasoline engine.

Your air intake already has a very large restriction in it called the THROTTLE. A partially clogged filter will limit the maximum output of the engine but unless you are flooring it all the time it won't change anything significant.

That being said, change your air filter on time anyway to help keep your engine clean!

Hey Red Flare, if you're really serious about doing all you can to reduce your gas consumption, do a google search for "Hypermiling".

Some of the techniques that hypermilers use are a little over the top in my opinion, but there's also some that are easy to implement.

There are 2 ways to dramatically increase your fuel efficiency:

1) Drive slower
2) Accelerate with a lighter foot.

Driving habits: I have done some experimenting, and I can increase fuel efficiency in any vehicle by 20% or more by going easy on acceleration and braking, and especially by dropping my speed to 60 mph / 95 kph when it's safe to do so. I hardly notice a difference in travelling time.

Tires: I switch from soft and grippy ice tires to harder-compound summer tires every year, and there's a noticeable change in mileage. If I was driving a truck/SUV as a commuter vehicle, I'd ditch the knobby off-road tires for efficient ones and throw a light set of chains in the back.

Regarding clogged filters: I think a badly clogged filter would give an excessively rich mixture, which would blow unburned hydrocarbon out the tailpipe. This would be worse with a carburated engine, since the mixture is fixed. A modern fuel-injected vehicle with an oxygen sensor and computerized mixture control should be able to compensate to some degree.

Don't believe the hype, Redflare. There's really not much you can do mechanically to improve your vehicle's gas mileage besides keeping it properly maintained. Personally, the single thing I have noticed that makes a big difference in my own gas mileage is to drive smoothly and without hard acceleration. The difference in your gas bill at the end of a week of driving aggressively and driving smoothly is substantial.

I see it all the time--I'm cruising down the street and a car pulls up close behind me, changes lanes to accelerate around me...and a minute later, I catch up to the guy stopped at a red light. As soon as the light turns green, they zoom away again. So many people drive that way, and they complain about the price of fuel?

They revisited that one. It wasn't A/C vs not it was A/C vs windows down.

They determined in the end that it all depends on how fast you're going as the first and second episode tests had opposite results.

As others have said, it's mostly the nut behind the wheel and not so much the machine. Good maintenance is important but doesn't offset "normal" (meaning - the usual unconscious, ill-advised, distracted, skill-free typical) technique.

I drive 100 miles/day commute to/from work ( karmic payback I guess for the 17 years where my commute was 2.5 miles). I've been able to get about 20% better mileage on a mostly interstate highway profile by adopting some additional techniques over my previous conservative and boring driving style. I have a mpg meter on the car that has helped me refine my techniques and rewards me with higher numbers if I do everything right and catch some lucky breaks on timing stoplights on the route.

Hypermiling has many valuable techniques in their list but they also have some that are uncomfortable, likely to cause more maintenance and up into outright dangerous behaviors.

I'm sure the construction guys in their empty F350 pickups I see blazing along tailgating and laneswitching their 90mph way to work are paying at the pump. They probably don't want to know how much of the bill is under their control. (Don't try to tell them either!)

I think one of the most fuel efficient ways to drive is to do so in a way that minimizes use of the brakes.

If you can drive on the highway without needing to brake and slow down for other traffic, then all your fuel goes toward moving your vehicle. It is not getting wasted speeding it up, for the brakes to slow it down. It means when in an area with lights not driving racing from red lgiht to red light. It means when you know a stop sign is ahead, getting off the gas and allowing the car to slow down without using the brakes before you get to the stop sign. Sure, you will have to use the brakes at times, but driving with the idea that you are trying to minimize their use is good conservative driving.

I'm sure its not the only place but these kinds of efficiency issues have been debated for a couple years on the Prius sites, like priusonline.com and priuschat.com. There's some real world evidence and data to back up alot of these things, mostly because the Prius comes standard with a screen that estimates your mpg every 5 minutes of travel, and a dynamic read out that gives you a sense of fuel consumption every 10-15 seconds. You obviously use more fuel heading moderately uphill, but its kinda amazing how little fuel you can use heading downhill or on low uphill slopes. So a few conclusions I can draw from my own driving habits since 2002 driving 2 Priuses:

- tire inflation is good; proper at least, a bit above that for a 2-5 mpg bump (but never exceeding the maximum psi); you have to check this often and keep the right inflation to benefit, and you should invest in a tire gauge that gives an accurate readout too, not one of those little stick gauges
- low rolling resistance (LRR) tire models are good, replacing the stock tires with a better brand were worth a couple more mpg in my case anyway; they don't necessarily wear out any quicker, my current set are a 40,000 mile brand, but they aren't great in all conditions, so shop carefully and reward the vendors with the safe, long-lasting tires on conditions that you drive
- changing or cleaning your engine air filter is good, its like your lungs, you want the right amount of good clean air for proper combustion
- changing oil is good, my mpg always bumps up 2 mpg after
- as is keeping up on general maintenance, particularly tire alignment, there aren't too many pigeon-toed four minute milers and the same goes for your car
- AC makes no difference, in fact on the Prius folks report better mileage with the AC set to On; I've never noticed any mpg difference with AC on or off so usually just leave it on
- hypermilers aside, *in a Prius* a quick start isn't penalized as much as in other cars, owing to the high torque and assist from the electric motor; getting up to your cruising speed quickly lets the engine cruise longer; anyone's mpg may suffer in stop and go traffic, but at least with a Prius when the traffic stops so does your gas engine; outside a hybrid ymmv literally
- hypermiling really does work in the Prius anyway, but fwiw its such an annoying way to drive alot of folks forego it and just live with their 45-50 mpg. Thanks to the interweb I'm now stuck behind Cadillac Escalade's trying to emulate the Prius hypermilers, all so they can get 12 mpg; and there's nothing worse than those Prius owners bragging about 70 mpg, they drive like little old ladies (with apologies to little old ladies anywhere, they are sweet, bragging Prius owners are not)
- lowering your speed really helps, 60 mph seems a pretty good speed to go, 70 mph and you give away alot of mpg in a Prius, although I still get about 45 mpg on 200 mile round trips heading up and over Snoqualmie Pass along I-90.

Exactly right. Coast to the stops. Every time you step on the brake you have wasted some gas and are working on an expensive brake job. Don't race to get to a red light. Start to accelerate after a stop by just taking your foot off the brake and letting the idle get you to 5mph. Then use the accelerator like your pumping gold out of your tank.

In other word drive like granny. Who probably learned to drive during the depression. When gas was precious and car repairs expensive.

FWIW...One of my clients was telling me a cold air intake adds a little power and improves fuel efficiency. He had that in his car along with an exhaust with better flow through. He said his power and fuel economy increased by about 20-30%.

Dan_McI
Art_in_FL

You said exactly what I wanted to say ( and in a better way)

Its good to check air filters and tire pressure but many drivers waste too much gas in needless acceleration and speeding. And then they dont waste money on gas, but brake shoes and other parts, not to mention dented fenders.

Furthermore this improves tire life significantly. However, no matter how well you maintain your tires, tires do get old.

Jeanette Isabelle

As others have noted, "driver slower" is such an over-simplification as to be wrong. Anticipation is more important - not so much not using brakes as not needing to use them. Cars have an optimum speed which is usually around 50mph, and which varies from car to car, so driving slower can be worse. (The extreme case is driving at 0mph with the engine running, which will use up all your fuel without getting anywhere.)

AC tends to be more efficient than opening a window at high speed, and less efficient at low speed, with the cross-over point depending on the car.