Air Filters

You might want to use SEARCH on this topic... it's been covered in a lot of detail...

 

I didn't notice any difference when I changed from stock to K&N in my 2V GTSi.

 

I had a K&N on my 328 and it felt like it reved more freely, so yes i did notice a change. If i did not notice any differance i would not have bought two for my 355 last month. But they were put on along with a new exhaust system,and the car again feels more free.
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I always hate to be a party pooper on this issue, but so called "high flow" air filters make no appreciable difference in HP, especially no difference that you can feel. There are websites out there that have tested the high flows against stock air filters, found no real difference in air flow and dyno testing shows no difference at all in HP. But I've also see test reports that show that the high flow filters do a poor job in filtering out particles that can get into the engine and cause pre-mature wear.

On balance, IMHO, the added wear on the engine is not worth the unmeasurable difference in power, if any. You'll get a lot more HP kick out of opening up the exhaust or enlarging your intakes than you ever will from high flow filters.

Before I read a bunch of articles on this, I tried a K&N on an old Jaguar XJS V-12 I used to own. It took too filters, one for each bank. No difference in the feel of the car whatsoever. IMO, they ain't worth the money.

My $.02.

 

FWIW... I'm having a B^TCH of a time getting 348 K&N's for customers. The K&N warehouse in California is totally out of the 33-2656, and they're being replenished from the U.K. (30 days) If you want one for the spring season (whether you buy it from me or not...) get crackin. For the 348's, I've called about 15 resellers in the United States, and not found anybody with on-hand stocks.

So everyone's aware of my situation, I have the following filters on-hand:

33-2019
33-2518
33-2799
E-2690
E-2930
E-2940
E-2960

Anything else (until I get restocked) comes from California or Virginia.

 

Some may say the same for after market exhaust systems. Alot of money for a big brand name and no extra power. But others say that there is a power increase in changing the system. A point to think about is that if the K&N brand was not anygood they would not be selling out in the US especialy.

 

Umm, never understimate the selling power of strong advertising combined with a favorable urban legend. The quantity of STP, Motor Honey, etc. sold during the 60s thru 80s was phenomenal. Search the web for those names + 'class action' to see the real facts behind the myth!

Search the archives, there's a fair amount of facts there. IMHO, the 3x8 factory air filter already has an enormous amount of surface area compared to most cars, hence has relatively little restriction. The main injected car restriction is the K-Jet system, duct to throttle body, & the throttle body.

There's some evidence that the carb'd cars are being restricted by the carb risers (not the air filter) & www.durable1.com has a better idea...

 

Well said, Verell. There actually is some HP to be gained by opening up the exhaust. An aftermarket exhaust with less restriction will make the engine rev freer and pick up some noticable HP. Especially if you have CATs. There is also HP to be found by opening up the intake (along with the exhaust), but usually at a much high cost. K&N's won't do it, IMHO.

As noted, marketing is a major factor is what sells in the car market. Tell people it will give them a kick in the HP department, and they will buy it. In fact, along with your K&N, you should buy one of those magnets you put on the gas line that lines up the molecules, and a "Turbulator" or whatever the heck that thing is that is supposed to "swirl" the air in the intake, giving higher gas mileage and lots more HP. They are selling like hotcakes out there. Prove to me that any one of them actually increases HP or gas mileage or does ANYTHING beneficial for your car.

P.T. Barnum said it best. Don't be one of the guys he was talking about.

 

I remember the threads about the K&N, and from what i remember, using the k&n on a stock motor did not yeild much difference, but if you have performance upgrades such as exhaust, headers, bigger jets, hot cam, etc., the K&N is a nice compliment and actually helps add power (in the whole package). also, rejetting with a new K&N helps too. so its not just the filter, but other upgrades with the filter is the key. i have euro cams, borgo pistons, dual exhaust, bigger jets, and noticed a difference (not as much pull) when i just put back in the stock filter over the K&N.

 

All the above are good points. Its like our favorite cars ferrari, we all beleve the hype and the BS, so can you prove to me that ferrari are reliable well built and robust supercars let alone the best supercar manufacturer (allegedley) like other super cars that i could mention.
Also look at challenge grills for the 355s and 360, i drive both hard with the grills and without, any difference? No, The cars run just the same with no difference. Maybe they work on the race cars but not needed on the road, so take them of and throw them away. yes i agree about the power of marketing.

