From: Walt Konecny [wkonecny@uswest.net] Sent: Monday, January 22, 2001 2:22 PM To: 928 Subject: [928] Re: Comprehensive set of dyno tests ----- Original Message ----- From: David W. Moody Jr. Subject: [928] Re: Comprehensive set of dyno tests > Tom, > Am I reading that the K&N produced a loss over the stock filter? > And yes, I'm aware that isn't most relevant part of your research. > David W Moody Jr I've been posting K&N filter testing results for well over two years now, indicating that there is ABSOLUTELY NO POWER INCREASE to be realized by installing a K&N on a 928. Matter of fact, the K&N will allow more particulate to pass through, making it more harmful to the engine. Due to less filtering action, it may somewhat change the tone of the motor, and that may lead people to believe they are getting more power, but they're not. Everytime I'd post this, I'd receive a collective up-the-side-of-the-head-whopping from all the K&N lovers, claiming that they could feel a seat-of-the-pants power increase. Let's see now, K&N claims a 15% increase in power, that would bump an 88 S4 from 316 hp up to 363 hp. What? You don't believe it? As I've mentioned many times before - - -their claimed increase in power was developed by their marketing division, not their engineering division. Live and learn. wk ----- Original Message ----- From: Jay Kempf To: 928 Sent: Monday, January 22, 2001 3:08 PM Subject: [928] Re: Comprehensive set of dyno tests > Shouldn't rob power unless it is so oil saturated that it is restricting > flow. > > This K&N myth is just the best. They say "traps more and smaller particles > than stock" then they say "less restrictive". Must be one of those Physics > loopholes we always hear about. > > :) > > Jay K. > From: Mark Baistrocchi [kamm@interlog.com] Sent: Monday, January 22, 2001 4:33 PM To: 928 Subject: [928] Re: Comprehensive set of dyno tests I am going to stick my $.02 worth into this new finding. I think there was a HP loss due to the fact the K&N filter flows more air (98% increase according to one ad) creating a lean condition that could not be compensated for by the stock mapping system. I think with proper mapping there should be increased HP. It would be interesting to prove. Mark Baistrocchi 88 auto/w sunroof and no TBF related problems From: Walt Konecny [wkonecny@uswest.net] Sent: Monday, January 22, 2001 5:07 PM To: 928 Subject: [928] Re: Comprehensive set of dyno tests Sorry, but the amount of airflow being sucked through a clean filter is limited to a function of displacement and RPM. The motor can suck in only so much air, and it ain't gonna take 98% more. wk > -----Original Message----- > > Does anyone have any hard evidence that K&N air filters are > better or worse than the OEM Air filter? From: Jay Kempf [jkempf@10.10.10.67] Sent: Tuesday, July 31, 2001 10:36 AM To: 928 Subject: [928] RE: K&N vs OEM Air Filter. Nick, The below is my personal bent. I have never tried or wanted to try K&N for a couple reasons. Filters are rated in a couple ways but one of the big variables that manufacturers measure is flow loss or pressure drop. Filters with larger pressure drops NORMALLY trap more crud and restrict the flow more. Filters with low pressure drops can let in more air but at the expense of not filtering as much crud. More crud means more wear relatively. Each engine has size particle that it can pass through without hurting anything greatly. This size particle is related to the lubrication film thickness of the majority of the fits in the engine. If particles larger than the film thickness get through the moving parts ride on the particles and not on the oil film like they should. That is bad. You can be rest assured that the engineers at Porsche considered this when designing the size of the filter element and it's pressure drop and the particle size that it filters. You can also be rest assured that the people at K&N didn't consider anything but their profits. So the hard evidence that K&N filters are worse is that they market more airflow than stock. Guilty by their own specification. My opinion is that a K&N filter is worth about as much as a coffee can sized exhaust outlet hose clamped onto a 1" muffler outlet. Also, this particular subject is odd because after saying it it sounds like I have the opinion that aftermarket supposed upgrade parts are all bad. Not the case at all. There are a ton of great upgrades. This just isn't one of them. When you buy you just have to understand what you are getting and what compromises you are making. This list and other sources are great ways to find out about a potential upgrade. It is your job to collect all of the opinions and make a decision for yourself. Or you can just ask Wally ;) He tends to always know. Hope this helped. Jay Kempf 79 US 5ish speed (paper oem filter) From: Tom Middleton [midlman@seanet.com] Sent: Tuesday, July 31, 2001 3:07 PM To: 928 Subject: [928] Re: K&N vs OEM Air Filter. Just a couple of personal observations on the filter issue.... I have used both in my 87S4 A/T. While at the recent bracket drags (Pac NW) I was running around 14.1 secs in the 1/4 mile. Swapped out the stock filter for the K&N (freshly cleaned and oiled) and ran 14.00s and eventually down to 13.98. The dyno would not be a good way to differentiate any filter advantage/disadvantage since the airflow into the engine is nowhere near what it would be at speed on the road... My feeling is that since an engine is basically an air pump, then getting more air in and more air out is an advantage. I believe the K&N lets more air in (of course that means more particles and there are also other restrictions on air inflow --MAF/intake for example...). It did allow me to gain 0.1 secs in the 1/4. Worth it? To me it was..... I drive my car about 60% daily use and 40%track (not many miles this year). Ideally I would use the stock filter for the daily driving and put the K&N in for track of performance. Of course I haven't switched back to the stock one yet....... Also, while cleaning out my K&N (it was very dirty) in looked at the size of the grit that was being washed out of the filter. From a geologists perspective the grain size was on the order of a very fine sand to silt. If the filter can stop silt from entering then thats fine by me.....(coarse silt has an average diameter of about 0.016 mm). I just keep on top of my oil changes and watch out for those boulders that will take out my lowered S4s oil pan. >;-).. I guess the real question is has anyone documented significant wear of the valves or cylinder walls that can be attributed to "dirty" air? Later, Tom midlman@seanet.com 87S4AT From: Richard Davis [rkd@zipbang.com] Sent: Wednesday, October 31, 2001 1:59 AM To: 928 Subject: [928] Re: K&N filter killing my MAF ? How long has it been since you cleaned and re-oiled the K&N? Several Boxster owners have reported killing their MAF by having excess oil on the K&N and the oil migrating to the MAF. Not much luck cleaning the MAF, replacement seemed to be the only fix. Richit 90 GTless