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FREE horsepower.... yes please

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#41 ·
Couple things; I took mine out, if anything I'll take the 2hp. Also this won't void any part of your warranty. Like someone said they have to prove it damaged something. Also I am 100 percent confident my dealership service department wouldn't even know it was missing unless they were told to look for it. They don't know these cars well.
 
Discussion starter · #42 ·
Jzam86 said:
Couple things; I took mine out, if anything I'll take the 2hp. Also this won't void any part of your warranty. Like someone said they have to prove it damaged something. Also I am 100 percent confident my dealership service department wouldn't even know it was missing unless they were told to look for it. They don't know these cars well.
Click to expand...
Its not just a BRZ\86 thing. This is common on all new vehicles. Its an emissions thing. It certainly wont cause any harm though. Its honestly a useless device that manufacturers are using to shut the EPA up.
 
#43 ·
TRU-BOOST said:
I stumbled on this video from Engineering Explained who is a favorite of mine. He experimented with both the stock filter and a K&N drop in filter. He got dyno numbers and acceleration times of how they performed with and without the charcoal mesh filter inside the air box. Take into consideration this was on a subaru crosstrek, so the results will likely vary on other cars......

I decided to give it a go on my BRZ and made a quick "How to" for anyone who is interested. Its super simple and Im sure most of you could figure it out without any help, but some may want to see it.

1st loosen the inlet pipe clamp shown in red with a 10mm socket or phillips screwdriver. It does not need to come off, just be loose. Also unclip the harness for the MAF sensor shown in blue.
View attachment 6665

Next you will want to release the harness from the air box so you dont yank on the wires while trying to remove it. Pinch the tabs of the clip shown in yellow and push the wires free from the airbox. You can do this with your fingers or I used some needle nose pliers. View attachment 6666

After that move over to the lower right area of the air box and locate the 10mm bolt shown in white. Remove the bolt and set it aside. There is no nut on the bottom it just threads into the bracket below, so dont worry about anything falling. Also undo the clips shown in purple holding the air box lid closed at this point. View attachment 6667

Now that lid is ready to be removed. simply pull it up and back towards the engine. The rubber intake tube keeps a good grip on the plastic tube inside but just give it some good pulling and twisting. It will pop off and you will be left with this. View attachment 6668

This goofy thing is said to be for emissions control for air that comes out of the pcv system. I honestly dont think it does a darn thing other than become a restriction. The carbon filled mesh on ours is not held in the same as the one shown in the video. Ours is heat welded directly to the plastic air box. I just grabbed one edge with pliers and pulled it back until I could get a couple fingers behind it. From there just go around and pull until all the welds release and the mesh comes off. It does leave a bit of shaggy mesh behind, so I went over all the welds with a razor blade to clean them up a little. I did not spend a ton of time here because nobody will ever see it. The important part is just to remove any loose bits and shavings from the inside before puting it all back together. This is does after all sit behind your air filter, so any junk you leave there will get sucked into the motor. This is what mine ended up looking like after I was done.
View attachment 6669

Thats it..!! Just reinstall the box the same way it came out. Make sure to put the 2 plastic tabs into their alignment slots on the bottom 1st. Stick the plastic tube back into the rubber intake hose all the way. There is an alignment mark so you can see when it is all the way on. Tighten everything up and most important.... plug that MAF back in...!!
I only drove around for about 10 min after. I cant say I noticed much so far. There is definitely a little more intake noise which I did not expect. Not sure how much power can be expected by doing this, but I can guarantee that mesh is not doing us any favors. Let me know what you all think...!!
Click to expand...

Just took apart my filter box this weekend and found what looks like almost a KN drop in filter inside instead of this white material you have.
 
Discussion starter · #44 ·
U bought it new? The GR filter is made by K&N so it may have that. The white charcoal mesh should be located behind the filter going toward the engine. If not lucky you..!!
 
#46 ·
I just wanna add that you don't need to take the airbox off in order to take it out. Just need a little oomph to get it back into place. At least, as long as you don't care about the excess on the inside.
Took me maybe a min tops in some random gas station parking lot.
 
#47 · (Edited)
There's no filtration between the charcoal filter and the MAF sensor and the engine's intake valves. Any loose debris will fly straight into them.

