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K&N bad experience
Hi to everiibody,
I would like to tell you my story about K& N and may be save some MAF...... I have a CLK 430 since 2 years with 180.000Km now , 7 months ago I decided to put K&N filter because i was doing maintenance and i had to change MB filters. Aftre installing these i was thinking to have more power in particular at low RPM but may be waspalcebo effect..........but after a while i had code P173 and p170 and car start tu run bad at idle and loose power at high RPM. I tried to clen MAF with alcool and with special product to clean electronics, dry with soft compressed air..........but no result... So i cnahged MAF and put new MB filters and the car i beck to normal. This just to say you that for me this kind of filters are not working with car wich MAF like this. I hope thse can save some owner to buy expensive MAF. Many thanks guys. Alberto |
The K & N will kill any cars MAF..... many people are finding out the hard way.
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The only gain you will get from using a K&N filter is intake noise, big waste of money. :)
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When the oil dries out they no longer filter particles. Too much oil will bleed out and destroy the MAF.
The whole idea of a "washable air filter" makes about as much sense and "washing" your oil filter and reinstalling it! Overpriced junk and a big scam! If K&N they gave me one of those turds, I'd throw it back at them. Duke |
Some manufacturers specifically mention that washable or oiled air filters will void warranty just for that reason.
On the flip side, some people reported these filters can work okay as long as they aren't over-oiled. |
The MB Club website technical director posted a warning about K&N, of course some people got all bent out of shape. The over oiling distroys the sensor was part of the comments. If you want more speed get a bigger engine go AMG, "Renn Tech" , I toured their facility and did not see any K&N stuff
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K&N filters are used extensively in the racing community for two reasons. One is that the manufacturer sponsors the racers. The other is that the filters do allow more air flow. It should be noted that they don't filter fine particles as effectively as quality paper or oiled foam filters. That's not a concern on a racing engine where it will be torn down after the race anyway. Their main concern is to keep the big chunks out. It would be a major concern on a street engine expected to go for 500k.
Jorg |
Waaaaaaay back, K&N ruled the modding scene 'cause OE filters were lame and engines suffered from strangulation.
No more. OE filters are of very high quality today, and in terms of overall operating costs, cheap. Modern engines experience little or no benefit from having the intake alone opened up, the downside of potentially ruining expensive emissions and FI components outweighs any gain you might see. 20 years ago many 750SS racers simply left the intake horns on their flat-slide carbs open. During the short race, the odds of sucking something in were low, and the need to have as much as air flowing as possible was high. The only guys running K&N filters were those being paid to. On the street, many of us with modified bikes ran K&N's because the stock airboxes were either too small or did not fit bigger carbs. The drag racing scene was similar. I couldn't make the OE filter work with my roller small block, meaning a K&N was pretty much the only option. |
We ran stacks with rags stuffed into them in the pits. Some stacks had screens, most did not. K&N's had just made the scene. We were running Amal's and Lucas ignition. Kept us on our toes.
John, what bikes did you have? Jorg |
Alberto, I bet your MAF would've failed at the same day, same time anyway. Imo efi is a smog device, and the maf is the weakest link. I do not believe the K&N caused it to fail. There is no way that you or I can prove either way, but I had to throw in my 2cents. ;)
Hey, I've been dying to take one these MAF sensors apart. If you would be willing to ship it to me I'd pay you the $5 or whatever shipping. I'll also post pix of the inside if anyone cares to see. |
K&N is all hype. I have a Mustang I drag race and last time at the dyno we replaced the stock paper element with a K&N and got no HP increase!!!! Waste of thime and money.
