General Intake / Exhaust Mods

paisanpaisan Member Posts: 21,181
edited March 2014 in Mazda
Here we will discuss Exhaust Mods.


  • meredithmeredith Member Posts: 575
    Everyone wants MORE POWER!...

    This topic was active in Pickups, since it has
    "cross platform" applicability by engine type, we
    have relocated it here. Please join the
    discussions here.

    To read the original notes go to k & n filters in
    the Pickups Conference.

    Front Porch Philosopher
    SUV, Pickup, & Aftermarket and Accessories Host
  • scape2scape2 Member Posts: 4,123
    K&N air filters are worth it. They work. I installed one in my Ranger 4.0 and noticed a slight difference in how the engine keeps its rpms up. Also makes sense as to cost/replacement. This filter is good as long as you own your vehicle. Figure out how many times you change your air filter (every 8-10K? or so). It just makes sense.
  • gormalmitygormalmity Member Posts: 6
    how hard is it to install?
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    I think if all you have to do is insert the new type of filter without changing the housing, etc., it may indeed be worth it. But if you're looking for dramatic results or if you have to go through all kinds of ducting or special holders (carb-equipped engines perhaps), I think it's really debatable if it's worth it, even though they are replaceable. My car requires a $120 kit and really, just replacing the stock filter every 15,000 for $14 makes more sense. But your engine might *sound* a little better with a touch more induction noise perhaps...
  • bheplerbhepler Member Posts: 101
    K&N filters really make a difference if you make substantial performance modifications to your car. Initially, you may see only 1-4 hp gain in the higher areas of your RPM band, but when you start to push 300 hp and above, the K&N will show it's value more and more.

    Oh, and K&Ns are reusable as well as replaceable. Just wash them out, re-oil them, and put them back in.

    What do you drive that makes the filter $120? Are you sure it wasn't a filtercharger kit? I use a direct replacement for the stock filter and it was only $55. Four air filter changes and it will pay for itself.

    Gormality: It's just like your current filter. If you can change your current air filter, you can change to K&N. The only difference is instead of buying a new filter, you wash out the K&N, put the oil on it, and put it back.
  • MongoaPawnMongoaPawn Member Posts: 19
    Added a K&N to my previous car (turbo RX7) and to my current ride (BMW M3). Worth about 10HP on the M3...a little more on the RX7 when done in conjunction with less restrictive exhaust. More induction noise on both. In terms of $/incremental HP on these two cars... well worth the money.
  • gormalmitygormalmity Member Posts: 6
    MongoaPawn: you said you changed the exhaust on your RX7. how hard was that? i havent done much work on cars, so estimate how long it would take a beginner to replace the exhaust. i dont have an RX7, im just trying to get an idea how hard that sort of thing is. thanks.
  • MongoaPawnMongoaPawn Member Posts: 19
    Mine was a 3rd gen...Years 93-95. Piece of cake. Two bolts at the catalytic convertor, two bolts at the hanger in front of the bumper, one intermediate hook that slides through a rubber grommet underneath the car. WD40 on the bolts and rubber hook. Jack the vehicle up on car stands. Took all of 45 minutes. 2nd gen RX7 is dual exhaust and more experience there. I'm not a mechanic either but this was easy.

    The only way to tell how difficult the job is on any car...slide under the car and look. I wouldn't tackle any job that didn't have bolts and gaskets, i.e. clamps or welded. Also, penetrating oil or spray like WD40 a must.
  • Buck531Buck531 Member Posts: 14
    I'm looking to do mods to my car. It's a 98 Lumina LTZ, pushing 200 HP stock. I called the local mod shop and they said he can get me a filter replacement for my car for $45. Would it do anything if anything for my car? And could I reuse it over and over? I'm also looking for an exaust system for the car as well. If anyone knows.. let me know.. Thanks..

    [email protected]

  • lurch26lurch26 Member Posts: 1
    Can you get a K&N filter for the 2.5 Liter V-6 as it comes stock, or do you have to upgrade the air filter housing to that on the Contour SVT?

    Just looking for a few cheap extra horses.

