You mean to tell me that I can't get 2,000 HP out of just a 10 inch tube and a fan!
Thanks for setting me straight

 

The main filter does all the necessary filtering duties as far as dirt and other contaminents go, and will need to be cleaned/replaced eventually. The second filter doesn't need to be replaced in that same time, because it shouldn't see the filtration duties that the primary does, but instead just emissions. Apprently, Toyota sees this as a necessary measure on a host of other vehicles in their lineup as well.

I personally don't find the secondary filter to be restrictive enough to make a significant difference in hp (and certainly not actual street performance, if it were to provide even 1-2whp), but then again, most filtering elements do theoretically restrict airflow. I just don't think it would be enough to warrant removal, other than to either lengthen a mod list, or to post a cumulative number of hp gain, in tandem with other mods which do add hp. However, removing the primary filter, and replacing it with a free(er) flowing filter, would thus mean that contaminents will now be reaching the secodary filter, which it is not designed for, at which point I'd just remove it. One way or another, I believe Lexus struck a great balance with their air box, so I wouldn't modify the actual chamber portion itself.

 

If that top filter was removable I'd remove it and dyno test it as well, but it seems to be fairly permanent and it does reduce emissions, so it's going to stay in for me. I don't foresee it ever getting dirty enough to remove even with an aftermarket air filter, because the primary filter catches everything else and if something small enough does pass the primary and reaches the secondary filter, chances are that small piece will also slip through the secondary filter.

"The hydrocarbon trap is designed to be tamper proof so it does not require the use of costly on board diagnostics (OBD) equipment. The trap also has minimal impact on airflow into the engine and can withstand exposure to ice, water, salt, dust, air filter surfactant and engine backfire."

 

The engine's still the one making the power in the case of turbo- and super-chargers. Although these are modifications that will actually help your engine deliver more power to the drive wheels, rather than less.

 

Most every component manufactured for a car is over engineered. If the car only has 277 lb/ft of torque, you better believe that the tranny can handle a lot more than that.

For the sake of argument, let's say that the engine needs 1000 cfm of air max at any particular throttle/rpm situation. Let's also say filter material X provides the proper amount of filtration required and allows 100 cfm to pass through it per square inch.

What to do? It's not quite as easy as this as there are flow dynamics issues that need to be addressed, but all the engineers would have to do is install an 11 or 12+ square inch filter made of material X to get the capacity past anything the engine will ever need even with a dirty filter.

Am I 100% certain that they did this? No. However, if I was the gambling type, I'd take any bets that this was in fact done.

 

I think it would be almost impossible to get a full dose of dense air to the
engine via a snorkel type air way , then through 1 thick filter, then another
filter.. All engines are air restricted to some extent, it's not that the engineers
made a mistake, they just made it that way in order to make sure no particals
get in and so that the car is more quiet., they were'nt trying to squeeze every little
bit of extra HP out of it, all all costs.. (Like we are)

 

If that is true, why run a filter at all?

 

I think without actually putting the car on a dyno and testing with/without the filter this is all just conjecture. I can't imagine removing it would be worth more than a couple of HP at most though (if anything), which is meaningless unless you're building a drag car.

Also, while I'm no hippy, I'm not a big fan of removing a filter designed to reduce emissions. Peace man.

 

^sometimes mods like this don't necessarily have to "make POWAH" in order to be worthwhile... It could be just my imagination but seems like after I did the mod throttle response is a bit better than before.

 

as soon as i get my is250 this filter is coming out as soon as i pull it in the garage. i dont care what kind of emissions protection, or any other crap this simple filter can do.....its coming out. dropping my blitz filter in and joez intake and thats it....done.

 

I know some Acura TL, Caddy CTS-V, and Honda Odyssey owners that would disagree with that generalization.

I also disagree with that generalization. In theory, all parts are intended to be able to handle more stress than what can be expected in everyday service. But then the bean counters get their hands on the design and production cost estimates, and make certain "changes" to keep things in line with their price-point goals. Then they begin to abuse the part suppliers to get costs down, who in turn must find ways to make the parts cheaper so they can stand a chance of making a profit too.
There's also the problem with how parts of the car interact with each other, and with vibration, and unforseen stresses in the real world. Suddenly a bullet-proof part can become the weak point in the entire drivetrain. And it wasn't discovered until the parts started to be mass-produced and assembled during actual production runs.

Never say never.

 

Your point is well taken. However, for this discussion, we're talking about filter material, size, etc., which is miniscule compared to a major component like the tranny/drivetrain. The fact that there is a second filter engineered into the intake would suggest that the bean counters didn't get their hands too far into this aspect of our cars.

 

I agree with that. Assuming that the existence of the secondary filter isn't a "bandaid" fix for something else (which I doubt).

 

No the 2nd filter isn't a band aid. It is a part of the emissions control on the vehicle that enable it to have an ultra low emmissions status. It has some kind of chemical in the mesh that traps evaporative gasses from the engine when it's turned off and when we start the car the gasses are sucked into the engine and burned off. I'm definitely going to keep the filter in the car. Although I'm not a tree hugger, I do not want to do anything that will make me feel guilty for contributing more than I have to towards global warming.

 

Agreed. Even if removing the filter did improve performance, it might be something totally insignificant. Not worth bypassing emissions controls for a change that a person will probably not be able to detect. Also not worth the possible consequences when selling the car down the road, and having to fill in that little box where you promise that you've never tampered with emissions controls.