Dan |
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My "big" street bike was a heavily modified 81 CBX (yes, the ridiculous six) with a Vance & Hines big bore kit, lots of head work and six monsterous Mikuni flat-slide carbs. The thing handled like it had a hinge in the middle from day one, and with 180rwhp, it was unsafe. I added a Cal-Fab swing arm and upside-down Marzocchi (sp?) forks and it really changed the bike. Brakes were Honda racing bits with steel lines. My toodle around town bike was an 82 CB650, the last of the weak SOHC models. Nice little bike, easy on gas and great for around town. Even took it on a few trips into deep Alaska where there was lots of gravel and it held it's own very well. As I worked for Honda, I got bikes and parts at cost, sometimes even less. A few years back I returned to biking with a Honda 750ACE, and HATED it. 40hp? Cripes, it was slower than some cars. I got a good deal on it, but it had to go. My neighbour bought a new BMW K1200GT and I bought his 2000 Hayabusa and sold the Honda. Love it. Big enough to tour, very, very, very quick and fast. I've just finished a big bore kit and might add NO2 in the spring. Without the NO2 it should pull about 220 rwhp and might break 9's in the Q. Might be the last summer for the 'Busa though. I have been toying with the idea of something fun with four wheels, and if I find something, the 'Busa will be sold to raise $$. |
Aftermarket parts
I too agree that fitting an aftermarket airfilter is a waste of time and money. The stock one has had thousands of dollars thrown at it in order to achieve the best mix of flow vs protection. why screw with it?
Same goes with the exhaust. Unless you remove cats, polish and flow the head, modify the intake and re-tune the injection to suit, you are wasting your time. In the modern dirt bike scene, almost everybody puts an aftermarket exhaust on their bike. Why? Did yamaha purposly put an over-restricted exhaust on their motorcross bike so that it sufferes in the horsepower stakes? Yeah right. What they did do is spend millions of dollars designing an intake, combustion and exhaust package that compiment each other. Change one on its own and you destroy the harmony. When the exhaust on a bike is replaced and the dyno says more power, there is more power. BUT, where is the power being made now? Usually what is created is a razor thin power band of good increased peak power but because it is in such a small rev range it can be almost impossible to use to it's full potential. The original stuff was designed to win races! Of course, it is a bit different if the exhaust was designed to meet noise emission regulations. Then the engine can usually benifit from a re-jetting and freer flowinf exhaust. I would imagine that the oil in the filter has damaged the MAF rather that dust particles. If you want to go fast, buy a $5000 sports bike with a litre engine and flatten Enzo's!! Then go cruising in your benz. |
[QUOTE=AF300E
I would imagine that the oil in the filter has damaged the MAF rather that dust particles. [/QUOTE] And exactly how many thousands of MAF's have been replaced that were NEVER subjected to a K&N? DO NOT OVEROIL !!!!! :rolleyes: |
These K&N debates are always fun…
DANSMB: Easy answer, your stang either had enough air already, or it wasn't tuned to take advantage of the new filter. A stock engine probably isn't going to see much if any bennies. I like it because it's reusable and doesn't get restrictive as it collects dirt. But on my chevota I can tell blindfolded if someone were to switch in a paper filter, the benz motor I cannot. AF300E: Sorry, the motors air/fuel system are not factory tuned for performance like we hot-rodders call performance. Unless you meant tuned to the lowest production costs and California emission standards? If they really only had performance and filtering in mind, then most all filters would be much larger. The factory is a business, which filter/airbox combo is cheaper to produce? Every single part goes thru the bean counters, if they don't pick the cheapest one that’s “good enough” today, it's because they believe it won't be cheaper down the road. Eg; recalls, emissions, politics, tarnished image, etc. I’m really surprised you chose to attack pipes (you said dirt so I'm assuming 2-stroke). There is no single mod I’m aware of other than nitrous and forced induction that makes such a HUGE gain in performance. And they’re not a razor thin band either. Most people I know don't even bother to ride their bike until they buy a pipe, and quite often it's negotiated into the original purchase. I have no clue why the bike mfg's do not put better pipes on their bikes. Maybe it’s “power fixing”, remember when the Japs got busted for price fixing??? |
Where do you stop?
What is the best side for an air box then? Obviously, as big as possible. So then, sacrifice the passenger side front seat and put the air box there.