  • quadrunner500quadrunner500 Member Posts: 2,721
    I have had the K&N air intake kit with re-useable filter for my '94 Camaro Z28. It is supposed to add 15-20 horsepower, but if it does, you cannot feel it. I would not waste the money if I could do it all over again.
  • cobra98cobra98 Member Posts: 76
    15-20hp? Not quite! Despite the ads, most people (like you) haven't seen the gain. What I'm going to do this sprint (starting in 2 weeks) is first dyno my car BONE STOCK, and then add underdrive pulleys (and re-dyno it), add 4.10 gears (re-dyno it) add K&N (re-dyno), add Bassani X-pipe (re-dyno),.... you get the picture. The point being is that I will pass along what I find to be the truth in HP changes per modification. Hope this helps.
  • cobra98cobra98 Member Posts: 76
    oops, I meant this "spring", not this sprint....
  • bheplerbhepler Member Posts: 101
    Quadrunner500: if your Camaro is bone stock, you will maybe see 2-5 hp out of the K&N filter. But as I have said before, the more you invest in upgrading your engine, the more that K&N will give you, performance wise. When you start to push 350 - 400 hp from intake & exhaust mods, then the K&N will be worth the 15 hp over a paper air filter.

    Still, I think the filter is worth it just from a price aspect. Summit sells the recharge kit for $8.50. That's for an 8 oz bottle of the filter oil and it will last for several cleanings.
  • quadrunner500quadrunner500 Member Posts: 2,721
    Let me make clear, mine was not just a filter, it was an intake kit with new intake plumbing. It wasn't just a K&N filter. Hot Rod magazine, and several others did dyno the results, and I believe the dyno reported a pretty good gain of about 15 horsepower. You combine this mod with a 160 degree thermostat, and hypertech power tuning, and underdrive pulleys, you might find an extra one to two tenths shaved off the 1/4 mile time. But my point would be that while those increases are noticeable on the clock, they are only barely noticeable from the "seat of the pants." In fact, I've seen one tenth or more shaved off just from cooler afternoon air temperatures compared to mid-day temperatures.
  • rickroverrickrover Member Posts: 601
    I put a K&N in my Range Rover and noticed a difference not massive but noticably more responsive. I like the fact I can clean it and reuse it.
  • BlakJackBlakJack Member Posts: 18
    Hey Quadrunner500,
    May I suggest you look into an AEM air intake sys.
    I installed one in my 142 hp Integra and i can feel the diff. I recorded the tach in 5th gear and I have been getting the same speeds at around 300 rpms less than before. And my gas milage has moved from 32mpg to 37mpg. The only drawback is that the bottom of the air horn is about 8" of the ground. (The car is not lowered). The idea was to grab denser, cool air of the ground instead of the hot air in the hood of a car. AEM says the air intake adds at tops 15 hp. The retailer said an avg of 13. Now I need a good exhaust.......... any suggestions?
  • quadrunner500quadrunner500 Member Posts: 2,721
    That's exactly how the K&N intake kit works. The filter picks up cool, dense air from below the car, something else I have to keep in mind when otherwise splashing through snow, mud, and rain. But in my case, a 15 hp gain on a car that otherwise is cranking out 275 is not huge. Previously in my '91 Mustang, I removed the air horn silencer, and replaced the stock filter with an oiled K&N replacement filter. That felt more noticeable than the change on the Camaro, and it should have been the other way around, since the Camaro also got the less restrictive intake horn and cool dense air from underneath the car. But what it still came down to, in the absence of other mods, was that the Mustang felt faster because it made more intake noise after the changes. I liked it. The Camaro on the other hand sounds the same as before, and a tenth or two at the track is something you have to be real sensitive to feel for, if you don't have the clock there to prove it for you.
  • cobra98cobra98 Member Posts: 76
    "I recorded the tach in 5th gear and I have been getting the same speeds at around 300 rpms less than before."

    Not to call you a liar, but unless you changed your transmission gears or rear-end gears, this isn't possible. Even if your engine puts out an extra 2000hp, the speed at a given rpm in a given gear is a constant. HP increases can't change that.
  • cdkellcdkell Member Posts: 1
    Wanting to know what I can add to my truck to gain more power. I have a toyota tocoma with a v6
  • bheplerbhepler Member Posts: 101
    Nitrous. Bang for the buck, there is no substitute. Other than that, replacement K&N filter for a little (really little) increase. Check around, there are probably some Toyota performance sites out there, and that engine has to be used in some other vehicle, perhaps those vehicles have web sites related to performance.
  • shinershiner Member Posts: 19
    I'd have to say the filter alone is not worth it. On most cars you'll see what, 5 hp maybe. Not enough to make a difference. You might "feel" a difference, but that can happen anytime depending on weather, quality of gas, wind direction, price of rice, etc. You can get a Fram filter that flows almost as well as the K&N but costs MUCH less. Sure the K&N lasts forever, but at ~ $50 for the filter plus cost of oil for later I don't think you're really saving money. If you sell your car soon then you're definately losing money.

