TECH: Why Quality Matters Part 1 - Air Filters


We all have heard every automotive based media outlet championing the necessity of quality parts. While I won't doubt the appeal of being able to gain power or sort out ride height for pennies on the dollar, you do get what you pay for. This doesn't just go for wheels or turbo kits, even something as simple as an air filter matters. 


Air filters and various intake solutions have always been one of the very first bolt on modifications done to a car. While the improvements found from upgrading an air intake system today are not nearly as drastic as they were on cars 30 years ago, there is still improvement to be made either in performance or aesthetics. This also makes it all the more dangerous, why spend $50 on an air filter when a cheap $20 "performance" air filter from your local parts store chain will give you the same results.

Let's examine the experience that spurred this article. This comes from a gentleman on a local drift racing page who was using a cheap "Performance" air filter on his turbocharged BMW. The vacuum pressure in the intake system before the compressor pulled the air filter's loosely hot glued-in inner velocity stack cap off it's mooring. Once it was loose, there was only one way to go, right into the compressor wheel. A flurry metal shavings found their way through the intake system from the now destroyed the turbo. Luckily this happened while the car was at idle so the owner was able to shut off the car once he heard the noise and his sizable intercooler collected all of the shavings.

You're probably asking yourself, what kind of crazy boost level was he running to inhale chunks of the air filter? 10 PSI. That's conservative to say the least, in fact its half of the pressure that a new WRX runs. So, it's not like he was running some ridiculous amount of boost sucking in every mole of air within 100 ft of it.

So, before we turn into a mob of angry villagers hell bent on burning every air filter with an integrated velocity stack, lets look at the situation. Likely the failure resulted from poor brand quality rather than the nature of the filter design. We haven't had a statement from the brand, whom we're not naming out of professional courtesy, or anything but it's fairly common for mass produced cheap parts to have a higher failure rate than those which are higher quality.

So what's the difference between the filter in the story above and a higher quality air filter? For this we decided to give a call out to Dan Carey at Modern Automotive Performance. They've done no shortage of research on the brand of air filter they've decided to use with their turbo kits and we were wondering what went into their decision. Since the air filter can both limit the power output and also dictate the reliability of their turbo kits as well, this was a very important decision they had to weigh.

Dan stated that while outright performance and cost are important, reliability was the key to their decision. MAP could have gone with a well known brand like K&N or HKS, but they would mostly be paying for the name. Alternatively, they could of ordered filters 5,000 at a time from some no name factory in Guangzhou, China but then they would be going broke with warranty claims from chaps like the BMW guy above. So what did MAPerformance come up with for their air filters?


They chose Green Filter USA. Most people haven't heard of them, sans a few hipsters in Uptown. They're a smaller company from Pennsylvania and definitely not a house hold name like K&N. So how did MAP know they weren't getting rebranded Guangzhou Whatever Corp. filters? The construction process. It was the most important detail of a Green Filter versus a budget brand.

While a poor quality air filter company will be interested in streamlining the production process in a quantity over quality scenario, a quality company, like Green Filter, will choose the more time consuming but over-engineered process due to reliably. Every part of the process of production is closely monitored with Green Filter, from the process of the adhesion of the rubber nose cone of the filter to the thread thickness of the cotton filter element. They were even nitpicky about the exact metal used for the clamp at the bottom of the filter. The final production quality of the filters is actually arguably better that K&N since there is no extra rubber blocking the filter element.

These filters aren't exactly expensive either, they start at $24 and even have a lifetime limited warranty that protects from defects. Any company that stands behind their product like that should at least be considered. However, there are phonies that exist, according to Dan Carey at MAPerformance "There are tons of "green" filters on eBay, They may be the same color but the quality is nothing like Green Filters USA."

Green Filter USA is only one example of a good quality brand, there are other brands of less expensive high quality air filters around and all it takes is a little bit of research to sort out who's who. Generally when a search result features angry posts on forums and either poor reviews or a lack there of from automotive media sites, it's best to keep searching.

Snake oil parts like 110 HP tuning chips made of Czechoslovakian toaster oven microchips or pirated knock offs of legit brands will forever crowd the dregs of the aftermarket. Are people ever going to stop using knock-off parts? No, Unfortunately that is something that is here to stay but, the least we can do is educate people on what they're getting themselves into.

Frankly, performance air filters aren't as much of a requirement today as they were years ago when stock intake systems were horribly restrictive. Most people here will be fine with a stock paper filter but once you start to building power, this is where it all matters. Again, we don't blame people for cheaping out on a part that sits static on your engine and isn't really known for failure. It's hard to justify the cost, especially when you're operating on a budget. You have to ask yourself, is it really worth saving $10 on an air filter if it means it can fly apart and destroy your engine?