AIR SUPPLY
INCREASE YOUR RESPIRATION RATE WITH ADVANCED FLOW ENGINEERING
BREATHING IS A SCIENCE — just ask the six-pack brigade at the local gym — those guys who flip barbells and weights around like flapjacks. All along, we thought it was just a matter of “breathe in, breathe out.” But, no — it’s way more complicated. Breathing has to be timed via a series of puffs to get all the spent stuff out of your lungs. Is this why walking through a weight room at rush hour sounds like the labor room for a herd of Lamaze-trained elephants?
So, that’s how we breathe when we’re doing it right under load. What’s this got to do with your diesel pickup? Diesel engines are described by the engineers at Advanced Flow Engineering (aFe), of Corona, California, as massive air pumps. This is a fairly common analogy, but what this company does with this concept is uncommon. How air is taken in and then expelled is really important to the overall health of your truck. First, though, a bit of background: aFe hit the scene in 1999 with a group intent on building a better mousetrap — in this case a better filter and intake system, specifically for diesel engines. The company grew exponentially, beginning with a 3,500- sq. ft. facility in Corona. In just eight years, aFe has expanded nearly 30- fold into multiple buildings for a grand total of 103,000 square feet. During this rapid period of growth, the company has added exhaust systems and intake systems for gas-powered vehicles.
So, what’s the big deal about diesels and air filtration? Those of us with 4x4s put great value on keeping the dirt we kick up on the trail out of our engines. The particles that weasel their way into the combustion chamber and end up in the engine oil are identified as silicate. We all know oil is supposed to reduce friction between the pistons and cylinder walls and keep the whole process lubed and cool. If, instead, the oil ends up as a greasy sandblast, we’re doomed.
This is not brain surgery: clogged filters and reduced air in the combustion chamber are bad; fine-grained sand whittling away at our cylinders is worse. Because of the nature of a diesel, reduced airflow and gunk in the cylinders is even more lethal. Due to higher compression and boost levels, diesels have tighter tolerances than gas engines and require seven times the airflow.
Gas engines use spark plugs to ignite the air/fuel mixture once its been squeezed into the top of the combustion chamber. In the precise world of auto engineering, according to Paul Hardley, aFe’s director of product management, the tolerances between a gas engine’s cylinder walls, pistons and rings are relatively loose — in the 50 micron range. Diesels, on the other hand, rely on pressure alone and thus require tighter tolerances. All that torque we expect from diesel tow vehicles is a result of the engine’s high compression ratio. Even minimal silicate in the oil is enough to damage the works.
The efficiency of the filtration is critical, but so is the volume of air, primarily to keep exhaust gas temperatures (EGT) at safe levels. According to Craig Neveu with aFe’s sales and marketing, high air volume also reduces the throttle lag associated with today’s turbo-boosted diesels.
In an air-choked diesel, when the driver hits the go-pedal, the engine speed increases, the exhaust outflow picks up and, eventually, the exhaust-driven turbo kicks in with more power. With a less-restrictive air intake funneling more air into the combustion chamber, the whole process is markedly accelerated. The bottom line: more air, quicker boost for a significant increase in horsepower and load-moving torque — all this without blowing the EGTs through the roof.
The heart of an aFe filter is a sevenlayer medium called Pro-GUARD 7. Each filter includes five layers of progressively finer mesh; medical-grade, oil-treated cotton gauze whose fibers attract smaller and smaller particles, plus two layers of non-woven synthetic polyester fabric. The more open outer layers trap larger particles, allowing air to flow freely through the progressively tighter gauze and randomly porous synthetic fabric where the finest of particles are waylaid.
“A good but not perfect analogy is to compare the process to sanding a surface with different grit sandpaper,” explains Hardley. “Other filters’ constant- mesh media is like sanding the surface, four, six, even eight times with the same grit, say 80, sandpaper. The result is an 80-grit surface. Our progressive mesh is like sanding the surface five times using first a 40-grit, then 60, then 80, 100 and finally 120- grit sand paper. The result is a much smoother, finer finish because of the fineness of that final 120-grit paper.”
The concept of wee particles invading your engine may not strike fear in you if mud defines your off-road terrain. But if you’ve ever seen a soft breeze kick up a towering dust devil in the mud-less southwest, wee particles should play a major role in your automotive nightmares.
To capture those dust devils, some filter manufacturers use relatively heavy oil to treat the medium and increase its stickiness quotient. Others add tactifiers or surfactants (who comes up with these words, anyway?) to up the stickiness factor even more.
In contrast, aFe’s Pro-GUARD 7 medium is pre-oiled with the industry equivalent of a light canola oil, as opposed to heavier sesame oil. If you’re wondering why the company makes a big deal over less sticky, lighter oil, Hardley says the heavier stuff can coat the Mass Air Flow Sensor and activate your check engine warning light.
AFe’s seven layers are sandwiched between two layers of epoxy-coated aluminum wire mesh. The industry standard for filtration systems is 99.5 percent; aFe filters are 99.7 percent effective in filtering out silicates. The difference seems small, but so are the particles that lie in that 0.2 percentage rating.
Pleating the filter medium increases the dirt-catching surface, but there’s pleating and then there’s pleating. Too many pleats can over-pack the filter and restrict air flow. Sharp-pointed pleats compress the fibers at the face of the filter and divert air flow. AFe’s manufacturing process results in taller pleats (as much as 25 percent, depending on the product) with rounded tips and a more open pleating pattern, creating a much more usable surface for the air to flow through — and more surface to capture the dust that air carries.
The devil’s in the details, and the final filter detail is the polyurethane used in the seal. This material, as opposed to plastisol or air-foam, provides a pliable sealing surface that doesn’t become hard and brittle over time. Even with the constant tweaking and bumping our rigs absorb over tough trails, the mounting seal is designed to hold tight over the long haul.
AFe’s Stage 1 intake systems include an air box and filter and retains the factory intake tubing. Stage 2 replaces the whole stock system all the way to the throttle body on gasoline engines and the turbo housing on diesels. The company’s air boxes maximize the size of the filter used in the application without sacrificing the ability to use stock mounting sites or requiring relocation or modification of engine components. The air boxes are complete with all the necessary mounting brackets, holes, and PEM nuts.
The logical partner for an upgraded intake system is a high-performance exhaust system to expel the increased airflow. With a turbocharged diesel, the longer the exhaust loiters in the system, the higher the EGTs. Stock diesel exhausts work fairly well, as long as you’re not putting too much of a load on the engine.
AFe’s exhaust incorporates four-inch aluminized steel tubing, mandrel bent to eliminate sharp, restrictive bends and kinks. The system includes an eight-inch diameter, straight, flowthrough muffler that can be tuned for increased flow or a quieter ride. The exhausts come with adjustable clamps, muffler and section tubing for easy installation on standard, extended or crew cab vehicles.
We’ve said it before, but it’s worth repeating — off-roading puts huge demands on both our 4x4 rigs and our tow vehicles that haul them to the trailhead. Our trucks are true athletes and we can’t take their respiration for granted. Fortunately, neither does aFe.
SOURCE
Advanced Flow Engineering
www.afefilters.com