Review Update: Hurricane Racing Performance Air Filter
After having this new filter from Hurricane Performance Racing for the past week, I must say that Iím impressed, not only by its design but also by how it has changed the character of the bikeís engine.
But before I get into all the real good stuff, allow me to explain what this filter is. Like stated earlier in the review, the filtering medium is a pleated, fine stainless steel mesh, bordered by what seems to be a good silicone rubber. The mesh is fine high grade SUS-304 stainless steel. What is SUS- 304 stainless steel? Basically, (SUS) stands for System Usability Scale and 304 is the number of micro holes in a linear inch. Each hole is approx 45 microns in size (as a point of reference, a human hair follicle is approximately 50 microns in diameter, plant pollen about 40 microns). The materials and construction of this filter makes it very sturdy. The mesh is pleated and held in place in a way that makes it incompressible under suction (unlike my foam filters). As a note this came from Thailand, so the testing standards for air filtration are different than they are here in the U.S.
The maker of this filter does not make any claims of better filtration with this filter (neither do I), however they do claim higher airflow as well as several other things.
So that this review does not turn into a big debate about what type of filter is better (paper, cotton gauze or foam), I will simply say, it was hard to find a real concrete definitive answer. One very popular filter manufacturer had this to say about airflow and filtration,
ď We design our air filters to provide superior filtration of the contaminants that can harm your engine while maximizing the airflow characteristics of the filter in question. The ability of an air filter to protect your engine is generally measured in accordance with testing procedure ISO 5011. We subject a sample of our filter designs to this test procedure using Coarse Test Dust, which includes particles ranging in size from less than 5.5 microns to 176 microns. As a point of reference, a human hair is approximately 50 microns in diameter.
Doesn't higher filtration mean a better air filter?
No. The quality of an air filter can only be judged by reviewing all four important characteristics. 1) Restriction while loading with dust; 2) Filtration efficiency as a percentage; 3) Dust holding capacity before the filter needs cleaning or replacement ; and 4) filter life. Any company designing an air filter must make choices about these four characteristics and how their filter will perform in each area. Generally speaking, each characteristic of an air filter has an inverse relationship to at least one of the others, meaning, as filtration efficiency goes up, restriction increases and capacity or service life decreases. So an air filter manufacturer can design an air filter to have ultra high filtration efficiency by compromising the filters restriction, capacity, and/or service lifeÖ. So the basic answer to the original question is that higher filtration is not necessarily a good thing when it comes at the expense of restriction, reusability and/or capacity. While the benefits of a filter with 99.9% filtration are unknown, the benefits of low restriction are measurable and clear. Low restriction helps an engine perform more efficiently generating more power and torque.
That would lead a reasonable person to ask what then is a safe level of filtration. This question is literally unanswered. Minimum air filter specifications are generally not called out in vehicle owners' manuals, nor will you find much published information on air filtration requirements from vehicle manufacturers. We have never seen a scientific study concluding what levels of filtration efficiency correspond to various levels of engine wear.
The fact is that an engine is not a pristine environment. Fuel enters after passing through a fuel filter, combines with air which is ignited to explode in a pressurized chamber. The combustion is not 100% efficient and leaves residues behind that must be flushed from the engine. Engines have tolerances or measured gaps between surface areas. While there are few if any studies on engine wear, it would seem reasonable to speculate that particles less than 5.5 microns create little engine wear unless ingested at very high levels of concentration. As support for this theory, consider the filtration levels provided by fuel filters and oil filters that sometimes tout their ability to filter particles above 10 or 20 microns.
If you really want to compare two air filters, you need to know all four characteristics mentioned above. Consumers can then choose what matters most to them. But comparing two air filters with only one piece of information is like saying a bicycle is better than a car based solely on a comparison of mileage. Yes the mileage is better, but a car has a few other benefits (speed, comfort, keeps you dry in wet weather) that just may offset the mileage disadvantage.
More airflow means you are letting more dirt through, right?
No. Filtration testing measures the percentage of dust retained before the filter reaches a terminal test pressure, often 10" of restriction above initial restriction. We use airflow as a simplified term to explain a more complicated physical process. The more precise description is restriction: *** air filters create less restriction which helps an engine run better. An engine will only use the air it needs and our air filters do not result in an engine using more air than necessary. Rather, they result in the engine experiencing less restriction. The terms airflow and restriction are inversely related. Our air filters provide either less restriction at a fixed airflow rate; or more airflow as a fixed level of restriction. In neither case is more air being used than necessary.Ē
So what does all that mean? Hereís my takeÖ, the engine will get some dirt in it no matter what, whether it is from the atmosphere, driving environment or the engine itself (in the form of carbon deposits), so there is a small possibility of engine wear. Choosing an air filter is a balancing act. Performance comes at the sake of a little extra filtration, a little extra filtration protection at the expense of a little more performance.
Whatís the solution? Do what many lubricant manufacturers have emphasized for years, when driving conditions present a unique set of challenges for engine performance and durability; Preventative Maintenance. Frequent oil and filter changes as well as air filter cleaning or replacement is the best way to prevent engine wear.
Hurricane Performance Racing Stainless Steel Mesh Air Filter
Now the good stuff.
This is a really, nice filter. It definitely has changed the way the engine operates. The engine feels like itís turning with less effort and has smoothed out. The exhaust note has changed a little, the intake is not as grumbly as before in the low rpm range, but when you open the throttle up it sounds great. This is probably from the airflow being more linear than turbulent. Without question, the filter allows more air to flow. A definite difference compared to the stock air filter and the Pipercross Air Filter I ran before.
Do I believe the AFR has leaned out too much? Naw. Smoothed out? Yeap.
She's still making plenty power up top.
I have 15/ 41 sprockets because I do a lot of hwy riding. Getting up to hwy speeds, the RPMs seem to run up quicker, nice acceleration for the set gear up, especially around Ĺ throttle. There does not seem to be a big increase in HP, but the HP feels like it is being made more efficiently. I havenít had a chance to see if there has been a real change in mpg cause Iíve been wringing the throttle, but from what a can tell from running ethanol free gas, itís not going to change that much.
As far as dirt goes, Iíve seen nothing yet except a little pollen around the rubber edge (the pollen is super heavy this week). I really donít expect to see a lot anyway as my filter hardly gets that dirty. Am I concerned about any extra possible dirt? Nope. Iím going to keep my oil changed frequently like Iíve been doing and all the other maintenance required. I really want someone else to ride it, to tell me what they think. Maybe when Nemesis gets his filter, heíll give his opinion on it as well.
Stay tuned more to come.