Hyundai Elantra 2001-2006

jimijames · July 2004

Looks like the 01-03's have the sensor too - http://www.hmaservice.com/webtech/iindex.asp?id=394876132#_39487- 6132 - but they do not have the pass airbag off indicator light.

I'm concerned because there is no way for me to know if the pass airbag is on or off. It looks like the SRS has been redesigned for 04 (dual stage and such) so maybe the 04's have a different type of pass sensor... let's hope so anyway.

backy · July 2004

Quote from Hyundai's online shop manual:

The 2004 Elantra is the first Hyundai available that meets the advanced air bag
requirements of Federal Motor Vehicle Safety Standard (FMVSS) 208 - Occupant
Crash Protection. The amendment to the standard requires 20 percent of a
manufacturers vehicles sold in the United States manufactured between September 1,
2003 and September 1, 2004 to comply with NHTSAs Advanced Air Bag Rule. The
percentage will increase to 65% during the following year and by September 1, 2006,
all vehicles must comply. The advanced air bag requirement is a significant revision to
the Standard, intended to reduce the risk of serious air bag induced injuries, particularly
for small adults and young children.
The Occupant Classification System (OCS) complies with FMVSS 208 by detecting the
presence of a passenger in the front passenger seat and automatically turning off the
right side air bags for light weight or out-of-position occupants.

Also, the TSB that refers to this problem, 04-90-003, applies only to 2004 Elantras as noted in the same source, http://www.hmaservice.com/webtech/.

jlflemmons · July 2004

I went out to the NHTSA website and found the recall. According to the information I found, only 75 Elantras were built with the problem, and "Remedy:
ALL AFFECTED VEHICLES WERE DELIVERED TO ENTERPRISE RENT-A-CAR AND WILL NOT BE PLACED IN SERVICE UNTIL THE RECALL REPAIR WORK IS COMPLETE. CUSTOMER NOTIFICATION FOR THIS CAMPAIGN IS NOT NECESSARY." from the NHTSA bulletin.

So, am I missing something here, or is this a whole lot of hoo hah about something that does not affect the retail buyer???

backy · July 2004

I think there's a question as to whether the problem extends beyond the 75 vehicles that were recalled last summer. I read the TSB on the issue and what it describes is how someone needs to sit in the front passenger seat to make sure the air bag is activated or not. The TSB talks about things like making sure your legs are actually on the front of the seat cushion. It's reasonable that since the sensors are in the seat cushion, you actually have to be pressing on the sensor to activate it.

I think what this situation points out is that perhaps government regulations have gone too far in their attempt to protect us. New regulations mandate that carmakers do what Hyuundai did with the '04 Elantra and put a OCS system into the front passenger seat. Because of the regulation, all new cars will eventually have this feature. But that requires technology that can reliably determine whether someone of the proper weight is sitting in the seat. What if they aren't sitting in the seat in a "normal" fashion? Can the sensors be designed to account for variations like that? It appears that could be difficult. How much simpler to have, as someone has suggested, a cutoff switch for the front passenger airbag, so that we can be sure whether the air bag is on or off. I guess the government doesn't think drivers can be trusted to make that decision for themselves.

backy · July 2004

I just did some experimentation with my '04 Elantra GT (made October '03) and the passenger airbag OCS (occupant classification system).

First I put my 8-year-old daughter in the front passenger seat. She never rides there, but I wanted to see what would happen. She weighs 53 pounds. I told her to sit straight, legs resting on the cushion. I started the car. The "passenger airbag off" light flickered once, then stayed on, meaning the airbag deactivated like it should. I thought this was interesting because she is right below the limit for where the bag should activate (55 pounds). I shut the engine off.

Next my 12-year-old son sat in the seat, and I restarted the car. (He doesn't normally sit up front either.) He weighs 88 pounds. The "airbag off" light went out, meaning the airbag was activated as it should be. I told him to shift around in the seat a bit, and he did, including lifting his legs so they were no longer touching the front of the seat cushion. The light stayed out.

