Engine Air Filter recommendation

This is a copy + paste from K&N's FAQ section on their website.

"2. What increase in horsepower should I expect from a K&N replacement filter?
K&N does not complete vehicle performance tests (dynamometer tests) for every application we build a replacement air filter for. We do complete air flow testing for every air filter, and can verify that a K&N air filter will flow air with less restriction than its OEM counterpart. However, other components of the vehicle’s air intake system (like the air filter housing or tubing) can create air restriction and limit horsepower. The design of these parts varies among different vehicles and manufacturers, so there is no way to estimate a certain amount of horsepower gain from just replacing an air filter. The higher air flow and lower restriction will increase performance, but we cannot guarantee a certain/exact amount."

 

K&N have changed their response to questions about mpg.

Used to be this.

1. How will a K&N filter affect my vehicle's fuel economy?
We certainly understand why it is theoretically possible for a consumer to experience a mileage increase after installing a K&N air filter or intake system, however, we do not go so far as to make a general claim that our air filters and intake systems will provide an increase in mileage.

Now they cut to the chase.

1. How will a K&N filter affect my vehicle's fuel economy?
K&N does not make any claims or advertisements regarding fuel economy.

Air filters don't improve mpg.

 

that pic and bumper sticker go well together....

 

For what it's worth, here is my experience. Years ago I had a 1976 Chevy van that needed an engine rebuild at 101+k miles. Typical for that era engineering/manufacturing. After the rebuild, I ran a K&N air filter on the rebuilt engine for 121k miles. All in all, +/- 20k more miles and I live in Arizona with lots and lots and lots of dust.

 

While this is true they actually do have a video claiming the Toyota Tacoma V6 specificially shows a HorsePower increase with their Air Charger.
http://www.knfilters.com/dynocharts/63-9025_dyno.pdf (2005-2011 Tacoma)
http://www.knfilters.com/dynocharts/63-9037_dyno.pdf (2012+ Tacoma)

They do specify that results will vary. But, in the case of our Tacoma pickups they do claim a proven increase in power (albeit minor). Though it's interesting their graph shows that WITH the K&N you attain the 236HP rated for the engine by Toyota.

All that aside - I have a K&N Air Charger installed on my Tacoma. It definitely makes the engine LOUDER at higher RPM ranges. But definitely doesn't make it any faster. If anything, I dislike how loud it gets because the engine noise overpowers the exhaust noise.