Ya I heard that it takes a few days for the ECU to learn with the new filter.

 

Stock Box is just fine with the K&N. You should see much better results. I wanted my BOV to recirc and have a sound so I went with HKS. It surely gives you more horsepower, looks nicer, free up some space. It freed enough space that I finally have room for the CUsco Oil Catch Can.

 

I have the AEM intake installed currently on my Evo. You can certainly hear the stock BOV more clearly than the stock set-up. But it is only about 50% as loud as an aftermarket VTA BOV set-up. It's loud enough that you and people nearby will hear it....but not loud enough that the police will take notice.

I don't think anyone here can feel a 5hp gain with a 'seat of the pants' driving test. Afterall It's not even a 2% gain in hp over stock. But there is a measurable difference on a dyno.

I think adding an intake to an otherwise stock car is not really a needed mod. But it is an easy mod that is a good start for a person who has never really messed with working on their car before.

SC~

 

I forgot to mention that initially that the ECU may have to learn the new "Air flow pattern" and adjust accordingly. I had the sensation initially that the car felt weaker initially when it was only the computer adjusting. I drove it for a day, then the next day it felt like it did normally.

FWIW I would stick with the stock airbox (like I've said a few times) unless you find it necessary to change to something else. In my case the Buschur components like the MAF pipe and Upper Intercooler pipe, relocates the MAF sensor slightly and also uses room once occupied by the air box so it was necessary to remove it in preparation for my upgrade path.

Someone said that its good for up to 400 hp (Thats crank HP BTW) but that is quite a bit of mods, basically that would be most bolt-ons currently available up to cams and fuel injectors.. once you get cams and fuel injectors then you might consider the filter.

Again, the reason the air filter is usually a first mod is because how easy it is to install (Getting comfortable with modifying a brand new car that your not accustomed to is a formidable task) and fairly inexpensive, therefore if you choose not to use it, you can take it out and have not spent all that much time or money.

My attitude towards everything is generally "if it ain't broke, don't fix it", this is one of those things..

Just remember, the original question is whether the poor guy should keep his stock airbox, or replace it with an aftermarket filter assembly (Short stack, etc.. but it was the inexpensive filter upgrade, and not the more complex Cold Air Induction setups that are starting to become available)

in keeping all of this on topic, because most of the debate is academic at these performance levels, the best answer is "If you have to ask why you should get it, stick with what you have until you can give yourself a definitive answer" Ultimately you'll have to do your own research and use our advice as a basis for your decision, but make your own decision. Either way you will be happy because its what YOU want.

 

right now the point is that colder air and a smoother intake pipe are going to increase power a noticeable amount......we just have not decided the best way to do that. Have an open element filter in the engine bay has bever been a great idea.

On most of the dsm's I work on, we make an intake pipe that moves the filter into the fender. We log noticeable improvement in both timing and kncok, and the car feels far far better. Turbo cars DO respond to a properly made intake, its just a matter of having it be designed well.

 

Can you get the more HP with a sfac and tune the filter?

 

The S-AFC can be used to tune around anything that affects the cars a/f mixture.. Typically the problem with aftermarket filters are off idle drivability because the Karmann frequency changes faster at lower RPMs (because of the lowered restriction), At part throttle, the car will learn around it because of closed loop.. But at Wide open throttle (or over 30% throttle) in open loop, you may find part throttle stumbling, or a momentary lean condition at lower RPM's.. and you can use the S-AFC to compensate for that.