Modifying the Stock Air Intake System

[akaveli]

After reading this post, I decided to give it a try. After 15 minutes of cutting, sawing and removing plastic, I finally got it. I decided to take it for a test run. From a stop and go test, the car pulls alot better then it did before. I think it went bwt 5-6k rpm. I'm only guessing since I don't have a TACHOMETER!!!! And yes, its an automatic. but she is still my baby. lol The car seems to gain much better accelleration. Once I stopped and checked the air filter to see all the mess it collected. I never seen seen little bugs like these before. LOL. all n all, this modification I would recommend to anyone who is curious about trying it. It would be worth your time.

[akaveli]

question...do I need to up-plug the negative terminal and let it sit over night so it can reset teh ECU?

[goldstar]

question...do I need to up-plug the negative terminal and let it sit over night so it can reset teh ECU?

I'm glad the mod worked well for you. It can't hurt to reset the ECU but I don't know if it's absolutely necessary in this case.

02 DX Millenium Red

[THEGOLDPRO]

you only need ot let it off for like 15 seconds to reset. but do what you want.

[2000MBES]

I haven't tried the air intake mod yet, but only due to time and so many other things to do.
As to the concern I have read about, regarding the increased chance of ingesting water in the intake, I have some old, yet related information.
I recently bought a 1985 Toyota Motorhome. Yes, a motorhome powered by the 22RE 4 cylinder engine. I think I can, I think I can, I CAN!
When going through the engine bay to see what is there, I noticed the air inlet running through the metal plate that holds the radiator (front of the engine bay). The air snorkle is open ended just behind the grill, and infront of the radiator. The snorkle does have a slight elbow so the opening is pointing downward. This is actually a more severe situation than the modification discussed here.
It is standard from the Toyota factory and yes, the engineering behind it is 20 years old but, the Toyota 22RE motors are know to be bullet proof, even with this stock setup.
My point is, in my opinion, that water ingestion should not cause any loss of sleep.

WJH 2000 Midnight Blue ES

[goldstar]

2000MBES,

I completely agree with you. In addition to your Toyota, there are a number of other cars with factory designed forward-facing air intakes located in the grill area as is the case with our Proteges after the grill mod. Apparently, water ingestion is not seen as a potential danger in those cases. Additionally, as mentioned before, our intake systems have a total of 6 drain holes (4 in the snorkel, 1 in the resonator and 1 in the air box).

As I mentioned in post #122, I have even gone so far as to seal up the drain holes in an attempt to increase ram effect. Even driving in the rain I have so far not experienced any water ingestion. However, I have yet to drive in a really severe, long-lasting rain storm so I can't yet say that this mod is absolutely safe under all conditions. When I do get that opportunity, I'll be sure to post the results.

02 DX Millenium Red

[AlexB2]

I did a conservative version of the mod two days ago. I basically "swiss-cheesed" the horisontal surface of the plastic plate, instead of removing it. I think I took away about 40% of that cavity's plastic. The added complexity to the test was that I did this with a fairly dirty air filter ( 19K km ). Observations:

1. Basically feels like a new air filter - engine breethes easier, easier to modulate the throttle to hold the car at pace in 1st or 2nd in traffic crawls.
2. Easier to launch gently ( needs less throttle input )
3. Our wonderful 2nd gear is even better now. The revs rise faster, and I can actually notice the powerband kick at about 4000rpm. The revs fall pretty fast too, when you need that
4. Car is just slightly noisier after 3000 rpm ( bassy pleasant noise tho ).

Overall I'm very pleased with the mod. Kudos to the guy/gal that originally scratched their head and came up with this idea!

NOW I'm gonna clean my K&N...hehe

[goldstar]

Overall I'm very pleased with the mod. Kudos to the guy/gal that originally scratched their head and came up with this idea!

It's good that your mod was successful and gave you a noticeable increase in performance. As far as I can determine, Traveler, in his original thread on the Protege Club Forum, was the first person on all of our Forums to develop and implement the idea of cutting away the grill and reporting on its beneficial effects.

In like manner, Julian Edgar whose work has been cited many times in this thread, was the first person that I know of to demonstrate, using actual measurements, that removing the MAF sensor screen resulted in a reduction in negative pressure in the inlet duct. Additionally, Edgar has also shown, using data obtained by measurement, that ram air can have a positive effect on performance in cars such as our own.

This present thread probably wouldn't exist without the prior work of these two individuals.

02 DX Millenium Red

[goldstar]

Update on Sealing the Air Intake

I have now run~3000 miles with my intake sealed, up to and including the air box, and it's now time for an update as I earlier promised. During this time, I've driven through rain on several occasions without ingesting water and both the air box and filter have remained dry. As I've said before, I believe that although the air inlet is now open to the outside, its location protects it against water ingestion due to rain.

As you'll also recall, I sealed the six drain holes with 11 mil thick duct tape as I didn't want a more permanent seal at that time. After 3000 miles, the duct tape is in perfect shape seemingly unaffected by heat, cold or water and still provides an airtight seal. Although I've obtained some .030" thick ABS to replace the tape with a more permanent seal, I may just leave the tape in place (at least on the snorkel) as it does the job and is easily removable should the need arise. Because the tape is black and because it is located on the underside of the intake duct, it is completely invisible when installed. In other words, it doesn't have the "ghetto" look.

From time to time I open the air box and remove the filter to see if any debris has collected in the bottom. The amount of debris collected is very small and I have never found stones or insects inside. There are no nicks or tears on the inlet side of the filter and no damage of any kind that I could find. The internal piece of tape inside the air box is also in like-new condition and shows no sign of lifting or pulling away from its position over the drain hole. IMO, any debris inside the air box is due to the air inlet being open to the outside and subject to some ram effect rather than because the system is sealed.

