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Discussion Starter #1
I've just intalled the H&N air filters. I don't know if it just my mind but it seems a little more torqey and I hear a more whiney sound. That being said, what are the performance differences, if any, between the three options?
Seems that the cold air intakes pictures I've seen still take in air the same way as stock but ram air is a more direct and voluminous intake? Besides the different look, what is the difference between the H&N filter and cold air filter results? Don't want to toss away $$ for noth'n!
 

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Would that be K&N?

I jsut did the AA cold air intake together with the IATS relocate kit and there is definitely a difference in performance!

Well worth the cost and I get brake cooling as a bonus.
 

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Discussion Starter #3
Yes, I meant K&N. Since I've already opened up the front ducting by drilling holes and installing flex tube, I'm looking only at the air benefit of the K&N vs the cold air and ram. I know the kit you installed and I still might do it if the ram effect is better than the K&N effect. The brake cooling evens out.I've read a few interesting posts on the negative effects (supposed) of the K&Ns.
 

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I hate to burst your bubble but, I'd take those K&N's out.

The oil residue from them will foul the MAF'S.

They did mine - I just ordered new MAF'S today as a result.
 

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The kit also come with the K&N filters so your benefit would be the ram air effect.

I did have the K&N filters foul up my MAF.(they were replaced under warranty)

So right now, I'm running the AA CAI with the stock air filters.....Still works well though.

M5ROKIT said:
Yes, I meant K&N. Since I've already opened up the front ducting by drilling holes and installing flex tube, I'm looking only at the air benefit of the K&N vs the cold air and ram. I know the kit you installed and I still might do it if the ram effect is better than the K&N effect. The brake cooling evens out.I've read a few interesting posts on the negative effects (supposed) of the K&Ns.
 

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M5ROKIT said:
Yes, I meant K&N. Since I've already opened up the front ducting by drilling holes and installing flex tube, I'm looking only at the air benefit of the K&N vs the cold air and ram. I know the kit you installed and I still might do it if the ram effect is better than the K&N effect. The brake cooling evens out.I've read a few interesting posts on the negative effects (supposed) of the K&Ns.
Before I got my M5 I owned a '95 540i sport. I was going to switch to the K&N filter to try and up my performance. Here's a web site that I found that made me change my mind. Hope it helps.

http://www.bmwe34.net/e34main/upgrade/Air_filter.htm
 

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I would agree. Even though I have the AA CAI with K&N filters, I wouldn't use them again due to this problem occuring to more than just a few people. I clean my MAF's every 6 months, but I'm probably going to get rid of them and just use the stock filters from now on. :cheers:
 

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Discussion Starter #8
So is the reply to all this by K&N not the truth? Boy, it's really hard to figure out what the real deal is on this issue. I'm thinking as a compromise to put in the K&N for my track days and use the stock when street driving. I would think that where one lives and drives might exacerbate the problem ie dusty Texas, Nevada etc. I live in CT where it is not dusty.


http://www.bmwe34.net/e34main/upgrade/Air_filter.htm
 

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Rob, I seem to recall an article that stated that the stock paper filters flow as well as any after market filter. Maybe it was Dinan who checked this on a dyno. .. perhaps some other board member can help.

As for fouling your MAFS, well there are too many members here who have had that experience and that would be enough for me to stay away from the K&N's..

And then re the Ram Air effect.. just my opinion, but I figure for the AA system to really work, you would have to driving a little faster than the 55mph limit we are allowed to drive before you got any benefit... :M5rev:
I would install it only for the eye candy appeal and any hp boost that resulted would be cream for me ..
 

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M Power said:
Rob, I seem to recall an article that stated that the stock paper filters flow as well as any after market filter. Maybe it was Dinan who checked this on a dyno. .. perhaps some other board member can help.

As for fouling your MAFS, well there are too many members here who have had that experience and that would be enough for me to stay away from the K&N's..

And then re the Ram Air effect.. just my opinion, but I figure for the AA system to really work, you would have to driving a little faster than the 55mph limit we are allowed to drive before you got any benefit... :M5rev:
I would install it only for the eye candy appeal and any hp boost that resulted would be cream for me ..
Not a really good example...but...doesn't Dinan use K&Ns with blue dye on all of their CAIs? :viking:

Mark
 

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drallen said:
Not a really good example...but...doesn't Dinan use K&Ns with blue dye on all of their CAIs? :viking:

Mark
not sure if it's k&n or not, but it sure does look like a k&n with blue dye... (dinan colors!). I have them, and the inside of my CF intake tubes are clean, no oil residue, no dust etc. Dinan specifically recommends not cleaning and reoiling their filters.
Mike
 

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I think they are fine, if you dont over oil them and if you are prepared to clean your mafs from time to time, but then you also have to consider is the few Hp over the paper filters worth the hassle? and I believe the AA CAI may provide some ram effect at high speeds, I believe its primary purpose is to provide cool air channelled in from the front bumper, which I believe it would do, I am planning on going with the AA CAI with stock filters, Josh
 

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Re: K&N filter vs cold air vs ram air

This may be a moot point...but on a dyno run with stock paper in the air box, compared to nothing in the air box, the paper filter cost me about 10 to 15 peak horsepower...and a bunch of low end/low RPM torque...

I have yet to test with the K&N filters in...

Mark
 

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Re: K&N filter vs cold air vs ram air

Guys,

I have drop-in K&N filters. And YES, i did have to replace my MAF's. But ever since i washed them, lightly oiled them and kept them dry in the sun for a good 6 hours.... they have been wroking fine with me.

they definetly flow more air than the paper ones, thats a no brainer! they also work well with the AA ducts!

The question is... if the K&N's are so hazardous to the MAF's, then why do manufacturers like GruppeM and Dinan and others use them?
 

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Re: K&N filter vs cold air vs ram air

Ahmed said:
Guys,

I have drop-in K&N filters. And YES, i did have to replace my MAF's. But ever since i washed them, lightly oiled them and kept them dry in the sun for a good 6 hours.... they have been wroking fine with me.

they definetly flow more air than the paper ones, thats a no brainer! they also work well with the AA ducts!

The question is... if the K&N's are so hazardous to the MAF's, then why do manufacturers like GruppeM and Dinan and others use them?
I too have the AA CAI with the K&N filters. I have had this on the car for more than two years without an issue, until today when one went bad.

I have read studies that indicate that the BMW filters flow the same amount of air as the K&N's. Anyone know for sure?

Mark
 

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I have the AA CAI kit, but I attached the air hose directly to the air funnel in the grill. No air leaks except the stock drain holes in the air box. If there is any ram effect, I am getting it. I don't understand why anyone would cut the holes for brake cooling as that would be minimal and defeat any ram effect to the intakes. Air flow will always take the path of least resistance.

Just my $0.02 :M5launch:
 
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