I didn't test with my 15-year-old son (about 160) or my wife (weight withheld on threat of serious bodily injury), but I know from experience the light goes off every time they are in the front passenger seat.

I found this note about how the OCS works on the Elantra, on the Hyundai Webtech site (http://www.hmaservice.com/webtech/) under TSB 03-90-024 (good pictures, too):

The OCS's force sensor resistor (FSR) cells are located in the front passenger seat. The FSR's resistance values decrease with increasing weight. When a person sits in the passenger seat, the resistance in each FSR cell will decrease relative to the load. When a predetermined number of these cells have been detected, the PAB circuitry is activated and the "PASSENGER AIRBAG OFF" lamp is turned off.

The pictures show the Force Resistance Sensors, 56 of them, spread across the seat cushion. So I can see how if a person wasn't sitting normally in the seat, e.g. legs not on the cushion, not enough cells would be detected and the PAB circuits would not be activated.

I wonder if other cars have a similar OCS sensor system or use some other approach?

alpha01 · July 2004

"I think what this situation points out is that perhaps government regulations have gone too far in their attempt to protect us. New regulations mandate that carmakers do what Hyuundai did with the '04 Elantra and put a OCS system into the front passenger seat."

I would agree that in some circumstances, regulation may go too far. However, in this instance, it doesnt seem out of the realm of acceptability to expect that a sensor accurately detect the weight of a passenger in the front passenger seat. Yes, all carmakers are mandated to do that which Hyundai has done with the 2004 Elantra... however, it does not seem that other car makers are having this problem...

~alpha

backy · July 2004

That's why I asked if other automakers use the same design for the OCS. I think it unlikely that Hyundai designed its own subsystem for this purpose--more likely it uses a third-party system that is also used by other automakers. I found out that there are three major kinds of OCSes used:

There are literally dozens of systems on the market, Katzkins Leslie said. Every one is different, although there are three predominant systems in the U.S. This is an important issue because the OEMs are notifying their dealerships about these systems. Educating the marketplace about seat cover installation on vehicles with the new Occupant Classification Systems (OCS) is an important task that must not be taken lightly.

The source article has lots more info about OCSes, including descriptions of some of the types of OCSes used by GM, Honda, and Toyota:
http://www.atrn.com/ci_pick.cfm?id=118

As for other car makers not having this problem... not true, for example, see:
http://www.titanclub.org/airbag_post/

Anyway, after testing my own car I'm not sure if it is a problem or a misconception about how the OCS is supposed to work.

jlflemmons · July 2004

If my 60lb daughter is in the front seat, the indicator shows the airbag disabled. Unless I hit a good bump, which accelerates the seat upwards faster than her little behind, in which case the airbag is momentarily enabled. This tells me that the system GMC is using is similar to that of Hyundai.

It ain't a perfect world, folks. In my day, we little ones often stood up in the front seat between the folks while cruising at 70 on two lane roads with non-power drum brakes and no seat belts. Amazingly enough, most of us survived. Do I want to do that with my kids? No way. But I do not expect a risk free life for myself or my family. You just do the best you can.

Remember that passenger side airbags only showed up in the last 10 years or so.

smith20 · July 2004

"Anyway, after testing my own car I'm not sure if it is a problem or a misconception about how the OCS is supposed to work."

I am pretty sure it's not a misconception about how the OCS is supposed to work. I am pretty confident that at least some of the cars, I guess not yours, have a sensor that doesn't operate as it should. I wonder if there is a way to adjust the sensitivity (such as altering the electrical resistance it looks for) of the sensor because it seems like the one in my car works great and very consistently . . . only it turns on and off at 120 pounds . . .

