Debris behind air filter
08-12-2007 | 07:21 PM
#16
Rennlist Member
Joined: Feb 2003
Posts: 29,958
Likes: 185
From: saratoga, ca
if you care about filtration, seal the air box. this goes for the stock filter as well. if you dont care, then either one will work, and even dirty, a stock air filter will work well, as the needed air just goes around the filter.
lube the KN on one side, and that takes care of that issue.
KN has less restriction, (if both are sealed) and is re-usable, vs stock which has more restriction, (if air box is sealed) and is not re-usable.
pressure drop equals HP drop. how clean does the air need to be for most of the driving you will do? i would bet an un oiled KN would be sufficient. some racers only use screens (kind of crazy, if you see the stuff i pull out of my air filter. I mean, im pulling up rocks, huge pieces of rubber, dirt, sand, etc and thats after only one Session at Laguna seca!!)
mk
lube the KN on one side, and that takes care of that issue.
KN has less restriction, (if both are sealed) and is re-usable, vs stock which has more restriction, (if air box is sealed) and is not re-usable.
pressure drop equals HP drop. how clean does the air need to be for most of the driving you will do? i would bet an un oiled KN would be sufficient. some racers only use screens (kind of crazy, if you see the stuff i pull out of my air filter. I mean, im pulling up rocks, huge pieces of rubber, dirt, sand, etc and thats after only one Session at Laguna seca!!)
mk
05-04-2008 | 01:18 PM
#17
Pro
Joined: Feb 2005
Posts: 710
Likes: 1
From: 3rd rock
airfilter
on an 89 the airfilter I just purchased has one side flat and the other curved. The curved side had arrows to indicate airflow. Meaning the curved side is installed on the bottom and the flat side is on top. Does that sound right as I don't recall my last filter having a curved side.
05-04-2008 | 02:19 PM
#20
Drifting
Joined: Nov 2003
Posts: 2,733
Likes: 92
From: London, UK
I put an air filter in upside down once by mistake. Didn't take long to realise there was something wrong - the car wouldn't rev above 3000.
05-04-2008 | 04:26 PM
#21
Rennlist Member
Joined: Sep 2006
Posts: 1,556
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From: Oxford, CT
No problem. I went through this last summer when I replaced mine - had to go to the parts listing to figure it out.
IMHO, for all of the engineering that Porsche does, they didn't put enough thought into designing the air filter box - the filter can be installed upside-down and the cover can be latched with a wide-open gap in the back all too easily. They should have put the resources they devoted to adding a second windshield washer system to better use.
IMHO, for all of the engineering that Porsche does, they didn't put enough thought into designing the air filter box - the filter can be installed upside-down and the cover can be latched with a wide-open gap in the back all too easily. They should have put the resources they devoted to adding a second windshield washer system to better use.
05-04-2008 | 04:29 PM
#22
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Joined: Sep 2002
Posts: 2,181
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From: Madrid, Espaņa
Due to the oil the K&Nīs rubber seal is slippery and likes to glide out of position. Especially on the back side of the air box, thatīs how the dirt gets inside the air box. My PO used a K&N and when I switched to a regular paper filter, I had exactly the same debris on the MAF. Never had any issues again with a paper filter....
05-05-2008 | 03:28 AM
#23
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Joined: Feb 2003
Posts: 29,958
Likes: 185
From: saratoga, ca
dirt is vacuumed into the sides. Ive mentioned this for a while now.
nothing will get through a KN or stock filter, but the air box leaks and thats wher stuff can get in
mk
nothing will get through a KN or stock filter, but the air box leaks and thats wher stuff can get in
mk
Due to the oil the K&Nīs rubber seal is slippery and likes to glide out of position. Especially on the back side of the air box, thatīs how the dirt gets inside the air box. My PO used a K&N and when I switched to a regular paper filter, I had exactly the same debris on the MAF. Never had any issues again with a paper filter....