    Now if you get the filtercharger kit or some other cold air induction kit you'll probably notice a difference. But these kits usually start at $150.
  • BlakJackBlakJack Member Posts: 18
    Does anyone have a tornado installed in their aftermarket air intake? It's just a fan shaped disk that inserts into the air intake. It's suppose to spiral the air in faster instead of a flat vacume. Have anyone of you heard about it?
  • bheplerbhepler Member Posts: 101
    Shiner: I still disagree about the price benefits of the K&N filters. A replacement filter for my Mustang is approximately $20 bucks. If I replace my filter element every 10,000 miles or so, that's $200 for 100,000 miles.

    However, I buy a K&N for $50, and a can of the filter oil for $6 (Summit catalog). If I get 10 re-oils out of the oil bottle (it's an 8 oz bottle), it still only cost me $56 and I just got 110,000 miles out of it. Even if I only get five re-oils out of the bottle, $62 for 110,000 miles is pretty good, according to my math.

    BlackJack: I think I answered this elsewhere, but I can't remember if I was replying to you. In short: save your money, they don't work. If you ask nicely, I'll give you a point by point breakdown of why. I already did this somewhere in the town hall...
  • rickroverrickrover Member Posts: 601

    The instructions with my K&N says to clean it every 50k miles, I intend to do in about every 10 to 15k. Any thoughts on this?

    cdkell - Toyota makes a supercharger for that V6 about $3k.
  • shinershiner Member Posts: 19
    bhepler, sounds like K&N is cheaper for you. $20 for a replacement filter? Sounds mighty high to me.
  • bheplerbhepler Member Posts: 101
    That's about right for a cheap replacement from Trak Auto. I'll have to go double-check.
  • shomanshoman Member Posts: 97
    I have proof that a K&N makes real HP on the dyno. I owned a Dynojet Dynamometer for a while and did lots of testing on my own car and others. The Dynojet was built to test for tiny HP gains like those from an air filter. In fact the Dynojet was designed by engineers from K&N. This in no way invalidates the results, HP is HP and lots of testing proves the Dynojet about the most reliable and repeatable dyno around.
    I tested my SHO Taurus with mild mods (207 at the wheels, 245 at the flywheel) with the stock airbox re-installed and tested three air filters.
    New oiled foam (Amsoil, but the Accell is the exact same design), New OEM paper filter and New K&N oiled gauze. I did 3 runs for each filter with the engine cooled down the same amount of time before every test. I did a before and after baseline to check for changes. The results were averaged.
    The Oiled foam was 3 hp down pretty much across the rpm band from the paper filter and the K&N was 3 hp UP on the paper filter.
    Note the measurable gains were from 1500 rpm to redline with peak being about 3 hp and the lowest being 1. Overall I would say it was over 2.5 hp for the entire rpm band.
    While I had the dyno shop I sold K&N air filters and tested gains of as much as 10 hp on certain cars, usually Corvettes or higher powered cars, this goes right along with what another person here said that the K&N is worth more, the more HP you get. I still sell the filters on my web site/mail order business.
    Of interest was a test of a dirt track car with a typical big round K&N air filter. When we put on the K&N "precharger" foam pre-filter, the engine lost more than 10 HP! You pay to keep out the big chunks of dirt track! ;)
    3 or even 10 hp is not really enough to "feel" but per dollar it's about the cheapest and easiest HP you can buy.
    Also by oil analysis I have proved to my own satisfaction that the K&N cleans as well as a stock paper filter.

  • willvlvwillvlv Member Posts: 4
    Is anyone out there aware if K&N (or a compet-itor) make a replacement filter or a filter charger for the Cummins 5.9L Turbo Diesel that comes in the Dodge Ram pickup? Let me know,

