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Discussion Starter #1 (Edited)
I decided to do a video on changing out the Cabin Air Filter, which is included with my CT youtube videos now. The issue for me is which after-market filter will do the job, or continue to buy the OEM filter..??

I initially checked online to see what was available at the Auto Parts shops locally. The nearest Lexus dealer is about 90 minutes away for me, so that is a bit of a drive for an expensive cabin air filter. I noticed Sewell has it listed about $37. I'm sure my nearest dealer is higher.

I tried to learn a bit about the Lexus OEM filter, and found that it has two layers. One layer is called the foreign object filter layer for mechanical filtration, and the other layer is called an Electret layer. This means that the the layer has electrically charged polymer fibers. These fibers attract charged airborne particles to opposite charges on the media by coulombic attraction. Uncharged particles can also be attracted to charged media via polarization forces. I checked my OEM filter (8k miles) and it doesn't look to dirty really. Checking it with a 60 power loupe one can see the black particle bits attached to the Electret fibers. Not the filter media is not dense at all, sure "seems" like some particles could get through, hard to know though. There is NO data at all on the efficiency of cabin air filters. Would love to see something like a consumer reports comparison.

Napa Auto Parts website listed 3 filters:

Napa Gold - 4483, Napa Proselect - 224483, and a Altrom Imports 3602463.

The Napa gold filter was on sale at a bargain price of $13.17, so I went ahead and grabbed it. No carbon filter was listed for the CT on Napa's website.

Autozone list two filters CAF1816P and CAF1816C, I think they are normal and Carbon filters at $14 and $25

Oreilly lists 4 filters, 2 Microgaurd 3685 & 3686 (carbon?)$14ea, Wix 24483 $15, Fram Fresh Breeze CF10285 $21

I ended up finding that Napa has a Carbon filter in stock by cross referencing via the Wix Filter website.

Napa Gold Carbon is # 4511 (Wix 24511 filter)

In the end I went to Napa and also got the Carbon 4511. And had the Napa Gold 4483. Wanted to get the Fram Fresh Breeze (has carbon) but Oreilly didn't have it in stock locally.

When checking out the two filters from Napa, one could see that they are MUCH denser but also have about double the pleats and surface area. I was wondering if these filters would cause the airflow to be much less since they were so dense. Decided to weigh them.

LEXUS OEM - 30 gm
Napa 4483 - 72 gm (this is the Wix 24483)
Napa 4511 - 144 gm (this is the Wix 24511 carbon)

You can see the carbon filter is HEAVY! It did seem pretty good quality, but I was thinking it actually might be too dense and restrict airflow enough for concern...

So the next step was to try and see if I could tell that airflow is reduced by these after market filters.

I don't have any type of airflow meter, so I decided to make a home-made one. I used some heavy tape (metal) made for ventilation ducting taped to the dash and basically measured the deflection on a piece of cardboard for 3,4,5,6 fan speeds.

Already long story shorter, they both reduced airflow. I would love to know exactly how much by using some sort of electronic readout anemometer. The 4483 airflow was reduced a little I guess, but hard to know the % reduction. The Carbon Air filter -4511 reduced the airflow significantly. Enough to let me think it could actually be a problem longer term.. But I really have no idea. At higher fan speeds the airflow was still ok.

The Cabin Air filter does seem to filter the air in every mode. In the Pollen and Dust mode it just changes from what ever configuration it might be on and puts it in Recirculation with 100% airflow directed at the Face/Upper body area. This lasts for 3 minutes normally, 1 min if outside air temp is low. I guess to prevent the windows from fogging up.


So...

Which Cabin air filters did you all use if you changed it out yourself?
Does anyone think the reduced airflow of the Carbon Filter could cause a problem with the fan motor longer term?
Is the Carbon Filter even worth it? (maybe the electret layer in the OEM works just as well?)

Any ideas or info is appreciated. Might seem like overkill to think about this to much, but honestly I want a good filter for Cabin Air and it is always nice to find one at a good price if it works well.





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HAAA... this is really a nice research you have done on cabin air filter. Thanks for sharing with us.

I was equally anal about cabin filters for all of my BMW's, which by the way, the BMW's are forever cursed with mildew smell the minute the A/C cycles off. Carbon impregnated filter media will definitely help to keep fowl odor down. You mentioned about volumetric flow measurements; this I think will be the controlling criteria in your selection of filter media. Why? I believe that if you slow down the air flow it will affect adequate heating, especially in sub freezing temperatures. I haven't gone through my first winter yet, so I really don't have first hand experience on CT's ability to heat the cabin. The electric heated seats are one of the best in the industry, it really heats well, fast and evenly. My bad experience involved the first generation Ford Escape hybrid, which was in reality a Mazda Tribute. In winter time the interior never ever heated up, and fan speed would slow down to a crawl in electric mode. In the CT, I don't believe this will ever happen to us, because CT got an efficient heat exchanger that captures any heat generated by the ICE. But the heat generated during ON times will be premium at best, and this latent heat must be effectively transferred to the cabin interior via steady air flow.

If the air steam is restricted, either by thicker filter media or built up crap, there won't be any long term damage to the blower but the blower motor current consumption will increase exponentially; thus CT being a super efficient hybrid, every amp consumed counts.

So I would stay with the filter media that will maintain the highest volumetric flow, which will eventually decrease as you use it. May be that was the logic used by designers in selecting the OEM filter with highest volumetric flow?

PS: You can buy industrial gauges to measure pressure drop across the filter media by using pitot tubes. You record first flow measurement when the media is new, and record again after so many months of use, and you will actually see a head loss, as dust and other crap builds up. Ask any friend who is a HVAC engineer and he/she will explain to you how to do it.
 

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Discussion Starter #3
You mentioned about volumetric flow measurements; this I think will be the controlling criteria in your selection of filter media. Why? I believe that if you slow down the air flow it will affect adequate heating, especially in sub freezing temperatures.

If the air steam is restricted, either by thicker filter media or built up crap, there won't be any long term damage to the blower but the blower motor current consumption will increase exponentially; thus CT being a super efficient hybrid, every amp consumed counts.

So I would stay with the filter media that will maintain the highest volumetric flow, which will eventually decrease as you use it. May be that was the logic used by designers in selecting the OEM filter with highest volumetric flow?
The CT's filter is not dense at all and definitely allowed more airflow than the other two Wix/Napa filters I checked. The Wix Carbon filter was dramatically less airflow. For now I just have left the Lexus filter in place but do want to check out some other filters when I get a chance. Would like to get ahold of the Fram Fresh Breeze filter with Cabon and see what it looks like and how the airflow is. Hope other people will chime in and let us know which filter they've decided to go with.
 

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Thanks for the information and video. I was at the dealer for maintenance. He said I needed a new cabin air filter, $90 installed. I said I'll do that myself. I went to Oreilly today and got the Microgaurd 3686 (carbon) for about $14. Saved me some dough.
 

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Don't waste your money with the OEM cabin air filter (By Denso) which is extremely filmsy. Any aftermarket cabin air filter such as Fram will beat it and come with charcoal film as well.
 

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I just spent hours trying to find what would fit best from Amazon.
I measured my Lexus Dealer installed cabin air filter at 8.5" x 7.7" x 1.1"
But found most of the aftermarket were a bit short in the width or length, which would allow air to bypass the filter.
For example someone recommended the brand ATP, but it measures at " 8.375 x Cabin filter width A(in inches) - 7.5 x Cabin filter depth A (in inches ) -1.125". The 8.375" measurement would make it very loose, but probably not produce air gap, still the looseness would not be good, but the bigger problem is the 7.5" measurement which would eliminate any overlap, but if you line it up just right, the filter might fall down into the gap and form a seal, so it might work by a fluke! Don't buy it!
I found two filters that should fit well. They are still short of my measurements, but should be fine.
They have fewer pleats than the OEM, so I suspect media is thicker, so finer dust may get trapped better, but flow will probably be slightly restricted. But reviews seemed to indicate no complaints about air flow for these two models. Beware some restrict air flow, especially if you get a HEPA filter. HEPA would be nice, but I value the air flow more.
I ordered the Fun-Driving FDCAFT002 which they claim measures 8.4"x1.1"x7.7"
It got good reviews.
The other filter that I thought was good was the Spearhead Premium Breathe Easy 8.46 x 7.64 x 1.14 inches which should also be fine. I went with the fun driving because I think the 7.7 measurement is more critical and will provide more overlap for a better seal.
Examples of ones that don't measure up:
Fram CF10285 at 7.48 x 1.18 x 8.27 inches which I think will fall in and or not seal.
Puroma 7.60 x 8.43 x 1.18 inches which might barely fit.
Kootek 7.50 x 8.50 x 1.20 inches
Getting measurements was sometimes impossible. Often they publish the measurements of the package, but not the filter.
 

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you guys must have way too much time on your hands, all this for your cabin filter. Yes, all dealers and most independents are ridiculous about replacing them. I guess that is how they make their money. Easiest replacement ever.

My philosophy (same as air filters in my home) go cheap and often.
I use

FRAM CF10285 Fresh Breeze Cabin Air Filter with Arm & Hammer

$13.97 at Amazon

change semi-annual, same time I change my air filter.

Upgr8 U8701-3903 Hd PRO OEM Replacement High Performance Dry Drop-in Panel Air Filter Red (Fit 1.8L Engine Only)
$14.95 at Amazon
 

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Yeah, unemployed so have enough time to save money!
The Fun-Driving FDCAFT002 was almost identical in size. In fact it gave a little more overlap. I noticed no decrease or increase in airflow compared to my dirty filter.
I expect with fewer pleats it might benefit from more frequent changes, but at this price, I can afford changing more frequently.
Replacement is easy.
Open glove compartment.
Take out gloves LOL!
Remove shelf by pushing bottom left to the right then up. Once left side of shelf is released, pull shelf with maybe 15 lbs of force to the left. pull out shelf.
Remove black panel door by pulling button on left towards back of car while using fingernail to pull door away from left wall of glove compartment. Once released pull diagonally left and back to release right side.
Then remove white panel door by pushing button on right to the left and then pull out and back to the right.
Remove filter by pulling to the right and outward.
Be sure to replace filter with arrow in correct direction. Air Flow is downward. Some filters want arrow up, but if arrow goes with flow, point arrow down.
Push filter fully to left side.
Be sure to align all notches correctly when replacing doors and shelf.
White door button must be on right and there are ridges that hold the filter up.
60259
60258
 

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you guys must have way too much time on your hands, all this for your cabin filter. Yes, all dealers and most independents are ridiculous about replacing them. I guess that is how they make their money. Easiest replacement ever.

My philosophy (same as air filters in my home) go cheap and often.
I use
FRAM CF10285 Fresh Breeze Cabin Air Filter with Arm & Hammer
$13.97 at Amazon

change semi-annual, same time I change my air filter.

Upgr8 U8701-3903 Hd PRO OEM Replacement High Performance Dry Drop-in Panel Air Filter Red (Fit 1.8L Engine Only)
$14.95 at Amazon
cheap and often is a great plan!
I am concerned you won't get a seal around the Fram filter because it is too small.
Check it out if you ever get the time.
In photo of my installed filter, notice how filter's right side sits on plastic edge that it might not get a good overlap if filter element dimensions are too small, as I suspect is the case with Fram.
However if you align perfectly it might not be a problem.
That reusable dry filter looks interesting!
EDIT here is housing without element in place.
notice the ridge on left and right.
The Fram does not make the span.
it won't fall in because of support in middle and support from the white door.
But it could cause air to flow around the filter element.
Although air may get around regardless.
60261
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Cheap and often is the way to go. Activated charcoal is a plus.

you guys must have way too much time on your hands, all this for your cabin filter. Yes, all dealers and most independents are ridiculous about replacing them. I guess that is how they make their money. Easiest replacement ever.

My philosophy (same as air filters in my home) go cheap and often.
I use
FRAM CF10285 Fresh Breeze Cabin Air Filter with Arm & Hammer
$13.97 at Amazon

change semi-annual, same time I change my air filter.

Upgr8 U8701-3903 Hd PRO OEM Replacement High Performance Dry Drop-in Panel Air Filter Red (Fit 1.8L Engine Only)
$14.95 at Amazon
 
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