Stupid, isn't it? Obviously the airbox is built to a size and cost as well. Naturally when a car is designed for the mass market there are cost, longevity and reliablility factors involved also. I was with regards to dirt bikes actually referring to four strokes as that is where my experience lies. The reason that all the pros run aftermarket pipes is? - Sponsorship dollars. If you run them on dynos, there is not a lot that can be improved by simply bolting on a slip on exhaust can. It is, as I said before, only part of a bigger picture. I don't think Bubba would be last on a stock race bike!! |
The bigger the size the bigger the cost, not only for the box, but for everything around it. Generally they make it just big enough to get by. They don't need to be pass seat sized either, just made by K&N. ;)
Racers have a rule of thumb for air filter size: "The biggest you can get in there" Oic, dirt bikes and peaky power curves I was sure we wer talkin 2-stroke. They're not very popular where I live, I've only had one, a Yamaha 500. I put a pipe and Supertrapp on it soon after I bought it. It certainly made a bigger difference in power than any ex mod on any other 4-stroke motor I've played with. I too bet the gain was mostly in the muffler. I put in a K&N as well but didn't feel anything. |
John,
A big bore Busa with NO2 ? A 180 rwhp velvet hammer? Your a wild man! A friend had a CBX with pipes back in the day. Beautiful music! I had a ported H2 and could keep up but it wasn't a pleasant sound to say the least. I sold my last street bike, a box stock GSXR1100 when my son was born 11 years ago. I ran open class MX bikes recreationaly for another 6 years after that but it got too hard on the joints. I've been thinking about gettng back into it again and the need for two up travel has me looking at cruisers, but like you say, pretty weak. Do you think a Busa could work for two up riding with gear? Jorg |
Chevota, my engine is full boogie, 320 RWHP, 12.9 @111 @3550#. I run a stock 84 Mustang dual snorkel air cleaner for the dual cold air inlets and that with a stock paper element has made more power than the K&N with a open element or in the 84 air cleaner. The only way to tell what you get is to do it on a dyno as I have. We have tried some other cheap tricks also like carb spacers and venturies for the carb without any gains. Make sure you use the wide band O2 sensor when on a dyno to verify the mixture is correct.
Dan |
I'm not sure how big the filter is on one of those. I would imagine most stock paper elements of decent size could support that. The one my 3.2 V6 is the same as my V8. The V6 is getting enough air for sure, the 340hp V8 I don't know about, but don't really care since it's an SUV.
No need for a dyno to feel the power loss in my chevota, it's obvious. The filter area is 150sq", the next size up filter and the hood won't close. :( So who knows, maybe there's even more power to be had? So your car reads the O2 sensor at full throttle, or the dyno does?? I tried a Holley projection 4di about 5 years ago and I hated it! Open loop only at full throttle and very slow responding, it was joke actually. I'd buy one if it worked, but efi is still nothing more than a smog device imo. So tell me about that O2 sensor, if nothing else I might like to get one for my Autometer A/F gauge. |
I don't have my own wide band, the dyno has one and they weld a bung in your exhaust for it. Some one just came out with a good A/F gauge for street use but it is expensive, I think $395.
Dan |
These days, nearly all manufacturers do a fairly good job of designing intakes. Yes, there is usually less pressure drop across a K&N or other oiled cloth type filter at idle, but often the "design" of the piping causes flow disruptions at high rpm due to the fact that the "design" normally consists of aluminum ducting with elbows in it, no laminar flow possible. Believe it or not, but an improperly designed pipe will have terrible flow resistance.
Ditto for not having a filter housing at all -- another member posted dyno curves from his 280 SEL 4.5, and it generated MORE hp and torque with the filter housing on that with it off -- all has to do with getting air to move properly. If you oil a K&N lightly enough to prevent damage to the air flow sensor, it will pass huge amounts of fine dirt and you will grind the engine up, and if you oil it well enough to catch the fine grit was well as paper, it will toast the MAF sensor. The good platinum MAFs usually last forever if they are kept clean. It's easy to mistake noise for more hp, by the way...... Peter |
Peter
YAY! Someone who understands how many factors go into tuning an engine.
