So here's a tech question to debate today. Some of the guys and me were talking at work, and debating the idea of changing out my air filter. I have the K&N Typhoon intake system, and it has the filter that comes with the kit. NOw this filter is a bit smaller, but oddly shaped. What would be the drawbacks from going to a larger filter with the same flange diameter. Looking at going to an RF-3003 which has the inverted cone in the top, as well as more surface area and a uniform cone shape.

Has anyone done this yet on their K&N system? Will it throw codes due to me having a tune, or is that really just a myth from a couple years ago?

 

I wouldn't worry about throwing a code as much as skewing the fuel trims.

 

Good question. I've often thought about this as well since I usually just toss out the K&N filters instead of "recharge" them to prevent excess oil from getting on my MAF. Since the source of skewed fuel trims is turbulance in the intake air and how it crosses the MAF, I would imagine that a more symmetrical filter would eliminate part of that issue. An inverted cone would allow air to enter "straighter" into the intake tube and cross the MAF with less turbulance, or so I would think. I haven't tried this yet since I've only got about 15k miles on my filter so I'm not ready for a new one just yet.

 

Well if the trims get too far off it will throw a code, but I think the real question is whether the trims will skew towards stock +/- 0%, or if they will skew further away than what the egg shaped filter already does.

 

One of the main reasons why I'm not a fan of oiled filters before a MAF. I was thinking about just getting something like the AEM dryflow filter for the K&N sri.

 

If you are going to do Dryflow, check out Airaid or AFE dry filters. AEM are notorious for warping and element mashing.

 

I posed this question about a dry filter a few month back and didn't get much of a response. I have heard a lot of talk about the oiled filters not being good for these cars. I believe that k&n also makes a dryflow filter and I was intgerested in getting that when I throw on all my boltons this spring. Feedback anyone?

 

I don't predict any gains or losses from this.

 

Reasoning?

 

I don't think gains or losses are what we are discussing here. A different filter isn't going to net us 5 more hp. What we might "gain" is less fuel trim skew, and for those of us who are still stock or GMS1 (like me), it's an importaint factor. If I can bring my trims another few % closer to +/- 0%, it would definately be worth the cost of a new filter.

 

What kind of fuel trim do you have right now?

I run about +3.5% on 91 octane and about +7.0% on 91 + 1 gallon of E85

 

Mine is garaged right now, but it depends on the season and how often I try to fine tune the filter position. Usually in mid summer, on 91 with no ethanol in it, I'll get down to about 4.0%. In the spring and fall on the same fuel it will get up to 7.0% if I don't touch the filter's position. If I go to 91 or 93 with ethanol in it the trims shift upward another 1-2%.

 

Aaron, as earlier mentioned I believe the only reason the filter throws off trims is due to the turbulence caused by the shape of the stock filter that comes with K&N SRI. I believe if you go with a straight cone that will eliminate that issue all together.

Sorry didn't keep in mind that you're GMS1, it would be hard to predict how straight cone would affect your trims without trying it out. Personally I just datalog for any changes I make and fine tune to it accordingly. Have you considered going with an aftermarket tune or is that out of question? I think it would yield much better gains in the long run.