Being the lazy geezer that I am, I much prefer the paper filters to a reusable filter you have to clean. To me, this is a throwback to the oil bath air cleaners that I had on my first cars of the 1940s and 1950s. I don’t even like the foam filters on small engines. For a couple dollars, I’ll take the throwaway paper filters.
You’d probably be better off OP using your resources to change out the air filter more often with the same type that came with the car, rather than switching to a more expensive version.
Some years ago my oldest son bought a cold air intake system for his 96 Camaro with dual reuseable filters and which old dad installed. The claim was more horsepower/better mileage; neither of which happened. Go figure.
It’s a royal PITA to remove and clean the filters. The car has to be jacked up, a panel removed underneath, and the filters wrestled out through a cubbyhole with little room for tools to work the clamps. Minor cuts and bloodshed is usually the order of the day… 
Same goes for the 500 dollar Borla muffler which also claims more horsepower/better mileage. Zero effect there also although I admit it sure sounds sweet.
Since the subject is cold air intakes and aftermarket air filters, and we have lots of new posters here, I’m to take the liberty of repeating a story that I haven’t told for a while. Apologies to the old timers for repeating an old story.
A few years back I put some thought into a cold air intake. In looking into it, I discovered that the CAI would take the air from the same place as my stock intake snorkel did… the fender cavity. So how could the air be colder? I decided that the only possible advantage a CAI could offer was MAYBE slightly reduced restriction. However, my research determined that my OEM induction system had more than sufficient capacity for the four little cylinders to suck in all the air they needed anyway, so that advantage was fake. I also read a great deal about the numerous ruined MAF sensors due to the oil fumes from the filters. I concluded that the CAI system was 100% marketing hype and 0% real advantage.
What I decided to do was (1) create a system that really would feed from the outside air and also (2) act as a ram air system, reducing a bit of pumping loss. So, I opened a false “vent” in my front lower bumper cover and installed a screen made from expanded metal from the hardware store, created a “box” behind the vent, replaced the single snorkel on my air filter box with two shop vac hoses from the hardware store, increasing the capacity to the air filter box about 90%, connected the intake ends to the aforementioned collector box, and… a tidbit… removed the carbon filter from the air filter box ( I didn’t even realize it was there until I started… its isn’t even on the parts list separately). I also did a bit of research into the capacity of my injectors to be sure that there was no possibility of overwhelming them. I admit, I had access at that tome to Toyota engineering documentation that I no longer have access to.
Viola! The damn system worked! It made a very clear difference when accelerating to pass at speeds above about 40mph, and was especially noticeable on the highway. The new induction system sounded better too.
Caveats: my expectations were realistic. I knew it wouldn’t have a noticeable effect off the line, and it doesn’t. I knew I might pay a mileage penalty if I drove aggressively, and I do (about 3mpg penalty, however on the highway with the cruise control on I get the same mileage, as I expected).
Summary: the entire system cost a total of less than $40, it truly did put some punch in my passing power and a better, more “throaty” sound in the engine, and there’s been no price to pay whatsoever. Some might argue with the removal of the carbon filter, but I honestly don’t think the few HC molecules that might find their way to the outside world past the open intake valve when I shut the engine off will be sufficient to affect anything at all.
The first winter after I made the changes I removed the new tubes and reinstalled the old system, think it might be better to have warmer air being drawn in when the weather was cold. I noticed an absolute drop in highway performance and a loss of my nice sporty engine sound. That next spring, I put the new system back in and the difference was once again pleasantly surprising.
In conclusion, you can do much better than an aftermarket CAI system for far less cash and a bit of common sense… not on all cars, but I suspect on many, since the fender space is such a common place from which to draw intake air.
@“the same mountainbike” You should have dispensed with all that ducting nonsense and just gone for the old-fashioned full cold air intake.
Mountainbike, I did something very similar on my Matrix.
I re-routed the snorkel from under the hood just behind the battery to a space near the lower front grill, but not directly in the air stream.
I was concerned about water ingestion.
An OBD_II scanner shows intake air temp is lower, especially in stop and go conditions.
Midrange torque feels slightly improved in hot weather.
No change in sound or MPGs.
I designed in a solution to the water ingestion concern with a drain hole in the plastic box behind the vent. The intake hoses are attached to the top of the box, and any unwanted matter including water will, through its greater inertia, simply hit the back of the box and drain out the bottom. There should theoretically be too much inertia for the water to turn up with the airstream. Seems to work. When I built it I tested it by blowing water with a garden hose directly into the intake duct on the bumper skin for about three or four minutes. The air filter and its box stayed completely dry. The engine ran flawlessly.
