There seems to have been a lot of interest recently for those that don't want to get a cold air intake system, and would rather keep their stock airbox and run an aftermarket filter. Since I just so happen to have what I deem every filter worth testing, and the equipment to perform the test, I've decided to do a drop in filter flow comparison.
PLEASE, let's not turn this into a CAI's are better than the stock box thread, or this CAI is better than that CAI, there are probably hundreds of threads discussing aftermarket intakes, so please do a search if you're interested in doing some research on anything other than the stock airbox.
This test was performed on our in house Super Flow flowbench through the stock airbox, the stock intake tube, and snorkel (unless noted without the snorkel). The weather conditions are listed on the spreadsheet picture below. All of the filters were tested in about an hours time, so the weather shouldn't have changed much. To attempt to simulate the box & snorkel in the car, I took a measurement of the distances from the opening of the snorkel to the core support, and fabricated a plate with a similar contour to what's in front of the snorkel and mounted it to the snorkel the same distance as measure in the car. And now... The numbers, and other random filter info:
The box w/o filter, and box w/o filter & snorkel number are in red to kind of separate them from the rest. The box w/o filter & snorkel percentage difference is compared to the box w/o filter w/ snorkel as it was the fairest way I could figure to compare.
The fit & finish is just my opinion based on the construction, and quality appearance of the filters compared, and how good they fit in the stock airbox. The filter media is a combination of what I could find either on the filter manufacturers website, and/or hours of searching the internet; it may not be entirely accurate.
I had originally planned to show the prices of each filter from the manufacturer, and the cost per CFM gain, but I am not allowed to post pricing, so it had to be removed. You can get any of these filters direct from the manufacturer, although it may not be the cheapest place to get them. We do offer S&B drop in filters on the JacFab website w/ free shipping to the lower 48 on all current S&B stock for those that are interested...
Now onto a little less scientific test. A lot of people say they don't trust a filter they can see through. Within reason, I agree to that, however some of the filters tested do have over a 99% filteration efficiency rating as reported by their manufacturer. I did not post efficiency ratings of the filters because I could not find most of the ratings listed anywhere. For this next "test", I held each filter up to the sun to see how much light they let through, pictured below:
As you can see the highest flowing filter in this test was also the most transparent. And the worst flowing filters let through almost no light. Surprising was the S&B with came in at #2 on the flow test, lets little to no light through.
I had planned to try to rig up some filtration test, but I don't think it could be controlled enough to be accurate. If you are concerned with filtration, please do some research before you decide on a filter.
This test was performed to the best of my ability, and may not be entirely accurate, but the machine sucks what it can suck, and the sun is the sun. I hope some of you out there find this useful. That said, as I have mentioned before, the stock filter IS a restriction. With a better flowing filter, the stock box does flow pretty good IMO. It should also be noted that ALL of these filters have the potential of flowing much more outside of the stock box, and the box is still a restriction, the stock box will not out flow any cold air intake regardless of filter choice. If you want a cold air intake, do your research and get one. If you want to keep your stock box, by all means, take it to its limits!
*NOTE* Again, this test was not performed through a head, intake, and throttle body combo, and the flow numbers are reported at 28" of water, so they will most likely read higher than CFM numbers you find on the internet for whatever you product you may currently have. This test serves to compare these filters in the stock airbox, stock tube, ONLY, and these numbers are only accurate in THIS test and should not be compared to anything else you may see unless they test was performed in the same manner.
Keep it clean, and discuss.