I cracked a beer, then some plastic and took that restrictive POS out... Time will tell...
Ok. Drove today and had a noticeable difference in throttle response! Best free thing I could have done!
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Just removed Hydrocarbon filter
- Thread starter eskimochaos
- Start date
I cracked a beer, then some plastic and took that restrictive POS out... Time will tell...
Ok. Drove today and had a noticeable difference in throttle response! Best free thing I could have done!
ThreeFiveO
New member
Well, I removed the filter last weekend on my 08 V8 to give it a try. After driving around this week, I haven't yet noticed any difference in mileage or performance. I think there may be a slight increase in noise, but that's about it.
That said, my filter was completely clean on both sides when i removed it.
That said, my filter was completely clean on both sides when i removed it.
Jerrydog
New member
I removed my carbon filter about two weeks ago and added a K&N filter in place of the replacable filter, since then my milage has gone from 18.4 to 18.9 and may make it to 19. I drive 15 miles to work daily, about 1/3 of the trip is 35mph and the rest is 45-55 depending on who is in front of me.:lookout:
Just thought I'd share my results.
Just thought I'd share my results.
BlackWorksInc
New member
I would still like to see some dyno data and maybe a flow test. I find it hard to believe there is that much of a gain from removing the HCF. The scientist side of me is really curious. 
greenmonkey
New member
Love this!
I remove mine about three weeks ago and I've seen a .8 mpg increase. That is the only thing I've changed. Better air flow = better mpg.
bigwebb83
New member
more air = more fuel = worse mpg. Computer will always compensate for more air by adding more fuel to maintain target a/f ratio.
Roburban
New member
DING DING DING!!!! We have a winner!!!! :iagree:
If you INCREASE AIR, the MAS (Mass Airflow Sensor) MUST INCREASE FUEL!!!!!
Otherwise, you're running TOO LEAN which means TOO HOT and things will begin to fail.....warped heads, blown head gaskets, etc. The MAF will NOT allow that. It will just increase the FUEL FLOW to match the AIR FLOW for the correct FUEL/AIR ratio.
The ONLY result you MIGHT see is the INCREASE THROTTLE RESPONSE. That's because you are allowing MORE AIR AND MORE FUEL.
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Wrong-O
Removing this filter will not magically make your engine use "more air." The engine is going to use as much air as it wants. When you mash the accelerator, you are opening a valve that lets in more air. The MAS(mass airflow sensor) is calibrated to determine the weight of the air entering the engine. The ECM then, based on several fuel charts, determines the amount of fuel needed for that amount of air. The throttle meters air, not fuel.
So what happens when you remove this filter? You create a freer flowing intake. This means that the supply of air available to the valve(throttle body) is larger. Your engine will still get the same amount of air it requires, but it will flow a little easier. Remember that an engine is nothing more than a glorified air pump. Air in ~ air out. The more easily it can flow, the easier time the engine has moving it. This is the same reason that an unrestricted exhaust without a matching intake will not give optimal results. Also, forced induction, without a way to evacuate the added air(better exhaust), will not give the best results.
Thinking about this...you both are probably right.
Look at it this way...your lungs are like air pumps.
So, if you are only allowed 0.5 seconds to take each breath...which is going to give you more air at the end of the breath...breathing through a straw or garden hose?
Also, which is going to take less energy?
An engine's "breath" is fixed based on bore and piston stroke at any given RPM. If the piston/cylinder is capable of holding/drawing 15 cubic feet/s (just speaking hypothetically) of air, but the intake only allows 13 cf/s, then you are going to have some wasted volume.
On the other hand, if the intake was modified to allow 16 cf/s, then cylinder can get all (more) the air it can hold in 'a breath' so to speak. More air (and fuel)...more power and probably less MPG.
Also, since 16 cf/s is less restrictive than 13 cf/s, less energy/work is needed to draw the air through. Less work gives more available power for moving and probably more MPG.
...in reality though, I think the intake system on our 4Runners allows all the air the engine needs, so any gain most likely comes from the engine doing less work drawing in the air.
Look at it this way...your lungs are like air pumps.
So, if you are only allowed 0.5 seconds to take each breath...which is going to give you more air at the end of the breath...breathing through a straw or garden hose?
Also, which is going to take less energy?
An engine's "breath" is fixed based on bore and piston stroke at any given RPM. If the piston/cylinder is capable of holding/drawing 15 cubic feet/s (just speaking hypothetically) of air, but the intake only allows 13 cf/s, then you are going to have some wasted volume.
On the other hand, if the intake was modified to allow 16 cf/s, then cylinder can get all (more) the air it can hold in 'a breath' so to speak. More air (and fuel)...more power and probably less MPG.
Also, since 16 cf/s is less restrictive than 13 cf/s, less energy/work is needed to draw the air through. Less work gives more available power for moving and probably more MPG.
...in reality though, I think the intake system on our 4Runners allows all the air the engine needs, so any gain most likely comes from the engine doing less work drawing in the air.
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No no, I'm right :bigok:
BlackWorksInc
New member
A neat diagnostic tool that could be used in this instance would be testing volumetric efficiency.
Using the Volumetric Efficiency Calculator
Using the Volumetric Efficiency Calculator
I just pulled mine! I also have a K&N drop in panel filter. It is definitely worth it over the stock filter and hydrocarbon filter.
Altogether it literally took me 1 minute total to pull the hydrocarbon filter off(30 seconds) and drop the K&N filter in place of the OEM air filter.(another 30 seconds)
I immediately noticed better throttle response and smoother riding through the power band. I don't have any evidence to prove this(ie dynosheets) but I am happy with the way it runs now. I'm not gonna spend a couple hundred bucks to dyno research a mod that cost me nothing.
Hope this helps.
Altogether it literally took me 1 minute total to pull the hydrocarbon filter off(30 seconds) and drop the K&N filter in place of the OEM air filter.(another 30 seconds)
I immediately noticed better throttle response and smoother riding through the power band. I don't have any evidence to prove this(ie dynosheets) but I am happy with the way it runs now. I'm not gonna spend a couple hundred bucks to dyno research a mod that cost me nothing.
Hope this helps.
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I second this post. I just did the exact same two things a couple days ago and am pleased with the results.
Like others have said, I've also experienced a preliminary increase in MPG (although, I'll give it more time before saying so definitively - the real test will be the 5 hour drive I have ahead of me today).
Oh, and lonesouth is right. A less restrictive air filter does not force in more air automatically. It gives the engine the potential to introduce more in a shorter period of time. The throttle ultimately determines how much air the engine is going to breathe in, and this is what determines the amount of fuel that is added.
Cdn4Runner
New member
Pulled my HCF the other day. I also noticed an increase in throttle response. Time will tell if the mpg's go up. It was worth it just for the throttle response though.
