K&N Filter for VX: Evaluation

[gork57]

I've seen several discussions on intake enhancements for the Civic VX. Comments varied; some posters stated they thought that altering things too much (such as installing a tube-type K&N or other intake) could upset the precision technology Honda set up to make the VX so fuel efficient. Others said they didn't think it could do that much harm.

In any event, I decided to keep it simple and bought one of K&N's replacement filter elements for my '92 VX. These items are permanent, and K&N claims they last 50K miles between cleanings. It is also claimed that they allow for better airflow and thus produce better mpg and horsepower. I has been one gas fill up since I installed the filter, and I can state that my mileage went up from the previous one about 2-3 mpg-as a matter of fact, this tankful produced a best-ever 49+ mpg. I have also noticed that the engine runs smoother, with less sputtering at idle. To my surprise there is also a power increase-the car actually pulls a bit harder than before.

So there you have it. In my particular case the K&N air filter claims have proven to be true. I'm not one to swallow claims of any product; mom always taught me to be skeptical of advertisers hyperbole. K&N appears not be full of the usual bull-this product really does work.

I bought the filter from AutoAnything. The SKU# for the VX is 2185095. Price was $40.95 with free shipping.

[theholycow]

How old was your old filter? I'm not sure I believe it, but supposedly a filter can be clogged without any visible dirt.

Honda went to great pains to design the car for economy; it's difficult to imagine how they would have left the car with such an inadequate filter that it restricts airflow even when driven by a hypermiler (as opposed to someone who runs it up to redline at full throttle after every red light, where it still has to flow freely enough to produce power).

[Ratman667]

being someone who also has a k&n filter, i have to disagree on it adding more power. any gain will be very small. if you are actually feeling the power its because your old filter was clogged.
the only reason i have one is it will be cheaper in the long run. it was 28 bucks and considering a paper filter is 12, it will pay for itself after the second wash. but as for it flowing better, it does. but by flowing better, you lose filtration. you can look at the link at the bottom of my post and read all about it...

http://bobistheoilguy.com/airfilter/airtest1.htm

[GasSavers_RoadWarrior]

K&Ns vary by car.

[Mayhim]

I had a K&N filter on my 1998 Z-28. An oil analysis showed it was an effective filter. Any hp gains were too small to measure on my SOTP dyno. Throttle response did seem a little more crisp.

But, they flow more air, as has been shown in any number of tests. Am I correct to assume more air in the intake of a modern, computer controled A/F mix also equals more fuel? One fill up is kinda short for a decision...I got one fill up w/47mpg and the next at 40. Now my gas pedal foot is having some sort of malfunction and I'm getting into the 39mpg tanks.

Please keep the updates and editorials current on your mod, gork57. Every little bit helps. Thanks.

[Billman2002]

No, it is true, I have dealt with a lot of hondas on this subject.

The air filter will make a difference.

Putting on a bigger muffler will make a bigger difference.

You should see a 4MPG gain from doing both mods. Reason why is your creating more airflow, but yet, creating more nose with the muffler.

That is why Honda didn't do it. Cars don't design to be used with K&N.

They just go with standard factory filters. But 9/10 times, you will be able to tell the difference in your car even if your replacing a regular brand new filter.

Hope this helps everyone.

[theholycow]

I can kinda believe that Honda (the company whose very reputation is based strongly on fuel efficiency) sacrifices fuel effeciency to prevent noise (though GM manages to provide stock quiet free-flowing mufflers), but why would they spec a paper filter with insufficient flow? They could design for and spec one that flows unimpeded.

I'm not Honda fan, but I seriously doubt they'd do that, since fuel efficiency is such an important part of their reputation.

[suspendedhatch]

1) Nothing can increase airflow into the engine unless it's forced induction, a cam change, a piston change, or some serious pulse-wave tuning. The best you can hope for with a filter, intake, muffler or exhaust change is to unimpede the air flow in and out of the motor. In other words, the motor is pulling against these restrictions but there is a limit to how much it can pull in if you completely remove them (volumetric efficiency).

The significance here is that increasing the capability of the filter to flow air doesn't make the engine draw in more air. It doesn't effect mpg or power unless the filter it replaces was damaged or clogged.

A brand new OEM air filter flows just as good as a brand new K&N. In fact, the OEM paper air filter is designed to be able to flow more air than the engine demands even at low altitude. The benefit to the K&N is that it continues to flow at this level over a period of time while the OEM filter's flow quickly tapers off as it gets dirty.

The major problem with the K&N oiled filter design is that the oil gets past the filter and fouls up your intake tube, throttle body, intake manifold, IAT sensor, and intake valves. If the oil makes it's way to your MAP sensor then you will need a new one. You could argue that people are over-oiling the filter and I wont dispute that. But if that is the case then it is an extremely common occurrence. I must have been over-oiling mine then. I can tell you that it is not only my own experience speaking here. Ask anyone that does maintenance on vehicles and regularly encounters K&N filters.

This problem with the oiled filter design is what lead AEM to abandon it in favor of a new dry filter design that filters better and lasts longer.

2) It shouldn't surprise you one bit that Honda or any manufacturer would choose a cheaper maintenance part at the expense of power, economy, even long term durability. The air filter is not the only example of this on a Honda. The cost difference far outweighs the benefit. Not only in the initial production but also throughout the warranty period.

The VX was released in 1991 (in Japan, a year later in the US), which means that it was developed even earlier than that. At that time there really was no proven better means of filtering the air than a paper air filter. Certainly not a cost-effective one. Paper was and continues to be the best balance of air filtration and flow. You simply oversize the filter to allow for an adequate flow margin.

*The case of the intake tube (not so much on the VX) and the exhaust is a little different because there were other compromises made in their design. Namely, noise reduction. The VX would not have sold as well if Honda increased the FE by 4-5 mpg and power output by 4-5 hp if it meant that the intake made the sucking/scraping sound inherent in the CAI design and the loud/raspy exhaust sound inherent in the free flowing design.

A couple mpg and a couple hp is not going to affect a manufacturer's reputation as much as a loud, obnoxious vehicle.

[shatto]

I used an Amsoil foam filter in my 98 3.9 V6 Dakota. It didn't have a Mass Airflow Sensor, hence never an oil fouling problem. The inside of the airbox was disgusting after 10 years, but the engine did last 623,000 miles.

Today I use the Amsoil Ea Air Filter. Why? Removes smaller dirt and still allows better breathing than any other air filter.