What does a performance air filter do?

So you just heard from your friends that you could get extra horsepower by simply changing to a performance car filter? What even is a performance filter?

A performance air filter uses a different material to allow more air to pass through it. Allowing your engine to receive more air that it needs – to generate combustion and deliver more power to your wheels. A performance air filter does increase performance, but minimal. Typically 1 to 5 horsepower improvement.

Let’s go more in depth into performance air filters shall we?

To understand performance air filters, we must first understand what an air filter is. Your car engine needs a combination of air and fuel to combust and generate power. This is why your car engine needs to suck outside air into the combustion chamber when it’s running. An air filter is responsible to filter out any debris, bugs or dust from entering your engine, while allowing air to enter. 

Air filters need to ensure as much air is allowed to enter as possible, while ensuring no debris or any unwanted particles can enter. This can be quite hard to do because:

• Having an overly restricted air filter can filter out all the debris at the cost of less air flow. Less air in the combustion chamber means that more fuel is needed to generate the power. Which then means lack of performance and bad fuel consumption. 
• In contrast, having an air filter that’s not restrictive will allow more air flow at the cost of debris entering the engine. At the worst, this can cause the engine to totally malfunction and require expensive fixes. Or at the best, the debris will simply accumulate in your engine and cause wear and tear- Which degrades the engine efficiency.

Stock air filter is typically made of special grade paper that could filter debris and allow air to enter. This special paper is cheap and easy to replace. It can ensure no debris enters your engine as long as the paper is regularly replaced. However, many believe that this paper material does not allow enough air flow. Thus, preventing the engine from operating at full capacity. 

NOTE: Paper is just the most common material that’s used in air filters. There are others such as cotton, foam and steel. 

Enter the performance air filter. A performance air filter is made up from an oil based foam that allows much more air flow to enter. The clear advantage to the performance air filter is the potential for a slight increase in performance because more air can reach the combustion chamber (An improvement of 1-5 horsepower is typical). However, because it is less restrictive, debris and bugs are more likely to find ways into your engine.

Performance Increase

As mentioned, the performance of your car does increase a little. Typically by 1-5 horsepower. Accelerations of your car could also improve. (The lag when you press the paddle should be smaller now). In my opinion, not such a significant performance improvement. Considering it even has the word ‘performance’ on it’s name!

Reusable

For its maintenance, a performance air filter only requires you to wash them. Replacing them is not required. The manufacturers like K&N claim that washing is only required every 50,000 miles. In comparison, the stock paper based air filter needs to be replaced every 15,000 miles.

Though I find this a bit stretched. From what I hear from my friends and other online resources, a performance air filter needs to be cleaned after about 30,000 miles or so. Of course this depends on the environmental condition you are living in. Sandy and dusty areas will need more cleaning. 

Long Lasting

This point is related to the one above. A performance air filter can last a long time and needs regular cleaning after about 30,000 miles – 50,000 miles. This is different from stock air filters that need to be replaced after 15,000 miles. 

Better Sound

With a performance air filter allowing more air flow, the sound of the car also changes. These increased airflow will lead to a more aggressive sound when you drive. Although not so much, it’s still a noticeable difference. 

Risk Engine Defect

As we already discussed, a performance air filter is less restrictive. It allows more air to enter, but at the same time also allows more debris, dust and bugs to enter. In most cases, the accumulated debris will only cause your engine to be less efficient.

This is true in theory. But I have never heard anyone having engine defect because of performance air filter.

Requires Re-Oiling

Remember I told you that a performance air filter is reusable? You just have to clean them. Don’t need to replace ;). However! You need to re-oil the performance air filter once it’s dry. The re-oiling process is not complicated. But you need to be careful when doing so. Overcoating your performance air filter may cause the oil to leak into the air intake system and coat the MAF sensor. 

MAF Sensor is a piece of equipment that reads the amount of air going into your car engine. This is required to keep an optimal air to fuel ratio, which in turn is required to ensure your car runs at an optimal condition. If the MAF sensor is quoted with oil and becomes inaccurate, you will experience problems such as:

• Decreased performance
• Inefficient fuel consumption

Pricy(er)

A performance air filter from a reputable brand like K&N is not expensive (about $65). However, this is considered much pricier when compared to a stock paper based air filter that only costs $10! 

Though, if you care about improving the performance of your car from every angle, $65 is not such a bad price. 

Horsepower

Like I mentioned, a performance air filter will likely give your car an additional 1 to 5 horsepower. Wait, are you the ‘where’s the proof bro’ kinda guy? Well, I also got you covered. 🙂 

The guys from Engineering Explained ran an experiment to identify the car performance reading when equipped with different air filters. They loaded their car with four different air filters: 

• Dirty stock air filter
• Brand new stock air filter
• Cheap performance air filter
• Expensive (K&N) performance air filter

The result is as you would expect. The dirty stock air filter performed the worst and the expensive K&N performance air filter performed the best. However, the performance differences are very minor.

The expensive performance air filter yielded a 4.3 horsepower increase. So to be fair, yes there is a performance gain and yes performance air filter really works. But the performance gain is very minor. Did you expect more from a $65 investment?!

Here’s a YouTube link to that video.

More Responsive

Performance air filter will also make your car feels more responsive. Every time you push the throttle, your car will react and launch faster because more air flow is coming in.

This impact is more noticeable when your car is at a stop and you press the throttle. No major difference – but for a $65 investment, it’s good.

Even Better If Paired With Turbo

If your car has Turbo, every little air flow is going to help in the horsepower gain. This is why people often equip all the other performance mods like air filter, air intake and exhaust first – before they equip the turbo.

More air flow = bigger combustion = more exhaust that’s going to spool the turbo and give you horsepower. If you are not that familiar with turbo, read my other article here. Which Is Better: Supercharger Or Turbocharger

Replacing a stock air filter into a performance air filter is simple. It’s just a matter of opening the air filter compartment and popping the performance air filter in. If you have a cone shaped performance air filter, then you might need to use screws to lock it in place.

Here’s a YouTube link to install a rectangular performance air filter and another YouTube link to install a cone shaped one.  Do not get rid of your stock air filter just yet. You might need it back in case of incompatibility of your disliking. 

In this article I discussed that a car engine needs to suck air from the surrounding and inject fuel to combust and produce power. An air filter is required to filter out any debris, dust and bugs from entering the engine. A performance air filter is less restrictive – allowing more air to enter and thus, produce more power for the same amount of fuel. 

Pros of performance air filter:

• A slight performance increase of 1 to 5 horsepower is expected
• A performance air filter is reusable. Simply wash it every 30,000 – 50,000 miles
• A performance air filter is long lasting
• The engine will make a better sound due to a more intensive air flow 

Cons of performance air filter:

• With more air allowed to enter, more unwanted debris could also enter. The accumulated debris inside the engine could make the engine inefficient or worse, breakdown altogether. 
• Re-oiling your performance air filter is required when it’s dry. Do not overdo this. Excessive oil could leak and cause your MAF sensor to be inaccurate. Resulting in reduced performance and inefficient fuel consumption. 
• A performance air filter at $40 is pricier when compared to a stock air filter at $10

I have also discussed that a performance air filter is proven to give that additional 1 to 5 horsepower. Installing a performance air filter is easy. It’s all about taking out the existing filter and popping the performance air filter in. Here are the videos illustrating how a performance air filter is installed.

From my personal opinion, a performance air filter is definitely worth it given its price. For about $65, you will have an improved horsepower, more throttle response and helps your turbo in its work.

I hope you find this article useful and can decide whether to go for a performance air filter or abort! 🙂