I have went full circle on this topic over the years. I’m back to paper.
K&N has a few pros and cons, but when you ruin a $100 MAF sensor with the recharging oil, all of the sudden the cons far outweigh the pros.
Now that I think about it… The last time I had a K&N, over a period of 50,000 miles, I had to replace a MAF sensor, and clean it every time I changed my oil.
Since I got rid of K&N 4 years ago, I have only cleaned the MAFs on both my cars once, and honestly I did that out of boredom.
Here is a question… Are today’s modern engines able to benefit from more air flow than the designers set them up for?
Yes and no. Simply increasing capacity alone might help some vehicles, but I doubt of it would help most. In the quest for every nth of a MPG, manufacturers have pretty much maximized induction system efficiency, however manufacturers also consider induction system quietude, and I’m sure there are designs out there that made a compromise to keep the ride quiet.
However, using a ram air system increases the air pressure at the intake snorkel, reducing the effort necessary for the pistons to pull air in… sort of like a poor-man’s artificial induction system. That does have the ability to increase airflow and IMHO should be combined with increase capacity. I accomplished that by almost doubling capacity into the air filter box and by removing the carbon filter. I stayed with the OEM paper filter, which according to my research has more CFM capacity than the engine will ever need.
Needless to say, taking air from a colder spot than the OEM snorkel takes it from helps too.
I estimated the amount of air my engine needs. At any given time there’s one cylinder on the intake stroke. By taking the displacement of one cylinder (total displacement/4), and estimating the speed with which that cylinder fills with air at 6500 rpm (redline on my vehicle) I got a total number, than reduced it by 30% to compensate for obstructions such as turbulence around the valve (I guessed… actual engineering data was unavailable to me). Using an optimum stoichiometric fuel/air ration of 14.7:1, I was also able to judge the ability of the injectors to feed the flow (I did have the engineering specs on the injection system, the maximum the ECU is able to provide through the injectors).
It all worked beautifully. But I think when making any change it needs to be looked at in context with everything it might affect. The whole system needs to be evaluated. Just as you wouldn’t put a high rise camshaft on an engine without also looking at the spring rates, the rockers, and the rest of the valvetrain, to me modifying an induction system requires the same look-see.
I personally would not touch a K&N system with a ten foot pole. IMHO it’s 99.997% marketing BS.
In conclusion, the improved performance was better than I hoped for, but the sportier sound was a pleasant surprise.
I have got to believe that, considering the stringent CAFE standards we live with, if Ford or GM thought that a different air filter would give you any more MPG with a out a drawback somewhere, they’d do it in a heartbeat. I mean, holy cow, look at the new Aluminum body parts and the grill louvers that close automatically for aerodynamics. Some cars even lower the frontend by a couple inches when you go over 35 mph. They do all these things in the name of efficiency.
Also, when you think about the HP gains, it is a constant battle btwn car makers to top each other. The idea the K&N has come up with some profound idea, and automotive engineers at Chrysler who have their nose to the grindstone are behind the curve is almost absurd.
I have to assume that car companies are aware of any and all possible modifications to their products. I also assume that they have made educated decisions to implement or not to implement these changes, taking into their calculation every pro and con. Sometimes they are wrong, and sometimes they are right. As the consumer, it is your job to figure out which car company is wrong less often and then buy their product.
I wholeheartedly agree, dangerous. A great deal of research and analysis by the auto manufacturers goes into making the vehicles as MPG efficient as possible while still getting acceptable performance. K&N’s claim that their CAI system improves both HP and MPG is absolute BS. The only way to get more HP from a given engine is to make changes that will allow it to burn more gas. Gas is where the energy is. Internal engine changes such as lighter pistons, connecting rods, rocker arms, etc. would lighten the load a bit, but at a cost in dollars and in reliability.
ASE, that is beautiful… but someone put my engine sideways!!! And it’d stick out the hood! And I’d get snow all over it in the winter!!
I’d like to shake the hand of the guy or gal who made millions off the sales of that “tornada” or “vortex” thing that was all over TV commercials about 10 years back.
If I recall, it was an 8 oz piece of stamped sheet metal to put in your air duct between your filter and you throttle body. It supposedly made the air flow spiral, which OF COURSE, according to the laws of magic, gets you more HP and MPG.
Now, I dropped out of MIT before I even new what MIT was, so don’t take by opinion for fact, but that sounds like Dr. Oz crap to me.
Just a caution to those who are considering making modifications to their car’s air intake path. I’ve heard reports of check engine lights coming on after doing that, and after hours of diagnosis, turns out it was the air intake path modification that fouled up the computer’s measurement of intake airflow, so it couldn’t get the mixture correct, hence the CEL.