 

Sorry Chaa, you lost me on that last post. I just can't follow your logic. For my part, you won't hear me arguing that Ferraris are the "most" anything, except perhaps the most expensive car I've ever owned to get repaired. They are fun, they are different, they handle far better than most other cars on the road. But in the end, they are cars.

However, the point on the thread was whether so-called high flow filters produce any noticable or measurable difference in performance. I'll stick by my earlier statements and say that everything I've seen leads me to believe that they do NOT. Obviously, for whatever reason (probably marketing, but I have nothing other than a gut feeling to support that), some people think they are worth the money. That's what keeps the global economy alive, I guess.

I assume you had a point you were trying to make. I don't think it's about Challenge grills or bling on cars making any performance difference. Marketing hype perhaps? In any event, I ain't buyin' K&N's for my cars.

 

It does not take much to lose you does it. The point i was making was that maybe we all beleve some points of marketing. Like K&Ns , Challenge grills, and exhaust systems. Some beleve that they give more power some beleve they dont. I felt that the K&N fitted to my 328 and 355 reved more freely, and certain exhaust systems that cost mega bucks only make a nice sound and no noticable differance in power. And finaly Challange grills, we put them on and some might say included myself that they are a waste of time.

 

i think that a good dynamic air filter, in cmbination with a good exhaust system and cat removal coul improve the power...(not 50 hP but 20 HP yes...)
Here is a pict of my 2 BMC CDA...(not bad, i think...)
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wow bob348, nice induction setup - let them puppies breathe!!!
i been thinking of the individual air filters for each weber on my 308 instead of the airbox. i guess that kind of setup form pierce manifolds would be better if each carb had a filter on top of the carb too, instead of a cover. i have seen air filter covers for stuff like a GM air cleaner where the whole lid to the air cleaner is a filter element. anyone know of such a setup for the weber on a 308??? i would think this would cure the velocity stack height problem, as air can be drawn in from the top also. then with setup, perhaps i can plumb in fresh air to the tops of each carb. i have seen the tiny round air filter screens that fit into the velocity stack, but i think they are just for troubleshooting purposes to get at the linkage adjustments etc...any comments???

 

In my old 1989 XJS they made a big difference in the MPG and I did notice the car flt a tiny bit more pepy at mid revs. I also took the foam out form around the radiator that bocks air into the tubes.

 

Airflow, especially in a carb car, is a complicated subject. I don't use K&N, but the airflow to my Lotus is rather complicated compared to most cars I have seen. Two long horns go to a round metal case that holds the air filter, then a long flexable hose to the airbox, which is bolted to the back of the carbs. About 2 feet of ducting to the carbs total.

This gives a very uniform airflow which is exactly what the car likes. A K&N, bolted to the carbs as I've seen on other Europas gives a ragged airflow and I suspect causes a decrease in throttle response as well as flat spots. These guys are forever fiddling with their carbs while I think it's the airflow.

Nevertheless, I DO think a K&N will add HP if used with a freer flowing exhaust, ported intake, and modified jetting and advance. Alone, I question if they don't do more harm than good.

Ken

 

Well, this goes to show why some drivers are good racers and some are good racers and test drivers.

Which Filter is The Best?and the actual test with HP figures.

Test was originally found on this site: http://toyotaownersclub.com/forums/index.php?showtopic=11555

My point about not everyone being a good test driver is just to show the fact that just because you couldn't feel a power difference doesn't mean the isn't one. There are some very competent drivers in F1 who aren't able to feel minute differences to the cars performance as well as others. That's why engineers have all of the data acquisition they can get. We can use the rolling dyno which was used in the test above.

In short K&N do provide a HP gain. It will be more in some cars than others. As a whole though a naturally aspirated car will get a better benefit than a turbo charged car. Why? Because the turbo will overcome any hindrance the air cleaner produces. A for a N/A car that is a severe restriction.

Why all of you guys just can't chip in for a day's worth of Dyno testing to find this out is beyond me. Take one car of each model, 308, 328, 348, etc.. and do several runs with the stock filter in place to get a good base line. Then swap out the filter. Do the same number of runs at the same air temp and barometer rate. There you go! You have your answer. I'll bet you'll see HP increases across the board.

