I noticed a decrease in my mileage and thought that the air filter might be dirty, and it certainly was. I air compressed and a lot of dirt & dust came out of it and my mileage went up significantly. I use a stock air box and was wondering whether going to a K&N or Comptech filter is worth the expense vs. using a new stock air filter?

I was surprised to see that the air filter only lasted 10K miles.

 

It really does depend on what your looking for out of an air filter? The stock filter will be changed every service, where an aftermarket one should last for the life of the car. You have to bear in mind though, that an aftermarket filter will still have to cleaned periodically, and add to the fact that they cost a hell of a lot more, it really is up to your own personal decision on what you want.

P.S. You probably will not see any noticeable change in performance in your car with an aftermarket filter, despite what the manufacturers claims are!

 

How much are stock air filters? Looks like after-market ones are $50-70

 

if your keeping it stock just buy a new one they're cheap enough

 

I am going to buy a stock filter and send the old filter to ITG filters to make a custom one. Maybe I'll be able to put a group buy together for the ITG filters. They are extensively used in F1 and WRC and they a disposable and good up to 40K miles or something like that. Quite cool, should go around $40-60.

 

Just ordered a K&N filter for $50.00 with shipping included. Should have it by the weekend.

 

When you get the K&N, you won't be able to get away with using compressed air on it. In fact, the one you did use compressed on may already be damaged but then, your replacement is on its way, so no biggie.

 

The one I air compressed didn't appear to be damaged and it did significantly increase my gas mileage. I should have the K&N this week and I'll keep the old filter until I turn the car in at the end of the lease.

 

That's because you not only blew out the large pieces of debris, but you most likely blew out great, big, microscopic (oxymoron?) holes in the paper medium.

 

Those microscopic holes I created increase airflow!!! Should have the K&N filter today. UPS never leaves anything at my apartment and I end up having to go to thier depot to pick everything up :-(