The solution: Return the air intake path to stock.
George, in cases where that happens, I agree with your solution.
The reason it happens is because the typical aftermarket system changes the configuration of the path where the Mass AirFlow sensor resides, usually completely relocating it. The MAF measures the amount of air flowing by in essence measuring only a small portion of the airstream, in effect “sampling”. It extrapolates from its reading the total amount going by. And it’s designed to do so based on the CFM capacity of the airstream where it’s located. Dramatically enlarge that and you invalidate the MAF reading. It says based on the volume of air passing by it that there’s a specific amount of air gong into the engine, but change the ratio between the size of its sample and the total capacity of the are where it’s located and it’s now measuring a smaller portion of the stream and telling the computer there’s less total air flowing in than there actually is.
In short, the total airflow the computer is calculating might be 10X the MAF sensor’s sample. Make the total capacity at that spot 20% greater, and the ECU has no way of knowing the total airflow has increased by 20%… it still thinks the total air flowing in is 10X the MAF’s indication. It’s still calculating the injector pulsewidth based upon air coming in at a rate of 10X the MAF’s signal.
I support your caution. Unfortunately, people rely on the companies that sell these systems to have done the engineering necessary. They often don’t. In the case of some of them, I think they just pick a spot to add on a bunghole for the MAF sensor with no thought of how it actually works. They figure that as long as it has a place in the airstream it’ll work fine. That’s a false assumption.
TSM, great info, thanks. My Corolla’s air intake path has a rubber thing sort of shaped like a huge banana hooked into the path, but not part of the direct airflow path, after the air filter. Someone here explained that part provides a storage chamber of filtered air ready to go into the engine whenever the driver steps on the gas, and also filters variations in air flow. While it seems to be a useless part from a simple visual inspection, it is necessary to be there, otherwise the air flow sensor wouldn’t be accurate.
That banana is a resonator designed to attenuate fluctuations in the intake path, to “filter out the highs and lows” as it were. These fluctuations are a normal byproduct of the fact that the intake path is constantly being opened and shut off as the valves open and close and the cylinders keep each starting and stopping their sucking action.
It has a specific name… which I cannot remember… Hertzwold resonator or something weird like that. Can anybody here think of it?
@DangerousDIY You also have to keep in mind that automotive engineers are also at the mercy of the beancounters. Suppose there was a magical intake that could product 5 more HP than the one they were using. The magic intake costs $150 per car more than the non-magic one. Guess which intake is going to used for the production car?
A good example of this kind of thing is mentioned in the book “Iron Fist, Lead Foot” . It chronicals what John Coletti had to go through to get the 2003 Mustang Cobra built. The beancounters wanted to use the stock cast rods for the 2003 Cobra’s supercharged V8. Coletti insisted that forged Manley rods be used. The Manley rods added something like $144 to the price of the car and Coletti basically had go to over the beancounter’s heads to get the job done.
@Fodaddy
I can see that point for HP, which is only a market pressure. But I don’t think cost is spared for tgr Gov’t mandated CAFE standards.
Look at all these expensive alterations implemented lately in the name of MPG. Ford even cut the entry level HP in the F150 by 19, because it gets better fuel economy. Granted, with the 700 lbs whack by added use of aluminum body panels, the HP to weight ratio actually improved.
I’ll acknowledge the point about bean counters vs HP, but I think nothing trumps EPA inspired Fuel Economy quotas.
Nothing trumps the regulatory agencies operating under the Executive Branch. Except perhaps the judicial branch… but it takes an act of God for even that to happen, Evidence if you will the SCOTUS decision in 2013 giving the EPA the authority to regulate CO2 emissions even though CO2 is nowhere authorized in the mandate of the Clean Air and Water Act, which the RPA was formed to promulgate regulations to enforce. The mandate of the executive branch, accomplished by the creation of regulatory agencies, is defined by the Constitution as to enforce the laws… but they’ve long since stepped past that to creating their own law, even though the constitution and the division of powers was specifically designed to prevent any one branch from operating autonomously, as a body separate from and above the other branches.
The feds don’t give a damn about the cost. The agencies are run by power hungry appointees.
Dangerous, the lighter pistons you mentioned are exactly what I was describing vis-a-vis the modifications to the engine’s internals that can yield more net power without sacrificing mpg… but at some cost. Lower reciprocating weight and the energy in the gas that no longer goes toward continually fighting the inertia goes straight to the crankshaft.
Helmholtz resonators!!! I got it!!!
I would have stayed awake all night bugged by that one.
Sorry guys.