H&N filter vs cold air vs ram air

M5ROKIT · 7th June 2005, 16:40

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!

DavidsM5 · 7th June 2005, 17:00

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.

M5ROKIT · 7th June 2005, 17:34

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.

tranck · 7th June 2005, 17:39

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.

DavidsM5 · 7th June 2005, 18:00

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.

Quote:

Originally Posted by M5ROKIT

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.

FredW · 7th June 2005, 18:03

Quote:

Originally Posted by M5ROKIT

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

XrayMD · 7th June 2005, 18:18

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.

M5ROKIT · 7th June 2005, 18:26

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

M Power · 7th June 2005, 18:37

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...

I would install it only for the eye candy appeal and any hp boost that resulted would be cream for me ..

drallen · 7th June 2005, 18:48

Quote:

Originally Posted by M Power

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...

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?

Mark