DIY FREE INSTANT Air Intake Performance Improvement

[DocJohn]

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.

Glad to know this worked for you.
Now that you found a non-destructive, reversible way to remove the secondary filter I will give it a try. You might want to post a photo or two of how you did it as some folks may not know about the secondary filter location.

[ndoyank]

yes please post some pictures. As im interestd in doing this mod.

Thank!!!!

[mmcdonald]

Well, I got rid of my web site so I don't have a place to post the pics. Also, by removing the secondary air filter, it kind of destroys it, so I am not sure if it is reversible. I am sure that I could buy a new secondary air filter and put it back in without the need of the rivets. But here are the steps:

(Remember, as stated previously, the top of the air box contains the air flow sensor, so don't drop the top while you are working on it.)

1. If you can, photograph the air box before you start as a reference.
2. There are 3 vacuum lines on the passenger side of the air box, and 1 on the front. Make a note of their locations and remove them.
3. Unclip the sensor leads from the top of the air intake tube.
4. Loosen the clamp on the intake hose on the back of the air box. (You have the choice of loosening one of two clamps. You may choose to loosen the clamp farthest away from the air box since removing the one closest results in having to do some extra finaggling to get the box top back over the filter and into place while fighting the intake hose placement back on the air box. If you remove the hose with the air box, you won't have this problem. You'll see.)
5. Loosen the two 10mm nuts on the driver's side of the air box, one in front, one in back.
6. Lift up on the driver's side of the air box and slip the box top off its half hinges that are on the passenger side of the box top.
7. Now you can replace the air filter, and you have the top of the air box in your hands and free of the car.
8. The secondary air filter is a cotton like material sandwiched between two pieces of plastic screen, and surrounded by a black plastic bezel, that is semi-permanently attached to the top of the air box with 6 plastic rivets. These rivets break easily, but so does the plastic bezel on the secondary air filter.
9. Using a small, flat blade screw driver, slip the blade in between the secondary air filter and the housing near one of the corners, and gently twist the screw driver until the corner rivet breaks. You can repeat this procedure on all six rivets, or you can pry up the loose corner and RIP IT RIGHT OFF! This last option will break the plastic bezel on the air filter.
10. Make sure to clean out any stray plastic bits. Don't mess with the air sensor in the housing.
11. Reinstall the top of the air box by reversing the removal instructions. Oh, and if you are going to all this trouble, replace the stock air filter since it is a piece of crap.

Sorry about no pics. This really is quick and easy.

Gas mileage is still up. No idiot lights have come on.

[cs1044]

Is it possible that this mod could damage the engine? because it would be taking in more air than it is designed to take in.

[DocJohn]

Is it possible that this mod could damage the engine? because it would be taking in more air than it is designed to take in.

I am absolutely certain that this mod will not damage the engine because it would be taking in more air than it is designed to take in. An engine will only take in as much air as it needs. If this premise were true then every AM cold air intake or short ram intake would be damaging engines.
You only risk potential engine damage of this sort if you are over-boosting intake manifold pressure with a turbo or supercharger.

[mmcdonald]

Ditto to DocJohn. Unless ou are FORCING air into the engine, unrestricting its breathing won't damage the motor. In fact, most internal combustion gas engines work most efficiently at full throttle (of course its not recommended to run them at full throttle all the time) so allowing the engine that intake range when needed is a good thing.

No ill effects since the mod. In fact, mileage is up to around 32mpg for the trip in to work (mostly highway, but the last 20 mins are city.)

[cs1044]

Oops, sorry about the last comment.

I have a 4-cylinder Gen2 and tried this mod. I took some pics after I modded. Is this what I'm supposed to mod? The air intake set up for the 4cyl and 6cyl look a lot different.

[DocJohn]

Oops, sorry about the last comment.

I have a 4-cylinder Gen2 and tried this mod. I took some pics after I modded. Is this what I'm supposed to mod? The air intake set up for the 4cyl and 6cyl look a lot different.

Thanks for these excellent photos. I don't see anything here that looks like the IAC system used in the V6. The device you have circled in red is the MAF sensor and you don't want do anything to it.
If I had an I4 engine I would just buy an aftermarket intake system. I think 1 or 2 companies are making them for your car.

[cs1044]

Thanks for the correction! I guess I need to re-route the tubes to the orginal spot... So I'm guessing your mod is probably only applicable for V6 Gen2?

