We’re not interested in selling something that has no benefit or that can’t keep up with the competition. Any performance product we sell will be backed up by thorough testing and analysis. A performance air filter has a simple job, minimize restriction while still effectively cleaning the air. Our manufacturing partner Green Filter USA has already tested the filtering performance, what’s missing is application specific performance testing.
The first step was to determine if the Double Apex filter flowed better than stock and to see how it stacked up against the competition. Next we'd make sure the bench results translated to the real world.
We constructed a simple flow bench using an actual air box from a VW 2.0T engine and in addition to the OE stock filter picked two popular performance filters currently on the market; an unoiled "dry" filter, and another brand oiled filter.
The test was simple. Using a variable speed fan we determined the minimum amount of power the fan needed to keep the ball afloat. Lower power, or voltage, meant a less restrictive air filter.
Bench Test Results
The stock filter was, not surprisingly, the most restrictive of the bunch. Coming in a close second was the dry filter. This made sense considering the primary advantage of a dry filter is easier service, at the expense of performance. On the other end of the spectrum were the two oiled filters with a slight edge going to the Double Apex filter. We believe the advantage can be attributed to the superior flow characteristics of cotton fabric vs. cotton gauze and lower rubber seepage into the fabric due to the precision molding process used.
The best way to test an intake component on a vehicle is in real world driving conditions. Outside of a full size wind tunnel it is nearly impossible to properly simulate air flow. Most dyno fans are single speed and don’t flow a realistic amount of air.
Using a Race Capture Pro, a motorsport grade data acquisition system, we measured the intake restriction at the turbo inlet and vehicle acceleration at wide open throttle. The OE filter and Double Apex filter were tested. Results are an average of multiple tests run in two directions to account for minor elevation changes. The test vehicle was a stock 2014 Jetta GLI with a 2.0T EA888 Gen 3 engine.
Road Test Results
The air flow restriction with the Double Apex filter was significantly less than the OE paper filter. This results in lower engine pumping losses, higher turbo compressor efficiency and as a result lower intake air temperatures. Improved acceleration and power gains were seen throughout the RPM range.