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Discussion Starter #1
For those RAV4World old timers, you all know that I put in a custom ram air intake onto my RAV. This intake consisted of feeding cool air from below the bumper using an air duct attached to the plastic splash guard.

The air filter was fully enshrouded by a carbon fiber cannister. The air was fed to it via a tube from the front air duct.






For more information regarding my custom intake system, check this out: http://www.cardomain.com/ride/683136/2

This worked very well, especially at speed; when cool air rushed into the system. However, recently I had the chance to remove the intake system; and this is what I discovered:




The K&N X-stream air filter pod was clogged with dust and debris. This probably was the reason that I had experienced a loss in performance within that past few months. I first believed that it was a change in my driving style in order to conserve fuel consumption (especially recently!). But after viewing the clogged up air filter, I realized that the loss in performance was due to the fact that air had a difficult time entering the filter.

Although the K&N was clogged with dust, a closer inspection inside the pod revealed that it was clean. I have to give credit to K&N, it kept all that dust from entering the intake manifold. :D



After contemplating what to do about this situation for awhile, I decided to dismantle the ram air intake. Now I have a cool air intake still using the same K&N X-stream filter pod. It is still being fed cool air from below the bumper via a carbon fiber air duct. The CF air duct was sourced from a NASCAR race car and custom fitted to mount in place of the plastic splash shield. As you can see from one of the pictures, the air duct exit (hole) is pointed straight up towards the front of the air filter pod.








Some impressions from the new system. Low end power is much better. This I believe is due to the fact that the filter is able to "breathe" better than being trapped in an enclosed cannister. The old system worked much better when the vehicle attained a sufficient speed in which cool air could rush into the intake.

I could probably get better results if the intake were now shielded from the heat created by the exhaust manifold.

Also, the new system should have better long-term performance due to the fact that it will not get easily clogged with built up dust/debris. For those of you planning to do a similar ram air type system, this is one area of concern that you might want to consider. :D
 

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Derek, i know exactly what you mean about the enclosed filter in a ram air intake setup getting so dirty. My enclosed filter also gets black from the outside but the inside is absolutely clean. I clean the filter every 6 months as around this time i normally notice a slightly less responsive engine. I used to have an open pod filter in the engine bay and apart from sounding cool it sucked in a lot of hot air = crappy performance as i didnt have a source of cool fresh air from the outside. You new setup may suffer a bit during stop/start traffic (if u get that in Hawaii!) as the thermatic fans will create a lot of hot air but it does look very nice :D
 

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Hi Derek very interesting info. What really amazes me is the amount of dirt that the filter collected on the outside. I think the idea of a heat shield is good I await to see how you do that one.
Clare.
 

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i once talked to one of the yamaha design engineers who worked on the design & developement of the head for the old 4k engine (had one in my old corolla). his comment was that toyota engines are all sensitive to the amount of clean air getting into the engine. he even suggested i replace the air filter as soon as it has any sign of dirt!!

anyways, i have a cone filter with heat shield and i clean & re-oil every 6 months or so.... it's really black & dirty after 6 months.... & i can really feel the difference after it's been cleaned!!

derek, your intake would work great if the pod was bigger & let air enter through the sides of your filter (the sides are quite clean and only the end is dirty!) or you change it for a cone type one. the way you had it before was really neat! i wish i could find such nice carbon fiber parts here!!

the power your engine developes is dependent on how much air it can flow, not how much gas/petrol you put in! keep those filters clean..
 
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Nice going dude.

I wish I have the money like you to get carbon fibre stuff. Most of the stuff I use on my RAV4 are broken bits from other cars which I modify and DIY myself. Hence the cheap price tag.

The dust you see are perfectly normal. Just need to clean it every 20,000km that's it. I do know that K&N filters are good, but not sure how long they could last with their recharger kit.

The Other thing is, the reason why your filter is so dirty in your opinion is the location of your intake. That place is where the dust rush in. As with your filter, it should be fine up to anything 2.5L engines if I'm not mistaken.

Good luck and drive hard. But mind you the gas price now AWWEE :(
 

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Discussion Starter #6
peterpogi2005 said:
derek, your intake would work great if the pod was bigger & let air enter through the sides of your filter (the sides are quite clean and only the end is dirty!) or you change it for a cone type one. the way you had it before was really neat! i wish i could find such nice carbon fiber parts here!!
That is exactly what I have been thinking Peter. :D The enclosure was too snug a fit for the air filter and limited its "breathability".

I can't afford another pod filter at this time, so the current setup will have to do for now. I do notice much more off the line power than with my old setup. I will have to fiddle around with this a little more when time and $$$ permits. Probably a heat shield as Clare mentioned is the route to go for me. :D
 

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Derek, that was one of the things that I was always contemplating. All the dirt and debris that runs in the area. But, that is why we use K&N filters. This alone shows how good these filter are. Anyway, man, you want your RAV4 to really go. Install a header dude. Then you will realize why Toyota installed such a crappy exhaust pipe. :wink: BTW, thanks for the pictures. Now I have a better idea how I'm going to do this.
 

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yap, i have a filter & pod like the red one in mohit'spost & i have it directly behind the headlight with a foam to help stop warm air from the engine being sucked in. i plan to make a shroud out of fiberglass (well, one day!) to get better isolation from the engine & try somehow to make the intake pipe straighter.. also some way to monitor the intake air temp.. yap, one day!!
 

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As I said last year to Mohit...."Having the intake down so low to the ground will suck in more dirt and debris kicked-up by other cars."

The best would be to go from the top (hood) but I realise that it is big bucks to do that.

One solution, that I am still scouting for the right parts for, is to route it into the space bellow the headlight on the driver-side (the side without the pulley's). This will give me the cold air I'm looking for but not reallly the most direct route. I'm not going for that Ram Air effect. If I was I would invest in hood vents and pipe it directly.

May be a new exhaust in my near future. I am starting to hear a rumble at certain RPM coming from the back so I think I'll have to start pricing soon.

Later. M.
 

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Discussion Starter #13
mensajero said:
Derek, the yellow hose you have coming from the throttle body. Is that a hose, PVC or what? Also, what is the diameter on both sides? 90 degree or 45 degree?
If I am not mistaken, it is a 90 degree hose made from silicone. It has 3" on one side and 2 1/2" on the other. From what I remember, it was very difficult to source this particular size; especially since it is a reducer hose that also has a bend in it. I had to do the research online to find this exact hose fitting and then could not find a seller online who sells it. I had to go to the local speed shop to special order it directly from the manufacturer. :(
 
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