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Registered User
Join Date: Mar 2006
Posts: 11
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air filter
Want to install new air filter. Stock, oem, is ok but wondering if an upgrade here is easy and increases performance.
Know about sales pitch on K & N filters and how much better these are, but also read the oil in the filter is not good for this engine 1987 928 S/4 Can anyone help
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dlp |
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Registered User
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Stick with the OEM...... Most folks on here will say the same.
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1984 red 928S Undergoing surgery ![]() |
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curtisr
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Could just be me but, I found that I had to twist the straps to get the top of the air box to fit on the K & N filter.
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1977 924 Guards Red (parted and sold) 1987 924s Alpine White (sold) 1987 924s Kopenhagen Blue (my Lowencash tribute track car) 1987 924s Garnet Red (with FIAMM air horns!) 1982 928 Silver (sold) |
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Network Native
Join Date: Jan 2007
Location: SoCal
Posts: 10,338
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K&N not a good match for a hotwire MAF car, ok in earlier cars, but you get nothing for spending the money.
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928: Serial Enabler
Join Date: Sep 2007
Location: Elkhart, Indiana
Posts: 2,929
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The MAF hot wire is key/core to the operation of electronic ignition.
So important that on shutdown the MAF wire gets a 4 second burst of electricity to heat it and burn residue. KN filter is oiled, so its a source of oil residue. Its unneccesary, potentially harmful and provides zero performance, all BS marketing stuff. Probably has a different sound that folks equate with power. I've run a MAF car, 84 Euro 928, with no air cleaner a couple of times and it sounds like I've added 100hp. Like flipping the lid on the air cleaner of a 327. No power, just sound. Similarly, most insist the KN has no value to the 84 and earlier cars either. For incremental performance, ensure knock sensors are not crumbled (if they are, they fail in the engine protection mode, adjusting timing a bit), then consider sharktuning and some opening of exhaust. There may soon be a set of chips available from Porken that would likely be a huge improvement, basically a substitute for sharktuning for a stock (non supercharged) 928 S4. It is said that the autoauthority chips aren't near optimal, just cheap quick moneymakers that won't have the mapping of the (hopefully) soon to be available chips. That's the rough synopsis as I see it regarding S4 performance mods in reading rennlist and here over the last 5 years. Stock air filter, fram, avail pretty widely.
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84,85,86 928 cars Last edited by Landseer; 09-22-2013 at 08:39 AM.. |
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Registered
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Stick with stock filters. They fit and less trouble. Anyway, the stock filter looks pretty big to me.
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1986 928S 32 valve engine All stock, automatic, 539 Weissgold Metallic, 70K original miles, Hankook Ventus 2 tires. Previously owned: 67 Vette, 427 L88 Stingray, 74 De Tomaso Pantera L. Latest addition: 2000 BMW Z3 Roadster |
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Registered User
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I wish'd that Amsoil made an air filter for the 928. I love my Amsoil filter in my Volvo. Non-oil type.
Years ago you could custom order an air filter from Amsoil. Probably not now.
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1982 Porsche 928, Auto, 4.5 http://i72.photobucket.com/albums/i166/hethaerto/928Mist2.jpg?t=1305333945 |
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1985 Porsche 928s
Join Date: Dec 2012
Posts: 312
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I've not really looked into it much but, to my mind, if free-flow filters like the K&N are letting more air through, aren't they letting more dust and crap through as well? Some OEM filters a rediculously small and restrictive but the stock 928 filter is pretty large. I would think much of the restriction is with the plastic intake ports.
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Network Native
Join Date: Jan 2007
Location: SoCal
Posts: 10,338
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K&N use oil and gauze that somehow grabs dirt, like static or something.
Prime lesson on filters, do not believe any test devised by a manufacturer of filters. Second lesson, use the factory filter unless you have a good reason otherwise. |
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1982 928 us
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to note. arrows/disregard as known to show both directions. installs convex side up/towards the airbox cover.
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1982 Porsche 928 us |
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curtisr
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The Porsche folks at Hershey had a couple of ONS 928 filters for $10.
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1977 924 Guards Red (parted and sold) 1987 924s Alpine White (sold) 1987 924s Kopenhagen Blue (my Lowencash tribute track car) 1987 924s Garnet Red (with FIAMM air horns!) 1982 928 Silver (sold) |
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Engineer of profanity
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My take on K&N filters is that they don't give any difference in performance when they are new and oiled. Most cars that I've put a K&N filter in don't start to make any difference in power until the oil subsides from them. I recently put one in my 944 and it's just now feeling like it's running better. That's been about 3 months. I can say the same thing about my other cars. It always takes a while for the oil to leave them. At that point you might feel a very marginal increase of power. You could just buy a new one, clean it, let it dry, and it wouldn't harm your hot wire Mass Air Flow with oil. Still I wouldn't expect but maybe 1 or 2 horsepower if that. You probably don't get as good of a filtrations if the unit is not oiled.
K&N makes a full recharger kit with oil and cleaner, but you can buy a bottle of just the cleaner that will strip the oil out of it.
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1970 Porsche 911T Black 1990 Porsche 944 S2 Red on cashmere 1984 Porsche 928S Euro ROW GP white on black Last edited by 924CarreraGTP; 10-17-2013 at 07:20 PM.. |
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