Review on k & n cold air take filter charger.

Have a 2015 Tacoma: put a 3" and 1" lift with 285 tires. Loss about 3 miles to the gallon do I installed a K & n cold air take charger. Has anybody experience better gas mileage or horsepower? I notice a little horsepower but so far no better gas mileage.

 

NO HP gain on non aspirated vehicle. Might respond better, be more throaty sounding. Night even lose MPG as others have said.

 

Honestly you get better gains with the paper stock filter. Absolute waste of money

 

It's louder, not more hp....I have a k and n drop in filter in my truck, because I need a new air filter the day of a long trip and it's all they had.
I have knoticed no increase/decrease in mpg. Any increase in "hp" is just you raving the engine more to listen to it.

 

Horsepower gains on Tacomas are more a state of mind than an actual thing you can measure ... unless of course you are adding a supercharger.

 

K&N garnered their reputation in the 60s when the automotive industry was retiring the old flat wire mesh oiled air filters for those "new-fangled" much better filtering throw-away (vs. the messy job of cleaning the oiled mesh units) pleated paper thingies--thing was that they put the better filtering paper filters in the same size housings (air box) used for the early OEM mesh things that a mosquito could fly through without getting any oil on it. The paper filtered MUCH better but because the physical size hadn't changed they were MUCH more restrictive.

Ken Johnson & Norm McDonald realised this and came up with the oiled cotton gauze filter they still make; a far superior filter as compared to the then too small OEM paper filters--this made them a HOT item, their main claim to fame an something they market and cash in on to this day.

However automakers are not really as stupid as we all like to believe, so even they eventually realised that the air boxes and paper filters were too small and were hurting engine performance. Then along came the CAFE (Corporate Average Fuel Economy) standards and the industry was forced to produced as free flowing an intake as was possible. Add in the horsepower wars and there was absolutely no reason for them to do otherwise. Air boxes and filters on all contemporary vehicles can pass 2 to 3 to 4 times as much air as the engine could possibly need. Most are also designed as CAIs (Cooler Air Intakes) drawing air from the grill and/or wheel wells, etc.

My '98 SL500 came from the factory with massive dual air filters (7" x 16" each) fed by 80 mm tubes from inlets on either side on the radiator:



The stock air intake on my '09 Tacoma 4.0 is a cooler air intake with a 75mm or better tube from the fender well feeding what is an enormous filter for a 4.0 L engine. The tube has what looks like a HelmHoltz resonator molded in just before it enters the wheel well, this is likely to tune the intake tract and reduce/eliminate standing waves at certain engine speeds, reducing dropouts and surges at targeted intake velocities.

For most all newer vehicles all a K&N drop-in filter will do is increase the amount of crud that gets past the air filter, and one they load up with the crud they do trap they will not even pass as much air as a quality OEM or OEM equivalent paper filter as they have a much smaller surface area.

Here is a rant re: K&N drop-in filters I published in December 2004, nothing has changed in their products or my opinion since then.

While we are talking intakes here is a good whitepaper re: "ram air"; applicable to claims made by K&N about their replacement intake "systems".

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See what happens when retired engineers can't sleep...

 

I'm by no means an expert on filtration, but I do have to say the K&N drop in does feel different compared to an OEM paper filter. It doesn't seem like I have to mash the throttle down so much to get to speed, but that could just be mind games. I do; however, agree with you on the filtration "protection". I switched back to paper filters for that mere reason. The oil from the K&N can mess with the MAF and end up doing more harm than good once the filter is clogged. I suppose if you live in a relatively clean environment and don't off-road, then the K&N will be alright. I know several individuals who have used these oiled drop in's for over 100k miles without a single issue. I suppose it's one of those things that really just depend on your driving habits and what you put your vehicle through.

 

The increased intake noise provides a powerful placebo effect--i.e. the "mind games" you mentioned. Also most anecdotal testimonials regarding improved "throttle response" are based on replacing an old dirty paper filter with a new K&N insert. Replacing the old filter with a new paper filter would provide the same increase. A dozen years ago we ran numerous back-to-back dyno tests on '99 to '04 4.6 L Mustang GTs and found no meaningful power increase from a K&N drop-in versus a new OEM paper filter, or even no filter at all.

As you have indicated the issue of over zealous re-oiling the gauze filters fouling MAFs is real (aerosol throttle body cleaner will usually clean them up). We often get trapped in the fundamental misconception that if a little is good then more has to be better...

 

I completely agree. I think K&N has a wide fan base which makes them so popular in the automotive industry. Their products have been purchased through several generations which keeps them in today's market.