Maybe there is an OEM quality control issue regarding the tolerances in the electronics sensor which interprets the results of the resistive force sensing pad. Or maybe there is a quality control issue regarding the manufacturing tolerances of the resistive values of the force sensing pad itself.

jimijames · July 2004

My beef wasn't with the fact that the sensor was defective or poorly designed or what-have-you, it was with Hyundai's response (refering to ABC link, post #4172). I understand it's new technology (and BTW Backy agree with you 100% on our nanny govt over-regulating), but the ABC article stated someone in the 150lb range was not able to trigger OCS. That is clearly a failure of this particular sensor in this particular car and it should have been replaced, no questions asked. Hyundai's response of sit in the back or buy a different Hyundai is not acceptable.

Apparently not all 04's suffer this problem, and much like that friggin mystery vibration, Hyundai's response is lousy to say the least.

jpryba · July 2004

I'm glad you mentioned the shimmy here as well, jimijames. We're talking about it on the problems & solutions board now.

Even with these issues, the Elantra is still a pretty good car. Remember that Hyundai's quality was not exactly stellar just 5 years ago, and although they are catching up (and have caught up or even surpassed other automakers in certain respects -- for example, the Elantra's bumpers), they still have some rough edges to iron out.

To sum it up, the main issues I've seen on the Elantra board are as follows:

1) the shimmy
2) trim issues (the peeling black tape)
3) transmission flare (fixed)
4) airbag sensor issues (I'm going to lump the current issue in with the one relating to the IIHS crash test back in 01)
5) paint issues
6) minor rattles, weird noises, etc

I'm sure I missed a few things, but this is pretty impressive when you think about what Hyundai was making just a few short years ago.

Issues 1 and 4 mentioned above are of the "nobody else has this problem for the most part, so why can't Hyundai get it right?" variety. These are the ones Hyundai really has to respond to with careful thought -- otherwise, I envision class action lawsuits. They've had one already for the false horsepower claims, so I don't think a shimmy or airbag-related lawsuit is very far away either.

backy · July 2004

Nissan for one has the OCS issue. Other automakers, including Nissan and DC, have had a similar problem to the Elantra's driver's airbag deployment problem. Also I think it's inaccurate to characterize the IIHS test result as a sensor problem. The Elantra uses the same sensors as the Sonata and Hyundai claims they never found any problem with the sensors. We'll see if they fixed the driver's airbag issue when the IIHS test results on the '04 Elantra are released.

I think the major gripe from what I've seen is not that the problems have occurred, but what Hyundai's response has been. I am particularly upset with Hyundai's lack of response on the poor frontal offset crash test result. Other automakers, like Nissan and DC, responded immediately when their vehicles got less-than-stellar crash test results, made modifications, and got a re-test. It's taken Hyundai over three years to do that.

wendy1 · July 2004

I am the person who originally posted the comment about the air bag problems. It is great to see all the responses here! I just don't know if the concerns mentioned here are enough for me to not buy the Elantra. I am less than 150 lbs myself. Will my own air bag work properly for sure?

Maybe I should want till the 2005's come out, but the rebate will probably only be $500, not the current $1,500 on the 2004. That is what the dealer said. Should I believe that? The resale value is not very good on Elantras, I've heard, so getting a 2005 or 2004 may not make a difference for that.

jlflemmons · July 2004

Is always enabled. The passengers side is disabled for small/light loads. A second benefit is that in a collision where no one is in the passengers seat, the airbag does not deploy, saving unnecessary repair cost.

I noted in a safety commercial airing here in Texas that they wanted to show what happened if you smoked dope and drove. Two crash dummies hit the test barrier at speed in a big car. (Maybe a Town Car?) What was interesting is that in all the obvious destruction and violence of the crash, neither airbags deployed.

I guess dope smoke dis-arms airbags...

backy · July 2004

If you are the driver of the car, this is a moot point (the OCS problem that is). That is a problem with the passenger airbags. If you are the one sitting in the passenger seat, tests the vehicle you are going to buy to see if the "airbag off" light goes out. The IIHS retest of the '04 Elantra has been done and should be published soon (we hope!), if you are concerned about the frontal offset crash test result on the '01 GLS. The '04 got five stars on the NHTSA frontal test for the driver and four stars for the passenger.

As for rebates... of course the dealer will say that, they want you to buy a car right now! They have no idea what rebates will be like months from now. The rebate on the '05 could temporarily be less than that on the '04, but who knows, maybe as the year-end approaches the rebate on the '04 will go back to $2000 (where it was earlier in the year) and the '05s will have a rebate of $1500. Who knows? Resale value is not great on Elantras, but that is not an issue if you plan on keeping it for 5 years or more. If you plan on trading in 2-3 years, you'd be better off cost-wise with a car with high resale value like Civic or Corolla.

jpryba · July 2004

"I think the major gripe from what I've seen is not that the problems have occurred, but what Hyundai's response has been. I am particularly upset with Hyundai's lack of response on the poor frontal offset crash test result. Other automakers, like Nissan and DC, responded immediately when their vehicles got less-than-stellar crash test results, made modifications, and got a re-test. It's taken Hyundai over three years to do that."

Actually, the IIHS tested the 01 Elantra 3 times. Here is a quote from their website:

"The Insurance Institute for Highway Safety has evaluated the crashworthiness of the Elantra in three 40 mph frontal offset crash tests into deformable barriers. After the first test, Hyundai indicated the dummy's lower leg injury measures were different from those recorded in tests the company had conducted and requested a retest. Results of the second test were somewhat improved for lower leg injuries, but a high right foot acceleration occurred. More significantly, the airbag deployed late, contributing to poor head injury measures. A third test was conducted after Hyundai could find no evidence of a problem in the airbag deployment sensing system and suggested the late deployment might have been anomalous. However, the airbag also deployed late in the third test. Due to the similarity of results, the evaluation of the Hyundai Elantra is based on all three tests."

So, Hyundai does seem to care to a certain extent. At the same time, though, if the 04 Elantra doesn't get an acceptable or good rating, it's going to give people the impression that Hyundai didn't look into the issue any further and that they don't care about the IIHS findings. This could be another public relations nightmare for them if they don't handle it right.

backy · July 2004

I think you're missing my point. The three tests were all done at roughly the same time. Hyundai did investigate, but the reason for the late-deploying airbags remained unknown and there is no evidence that they pursued the matter after that (I even asked HMA about it later, and they knew nothing of any investigations on the airbags). However, there was a simple fix for the driver's leg hitting the dashboard (contributing to the "poor" overall score on the IIHS frontal offset test): redesigning the driver's side seat track. Hyundai made that change in 2002 but applied it only to Korean-market cars--not to cars in the U.S. They also did not recall any cars in the U.S. to replace the seat track, a $6 part. I think but am not sure that the new part is being used in '04 Elantras, which I suspect is one of the reasons Hyundai asked the IIHS for a re-test this year.

If the '04 Elantra doesn't get a "good" rating on the IIHS frontal offset test, it will be one of the few small cars that does not have that rating and I agree it will be a PR nightmare for Hyundai and will hurt Elantra sales until they get it right, maybe with the redesign next year.

baber1 · July 2004

Does anyone remember the government mandated seatbelt interlock fiasco of 1974? The car wouldnt start until the drivers seatbelt was fastened. This was so unpopular the Government scrapped this regulation. Remember the terrible automatic seat belts that were Government mandated? Hundai should be able to bypass the sensors and leave the airbag on all the time or install a manual cutoff switch but I bet the Government wont let them do it. Hyundai and other manufactuerers face a big lawsuit if people are hurt because of this.

wendy1 · July 2004

Thanks, everyone. I think I will wait till the fall, till after the 2005's come out. They will have to be more improved than the 2004's, I'm thinking, and Backy thinks there will be rebates then, so there's no rush to get it. Thanks for all the input.

backy · July 2004

Wait for the '05s if you want, but there's no crystal ball on rebates. We found that out when the rebate on the '04 went from $2000 to $1500 recently. As for improvements for '05, Hyundai just refreshed the Elantra for '04 and a new design is due for '06, so IMO there will be few if any changes for '05. But you never know...

jimbeaumi · July 2004

Well, folks, my beloved little Betsy turned three yesterday! With a bit over 45K miles, I am still very happy.

I am waiting on delivery of the air filter for the A/C system; after just one year the old one is quite loaded with dust and debris. Brakes are still fine, along with all other parts of the car.

I still see very sharp black GT hatchbacks in town and I am sooooo tempted. But the other part of me wants to see this car out to 200K miles. Besides that, she'll also be paid off in about a year.

jimijames · July 2004

"I am waiting on delivery of the air filter for the A/C system"

wha-what? The Elantra has a cabin airfilter? I'll have to check my manual after work... that would be a nice suprise if it does :-)

altsuv · July 2004

Apparently the Elantra has a housing for a cabin air filter, but you have to install it yourself. I'm thinking that maybe earlier models didn't have the filter installed, but newer cars have it. Either way, check out

http://egt.gwebworks.com/garage2.shtml

- you have to remove your glove box to get to it.

jimijames · July 2004

good bit of info there on the cabin filter. Thanks altsuv.

jimbeaumi · July 2004

Cabin filter is offered in Korea, but not in the U.S. to my knowledge. The space for it would still be there, of course. This year's filter is taking more time to arrive than last year's. It does a good job and to me it is worth the $50 I'll be paying. Your dealer should have a part number for it in his system. It might be the same unit for Tiburon.

jimbeaumi · July 2004

I picked up my cabin filter today and installed it. A word to the wise: be very careful when removing or installing the two screws holding the metal bracket in place. I nearly lost one of mine.

Today I put in an order for a K&N filter (what took me so long?) and it will arrive in a week. I am interested in feeling the (promised) performance difference.

Betsy rolled 46K miles yesterday.

browney · July 2004

For those (like me) to cheap to spend $50 for the stock air filter, my post #1754 from 8/29/01 shows the dimensions at: Width=10.5in Depth=9.25in Height=1in
I made mine from an old electrostatic furnace filter that had an adjustable plastic frame.
It made a big difference in the amount of pollen that made it into the passenger compartment.

vadp · July 2004

Today I put in an order for a K&N filter (what took me so long?) and it will arrive in a week. I am interested in feeling the (promised) performance difference.

There will be no difference, unless your stock filter was extremely dirty.
But I'm sure you'll feel more power. It will be all in your head.
Also it will more than likely allow more dirt in your engine too.

fushigi · July 2004

I'll agree that the power difference is minimal, but I wonder why you say it'll allow more dirt in the engine. Please elaborate or provide a link. Thanks.

The reason I put K&N air filters in my vehicles is actually for cost savings. 1 $40 or so filter for the life of the vehicle is a decent savings over the $8-18 twice a year. I also clean the filters annually.

jimbeaumi · July 2004

While the psychoanalysis is not welcome, I do welcome comments from people who have used these filters and can comment on how well they trap dirt, etc. My current paper filter is about a year old and not very dirty (just a bit gray). Is the re-oiling process simple?

fushigi · July 2004

Re-oiling is easy enough. Take out the filter, tap out any debris that'll come loose, hose it clean, let it dry, spray on the oil (the $10 can will last for several cleanings), IIRC let that set a bit to drain any excess, reinstall. In theory you do it every 50K miles but I do it annually. There is a lot of construction in my area (Chicago suburbs), so lots of dust gets raised in addition to the normal garbage in the air we and our cars breathe.

I have them in my 99 Galant (90K miles) and my wife's 01 Elantra (37K miles).

lngtonge18 · July 2004

I've read a lot of conflicting info on K&N filters. This one website stated they decided to put K&N to the test by installing the filters on their construction equipment(tractors I believe), since they operate them in heavy dust areas and the added power and longer service life was of interest to them. According to their findings, the K&N filters provided negligible increases in power and actually caused internal damage to the engines (leading to a few engine failures if I remember correctly). Their thought was that the oil doesn't provide good enough protection from smaller particles entering the engine and scouring metal surfaces. They stated the regular paper filters offered far better protection and they switched back to them, with no further internal engine damage. This does make sense to me because added airflow has to come at a cost. There is always a compromise involved with HP gains. Race engines may use them but they aren't expected to last long either.

I've also heard that if a K&N filter is too oily, the oil can actually get sucked into the intake and mess up sensitive sensors like mass airflow units.

While this is all heresay and some people swear by them, these reports are enough to make me pause about putting one in a new car under warranty or one I plan on keeping a real long time. I do currently use one in an 84 VW GTI with over 200k and its been there since 1996 with no reoiling and I haven't noticed any ill effects, but I haven't opended up the engine to look for scouring either...

fushigi · July 2004

Before getting beat up for drifting so far OT...

Thanks for the info. Interesting read. Still, I would hazard a guess that the needs of construction equipment would differ from that of passenger cars. The airflow rate may be too high for the K&N methodology to work reliably. Also, I would assume the construction equipment is diesel and not gasoline. Diesel systems may be more sensitive to a little oil/dirt in the mix than gas engines.

Again, I'd agree the power increase is trivial and probably barely measurable let alone noticeable. But I think if you don't over oil the filter they work fine as a lifetime replacement. My dealership's service department knows I have one and has never mentioned anything bad about them to me.

K&N says their filters won't violate a new car warranty, so if damage does occur, they could be held liable. Important for those of us with the Elantra's 100K warranty (how's that for bringing it back on track?).

nickimom · July 2004

Hello folks. I am a new owner of a 2004 Hyundai GT hatchback. Purchased June 14, I have about 1700 miles on it. Usually only have kids in car in back seat. Hubby and I have been in car together recently, and airbag light stays illuminated. Took it in and they called me back today to say don't worry. I read bulletins, and if hubby's 220 lbs or my 160 don't cover enough sensors, there is a problem! It can also go on and off, and we aren't wiggling around. Any suggestions? Thanks

jimijames · July 2004

There was a fairly lengthy discussion about this in this forum starting at message #4172.

You said in the problems and solutions forum that the dealer said not to worry because the airbag will deploy whether the airbag light is on or off. In my opinion, your dealer sucks. Find another. Yet another example of how poor Hyundai dealer support is.. which is too bad because the cars are much better than they used to be. As I stated before, Hyundai's response to this airbag issue is cr@p... I am very disappointed with the Hyundai brand right now.

ironmanterp · July 2004

Edmunds' latest top ten list provides the top towing vehicles and they rate the Elantra at 9, commenting "No, this is not a typo. The Elantra offers 3,086 pounds of towing capacity."

I looked in the database and sure enough, Edmunds has the Elantra rated at 3086 pounds. I STILL think that this must be a typo - FWD, unibody construction, short wheelbase, and 135 hp are just not the typical specs of a hauler. The Santa Fe maxes out at 2,800 according to Edmunds. Can someone verify Edmunds' claim that this is a sleeper hauler or if there is some option or some explanation why Hyundai transforms Clark Kent into Superman for their towing champ?

3,086 really looks more like a GVWR for a vehicle in this class. I tried checking on other sites and only found one other. It lists the tow rating at 1,212, which is more in line with what I might normally expect. Thanks!

backy · July 2004

The secret behind the Elantra's humongous towing capacity is a unique design feature that helps distribute the load across the drive wheels. This feature has been described by some as "wheel shimmy" and is considered to be a defect by some, rather than a feature.

I'm sorry, that was not helpful but I couldn't resist. 8-)

vadp · July 2004

http://www.bobistheoilguy.com/airfilter/airtest1.htm

5port · July 2004

" If you are buying a high performance filter for airflow, K&N is tops in this test."

----------------------------------------------

Thank you. Thats all I had to know.

lngtonge18 · July 2004

So the findings about poor filtration doesn't matter to you at all? Just curious. This test is another one that proves what I've read elsewhere regarding the filtration properties of K&N. I'd rather less junk get in my engine with a smaller chance of internal damage then earn a 0.01 percent increase in hp or fuel economy.

altsuv · July 2004

I tried checking on other sites and only found one other. It lists the tow rating at 1,212, which is more in line with what I might normally expect.

Can you post a link to that site? I'm very curious about this...

thanks

5port · July 2004

Yeah, the filtration part of the test DOES matter and it was very enlightening. It showed that even with the Mazda paper filter installed for 500 miles...the secondary test filter still turned black. Which shows that no matter what filter media you use the micro particles will get thru.

Its all a matter of what lets you sleep at night. If using paper filters makes you sleep better so be it...use paper.

inharmsway · July 2004

Hi.
The owners manual states the trailer towing for the Elantra as 1874 lbs.
Niels

inharmsway · July 2004

Sorry about the double post.
Backy, does that mean the Elantra can tow 2 X 1874 = 3748 lbs. That should take care of any shimmy.
Niels

jimbeaumi · July 2004

I would prefer better filtration over negligible increases in airflow, so the K&N is off my list. Thanks all, for the help.

pat · July 2004

About the double post, don't worry about it - it happens to all of us sooner or later due to an oddity in the software here. If you hit Refresh (or Reload or whatever your browser calls it) after making a post, the message will repost.

It's best to use the "Recent Msgs" link on the page bar to redisplay a page after posting.

I deleted the duplicate.

ironmanterp · July 2004

nctd.com is the web site = New Car Test Drive. http://nctd.com/review-final.cfm?Vehicle=2004_Hyundai_Elantra&amp- ;ReviewID=1461 is the Summary Page for the Elantra and where I found the tow rating listed.

ironmanterp · July 2004

Thanks for the information! One more question if you don't mind - does the manual distinguish between braked and unbraked trailer tow rates? Thanks again.

fushigi · July 2004

Not a bad comparison at first glance, but it falls apart quickly. It was neither very scientific nor very accurate.

A color comparison is not valid. Not all airborne particles will have the same reflectivity and thus will not impart the same degree of 'darkness' or color. A more valid test would have been to weigh each secondary filter as closely as possible. Say to the thousandth of a gram. Weigh before and after and compare to determine which filter let the most particulate mass through.

Even more startling, though, is the lack of a controlled environment. Each filter was tested under different conditions - mainly driving them at different times. Simple things like construction equipment driving through the area, recent rainfall (or heavy wind or other weather activity), the traffic immediately ahead of the vehicle, etc. can dramatically alter the localized air conditions. Specifically the particles in the air. Think of how mold and pollen counts change on a daily basis depending on the weather. He even mentions being close to what is in essence a rain forest. This was not a controlled environment test.

While I will agree with the basic conclusion that more airflow will by and large come with less filtration, this test is nowhere near scientifically valid. I would not draw any conclusions regarding filtration capabilities from that article.

starriver · July 2004

I agree that they are related but you may get both if you do properly.

For simple model, let's take a screen as the model of the filter
     | | | |
   --|-|-|-|--
   --|-|-|-|--
   --|-|-|-|--
     | | | |
The filtering size will be determined by the size of the rectangular window of the screen. The filtration rate will be determined by (Area - Blocked area)/Area. Blocked area is the area taken by horizontal and vertical lines. I guess what I want to say is that when you use thiner wires you can achieve both good filtration and flow.

Hyundai Elantra 2001-2006

Comments

Helpful Tools

Most popular vehicles