by Pat Goss
There’s a myth about air filters that dirty air filters will affect gas mileage. Well back in the day when cars had carburetors, like this old one here, well yes that was true but carburetors have been gone a long time now and modern cars they have fuel injection and a dirty air filter will not affect fuel economy. The reason being is that when the air was restricted on the carburetor, there was no way to shut down the amount of fuel going into the engine because the carburetor was mechanical.
Today, we have fuel injection, and that’s all electronic. So, we have a device on the backside of the air filter that measures the amount of air coming through the air filter. It tells the computer how much air is coming in, the computer mixes the proper amount of fuel, so it always maintains the proper air/fuel ratio.
Now granted if you have a filter that looks like this you need to replace it because it has to protect your engine, and that isn’t going to do much of a job at that.
Now, next thing, here we have a high performance air filter. Most of these are oiled. They do a great job; they usually last the life of the car. But, will they give a stock engine huge improvements in performance or fuel economy and the answer to that is no. The reason is that an engine only takes in the amount of air that is needed, not the amount of air that is made available to it. So you can make all of this air available, it’s not going to use it. Now, if you modify the engine, what you’re doing is you’re making it take in more air, then you absolutely need a high performance air filter; only way to go.
Alright, another filter on the car you need to be aware of: most cars these days have cabin air filters. This is an extreme example of what we pull out of cars periodically: really nasty and doesn’t smell too good either.
Now, let’s take a little comparison here. We’ll take this one out of this new car. You can see the difference. Now, what you want to do is read your owner’s manual and see how you go about checking this, where it’s located, and so on. And at least a couple times a year check it, or if the owner’s manual says to replace it, at a certain interval, replace it. You’ll be a lot more comfortable in the car.
And if you have a question or comment, drop me a line, right here at MotorWeek.