DIY FREE INSTANT Air Intake Performance Improvement

[DocJohn]

I've found a FAST, EASY (and totally reverseable) way to re-route the vacuum hoses so that you bypass the Vacuum Switch Valve (VSV) and then IAC valve #3 (the "flapper valve") is ALWAYS FULLY OPEN at ALL engine speeds. RESULT: less air flow restriction, decreased throttle lag and some improved low-end performance.

Here's how to DIY, see: http://www.angelfire.com/ky3/gabby/intake_mod.htm

[michaels artic frost]

Nice work DocJohn. Keep us posted on your long term results.

[Willy7o2]

Wow, cool stuff.... I'm gonna give it a shot today...

[Arthur2k4]

well i just did this right now and took it out for a quick spin.... and i dunno if i felt much difference if any...what does this all really mean anyways...lol

[DocJohn]

How do you know it will not make your CEL Light come on??? And what are the gains 1/2 HP??????

Because I can read a manual and understand how my engine's ECU operates, and because my CEL is STILL not on after over a week of driving and neither is Swiftoy's months after his similiar mod.

Don't know what the hp gain is, but I do know my throttle lag problem is virtually gone now. For what this mod cost ($0) its is well worth it. As I said, untill someone makes a CAI or SRI for our cars, this is the next best thing.

This pic illustrates my point (photo credit: SWIFTOY)...



This is a photo of the inside of the air box. The small opening (labeled "1") is the only air intake source when IAC valve #3 is closed. On the stock set-up the only time IAC valve #3 opens and allows air through the large air intake opening (labeled “2) is when the when the engine speed is more than 3,200 rpm and the opening angle of the throttle valve is more than 30 degrees.

With this mod, the large air intake (“2") is open at all times allowing for at least 4 times more air flow without any delays from the ECU to sense engine speed and throttle position, then trigger VSV #3 to finally open IAC valve #3. Now, how can this mod result in anything but a performance improvement to at least some degree?

[jbauer]

Just did mine a few days ago. Took maybe 2 minutes and the lag IS totally gone. Haven't noticed any drop in MPG either.

Nice work DocJohn.

[Willy7o2]

What bothers me is," Why did toyota created it in the first place?" There's gotta be a reason for this setup

[DocJohn]

What bothers me is," Why did toyota created it in the first place?" There's gotta be a reason for this setup

Here's my take on this... This is one of those situations where something works better in theory than in practice. According to the manual, this system reportedly, "reduces intake noise and increases engine power at low to high engine speeds".
Well, as some of us have now seen, it just doesn't really work this way on the street. The system does decrease intake noise, but actually adds to the throttle lag problem (which some have said is mainly due to ECU programming issues) by causing an unnecessary and undesirable delay in available airflow to the engine when required for increased RPM’s.

[mmcdonald]

Thanks DocJohn, that reeeeeally works. I did this last night (took about two minutes) and what a difference! This is much better than driving in manumatic all the time.

Now to remove the white permanent intake filter...

[someazn]

does this work for the 4cyl?

[DocJohn]

does this work for the 4cyl?

I'm still checking on that, I don't know if the 4 cyl has the same air induction system. Maybe a 4 cyl owner can answer this one if they check under their hood and look to see if they have same intake set-up as seen in my photos.

[mmcdonald]

Did the 2.4L have the lag problem?

I am getting about 1mpg better with this bypass, and better power availability. I am not sure if there is an increase in horsepower, but what I do have is right on tap, instead of the lag.

[DocJohn]

Did the 2.4L have the lag problem?

I am getting about 1mpg better with this bypass, and better power availability. I am not sure if there is an increase in horsepower, but what I do have is right on tap, instead of the lag.

I really don't know much about the 4 cyl Gen 2 or if it has a lag problem.

I'm seeing exactly the same performance improvements as you describe here. Its great. Thanks for the update.

[mmcdonald]

Well DocJohn, I did the vacuum trick, and removed the secondary air filter, and the thing works great. Much better mileage, and the power is right on tap.

There is additional engine noise after removing the seondary air filter, but that is a good thing. Once you are at highway speed, it blends in.

Mileage is up on the highway (averaging 34mpg highway this morning.) In town is great as well. I can't seem to get it below 28mpg, even with horsing around.

This is way cool and easy.

BTW, on the secondary air filter removal, it does not require a Dremel tool. Just take a thin flat blade screwdriver, slip it in behind the filter element at one of the corners, and ROTATE the screwdriver. Don't use it as a pry bar because that will crush the lip on the filter housing. I should know! Once you have one corner free, you can pull the rest of the filter out. It just comes away easily.