Air filter recommendations?

#1

What are most people running? Are there advantages to the free flowing, but very expensive K&N type filters or is it best to stick with the OEM equivalent replacement? It seams the tweaks in the intake system tend to effect the A/F ratio and maybe it is worth it to spring for the better filter…

#2

Stock paper element. Air cleaners do not make horsepower, at least not on our cars. We removed the cleaner for a dyno run…no difference.

Should you have the dyno time to fine tune a/f ratios there maybe a difference in the hp number. But, if you are there to do that kind of tuning, why would you not tune with an element that is a known item as far as “clean air” is concerned?

Yep, the others flow more air, but at the expense of dirt too.

RP (been there done that with turbo diesel engines, too)

#3

I have been through the R&D facilities at K&N… All the research and development at K&N is scientific and stringently performed under a very tight set of rules and policies. While K&N in an E30 application is a small if any improvement over an OEM replacement filter, it is more consistent over the long term. A K&N will also permit far less dirt than a foam filter and less than many paper filters.

Despite the internet rumors, the oil on their filters does not leave the filter substrate and the dirt is indeed captured by that oil as advertised. I was even able to help during a bench flow test for a Warranty claim from a dealership who claimed the AF meter was destroyed by the use of a K&N filter and they were able to show it was a faulty AF unit - the silicone had migrated out of the AFM to the sensor wires and cooked there causing the issues.

So anyway I’ll get one once the budget frees up.

#4

I’m running the K&N. I have always been a fan of their filters. Remember they actually work best with a little dirt in them and don’t need to be cleaned until 100,000 miles or so if you keep your car on the pavement.

#5

Recently had my car on the dyno - back to back runs - air filter vs no air filter. One hp gain without…

Asked the shop about K&N. They laughed - said that on their IT VW Golf race car they saw a 5 hp decrease in back to back after installing the K&N.

I’m staying with fresh stock filters.

#6

FWIW, I think K&N’s are not good when they’re new. Not entirely sure why. Something to do with excess oil when new, or something.
I’d be curious if anyone has dyno’ed a used K&N vs no filter vs a new paper filter.

#7

PDS wrote:

[quote]Recently had my car on the dyno - back to back runs - air filter vs no air filter. One hp gain without…

Asked the shop about K&N. They laughed - said that on their IT VW Golf race car they saw a 5 hp decrease in back to back after installing the K&N.

I’m staying with fresh stock filters.[/quote]
I’ve been present during the dyno tests that K&N performs on all its products… I’ve seen the research and the data being collected. And there are times that K&N does not produce any more power than a paper, but I doubt a fundamental drop in power.

Most of their research is for the “snorkels” they make, a filter change is a filter change and no more than that.

The key with K&N is that the performance changes almost 0% over 100,000+ miles. That’s the key… Go off track at BWRP and your paper filter is now flowing as badly as Plastic Wrap, the K&N in its place would flow close to the flow characteristics it had as new.

I’d never argue this point unless I’d been to the factory and research center in Riverside myself.

#8

I have nothing but a hunch to back this up, but I don’t think our cars are that sensitive to the air side of the equation. The limiting factor seems to be fuel.

The Miata is the opposite: plenty of fuel using unmodified stock components, but tweaking the air flow (AFM, filter, snorkel on early cars, etc.) is where the HP gains are. I’ve even seen mysterious holes appear in the filter housing of the later cars that have to use the stock box. :wink:

PS - If you pick your components based on what performs best when you run off track, you’re doing something wrong. :laugh: :laugh: :laugh:

#9

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I’ve been present during the dyno tests that K&N performs on all its products… I’ve seen the research and the data being collected. And there are times that K&N does not produce any more power than a paper, but I doubt a fundamental drop in power.

I guess I missed their advertisement where they stated “Hey, no hp gain, but buy our filter anyway”…

I have nothing against K&N, hell I’ve used their products in the past. I just tire of all the hype…

#10

Steve D wrote:

[quote]PS - If you pick your components based on what performs best when you run off track, you’re doing something wrong. :laugh: :laugh: :laugh:[/quote]hahaha you’re not funny j/k :lol:

Steve D wrote:

[quote]I have nothing against K&N, hell I’ve used their products in the past. I just tire of all the hype…[/quote]Well yeah you have a point :lol: