General Intake / Exhaust Mods

kyleknicks · July 2001

u're saying 30k miles for every air filter change? do you actually do that? granted, my manual does say every 30k miles, but it sure looks like it needs to be changed now that it's at 10K.... i figure i would change it every 10 to 15k miles

armtdm · July 2001

I change mine once a year whether it needs it or not. For less then $10 and minimal time to do it I just do it and for me that comes to 12,000-15,000 miles

jpstax · July 2001

I installed K&N air filters on both our cars last Saturday (wife's '00 Buick Regal GSE, and my '98 Lumina LTZ). Her car seems to have gained more power. The maximum SC boost was 7 psi, but now it's up to 8 psi. My car also seems faster. I also installed a Tornado unit (don't laugh), and the car lays rubber with only 1/3 pedal (was 2/3 pedal before). It could be psychological too. I might be imagining power gains that aren't there.

w_o_n_g_s_k · July 2001

I put a K&N air filter into a '01 BMW 325 and started getting that "rear-pressed-against-the-seat" sensation when I accelerate from a standstill. It's been there for 2000 miles and so far no problems. I noticed that the stock air filter has a giant piece of foam glued to the dirty side. That seems very restrictive and I've never seen a design like that before.

midlifecrisis · July 2001

I installed a K&N air filter in my 1999 Grand Am GT. I'm not sure if the results are anything to write home about. It does seem that the car at cruising speed pulls slightly less RPM's, but I'm not sure if that's possible (based on gearing). It seems to also be a little smoother during acceleration - like the engine is working less.

I'm concerned about a previous post regarding K&N's direction to disconnect the battery to reset the computer. No where in the instructions does it mention disconnecting the battery. Shouldn't the electronic sensors automatically adjust for the air flow? When a stock air filter becomes dirty over time, doesn't the sensors adjust for the restricted air flow? Something sounds fishy with the posts regarding reduced gas mileage. My mpg have gone up slightly, but probably only because I replaced a very dirty air filter!

bryancos · July 2001

Midlife...
Yes, over time the car's computer would *eventually* readjust on it's own -- but by disconnecting the vehicle's battery to reset the computer, you are essentially forcing it to reprogram itself IMMEDIATELY to the current engine conditions, so you'll see the effect now, rather than having to wait for it.

When I put a K&N air filter and a cat-back exhaust on my 99 Jeep Grand Cherokee, the tech suggested doing the same thing --disconnect the battery so that the onboard computer would re-adjust for the increased air intake and reduced backpressure... It made sense, so I did it -- and saw my MPG on the trip computer jump by 3-4 miles per gallon after my first tank of gas.

midlifecrisis · August 2001

What are the other implications of disconnecting your battery terminal? Besides losing your preset radio stations.

bryancos · August 2001

...you might have to reset your clock, reprogram your power seat and power mirror memory positions, etc. It'd be similar to what you would do if you had to replace your battery... but you're certainly not going to harm anything in the vehicle by disconnecting the neg. battery terminal for a few mins. If anything, it's an inconvenience... nothing more.

obyone · August 2001

We use to run the tornado units in some of our company vans for the reported increase in mpg. Sad to report that it is nothing more than a piece of metal that does nothing. I also read the testing that was done in a mechanic's trade journal and they pretty much verified our findings. What do you expect? They were designed and made in Korea.

friendinthebiz · August 2001

The supercharged 3.8L in our '90 SuperCoupe Thunderbird felt stronger with a K & N. Easy and low tech...leaves more time for driving.

scotian · August 2001

Any thoughts on these? They seem to have more surface area than K&N (inner filter element as well as outer). There's even an inlet hose you can attach and route away from the engine.

http://www.autophysics.com/cones.html

scotian · August 2001

Where's a good place to get a length of 3-1/8" or 3-1/16" tubing that can be used for a cone filter install, either stores or on the internet? I've seen kits for specific cars, but not just tubes that I can use.

When I ask at car stores around here, I get strange looks -- this happens a lot as I often ask for things that I think should be available but aren't. One guy was useful though and advised never to use PCV tubes for this purpose.

It would be cool to find some that can be bent at an angle, or better still, already bent at an angle.

_pumic3 · September 2001

I put in a K&N filter a few years ago in my wife's 92 Escort GT. I didn't notice anything different at first, and I figured it would just let me change my air filter less often. A few months later, I drove the car again and found that there was an increase in power in low RPMs. Now that I see it mentioned here about forcing a reconfig of the computer, I think that was what happened. Next time I put a new one in, I'll unplug the batt for a few minutes.

chikoo · September 2001

I simply picked up a vaccum bag from the vaccum cleaner - wrapped it aroung a wire frame and put it in place of the stock filter.

any educated guesses?

obyone · September 2001

Being that it has to filter all that stuff out of the incoming air at that high cfm.

chikoo · September 2001

thanks obyone.

BTW,
what is the impact of having a greater flow of air into the engine?

increased HP?
increased mileage?

??

chuasan · September 2001

I know this is a lil off topic. However, I just checked my air filter and I found that one side of the filter is really filthy (I saw a large dark spot of dust (?) and few bugs, leaves, etc.... Does this meant I should replace with a new one? BTW, this is a OEM filter, not K&N ones.

Recently, I found my car gets fewer mileage, do you think this is related to the dirty filter? (I changed my oil religiously and check tire pressure on the weekly basis and use brand name gasoline). Please help me out. Thank you

Chris

b_dunn12 · September 2001

About your comment you made that it was made in Korea, well alot of stuff is made in Korea and are reliable. I know there are things made in Korea that are not well made or any good, but you could say that about the U.S. made items as well as any other countries. And don't assume Koreans are dumb, by all means most of them are alot smarter than you could imagine. I bet you own a Sony product and I bet you don't complain about that. So lets not down grade a nation that you have no clue about.

obyone · September 2001

Increased airflow does equate to increase in HP and mileage as the engine gets to inhale easier AND to finish the cycle, you should help it to exhale easier for additional HP gain and operational efficiency.

b_dunn12

Ever heard of Kia and Daewoo? Are those considered on the higher quality or lower quality of products being produced in South Korea? One Korean company that DOES produce worthwhile products is Sam Sung. So yes, I do know what I'm talking about. They are smart enough to know that Americans will buy just about anything that sounds good, even if it sounds too good to be true. Maybe they learned this from GM?

And I'm curious to know what Sony has to do with Korea? Even if Sony products are manufactured in Korea (SEK), the products must still meet Sony specifications. Do you know what SEK stands for?

stever · September 2001

Please keep to the topic.

Steve
Host
Vans, SUVs and Aftermarket & Accessories Message Boards

lwittorf · September 2001

That is telling you that that is where the air is coming in from the outside.if that is the only place on the filter that is dirty I would just tap that plac on a step or something to knock the dirt and bugs out and turn the filter 90 or 180 degrees and run it for a while longer but if when you tap the filter you get a lot of dirt not only from that spot but all around I would get a new filter whether it is K&N or a stock replacement one. I use K&N because I can clean them and reuse for not much work and money. I will say that If you are in a lot of dirty driving I would use a regular [good quality] filter and change it real often. I was down at my sister-in-laws in Kennewick Wash and got in a dust storm and changer out a filter with about 250 miles on it and figured that was to long and other times you might get 10,000 out of one.

SPYDER98 · September 2001

has over 50k on it since its last cleaning. Is it dirty? Yes...Is it still doing its job? Boy..I sure hope so!

mudflat · September 2001

An engine wants to suck in a volume of air that's related to its parameters and the rpm involved. A filter that won't allow this will reduce power and also gas mileage. Any manufacturer who cares about such things and doesn't object to spending an extra fifty cents per car will furnish a low restriction one OEM. If they don't, then maybe a K&N can help. If you don't mind a little dust in the cylinders, be brave and run without a filter to see what that does for apparent power; or, more scientifically, have somebody check your time to distance through the gears with a stopwatch and graph out the before and after figures. If having no cleaner helps, get a K&N and repeat the test. Of course, access to a dyno makes things a lot simpler. Back in the olden days we'd often run with no filter or a makeshift one because standard cleaners were so restrictive they couldn't meet the air volume demands of many modified engines. But stock?

scotian · September 2001

makes a foam slip-on cover for their cone filters, I believe, that you can probably shake out from time to time for those especially dirty areas.

dgsg · September 2001

http://www.c3m.eyenaps.com/candle/default.asp

jlpicard1 · November 2001

Go to

www.perfomanceint'l.com. Lowest price and quick ship!

A happy customer!

lov · December 2001

I have been brousing around the net for a while and the effect that cold air (0 to -30 C.) has on an air intake system doesn't seem to have any info. I have wondered how a vehicles air needs differ between two identical vehicles run in different climates? Lets say one is run continuously in +20C. and the other under 0 C. -- should they both have the same air intakes as they do from the factory.
Also comparing K&N to standard air filters, what does -30 C. air do to the tacky oil that K&N provides for their filters--does it become hard as one drives along at 70 mph creating a huge windchill. Would one have to use a different oil or perhaps even a standard filter with no oil. Sorry for all the questions -- I just seem to be full of them tonight. I would appreciate it if someone could enlighten me or if there are any sites on the web with any info.

ezaircon4jc · December 2001

Cold air is denser (more O2 molecules per cubic foot) and therefore provides more "power". The engine is really nothing more than an air pump. More air in/out, more power. This is really a simple explanation as there are multiple variables.

As for web sites, try www.howstuffworks.com

stever · January 2002

bryancos "MY2002+ Chevy Trailblazer, GMC Envoy, Oldsmobile Bravada" Jan 7, 2002 9:33am

tidester · January 2002

there are multiple variables

Yes,there are! For example, if there are too many O₂ molecules in the fuel/air mixture, much of the energy available to do work actually goes into heating the excess O₂ molecules, i.e., the engine runs less efficiently.

There should be an optimum mixture of fuel and oxygen. It's not clear, to me, what the net effect of cold air should be without more detail.

tidester
Host
Aftermarket & Accessories

scotian · January 2002

http://www.martelbros.com/cgi-bin/store/ws400CS.cgi?store=KNN&category=knn/index.html&cart_id=1020118092920729

anonymous02 · January 2002

I thought that the warmer the air, the more efficiently it burns. The opposite being that the colder the air, the more dense (more of it) that air can be. Don't you really want the hot air to enter the engine for all intents and purposes as far as efficiency?

I think the stock airbox with a freer flowing filter might do the trick.

Next question: Does a K&N with particles in it flow more or less freely than a paper filter after same time period?

Is this all just a bunch of hype???

scotian · January 2002

Well, NOS is nothing more than very dense oxygen, and NOS makes engines go faster, so the denser the better. However, I've heard of NOS bottle warmers, so there must be a point where the temp is so low that it hinders the ignition/burn process more than the dense oxygen provides power. I imagine that this is well below normally encountered outside air temps, though. Or maybe the warmers are just so the NOS delivery lines don't freeze up.

coonhound · January 2002

I've read the post about re programing the computer, but thought what a waste of time. Anyway the MPG on an astro van decreased by 3 mpg after installing the K&N drop in replacement filter. Now I am going to try and disconnect the battery and short the cables together for about 10 minutes. If this doesn't help it's $50.00 spent on experience and gaining knowledge.

anonymous02 · January 2002

I don't get the short the cables comment.

There wasn't a smiley :-) , so I am not sure if you were serious or not.

coonhound · January 2002

To remove the ECM data you remove one battery cable. Safer to remove negative, and short the cable or jumper it to positive. This is the same method you use to erase fault codes form the computer, (electronic control module). Reconnect the negative battery cable, reset the radio and clock and your on your way. However there may be some unusual transmission shifting, throttle response, etc. until the computer learns all over again. I do this occasionally on vehicles to make sure they haven't picked up any bad habits. Just like saving all your computer data, reformating the hard drive, and re loading the software.

scotian · January 2002

So, disconnecting the - cable and touching it to the + post does something useful?

dgsg · January 2002

Disconnecting the battery cable will reprogram the cars ECU so that HP is increased by 35%, fuel mileage will increase 25% and you will look ten years younger!;)
Urban legend file.

coonhound · January 2002

K&N reportedly advised someone on this site to disconnect the battery for faster programing of the ECU to correspond to the change in air flow sensed by the MAF sensor, oxygen sensors, manifold pressure etc. etc.. I don't know if it helped the fuel mileage or not. If it doesn't help my van mileage, to at least to where it was, I will have a K&N filter for sale at an old world price.

zr2rando · January 2002

Just some trivia, I remember back in my Chemical Engineering days,,,The formula for calculating efficiency in internal combustion engines had a term in the top portion that was " (t1 - t2)..the difference in the hottest and coldest temps in the engine process...which would be the intake air (coldest), and the exhaust peak temp (hottest). There were lots of variables in the efficiency = x over y formula, the x contained the (t1 - t2) term.. the bigger that difference the higher the efficiency of that engine. (Cold air expands more as it heats up to the combustion temp so provides more pressure increase) This only means more power for the given amount of fuel. That would not always mean you get more miles per gallon, only that the engine drives stronger...I have almost always noticed better gas mileage during the summer but the vehicle DROVE better during the winter,,,,usually more noticeable with older carb engines. Newer computer controlled engines (with air intake temp sensors) modify the mixture trying to keep it constant.
So intake air being cooler DOES increase engine efficiency, but does NOT always give better gas mileage...kinda weird huh?
Good mornin
Rando

zr2rando · January 2002

A free'er breathing filter makes the mass air flow sensor register more incoming air which allows more incoming fuel to make the mixture correct...sorta like having a blower, but to a much smaller degree. You may be noticing the reduced mileage more than the corresponding increase in performance,,,,that's usually how it is too, unfortunately. You probably wouldn't notice much power increase unless you hit higher rpm anyway, then you can tell a difference because at higher rpm a clogged filter actually does restrict that extra required air...most of us don't drive that way very often of course but that is where you would notice any difference.
A clogged fuel filter does the same thing, doesn't hurt anything as long as fuel flow is low, but at high flow rates it can start cutting down on flow when engine needs it the most.

anonymous02 · January 2002

Yeah, but wouldn't EVERYBODY notice these effects when driving 65-75 on the highway?

I had the K&N on my 92 Civic, and would not do it again. It made more noise than power. (Friends said it sounded like a v8, but just laughed because it went like a Honda!)

I now have a Jeep, but will use the OEM filters, just change more regularly.

zr2rando · January 2002

But I don't notice any difference on my trucks.
I put the K&N filter on my 95 Blazer and 99 ZR2 just to have a theoretically better flow filter but mainly to avoid buying several air filters over the life of the vehicle. I usually buy vehicles new and keep them till they rot so getting lifetime stuff
(brake service/alignment/air filters) usually pays for itself,,,so far it has anyway. I never really expected any power or mileage gains, and so far I haven't seen any either. I doubt that I would notice any power improvement, I don't do the jackrabbit thing, I'm a pretty easygoing driver. Something else, 65-75 mph is still about 2200 rpm in those trucks, probably wouldn't notice anything until you really got a good bit higher rpm than that.
As an example, put a bandana over your face like the old cowboy train robbers and take a walk-no problem, now go running and see how it restricts the air when your breathing hard, then you would see the difference...air filter/fuel filter/oil filter...same thing.
Unless you keep the vehicle for a long while it wouldn't pay for itself at all. We used to turn the top of the air breather cover upside down on our trucks back in the 70's, made LOTS of noise doing that too, that brings back memories!

anonymous02 · January 2002

Yeah, I remember the air cleaner cover trick!

