K&N Fliter or Air Intake Performance Kit

May 30, 2004 3 Replies

I am looking for words of wisdom (and experience) and advice on improving my '99 performance.



Should I just get the K&N replacement filter (~$40) or purchase one of the aftermarket Air Intake Performance Kit (~$230)?



If it's the kit, which one do you recommend and where is the best place to purchase it.



TIA,



- Pat


The MonsterFlow probably offers the most performance for an NB:

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claim 10 hp. Don't bother unless you get the CoolBox with it. Not CARB approved in California, and foam filters don't filter as well as OEM paper.

Or, if you don't have cruise control, the Randall duct is much cheaper and delivers cool air while retaining the superior stock filter (5 hp claimed):

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In either case, don't expect more than a just-noticeable difference--on a stock 1.8 Miata, the intake is not a source of restriction, though cooler air is always good. Avoid K&N and other intakes that don't draw directly from an outside air source--all you'll get is extra dirt in the engine, and probably a power loss. The K&N advertisements are...let's say highly imaginative.

Your performance dollars will work harder in the suspension than under the hood. Alignment, tires, shocks, and swaybars will make real improvements in your car's capabilities. A driver's school will make real improvements in yours.

. Not

Does anyone have experience with the FRAM AirHog cotton filter?

I've had the Monsterflow on a 2000. It sounded great at WOT but the performance gain was hardly noticable.

3 years ago, I did some testing of underhood temperatures. As I recall, the temp at the Monsterflow intake quickly went up by 30-50 degrees over ambient when stopped. Within a half mile after a stop light, though, it went back down to ambient plus 10 degrees, the normal temp while driving. From this, I suspect that ducting cold air into the intake would do more than any air filter.

I'm working with my third Miata. I don't push the handling anywhere near the limits car but I would like a little more zip around town. The single most noticable improvement I have found was advancing the timing (it can be done with an M2, BTW). Oh, I've made exahust improvements and tried cold air intakes on both an M1 and M2, and I found that I spent lots of bucks and got little improvement for my money. I've decided to either leave my new Miata stock or follow Leon's example and install a supercharger - anything else seems like a waste of money.

Randy

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