DIY: Secondary Air Filter Removal

ok my 01 tacoma doesn't have one
also no sign that there was ever one there

 

My '03 Tundra had one.
Wife's '04 Rav4 doesn't.

 

My truck does have one. I removed it for inspection and found it to be distorted, "charcoal" element had settled and the vacuum from the engine was trying to suck the screen/gauze into the engine. I will get a replacement filter. However, with the charcoal filter gone, a KN installed and tonneau, I get consistently 20 mpg all around and better throttle response. BTW the KN does work (the paper filer is too restrictive. The tonneau makes sense as well (before, its like dragging an anchor, and it worked on my Dakota). I probably can't ask more from this truck as is. Its a daily driver 52 R/T and my fun off roader.

 

You have absolutely no flowbench data to back that up.

I'm getting 24mpg on the OEM filter.

 

I continue to get great mpg with a OEM with 40K on it. I'll change it at 60K.

 

Bingo.

The K&N does flow "better" than stock, but to say that the stock filter is "too restrictive" is submitting to K&N marketing hype.
And even Amsoil admits that their washable filters (AFE) do not filter as well as OEM.

 

Ok. Thanks to Rich & Worthywads I'm NOT doing this mod, slightly interested before - slightly, but now after hearing some logical info on the subject - I think not.

Thanks guys - Rich, Love your Truck - very tasteful, classy, and economical.

Question though: Can you point me to the info about AFE saying their filters aren't as good as OEM? Just curious cause I just bought an AFE based on all the damn hype on these forums. I've been running OEM air filter now for 30k miles.

 

Interesting... Amsoil (AFE) seems to have modified their marketing and is now claiming significantly better filtration than cellulose.

But here's some real-world test results of several filters:
http://www.bobistheoilguy.com/airfilter/airtest3.htm

Also interesting, related to the "how much is 'good enough' question:
http://www.bobistheoilguy.com/airfilter/airtest2.htm
"Best" was the K&N at 0.231psi
"Worst" was Napa paper at 0.249psi.

Having a hard time finding the charts that used to be posted.
I found one that showed the Amsoil to be equal to quality cellulose, but it appears to be referring to the 2-stage foam filter.

Anyways, a couple of years ago, Amsoil's marketing materials included a very good chart comparing 5 or 6 filters, including K&N, AC Delco, foam, and a couple of other "paper" filters.
The graphs showed the "paper" (cellulose) being the most restrictive, but the best filtration. The Amsoil (AFE) came in below paper on filtration, but significantly higher than K&N... but with marginally better flow than K&N.

Could be that those charts were removed because Delco wasn't happy about it? I don't know.

 

there is a difference between how well something flows & how well it filters. removing the filter all together will give the best flow but no filtering. so which one are we after???

 

So.. What's better for fuel mileage? More or less flow? This whole filter thing gives me
a headache. I want good fuel mileage but don't want to be confined to paved roads.
I really don't like k and n, filters. They are a pain in the ass to clean and oil.
I like foam filters, they have been used for years on the track, only problem is I can't find one that fits as a drop in filter. There is one made by Blue Monkey I believe.. Not positive..
Im not sure I'll upgrade to a cold air intake, to many problems with not enough choices of piggy back tuners.

 

Given the minimal difference in flow....

 

Well after installing my AFE yesterday and comparing it to my OEM Denso Air Filter, I can see the difference. Yes the AFE will give better performance due to less air restriction, not a significant difference though. I mean, If I didn't know i had changed air filters, I wouldn't know - ya know?

I'm going back to OEM after I use this AFE for a while. The OEM Denso is literally 3 - 4 times thicker in my opinion. I'm looking the for best filtration, I'm not worried about performance, if I was, I wouldn't be driving a 2.7L or even a 4.0L 6 for that matter.

Conclusion - Stick with OEM Denso Air Filter. Thanks for the links. Good tests, I've been to BTOG's site a few years back. . . Bums me out about the Napa results. I did a ton of research after I bought my Tacoma regarding which Oil Filter to use and I came to the conclusion that the Napa Gold by WIX was the best / and easily available. . .

Not falling for the AMSoil hype anymore though. I've been using it since my truck was new. Just changed my oil on Sunday after 5700 miles - hate going that long but it was the first chance I've had to get to it - 5700 MILES - AMSOIL was JET BLACK. This is the AMSoil that claims 25k between Oil Changes - Well I'm calling BULLSHIT!

Done with it, switching to Mobil One, at least I'll save $2 / Quart.

 

A lot of the perceived performance difference, especially with CAI units, it the noise.
The engine sounds like it's making more power, and added power actually felt is mostly from the throttle being mashed a bit more.

Drive normally wearing a pair of earplugs and the difference won't be so pronounced, as you saw with the replacement filter in the OEM box.

 

Going to do this right now!!

 

That filter has to eventually go bad. Are there any after market upper-air boxes? I have not been successful in finding any online that look like they fit.

 

It's not a filter, so it won't go bad.

It is a sack of activated charcoal pellets and it captures fuel vapors that come back out of the throttle body after the engine is shut down.
When the engine is restarted, the fresh air pulls the captured hydrocarbons from the charcoal.

As long as the air filter is changed regularly and not replaced with an oiled element, the secondary mesh will last the life of three Tacomas, just like the charcoal canister in the evaporative control system on the fuel tank.

 

if its sole purpose is to capture fuel vapors ..does anyone have an explanation on why removing it effects the 4cyc more than the v6?

 

No, just a rumor with no backing.

 

It doesn't.

It's psychological, just like a CAI.

 

Installed KN air filter and replaced plugs @ 90K......increased mpg by 2-3 mpg.
I also got great MPG when traveling to/from Moore, OK to CBUS,OH running 75+ mph with A/C running.....around 24 mpg.
Go TACO!