You confirmed what I have observed. It makes no power difference for all intents and purposes.

Maybe in a race track environment where it is at full rpm all the time, and you don't care about certain other things, it might make a difference.

But to buy it for performance...???

coonhound · January 2002

Thanks for the good information. Now I understand why I nearly flunked thermodynamics. I've had my heart set on installing a $220.00 Ganatelli mass airflow sensor. They claim, improves mileage, 10- 15 more rear wheel horsepower. But this may be like the increased HP in the astro from 165 to 190 HP vortec sequential port injection, bla, bla, bla, at a cost of 2 to 3 mpg. Yes, it does have more HP but why couldn't the tuning have been to maintain the previous fuel mileage when we're just cruising down the hyway.

In all fairness to K&N there was no claim for increased MPG. It possibly may have some benefit under loaded conditions such as pulling the 30' Award travel trailer. That is the main use for the van anyway. Also winter blended fuel may be a contributing factor to poor mileage at this time.

I got the K&N gotta have bug from the Olds. Intrigue site, as it is always an in demand item there since K&N does not list a filter for the Intrigue. A lot of owners purchase a non listed K&N for the Intrigue. Sort of reminds me of a child instinct for candy, if you can't have it the more you want it. I even put one on my 2000 Alero 2.4 liter. Another waste of money.

zr2rando · January 2002

You passed thermodynamics? he he

coonhound · January 2002

But my thermodynamics was back when fire was just being discovered.
I disconnected the battery and shorted the leads.
Picked a spot at the service station and filled the tank to completely topped off. Took a short 60 mile highway trip and fueled up in the exact same position to topped off completely. The mileage was 25.3 mpg. This is not a real world test as I was trying to determine what was going on and maximum mileage. I drove a nominal 60 mph for the test. The normal loaded mileage at 65 to 70 mph has been 20 to 21 mpg. But my daughters and family's got that ridicules 17.86 mpg on a 500 mile rt.

I had done things trying to get better fuel mileage.
Mobil 1 in the differential.
Semi synthetic in the transmission.
TOYO 800 ultra tires at max rated 44 psig.
Lubricated brake calipers to reduce drag.
Use Mobil 1 10/30 in the engine.

Fuel mileage is only for bragging rights anyway. I have always spent more in trying to obtain better mileage than than the fuel advantage will ever return.

zr2rando · January 2002

we read that fire was a myth and not to believe anyone that took it seriously!!!
If you are really trying to get good gas mileage on the vehicle you are probably driving it pretty easy, easy start, easy stop...you can get a vac gauge and install it in the dash. Light foot gets high vac and gets better gas mileage, it's a constant reminder to watch a leadfoot...
and also use the lowest octane gas that does not ping.
oh yeah, back to topic, the K&N filter should not make any noticable diff in the gas mileage, so enjoy the freedom of not changing it very often.
Fire was actually discovered huh, never would have believed it...
Auburn Chemical Engineering 1984
Good luck

lmacmil · January 2002

The only hard data I've ever seen on a K&N performance increase was from a guy who actually did before and after dyno tests on his Aurora. I think the dyno showed a 2-3% hp increase above 4000 rpm. I would guess that would be barely noticeable in anything but a flat out 1/4 mile drag. As I recall he also opened up the airbox so that probably contributed to part of the gain.

Most of the claims are anecdotal and most of the gains are psychological. People spend $40 to replace their $7 paper air cleaner and they want to believe they got something for their money so they "feel" the performance difference.

P.T. Barnum had it right.

coonhound · January 2002

lmacmil: I think I have to accept the fact that you are right. But I will still cling to the hope as I pull that trailer over the mountain out of Pagosa Springs that there is that K&N is doing it's thing.

But I can hear the deeper breathing under full acceleration and extra noise means extra HP, right! That is what all the Hondas have with those pipes and big open mufflers they add on. Or maybe with the Honda it's the dished wheels and 45 or 55 series miniature tires. They must run like a real performance vehicle with those changes.

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