  • shinershiner Member Posts: 19
    This message was posted on

    >Well, as some of you have been eagerly
    >anticipating the dyno day III results from today
    >here in Houston. Here you go!
    >We tested the Fram vs K&N filter dispute on two
    >different cars. The same filters were used on
    >both cars. A brand new Fram filter and my K&N
    >that I cleaned last night.
    >First car - '99 WS6 Trans-Am M6
    >HP difference: 0.2 hp winner = K&N
    >TQ difference: 0.1 ft-lbs winner = K&N
    >Second car - '98 Bone stock Z/28 A4
    >HP difference: 0.2 hp winner = Fram
    >TQ difference: 0.1 ft-lbs winner = K&N
    >The curves on the dyno were exactly the same for
    >both pulls on both cars. There were NO gains at
    >all from just changing filter types. Who gives a
    >d_mn about 0.2 hp and 0.1 ft-lbs, which could
    >easily have been caused by the engine warming up.
    >On the first car, the first pull was made with
    >the K&N, second with the Fram
    >On the second car, the first pull was made with
    >the Fram, second with the K&N.
    >So, put the filter dyno theory to rest, those of
    >you that showed any losses or gains just from a
    >filter on a dyno probably tested on inaccurate
    >dynos. All of the cars dynoed today ran nearly
    >identical pulls on the first and second pulls.
    >We dynoed about 18 cars today also. I would say
    >that the MTI dyno easily repeats the same results
    >after seeing this.
    >So, run whatever filter you like, they perform
    >the same. I just like the K&N because I can
    >clean it over and over again.
  • PyroCPUPyroCPU Member Posts: 5
    Do the K&N filters produce a more "throaty" intake sound? My ricer buddies have Akimoto intakes in their Accords and Civics, and those intakes sound pretty sweet. Also, with K&N, it's not necessary to replace the tubing from the filter to the (ack... I'm guessing here) intake manifold, right?
  • bheplerbhepler Member Posts: 101
    The only sound you may hear on a K&N in your stock airbox is the air whistling a little bit as it goes through. At least, that's all I hear on mine. Remember, you're just replacing the filter element, not the entire assembly.

    The Akimoto intake (see below) makes that noise because you have removed the airbox, and now have an open air filter sitting in your engine bay. The Akimoto "funnel ram" kit includes the extra tubing, but the basic kit is the filter, an "air horn" which looks suspiciously like an adapter, and a clamp to mount onto your stock air inlet tube. From what I understand, the Akimoto uses a K&N for the filter element.



  • PyroCPUPyroCPU Member Posts: 5

    Wow, thanks for the explanation! Is that a Prelude (pre-97) motor sitting in the engine bay? Sure looks sweet! Okay then... so it's the entire Akimoto assembly that makes the sound. Of all of the other intake systems (DC Sports, GReddy, etc) which produces the most "sound?"
  • bheplerbhepler Member Posts: 101
    Got it in one.

    As for intake sound comparisons, I can't help you there. I just have the replacement filter tucked away in an airbox.

    However, IMHO, the best intake sound is the sound of a blow-off valve to a forced induction engine. I think some companies actually make sort of "horns" for their blow-off valves.
  • JettamanJettaman Member Posts: 6
    I just bought a brand new VW Jetta. Love the car, but the 2.0L 115hp is a little slow. I don't know a thing about what I can do to increase HP, but I'm slowly learning. Sounds like an after-market air intake manifold is the surest and cheapest way to go. Problem is, the model is so new, no one seems to make one that will fit the new Jetta yet. Any suggestions? Thanks.
  • bheplerbhepler Member Posts: 101
    For starters, see if you can find someone with a previous year Jetta and see if the intake manifold has changed from last year to this year. If not, the kits designed for previous years should work on your model.

    If the above doesn't work, get the K&N filter replacement anyway as a beginning. If there is an air silencer (kind of a snork looking thing on your airbox) yank it out.