With the exhaust thing, many people don't understand that a properly designed exhaust will not only have good flow, but in fact develop suction due to air inertia. This, coupled with a carefully designed camshaft/s profile means that it is possible to "overfill" the cylinder with air/fuel resulting in increased performance. By "overfill" I mean that say the maximum amount of air/fuel that can be sucked into the chamber by a down-moving piston is 100%. Now, say that as the exhaust exits the chamber through a properly designed exhaust pipe and cam, the inertia of the exhaust gasses causes a sucking effect resulting in there being vacuum in the bore after the valves have closed. Say this vacuum is 10% of the cylinder capacity. Then, as the air/fuel is drawn in through an impeccably designed intake system, the same happens but in reverse. The 10% vacuum fills. Then the normal fill takes place (100%). So far we have 110% of the standard fill. Then the inertia of the fuel/air causes yet another 10% to be drawn into the cylinder before the valves close (you can see how important the valve durations are here!). Now we have a maximum cylinder fill of 120% where before it was only 100%. It is in fact possible to get up to 125% filling depending on bore dimensions. It's almost as good as forced induction. It's very important to have everything right. The most free flowing intake (i.e biggest airbox) and exhaust are not perhaps the best. Ok. Now which average workshop has the tools and resources required to measure all of these factors and then design an induction and exhaust system to suit? Indy teams and Formula One teams do. The big motorcycle and car manufactures do! Look at their budgets!! When you buy a K&N filter or an aftermarket exhaust for your motorcycle, what are the chances that it has been subject to this sort of testing on your type make and model of vehicle? Answer? NO CHANCE. Wonder if anyone agrees? |
Is this thread still a K&N thread? Just for the record, I over oil all my K&N filters, but the MAF and intake tube are dry as a bone.
I understand very well how an engine works, from before air enters ‘till I leaves, but making the correct intake and ex for our cars would not look much like the oem setup, and would be very difficult and/or expensive. Oh, and not that it matters much to me, but the real fixes are not be legal either. A K&N is an easy and legal bolt-on that’s reusable and won’t clog up like paper. If there was a better intake tube design, or mod for this one, I’d be interested to hear about it. I would love to have an efi that worked right, or a nice carb, intake, cam, headers etc. But in real life my choices are limited on a 3.2 Benz to bs like a filter and muffler. I could buy a blower, but I just can’t see spending that kind of $$ for what I’d get. If I really wanted to make everything right, the easiest and cheapest would be to pull the motor and put in and old chevy v8 with all the goodies that do flow right. Which btw is exactly what I’d do if this benz motor ever took a dump. |
Not worth the risk
What is the power gain from adding a K&N filter to you M112? 1% ? 2% ?
Is it worth the risk for an extra 2-4 horsepower? Also, I do not attribute all MAF failures on engines with K&N filters fitted to the filter as cause. We all know how reliable the MAF's are. Having said that though, just because the tube after the filter is dry, it is impossible to know for sure, without measuring, if any oil is sucked into the motor and over the MAF. Who knows how much oil it takes to screw a MAF? |
Power gain may be 0%, but like I said, it will never cost me power and it will last for life.
If there is no oil in the intake tube, then there's none on the sensor, pretty simple. Not that I believe oil will hurt it anyway. Yes, it's worth the "risk" imo. I've done far worse to engines iso power. :rolleyes: I'm starting to get the impression you don't approve of K&N filters. ;) |
It's not that I don't approve of K&N filters alone. I just bundle them into a same category as all that other useless crap that people bolt to their cars with absolutely no proof that they result in power gains and then they swear black and blue that the car goes better.
Don't get me wrong, I've fallen into the same trap. I put a yamaha motorcross exhaust on my yamaha trailbike and am swear it goes better. But it's probably just the horny noise it makes now that lets me think that :D |
I know what you mean, it's like fishing lures. there are two types; the kind that catch fish, and the kind that catch fishermen.