[DocJohn]

Thanks for the correction! I guess I need to re-route the tubes to the orginal spot... So I'm guessing your mod is probably only applicable for V6 Gen2?

Yes to all above.

[DocJohn]

1. If you can, photograph the air box before you start as a reference.
2. There are 3 vacuum lines on the passenger side of the air box, and 1 on the front. Make a note of their locations and remove them.
3. Unclip the sensor leads from the top of the air intake tube.
4. Loosen the clamp on the intake hose on the back of the air box. (You have the choice of loosening one of two clamps. You may choose to loosen the clamp farthest away from the air box since removing the one closest results in having to do some extra finaggling to get the box top back over the filter and into place while fighting the intake hose placement back on the air box. If you remove the hose with the air box, you won't have this problem. You'll see.)
5. Loosen the two 10mm nuts on the driver's side of the air box, one in front, one in back.
6. Lift up on the driver's side of the air box and slip the box top off its half hinges that are on the passenger side of the box top.
7. Now you can replace the air filter, and you have the top of the air box in your hands and free of the car.
8. The secondary air filter is a cotton like material sandwiched between two pieces of plastic screen, and surrounded by a black plastic bezel, that is semi-permanently attached to the top of the air box with 6 plastic rivets. These rivets break easily, but so does the plastic bezel on the secondary air filter.
9. Using a small, flat blade screw driver, slip the blade in between the secondary air filter and the housing near one of the corners, and gently twist the screw driver until the corner rivet breaks. You can repeat this procedure on all six rivets, or you can pry up the loose corner and RIP IT RIGHT OFF! This last option will break the plastic bezel on the air filter.
10. Make sure to clean out any stray plastic bits. Don't mess with the air sensor in the housing.
11. Reinstall the top of the air box by reversing the removal instructions. Oh, and if you are going to all this trouble, replace the stock air filter since it is a piece of crap.

Yesterday I removed the "secondary air filter" as per mmcdonald’s excellent instructions. Instead of a screwdriver, I used a single-edged razor blade to cut the heads off the 6 plastic rivets that hold the filter in place. (Therefore this is NOT an irreversible procedure; if you want to replace this filter you would have figure some way to fasten it in place [epoxy?]).

Based on what little I can find in the service manual, plus some of my own conjecture, this "secondary filter" as we have been calling it isn't a filter at all. I couldn’t understand why Toyota would use another “secondary filter” after the “primary” air filter that is courser (less effective), non-replaceable and can’t be cleaned. That’s because this is not an air filter at all, but rather some sort of “acoustic dampener” to help reduce intake noise. What I do know for certain is that whatever its function was, its not restricting/disrupting air flow to my engine anymore.

[cs1044]

Thanks for these excellent photos. I don't see anything here that looks like the IAC system used in the V6. The device you have circled in red is the MAF sensor and you don't want do anything to it.
If I had an I4 engine I would just buy an aftermarket intake system. I think 1 or 2 companies are making them for your car.

DocJohn, I have circled what I think is VSV in yellow and what I think is MAF sensor in green. Is this right?



The following link is the installation instruction of K&N Typhoon cold-air intake system for the Scion tC (which has almost identical set up as 2004 Solara I4), and it shows VSV and MAF sensor.

http://www.kandn.com/instructions/69-8607.pdf

[DocJohn]

Thanks for these excellent photos. I don't see anything here that looks like the IAC system used in the V6. The device you have circled in red is the MAF sensor and you don't want do anything to it.
If I had an I4 engine I would just buy an aftermarket intake system. I think 1 or 2 companies are making them for your car.

DocJohn, I have circled what I think is VSV in yellow and what I think is MAF sensor in green. Is this right?

The following link is the installation instruction of K&N Typhoon cold-air intake system for the Scion tC (which has almost identical set up as 2004 Solara I4), and it shows VSV and MAF sensor.

http://www.kandn.com/instructions/69-8607.pdf

I agree these parts are the MAF and a VSV.
What I don't know is what this VSV (vacuum switch valve) does in the I4 engine. I can tell you this VSV does not have the same function as VSV #3 in the V6 does. I base on this parts location along the intake system of the I4 engine, and the fact that this VSV is retained with the installation of the K&N intake system.
I will try to find the vacuum diagrams for the I4 engine and then give you a more definitive answer as the function of this VSV.

[ironi]

is this applicable to the Gen 1 V6? i could always use more power and better gas mileage