    Other than that, contact the typical gamut of aftermarket manufacturers, and ask them when they'll be ready. They will probably tell you if their product will fit the new model.
  • nutypenutype Member Posts: 15
    if you want the intake for the best sound and okay power try weapon R intake. They have a unique hissing sound and sounds like a supercharger whine as you push the throttle. I use a AEM cold air intake in my 99 civic ex. this intake was dynoed to make 15hp. The cone filter sits rite behind the frount bumper where cold air gets and hot engine air doesn't get in. also the tubing is painted inside out with heat resisting coating. The velosity stack built in to the K&N filter makes a nice sound. The weapon R and AEM are both specially designed for each applications.
  • tiptronictiptronic Member Posts: 2
    i recently bought a brand new 99 vw passat wagon, i love this car so much, and getting spoiled with the turbo power it offers...
    however, i am curious, if changing the airfilter would add an extra oomph to its already excellent pull....
    although i have plans to rechip the ecu and maybe later upgrade the k03 turbocharger to a k04 (similar to the audi tt) BUT, i'm worried about the warranty of the engine if i do change this items......
  • tiptronictiptronic Member Posts: 2
    to help you with your 99 jetta, you may want to purchase a EC european car magazine, lately, they hae been writing articles regarding increasing the power and performance of the new 2.0 jettas.....good luck...
  • rlm1214rlm1214 Member Posts: 1
    i have a 99 Z24 and was wondering what i could do to increase to hp. i've already installed a K&N airfilter. it made a little difference
  • turbocoupeturbocoupe Member Posts: 1
    I found that a "Weapon R" re-useable filter is much better than K&N. Is is just like the cone style but it uses a foam instead of the cotton and wire of the K&N.
  • 300michael300michael Member Posts: 1,815
    Do they have a web site? What is the cost?
  • nutypenutype Member Posts: 15
    weapon R is a complete set including the intake pipe unless you will be making a custom pipe. the filters run about 45 dollars and 150 including the intake pipe. Weapon R makes intakes for most imports. The web site is
  • adg44adg44 Member Posts: 385
    The K&N filter won't make much horsepower unless you have a huge V-8 engine. The OEM airbox is restrictive so that it can quiet the sound. If you get an intake system wrapped with a cone K&N, you'll feel the difference.
  • bheplerbhepler Member Posts: 101
    ... to that last statement. I would say that a K&N won't make much horsepower unless you have a huge V-8 engine or equivalent. A high-horsepower forced induction engine will benefit as well. It really comes down to "the K&N won't benefit much until you start getting into serious HP numbers". I'm talking about 400 hp and up range. Below that, its about 3-5 hp, at most.
  • sebringjxisebringjxi Member Posts: 140
    I just installed a K&N conical filter in my 1997 Sebring JXi with the 2.6 liter Mitsubishi-built V6. I *think* I can tell some difference, of course, prior to the K&N I had cut the bottom of the factory air box out to get more air in there. It was breathing through a hole about the size of a business card. I used a K&N universial conical filter #3130. E-mail me at [email protected] for details. It's too lengthy to post here and not everyone wants details on a Sebring. Now, if I could just get some cool air forced in there to it????? The engine compartment is so tight and restrictive I haven't figured out a way to duct it yet.
  • adg44adg44 Member Posts: 385

    you need to get a cold air intake for your car! That will keep the air cool as it goes into the MAF. I don't know if they make one for your car or not....
  • enigma23enigma23 Member Posts: 36
    I had a K&N conical filter in the engine bay of my 96 Probe GT but noticed in warm weather that too much power was being robbed by hot air being sucked in by the open filter sitting in the engine bay.

    So what I did was, about 2 weeks ago, purchased a universal kit made by PRM. They make cold air systems. Basically what it uses is a K&N conical filter but wraps it in a plastic housing. This way no warm or hot air is ingested during the summer months and the filter also stays cleaner. They make a universal kit that kits any car with a 3" opening, which is most cars, and then they also make specific application cold-air intakes with full downpipes, etc.

    With the universal filter I basically bought some 3" diameter dryer ducting from Home Depot. I simply ran it from the PRM filter assembly down to the bottom of the car. This way I get cold air or cooler air even in the summer and the filter stays cleaner.

    After installing it I noticed a big difference in running smoothness and a slight increase in performance. Basically, now the engine revs smoother with less dips in power and alot less hesitation in warm weather. Higher end power has been increased because of the "ramming" effect this setup has. And it's also louder at high RPM's than my previous setup was.
  • nutypenutype Member Posts: 15
    PRM makes the Race cold air intake for your car. You didn't have to get the universal one, they make it for the v-6 mx-6 and sure that one fits the probe. I use a aem cold air intake in my 99 civic and that works great. Very nicely engineered. Also try reseting your ecu, i get better gas mileage and seems like more power.
  • enigma23enigma23 Member Posts: 36
    I thought about getting the Pro-kit from PRM but it costs a bit much at about $189. I bought the universal kit off a friend who used it on his 99 Honda Prelude. I only paid $50. The filter assembly's are all identical. The only difference's with the specific application kits are the siliconce reducer's and downpipes. The other reason I just rigged up my own setup is too force more air through the air mass sensor and into the intake. with my setup the pipe at the bottom of the car is pointing straight ahead, this was more air is forced through the tube and into the filter. The downpipe that comes with the PRM kit doesn't do that, the downpipe just kind of points down to the ground. The only real problem with my setup is that it now ingests large amounts of leaves. This means I gotta clean it every week or so. But it's worth it for the power.
    My friend replaced his PRM system with the AEM setup on his Prelude. I have to say that is one of the best made aftermarket systems I have ever seen.
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