DIY: Secondary Air Filter Removal

You would think this would put an end to this zero effect mod, but yet it continues?

Over at toyotanation lots of v6 owners raved about the increase throttle response, lower rpm?, and badass growl, at least on this thread anyway a few understand it doesn't do any for the V6, but it doesn't do anything for the 2.7l either.

I sympathize with you Chris4x4, often reason and facts fail.

 

Excellent data set!

I see a detrimental effect at the low end of torque according to chart. It appears to show "with filter" to have a higher rate of torque or rpm (upper data set) at the engine ramp up. This is my experience after removing the filter. It keeps up and goes, don't get me wrong. However, it exhibits a definite lag at the top end of my gear shift in manual. It feels like almost the engine is gasping, starved for something. Fuel? Air? When I buy a newer taco I wont remove the filter for sure.

 

Ah but your wrong. If the very bottom lines are A/F ratio, there was a change. If they are throttle position, the person let off on the gas earlier. If those lines represent speed it would say MPH on the side. One dyno sheet does not prove anything. For all we know those runs could have been done with no changes made back to back.

Here is a dyno sheet from my Mazdaspeed3 when it was bone stock. These runs were done one right after the other. Looks exactly the same as the sheet above. Fact of the matter is you remove an obstruction from the inlet, something is going to change. May not be measurable but its going to change.

 

An unmeasureable change isn't worth much. No 2 snow flakes are the same either. Too bad the much tauted improved throttle response has no measurable artifact.

If there is no measurable difference at WOT there will be none when the throttle plate overrides the filter obstruction at part throttle.

 

Seems lots of people here respect Gadget enough to concede that taking the carbon filter out of the 4.0 does nothing. The 2.7L is not immune to this reality.

 

Good for him, not trying to be funny but I probably have as much experience tuning cars as he does, I am being dead serious. Been modifying cars for power since 1995, working at Turbo Tune until Mark died in 08, still do work on the side. I have lost track of how many turbo manifolds I have welded together from scratch. One thing I have learned that you haven't yet is the dyno is not the only measure of performance, gas mileage also works if the mods weren't accompanied by changes in fuel pressure. His test can also have been messed up by rising humidity and temps while he was removing stuff through the day. There are many things that can change results, thus why I tend to not take dyno results seriously. Trap speeds on a drag strip are a better measure of possible street gains.

Either way, what does it hurt to remove the secondary filter? It causes no changes in driveability, it costs nothing, and measurable on a dyno and measurable on the street can sometimes be mutually exclusive.

 

Didn't say it would hurt but I haven't seen any evidence it helps.

Even drag trap speeds will be effected by temp and humidity, can't trust those, but i'm really only commenting on mpg with the secondary filter.

Here is a study that did not find any reduction in fuel consumption after restricting the filter way beyond any restriction that this carbon filter is causing. They did 3 different types of drive cycle tests on a dyno eliminating variables.

http://www.fueleconomy.gov/feg/pdfs/Air_Filter_Effects_02_26_2009.pdf

Are you really saying the butt dyno is more accurate?

 

Can't argue with that. Especially the portion about the airflow limits of the charcoal filter. It is one thing to post up a dyno sheet and say here is proof. It is another thing to have the person come in and explain the conditions and methods of the dyno. Thank you for taking the time to clear that up.

 

After plugs and afe cai (pro dry si what ever the f it is) I went from 16.8 to 18.5 mpgs(big tires) I suspect that it had more to do with the (old) plugs. Throttle response is tighter and truck is louder under load. especially with the little rubber gasket taken out. I leave it in.

Overall happy with afe cai but kept all stock stuff in garage in case I need to revert.

FYI. Old plugs ranged from .040 to .065 and have been using mobil 1 for last 5 oil changes.

 

i have a 99 tacoma and i was wonderin if i could do this mod to mine. anyone know if it will help or just hurt?

 

ok thanks and whats the deck plate mod?

 

So the carbon filter toyotas engineers has put on your air cleaner box has a purpose. It's been put there to prevent HC's from escaping into the atmosphere. Ok if your not sure what HC's are it's partially burnt fuel. Now in theroy I would think if your worried about gas milage you would want this, this way your optimizing all your fuel. As for removing it so you take in more air for performance once again it's killing your mpg, more air means more fuel. I really can't see a paper thin filter being removed actually increasing horsepower. I mean the regular air filter most likely causes more restrictions than the carbon. I mean if you want a noticeable horse power increase buy a cold air intake and up grade your exhaust cuz remember what goes in, in large amounts has to go out in large amounts. Just remember if you take something you have to give up something and that is fuel economy.

 

just pulled mine out. drove it a mile or two, i guess i see a little difference in throttle response. well see with time what happens with the mpgs.

 

I took mine out a second ago...if I dont really need it, I didnt care to break the prong things...its gonna sit in there without em if there is a second filter as well.

 

@SR5, The thing is, the harder it is to breath the more energy is consumed, so a cold air intake, with high flow exhaust = more performance with less efforts. problem is, us humans like to step up the aggression with the throaty exhaust, and accell harder just to hear the roar of our new toy. if you keep the same driving habits with the new mods, you will have better mpg. just my 2 cents

 

Not true.

Under anything but near full throttle your throttle plate intentionally makes it harder to breath so your engine doesn't hit to the rev limiter. The CPU doesn't care about the slight restriction of the air filter and carbon filter when the throttle plate has it way more restricted than either.

 

I took mine out last week.... Have an Air Raid filter in as well and use a Scan Guage. I hear the diff in my Gibson exhaust and driving my normal lead foot... jumped +2.1MPG (from an even 17MPG). ALL city driving.

PS I didn't know this mod was here... I just broke mine out with a flathead!