: So K&N air filter is no good?

09-08-05, 11:54 AM
It seems like most people on the forum doesn't believe in aftermarket air filters, I installed a K&N air filter when I changed my plugs and wires so I can't tell a difference in performance. However if the K&N filter is letting more dirt into my engine(and other bad things people say about it) should I use something else? I want honest and detailed explaination please.

If K&N is no good why is it in so many performance vehicles?:confused:

09-08-05, 12:20 PM
For some applications it is good, but the airbox on the Northstar is very efficient already,with the AC Delco stock air filter, which is far FAR cheaper and easier to work with. At 55 bucks, the K&N cost, you can buy seven of the $8 Delcos, giving you $85,000+ miles before the costs even out. And that's before you spend the money on the recharge kit for the Delco, which is worth two more Delco filters. The Delco filters better, as proven in the graph on a recent thread, and there is no difference in power, as has been shown on this forum many times. All you're doing is throwing money away and putting dirt in your engine. In SOME applications, it does do great things for fairly cheap, just not for the N*.

09-08-05, 02:05 PM
Several years ago one of the Mustang mags did a dyno test of various mods to see the actual benefit of each. They did K&N early and got 1hp I think. At the end they put stock one back on and lost 5 ( this is from memory). At stock level , little or no benefit from K&N. modified picked up some. They verified changes. It was a good article.

09-08-05, 02:20 PM
You can get the least air restriction, and more dirt-filtering-capacity by going to a WIX brand filter. At least according to that site that tested the various filters... Performance on par with the K&N (like 1/2" water vacuum difference between them), and only 10x the dirt pass through as the stock filter (but still roughly 1/2 the K&N)...

More dirt = more wear. I wouldn't use a K&N... There are other things that flow almost as well with less dirt getting through.

09-08-05, 02:51 PM
FSM recommends changing the air filter at 30K I believe. At $6 a filter X 30K you won't break even til about 275K based on Spyders K & N price of $55.

09-08-05, 03:12 PM
For the little to no HP you'll get at stock levels it is not worth the extra dirt you'll get in the engine.

09-08-05, 04:33 PM
From what I've read and heard K&N does allow more dirt which each engine wear. Even if a K&N gave you a fantastic 10 HP boast I wouldn't do it because of the extra dirt. Plus you need to add oil to the filters and what happens if you forget?

09-08-05, 05:24 PM
For years aircraft used the oiled flock filters like the K & N. These were known by the Air Maze and Donaldson brands. It was a tremendous leap forward in engine longevity, especially when operating from unimproved fields, when these were rejected, manufacturers adopted pleated paper filters, and AC produced wetted foam replacement filters for the Donaldson and Air Maze. Ring and cylinder life doubled instantly. Interestingly enough the inspection for the flock filters to tell if they were worn out was to hold them up and see if you could see sunlight through them. I have never seen a K & N that I couldn't see daylight through. They are no damn good when they leave the factory. The AC filters were very good. The secret to them was the wetting agent for the foam that was rumored to be a glycol compound. Since then the AC foam filter business has changed hands a couple of times but the filters still work very well. The idea of using oiled flock filters was discarded completely 30 years ago in aircraft and here they are again being foisted off on ignorant auto owners. What is really ironic is that K & N made their name with treated foam replacements for flock filters for dirt bikes back about the same time as AC started the aircraft foam filters. The K & N filters were sold with a "Green Weenie" catch phrase and were pretty good. I didn't like them because if you got them wet you might as well have a wet rag shoved in the intake. They were a complete stoppage.

09-08-05, 07:31 PM
Okay I put on about 3000 miles since the air filter got changed, how much damage am I looking at here? I need to change my engine oil soon anyway so I'm trusting all you guys' opinion and go back to paper filter.

09-08-05, 07:48 PM
If it's on there I wouldn't get too excited about it. Take it off at your convenience, don't loose sleep over it. I had one on a 5.0 Mustang for a long time and it was running good and not using oil at about 150K. It was on there when I got it at about 45K. I cleaned it about every 5K.

09-08-05, 09:01 PM
I doubt you did any damage at all in 3K unless you were driving on dirt roads behind a semi.