 

Maybe becourse no matter what proof any test may provide, there will always be the smart arses argueing some point or another. Thats F.chat.

 

Installing a K&N probably isn't worth the negligible HP gain a small displacement engine would get. Dyno tested hp gains on Crown Victorias (I know, but hey, they have a mustang engine) netted a -1 HP gain. The best I have ever seen is about 3hp on highly modified cars.

Will anyone ever feel 3hp? Unless you are starting from 3hp stock, you ain't going to feel it in the seat of your pants, nor are you going to notice any sort of difference whatsoever in any sort of driving that most of us do.

What does 3 hp get you? A lot more dirt and dust into your engine, which does a great job of scratching fragile internal parts.

Is it worth it? Not really....

 

Is it worth it? Not really.....i disagree

Even if there was NO HP gain, it IS worth it. stock Ferrari filters are around say 50 bucks each, change one each year for 10 years and you just shelled out 500 bones. a K&N costs me 50 bucks, and the reccharging system is another $20. so $70 versus $500 is a BIG worth it for me......i have used my K&N for 7 years now...............

since i do not live on a dirt road, i am not too worried about minute particulates making it into my engine.

 

I've posted my chassis dyno results in previous engine development threads, but as I remember on my Weber carburreted car there was about an 8 rwhp increase with the K&N+stock airbox over the Ferrari paper filter at the top of the range. No signifigant A/F change between filters. An unfiltered stock 308 airbox cost about 8 rwhp as well over open air horns.
I have just put on a set of the short air horns which I've documented elsewhere ( http://ferrarichat.com/forum/showthread.php?t=47676&highlight=hotrodders ) as the theory was supported by my experience. I have not dyno'd it yet, although there is one available on the website.
For other various and curious air cleaners I have tried, check out post #87:
http://ferrarichat.com/forum/showthread.php?t=2788

It's often discussed in the Alfa boards how webers like a lot of area over the air horns to set up good flow.

Great discussion, many thanks
rt
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On NSX Prime this very discussion was debated at length and before and after dyno tests were completed on a relatively stock nsx and it was found that there was no increase in horsepower. The factory filter was at least equal to the K&N filter.
Further they found that there was an increase in debris in the intake manifold after long time use. Debris equals engine wear.
I personally had installed the K&N filter (stock filter box) in my NSX at the time and found that there was increased air intake noise (nice sound) along with an unpleasant "whistle" noise on part throttle ......sort of like a turbo howl.
Some might perceive the noise as equating more power?
I also noted that the garage smelled of gas fumes after a long run (with the K&N filter ) for several hours afterward . It appeared that the K&N oiled filter allowed the intake to vent fumes on cool down . I also noted this same unpleasant odor from a motorcycle as well after I switched to the K&N from a paper filter.
Perhaps this is why K&N are not installed as factory options???? won't meet emission standards due to venting on shut down?
Anyways, I returned back to stock factory filter and was much happier for it.

 

It is funny how this debate comes up every 6 months or so. Every model (and sometimes individual cars) take to K&N's differently. It has been proven with back to back dyno tests that they work AND don't work. So I guess the jury is out. I personally have used them on many cars, and a motorcycle with no ill effect...both cars went well over 100k miles, heck my Honda Accord went over 160k miles with a K&N...so the "extra dirt" may or may not have any lasting effect....who's to say?

Currently, my BMW and Ferrari do NOT have them installed...I may purchase them....or may not...hmmmm

 

Interesting thread and debate. Some of you may have seen my posted dyno readings showing a 25hp gain with BMC's on a 550 Maranello.
The airboxes of the 550 are the same as that on the 355, think about that for a moment. Ferrari have speced the same airbox on a 300hp and a 500hp car. If the naysayers are to believed and Ferrari does not use poor design and insufficiently specced components, the airbox should flow enough for 500hp and there would be little, if any gain by marginally increasing the flow characteristics of the airbox. From my experience the 355 airboxes are totally insufficient for 500hp and the increased flow from BMC filters translates to an instant and cheap power increase. The new Superamerica is a good pointer, power of the 575 motor has been increased for 508 to 540(approx) by Ferrari inceasing the capacity of the induction system, A 30+hp increase from an increase in intake flow alone.
Will you get a power increase by changing filters? IMO the real answer is that it depends on whether your current airbox/filter is causing a restriction.