How often do you change the air filter?

[Studebaker]

I grew up when you could put a shop light under a round air filter and tell when the it needed replacing.

Now I want to replace the air filter at every oil change. Some of them I put back. Sometimes I just replace them. Always not knowing if they needed it or not.

Question How often do you change the filter? How do you know it needs changing?


Thanks David

[navdoc101]

I have a K&N filter so I never change it. I check it every oil change & clean & re-oil it as needed.

[rmoltis]

Drop in k&n filter never have to replace it. Plus it flows %7-%10 more over stock.

Is the festiva airbox the same as the aspires???

[Tommychu]

I usually tap mine out (whack it against the fender lightly) every oil change and change it out every fourth oil change or so.
Color is the best way to tell. They start out white, dust/dirt is not white. Also if a ton of dust comes out when I tap it that's a pretty good indicator that it's time to grab one.
Edit: another indicator is whether the pleats are deformed. If there's enough blockage to create a significant pressure drop it will start sucking the paper up towards the intake slightly, and the filter gets a squished look to it. That means you should have changed it a while ago.

[Movin]

If you don't eat dust you don't need to change the filter!

[navdoc101]

K&N drop in filter that fits the Festiva air box is part # 33-2222. Same as '93 KIA Pride.

[rmoltis]

I was gonna say that was the filter I have as well. I always look up the Mazda demio for referance because they are the same filter as well. So festiva 1st gen, second gen, and third gen all have the same filter.

I compared a brand new stock filter to this one after it had just been cleaned the night before and the stock filter got me %75 volumetric efficiency. Whereas with the k&n I get an %85 volumetric efficiency. This was all based off of my scanguage II feeding me data from the ecu. So I noticed a %10 power gain. It didn't seem like much with the stock exhaust when I had it but it gave me torque at low end. Then when I got my header and exhaust the power band shifted and the midrange fattenned up quite a bit. The peak torque point being now at 4300rpms. That's when I realised the stock airbox flows more than even neccassary. Would reccommend the washable k&n to anyone who still uses the stock box.

For $40 its the best bang for buck for a gain in up to %10 power without sacrificing low end for a pod filter.
Well worth the money in my opinion. Don't ever buy a paper filter again.

[JMSA540]

sorry to bring up a dead thread, but I found this thread to be very informative.. also cool how it flows 10% over stock.. good read.

[TominMO]

Just toss the lower airbox, or drill it full of holes. I would guess that would yield you a greater flow than using the K&N with a stock, unmodified, restrictive airbox. At that point some other part of the intake is the restrictor, not the airbox/filter.

If anyone has any valid research on this, it would be interesting for you to chime in here.

[navdoc101]

I modded the stock air box, drilled the bottom full of holes & removed the little snorkle on the fended side. & I have the K&N. Must flow better than the stock filter & moded box!

[TominMO]

I modded the stock air box, drilled the bottom full of holes & removed the little snorkle on the fended side. & I have the K&N. Must flow better than the stock filter & moded box!

True--but, the question at this point is how much air can get into that small plastic tube going to the throttle body? I think the stock filter with a modded airbox will do as well as the K&N. This is what should be studied.

[navdoc101]

That could be. I did install the Aspire intake tube, which is larger in diameter that the flattened Festy one. The main advantage to the K&N; besides increased flow; is that you only have to buy one,ever.

[TominMO]

That could be. I did install the Aspire intake tube, which is larger in diameter that the flattened Festy one. The main advantage to the K&N; besides increased flow; is that you only have to buy one,ever.

Agreed.

[rmoltis]

So I had a stock box I had modded with a wider opening before with this k&n filter
And because of the reduced velocity of the incoming air charge due to more opening it actually lowered my volumetric efficiency.
I ended up buying a new stock intake box to recover my low end lost.
And not to mention even with a header and the stock box with k&n filter it will flow as good or close to a replacement cone filter.

[TorqueEffect]

After watching that mightycar mods video on the air filters, and pod filters, I pretty much decided it isn't worth it.

https://www.youtube.com/watch?v=PAIxeQUSg-Q