Drop In filter test! Stock, Apexi, No filter
 

Event: Dyno Tune/Product Testing
Location: ZipTie Dynoworks, Salt Lake City, Utah
Ambient Temp: 87F
Elevation: 4600 Feet
Weather: Sunny
Car: 2013 Subaru BRZ
Tuner: None, this was for a Baseline
Dyno Info: Mustang Dynamometer
Transmission: Factory 6-speed
Gear: 4th
Peak HP: 150
Peak TQ: 116
Fuel: 91 Octane

Modifications:
-Apexi Panel Filter
-Dimple Magnetic Oil Drain Plug
-Prova Oil Filter
We wanted to get a good baseline on our local dyno, so we packed up and headed over to ZipTie Dynoworks. When we arrived they had everything set up and ready to go it was as simple as handing them the keys while I relaxed and watch them strap it down. Once they had the car secured to the dyno, we did a few runs to let the oil get up to temp to get an accurate power reading. After the first few pulls we had a maximum of 147HP and 114TQ. This was a bit better than I had expected having seen some other stock BRZ dyno numbers, but still seems to be right on par based of the Dyno we and others have used.

Next we wanted to see what would happen if we just removed the factory filter, so we popped the hood and quickly removed the stock filter. One thing I will point out is that the factory air filter actually looks really really good, it has quite a bit of surface area and seem to be of super high quality, so we were impressed by that. But this is not a stock filter review, we are here to get some numbers! So we made a few more pulls with the factory air filter out of the box, and we got a maximum HP of 148 and max TQ of 114. We were hoping to see more gains out of this, but it seems like the power delivery was not as smooth, and while we did gain 1 horsepower overall, the majority of the time, we were actually under power compared to the stock filter. I am guessing this has to do with the way the air floes over the MAF sensor itself, and I do think having a filter in the box creates the proper air flow over the MAF. Now that was all done, we wanted to try out the new Apexi drop in air filter. Removing it from the box, you can instantly tell this will be a much better flowing filter than stock, and if not that, at least it is looks much better.


We did have some issues installing the new air filter in the air box, this might have just been us trying to hurry to get the car off the dyno, but we had to physically remove the air box, put the filter in, clamp the air box together and bolt it back in the car.


Something about a bunch of monkeys and a football comes to mind looking back on this… Once the monkeys got the air filter installed, we fired up the engine for a few more pulls. With the engine breathing much better, we achieved a maximum HP of 150 and a Maximum TQ of 116. Now this is what we are talking about! Not only did we see a gain of 3 HP and 2 TQ over the stock filter, but throughout the entire RPM range it made more power than the stock filter. Not too bad for a drop in air filter and what should have been a 2 minute install haha.

Driving the car, it does seem the throttle response has improved ever so slightly, and the car does seem to pull a bit easier as well through the RPM range. Not a huge performance gain, but I figure it is a very worthwhile modification if you ever have to replace the factory panel filter and do not want to go with a true aftermarket air intake system.

Just wanted to give a big shout out to all of the guys over at ZipTie Dynoworks, this was the first time I have been to their new shop and it is nice to see a clean, well-organized shop, and all the smiling faces over there always helps too. :)

Also make sure to check out our video of our little dyno adventure :)
[ame="http://www.youtube.com/watch?v=ARCTRzX_E3k"]The Albino Rhino BRZ hits the dyno! - YouTube[/ame]

Before anyone jumps the gun!

We know it should have been a 5th gear pull.

Yeah we realized that after the dyno was done :-/

As long as we stay consistent with our 4th gear pulls should not be much of a issue as the results will be consistent.

I am a complete noob with dynos, but why would you need to dyno it in 5th gear?

Ideally on a Dyno you want to have the gear ratios as close as 1:1 as possible to get the most accurate results. We did discuss this a bit and decided on 4th as we did not know the exact ratios, and we really just needed a baseline to compare aftermarket mods to, so as long as we do the rest of the Dyno pulls in 4th, everything should stay consistent :)

thanks,
Rick

Thank you for explaining that sir :).

You bet, I fear I did not give the best explanation, so someone can correct me if I am wrong on anything, but that is the way my feeble little brain understand it ;)

Thanks again,
Rick

what I find interesting is that the AFR increased by a half point, that is where the power was made, so I believe once we are able to tune we may worthwhile gains. Thank you for the testing!

I was thinking the exact same thing! Should be interesting to see what people are able to do with the stock ECU's. :)

thanks,
Rick

What was the average of the runs? To compare such small gains (if any) you need to do about 5 runs and average the middle 3 to get one number. Use this to compare between the different scenarios.

I'd call this even on all fronts. Which is the usual result for air filter comparisons.

The filtration ability tests are normally NOT EQUAL however.

For the test did 3-5 pulls in each configuration. As the motor got hotter and hotter it made more and more power. We then would stop making pulls as the car stopped producing increasing power output.
The results of our tests are the highest readings that we gathered from each testing session. As it took a few min to swap out filters and so forth the car would cool off slightly, so doing an average would have not been accurate as it was anywhere between 1 min-5min between each batch of tests.

We felt that using the highest power producing runs between each test was the most accurate way to compare the data given the test environment and the limited data we where able to gather given no ECU monitoring software currently being available. I wish we had ECU data monitoring available as then we would be able to do complete testing with much better consistency, but we did with what we had at hand for the time being.

Kirill
RallySportDirect.com

Would the lower hp of no air filter be the results of micro dust particle's reaching the combustion chamber where as the filter would have filtered it out?

With out having data logging available at this time we are not able to monitor some of the engine parameters.
We are thinking that the loss in power is more related to the air flow going over the MAF sensor being unstable, where as with a filter is not as turbulent and the sensor being able to more accurately measure it.

Kirill
RallySportDirect.com

are you guys going to try dynoing the k&n filters?