I also see lots of people bolt on genuine hi-po parts and endup dissapointed. A K&N or a big carb, etc doesn't help much when everything else is stock. A K&N on my stock 3.2L car = nuthin, my free flowing 6.6L chevota = power! The muffler on my 3.2 car works ok I guess, but if I put it on my chevota it would screw everything up. |
I almost forgot; If you want a real power gain you need a fuel line magnet and a Qt of Slick 50. They're guaranteed! Itz gotta b reel f itz gotta gayronteee! :rolleyes:
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Lol
Hey, they say that stuff works man!!
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Does my 87 300E have a Mass Airflow Sensor? If so, where is it located and what does it look like?
Regarding K&N: Did anyone mention gas mileage? I have been using K&N air filters for years and always notice an increase in MPG. The larger the engines displacement, the bigger the MPG gain. 6mpg difference in my full size pickup and 3 in my 300E. Angel |
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Come one people, Back Me Up Here..... I have been installing them in every car I own/owned for the last 15 years. Always get an increase in mileage. |
Logic won't allow me to accept your statement. If true, you've single-handedly discovered a way to reduce our dependence on oil for transportation by roughly 10 to 30%. Auto manufacturers go through Herculean efforts just to squeeze 1% more mileage out of a car. I don't think they'd ignore something as simple as installing a $(50?) filter to achieve a 10 to 30% gain.
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I know that I'm not the only one who has noticed a gas mileage increase :cool: |
Just putting in a clean filter of any description can restore your mileage to the proper figures. Driving around with a filthy one, then changing to K&N can distort your perception of what the K&N is really doing for you, both in power and mileage. Just my $.02.
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Sorry to post this so late . .
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http://home.usadatanet.net/~jbplock/ISO5011/SPICER.htm I have removed my K&N filters for good-old-paper! |
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Appreciate the link to this interesting whitepaper. I want to share a maximum airflow formula to use when determining whether the air filter is really the bottleneck in your intake system. The background for this discussion is my previous experience tuning forced-induction V6 engines. Effective displacement of those engines was comparable to any respectable V8, and the tuning requirements arguably more complex. Unfortunately most of my "black art" tuning models were developed using output from the MAF/MAP as measured by an OBD-II compatiable scanner. My 1995 E420 more or less leaves me "blind" to engine performance tuning at this point. One of the sacrifices I made by choosing a pre-1996 model Mercedes... anyhow, back to the formula: (eng speed * displacement) / 3456 = xxxx cfm * VE where units are standard, and VE is engine volumetric efficiency. Let's use the 5.0L 119.974 as a working example: The maximum engine speed for an unmodified 119.974 is 6000 RPM. Displacement is 4973 cubic cm, or 303.5 cubic inches. Maximum horsepower is measured at 5700 RPM, the stock full-throttle (WOT) shift point. Our question is whether the filter affects ability to reach peak engine output at the highest shift point. (5700 * 303.5) / 3456 = 500.56 CFM This figure represents the theoretical airflow through the engine without restriction and without accounting for thermal issues. The volumetric efficiency (VE) factor allows us to account for limiting factors (material, thermal, etc.). The M119 mostly suffers from underhood thermal issues, especially with an aluminum block that soaks up ambient heat. If we use the common 85% VE factor, estimated airflow at 5700 RPM becomes 500.56 * 0.85, or 425.47 CFM. The 119.974 engine attempts to pull a maximum of 425 CFM through the filter and intake, assuming no underlying mechanical problems that would decrease peak airflow. It seems to me that most stock (paper) filters are tested to flow at least that much air, if not more. My interpretation is that you will never encounter a need with an unmodified 119.974 to flow more air through the air filter than a stock paper element allows. It also goes without saying that a comparable K&N product flowing 3000 CFM allows more dirt, oils, woodland creatures, etc. to pass through the filter than the paper filter. This has been demonstrated using empirical methods like those described in the whitepaper, and through basic oil analysis from engines where a free-flowing intake filter is used (higher silica content and other particulate matter). I wonder just how many performance engine failures are due to oil breakdown once too much airborne junk passes the filter barrier. Agreed with Jim -- make mine a quality paper filter! -DM |
Funny my car runs better and accelerates better with the standard paper filter than it does with the K&N! I am talking about my 190E not my C class. The C class I would never put a K&N in due to the MAF and me not wanting to need to buy a new MAF for it!