Here’s a procedure I would propose for those contemplating this improvement for off-highway use:
  1. Completely remove airbox per procedure given by @TRU-BOOST in his OP
  2. Remove MAF sensor and set it aside in a safe place so you don't break it or contaminate it
  3. Use a utility knife with a fresh razor blade to cut away the center portion of the mesh filter. You are left with a 3/8" wide perimeter of mesh heat-staked to the airbox
  4. Go in sideways with the utility knife, under the mesh, and carefully slice through the heat staking one by one
  5. There will still be some white mesh and bits and pieces left at the heat stakes. Use the knife to remove and clean up as much as possible
  6. Use ~180 to ~220 grit sandpaper at this point to sand down the remnants of the heat stakes and filter mesh. Use compressed air to blow away dust and debris
  7. With a propane torch set to its lowest possible flame, carefully and quickly "kiss" the sanded areas by waving the flame over them. This will very slightly melt the tiny plastic "hairs" caused by cutting and sanding. It will get rid of the "sanded" appearance and make it look black and shiny again, as well as prevent any tiny loose bits from dislodging later
  8. Re-install MAF sensor, taking care to re-start the screws in the same threads in the plastic so they don't strip out
  9. Re-install airbox and re-connect everything in reverse order of disassembly
 
#52 ·
There is a mild change in sound.

Don't have a data logger but I very highly doubt there is any difference in flow, definitely not enough to overcome the temperature density changes the computer does on its own stock.

Maybe @TRU-BOOST will data log and share the results
 
#53 ·
Wayward67 said:
There is a mild change in sound.

Don't have a data logger but I very highly doubt there is any difference in flow, definitely not enough to overcome the temperature density changes the computer does on its own stock.

Maybe @TRU-BOOST will data log and share the results
Click to expand...
Just want to know if any potential long term annoyances before I rip it out.
 
Discussion starter · #54 ·
It wont run lean. The ecu reads the MAF and AFR. If it is not getting the AFR it wants it will simply adjust the fuel trims. Next time I pull out the scanner I can take some logs, but I dont expect anything really. My dyno also shows it holds a solid 13:1 AFR all the way through the powerband. That was with the charcoal removed, and it was the same before.
 
#56 ·
TRU-BOOST said:
I stumbled on this video from Engineering Explained who is a favorite of mine. He experimented with both the stock filter and a K&N drop in filter. He got dyno numbers and acceleration times of how they performed with and without the charcoal mesh filter inside the air box. Take into consideration this was on a subaru crosstrek, so the results will likely vary on other cars......
I decided to give it a go on my BRZ and made a quick "How to" for anyone who is interested. Its super simple and Im sure most of you could figure it out without any help, but some may want to see it. 1st loosen the inlet pipe clamp shown in red with a 10mm socket or phillips screwdriver. It does not need to come off, just be loose. Also unclip the harness for the MAF sensor shown in blue. View attachment 6665 Next you will want to release the harness from the air box so you dont yank on the wires while trying to remove it. Pinch the tabs of the clip shown in yellow and push the wires free from the airbox. You can do this with your fingers or I used some needle nose pliers. View attachment 6666 After that move over to the lower right area of the air box and locate the 10mm bolt shown in white. Remove the bolt and set it aside. There is no nut on the bottom it just threads into the bracket below, so dont worry about anything falling. Also undo the clips shown in purple holding the air box lid closed at this point. View attachment 6667 Now that lid is ready to be removed. simply pull it up and back towards the engine. The rubber intake tube keeps a good grip on the plastic tube inside but just give it some good pulling and twisting. It will pop off and you will be left with this. View attachment 6668 This goofy thing is said to be for emissions control for air that comes out of the pcv system. I honestly dont think it does a darn thing other than become a restriction. The carbon filled mesh on ours is not held in the same as the one shown in the video. Ours is heat welded directly to the plastic air box. I just grabbed one edge with pliers and pulled it back until I could get a couple fingers behind it. From there just go around and pull until all the welds release and the mesh comes off. It does leave a bit of shaggy mesh behind, so I went over all the welds with a razor blade to clean them up a little. I did not spend a ton of time here because nobody will ever see it. The important part is just to remove any loose bits and shavings from the inside before puting it all back together. This is does after all sit behind your air filter, so any junk you leave there will get sucked into the motor. This is what mine ended up looking like after I was done. View attachment 6669 Thats it..!! Just reinstall the box the same way it came out. Make sure to put the 2 plastic tabs into their alignment slots on the bottom 1st. Stick the plastic tube back into the rubber intake hose all the way. There is an alignment mark so you can see when it is all the way on. Tighten everything up and most important.... plug that MAF back in...!! I only drove around for about 10 min after. I cant say I noticed much so far. There is definitely a little more intake noise which I did not expect. Not sure how much power can be expected by doing this, but I can guarantee that mesh is not doing us any favors. Let me know what you all think...!!
Click to expand...
It gives you more power starting from the upper mid range all the way to the redline. At some point it has upto 10hp gains. There is a video on youtube by HunterTuned.https://www.youtube.com/watch?v=fDVXAkrKDQE
 
Discussion starter · #58 ·
It will improve airflow. It will not change how the MAF reads which is the problem with many aftermarket intakes that do not have the MAF in the proper size tubing or in a bad location to meter the air. No harm done.
 
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Wayward67
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