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Anecdotal
I've had KE filters in my 400E for over 100K miles. No problems. Can't comment on before and after mileage but car does get 27 mpg in hot weather interstate driving at 70 mph. Car has 128K on it.
I've had a KE filter in my 944turbo track car for over 55K miles. No problems. I installed the MAF system 8 years ago. It came standard with the system. This argument goes on and on and probably will never conclude. It's almost like an argument about religion. No one will have their mind changed.... BTW, I also use green antifreeze. My SL is 25 years old. The green stuff has not harmed it or allowed it to be harmed. But I do change antifreeze every 24 months. |
I was wondering if that article would show up. I'm sure it's correct, or close. If people want to say that a paper filter doesn't flow quite as well, but "good enough," then I say a K&N filter doesn't filter quite as well, but "good enough!" :D
DangerMouse: It's not quite that simple... Even a carb/EFI mfg will tell you need more than the calculated # at 1.5" vacuum or you're screwing yourself. (We are talking 1.5 right?) A good 50% larger is a nice start ;) I bet the oem EFI on my little 320 is capable of flowing 4 times or more what your formula says. Shoot, even my 2.3 4cyl intake system is huge, the motor could never flow that much. I'm a fan of flow and all, but I wouldn't go that big. benzfan: I agree 100%, that's how Split Fire spark plugs made $$. Guaranteed to perform better! They never said guaranteed to be better than a new plug, because it can't. One key factor for me on the K&N is that it still flows well when it's dirty. So keep your paper, just remember to change it constantly if you want those flow #'s. I see a lot of dust in my truck and would need a new paper filter every 20 miles. Paper would start out with degraded performance from square one, but would go down hill quickly from there. My K&N always flows fine. |
My 190E was kinda sluggish and I installed a K&N air filter and it actually helped. I didnt feel a difference in power, but it helped.
I feel a difference with a K&N air filter on my ATVs. But they dont filter good at all. Foam filters are the way too go. |
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I have to disagree regarding theoretical airflow calculations: it really is a simple matter of physics. That formula is a longtime staple of internal combustion engine physics taught from Stanford to Stuttgart. I think it is mentioned in every ICE design text on my bookshelf, and one of the first taught to automotive engineering students. If you have an open mind to learning about this subject, please continue reading. The theoretical airflow calculation results in the most *optimistic* value possible under normal atmospheric conditions, based on physical dimensions of the cylinders. I would be glad to recommend engineering texts to anyone who wants to take this subject seriously. I presented a simplified version of a more accurate equation for determining intake requirements. Here is the original formula version, using the 119.974 for reference: bore * stroke * pi = cylinder volume 3.79in * 3.35in * 3.141... = 39.88 cubic inches cylinder volume * # of cylinders = total displacement 39.88 cubic inches * 8 cylinders = 319.04 in^3 (cid) cubic inches / 1728 = cubic feet (we are calculating cfm) 319.04 / 1728 = .18463 ft^3 displacement (cf) * engine speed (rpm) = airflow (cfm) .18463 * 5700 = 1052.39 cfm Looks like the old DangerMouse goofed, right? Wrong. We still need to divide that value in half because any beginning student knows that a four-cycle engine breathes air every other revolution: 1052.39 / 2 = 526.19 cfm at 5700rpm Remember the message earlier about volumetric efficiency. Everything about tuning a forced induction setup has to do with increasing volumetric efficiency of the end-to-end system. Forced induction systems function by increasing the intake charge pressure above atmospheric ('xx psi boost'). The same thing would happen if your naturally aspirated car exceeds some absurd vehicle speed.. air molecules would compress, increasing your effective atm. Back to physics 101, heat is generated by friction whenever air molecules are compressed. Theoretical volumetric efficiency thus exceeds 100% as engine displacement has not changed, but is brought back to reality because of heat-induced efficiency loss at the intake manifold and supercharger housing. Note that this is the basis for all thermal management via intercoolers... decrease the pressurized intake charge temperature before it reaches the cylinder. Anyhow, the well-designed street engine (na) realizes 80-85% volumetric efficiency at maximum engine speed. This means that the 119.974 on a good day is sucking in 526.19 * 0.85 = 447.26 cfm at 5700rpm. 447 cfm is still far below the capacity of a K&N 33-2678 panel filter; any reputable paper element (Hengst, Knecht, etc.) can handle those flow requirements without breaking a sweat. My last car with a six-inch K&N cone filter flowed 405 cfm in good conditions under maximum boost pressure; much lower than the filter rating and stock throttle body limitations with room to spare. If someone wants to select a free-flow / low-restriction filter for reasons other than performance gains (K&N marketing spin), more power to you. I think you will run the risk of introducing particulate compounds (esp silica) that can eventually damage the cylinder walls. I also think you run a higher risk of damaging the delicate MAF element with the K&N filter oil. I had to replace mine twice in three years because the wire element was destroyed by filter oil blowby. Just something to consider. Regards, -DM |
Chevota,
For a dusty environment have you considered an oiled foam filter (with specialized oils) such as used on motocross bikes? They provide excellent filtration and flow and are infinately re-usable although they do have to be cleaned thoroughly and often. Jorg |
Am I the only one who has ever tried a K&N on a dyno? I read that ISO report and it just confirmed what I already know, keep a clean stock filter in your vehicle!
Dan |
DangerMouse:
Yes, I have an open mind and absorb all performance car info like sponge (a lot leaks out, but I try). The theory is nice, but real life is different. The flow #'s are based on 1.5" of vacuum, a normally aspirated engine does not draw that much, so all those # are based on an error. The 1.5” number is used because it’s easy to work with for testing cfm, much easier than say 0.1”. Vacuum means there’s a restriction, restriction means power loss. If you’re running vacuum at full throttle then you need a bigger carb, efi, filter or whatever. Btw, a well designed smog engine may have 80% efficiency, but not a performance motor. Not that 80-100% is a huge difference, but 1.5” vs 0.1” is. I don't agree with your forced induction and heat theory btw, I didn't make sense. Not insulting you, just doesn't make sense. :confused: 89-300ce: Yes, I do run a prefilter, but again it was difficult to find one that didn’t kill flow and power. Mesh and typical foam like those used for dirt bikes are too restrictive; once again I found the solution from K&N. The prefilter is open foam, the cells are huge and flow nicely. I use regular K&N oil, not foam filter oil. It’s really amazing how well K&N filter oil works, The prefilter can literally be backed in oily sand, yet the cotton filter is 99% clean. I can only guess the cotton filters out 99% or more of that remaining 1%. Oiled cotton can catch smaller particles than any dry paper filter, just like an old oil bath setup. mctwin2kman: You need to tune your car to run with the increased airflow of a K&N. :rolleyes: I have a K&N in my 190E too, but it runs fine either way. |
On my 99 C280, the MAF died at 75K. No K&N. Stock air filter. The minute I told them the codes, the shop and Gilly said it was a MAF. Changed that and it went away till I totaled the car 10K later. On my Ford Ranger, I noticed a dead spot at WOT. Sprayed the MAF with some brake cleaner and it went away. On my 91 Firebird that was making 410HP at the wheels, I ran without any sort of piping in front of the TB and I was making 20HP more. Put a paper filter with the pipe and I lost 25 HP. That means that I am losing 5 HP between K&N and paper.
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Chevota, I did change the mixture and all for the K&N. Just seems to breath better with the paper one, especially at higher engine loads such as when on the highway. I switch back and forth once in a while to test it out and the engine just seems to run smoother with the paper one than the K&N one. Personal opinion I guess. Really no diference in my mind. But I still have it in case I want to throw it in.
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Question: The tests are all wonderful. However, the truth of the matter is that even the best filter lets some matter thru. No engine runs on 100% pure air all day long. There is always something that gets thru the best filter because it is finer an item that will be filtered out. Just like a fishing net. Something will get thru. So, at what size does it become an issue to the engine?
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