I've previously mentioned the improvement in performance noted at higher speeds due to the enhanced ram effect provided by sealing. After living with the mod for awhile, I became aware that there also seemed to be an increase in performance at speeds below which ram effect should occur. I now believe that sealing the intake system has a secondary effect that may be as important as increasing ram. The snorkel sits over the radiator and adjacent to the exhaust manifold. Obviously, the four drain holes in the snorkel are perfectly positioned to ingest hot air into the intake. Since one of our goals is to ingest only ambient temperature air for best power production, any air ingested through the snorkel drain holes will raise the intake air above ambient and defeat the purpose.

I am suggesting that even if you don't want a sealed system, at least seal off the snorkel drains. The drain holes in the resonator and air box will still be effective and even though underhood air can be drawn in, at least it won't be as hot as that in the vicinity of the snorkel. Just tape up the holes and give it a try.

At this point, I'd like to recap all the mods I've done so far to my OEM air intake system as I believe that each one of them, taken together, has made a contribution to improving performance.
1. Removing horizontal grill support to expose air inlet to outside ambient temperature air and potential ram effect
2. Removing MAF sensor screen to reduce negative pressure in the intake duct
3. Smoothing part of the intake duct to improve air flow
4. Sealing the intake duct between air inlet and air box to improve ram effect and to block off underhood temperature air from entering intake system through drain holes

02 DX Millenium Red

[rwindleyme02]

Hey guys, I know this is my first real post and I don't want to step on any toes by giving my professional opinion on this post. I'm a mechanical engineer and have done numerous mods to my car and wanted to share my experience with you guys with reguard to these mods.

First off, the "air ram" mod is a pretty good mod IMO. I'd go the conservative route and only block up half. If you wanted to run a total blocking of the grill, invest in some water wetter to lower your radiator temps if it gets hot in your area.

Next thing is the MAF screen and the fact that people are removing it without knowing what it does or exactly what effect it has on HP. You guys are exactly right, it serves no protective purpose. If a chunk of something that big gets into your engine, you've got bigger problems with your air filter! The MAF screen infact reduces turbulence into the sensor. The sensor takes airflow data, whatever it may be, and adjust A/F ratios accordingly. The "waffle" design is just a cheap way to smooth out the air. What you guys are feeling in terms of revving more freely or butt dyno gains are just that, placebo effect. Dynos have been done on various cars with the stock MAF, w/o the MAF grid, and with specially designed grids engineered to maximize flow while still create more laminar airflow. In all cases that I've seen, (except for one case of a re-designed grid), the stock grid produces more HP than messing with the grid by cutting it or removing it alltogether. Even the example I have seen that did produce a dyno with positive results has also seen negative results in some cars.

Again, I don't want to be the bearer of bad news, but as an enthusiast & engineer, I want people to get the most out of their cars. In summary, do the "air ram / snorkel" mod (and change your airfilter often) but don't remove the MAF grid.

[goldstar]

rwindleyme02,

Thanks for your interesting and informative comments. However, I do take exception to your position that removing the MAF sensor screen has no positive effect on power production.

In post #1 of this thread, I cite an article titled "Eliminating Negative Boost", Part 4, by Julian Edgar. He provided measured data indicating that removing the MAF screen reduced peak pressure drop (in one instance by 19%) in the inlet tract following the MAF sensor.

In post #2, I referred to the book Four-Stroke Performance Tuning, Third Edition, by A. Graham Bell; Chapter 2, The air Inlet System, page 26. Here, in reference to the MAF hot wire sensor Bell states that removing the screen(s) reduces intake flow restriction and may give a 1.5 to 2% power improvement at maximum rpm.

In the same post, you'll note that I agree that the function of MAF sensor screens is to reduce turbulence in the induction air and provide a more laminar flow through the MAF to improve metering.

I based my contention that removing the screen in our cars would be a beneficial mod, based on these results, not simply on my own subjective impressions that doing so resulted in "butt dyno" gains. Without this data demonstrating a reduction in negative air pressure, I would not have recommended this mod.

I'm gratified that someone with your obvious knowledge and expertise in this area agrees that the air ram/snorkel mod is beneficial, as I have found this to make a signifigant difference in improved performance in my own car. However, I'm not quite sure what you mean by advising to only block up half, as opposed to all, of the grill. I don't recall that I ever advised blocking the grill at all unless I'm not understanding your point. Are you perhaps referring to those who have incorporated scoops behind the grill? In this case, I agree that the area occupied by the scoop would block off some radiator cooling air.

Again, thanks for your input.

02 DX Millenium Red

[Iceman112k3]

he was not only refering to your posts gold... farhter into the thread you will begin to see suggestions of people wishing to mold a scoop from the air inlet down through the new cut opening and into the area behind the grill. he was speaking to everyone in general.


I myself have completed the old air ram grill chop mod and your right, it worked great :D

[mazda323]

Hey guys I've just read through this entire thread and it was a bit informative. I don't know much about what you guys were talkin' about but I learned a few things. It's just to remember them now.

Anyway, you guys mentioned the "snorkel".

If I'm right, the snorkel is the part which directs the air to the intake before the air filter?

I removed that part from my car altogether.

[goldstar]

mazda323,

Good that you found this thread useful. Yes, you're correct. What's called the snorkel here is the duct which directs the intake air to the air box and the atmosphere side of the filter. Snorkel is probably not the official name of the part as the '02 FSM at least refers to the part as the Fresh Air Duct.

02 DX Millenium Red

[Mazda96Protege]

Has anyone on here done it to a 2nd gen? i did alittle awhile ago and every time i drive it it gets hot faster but my temp gauge reads normal and it smells kinda like something is burning and smokes alittle? why would it be doing that if all i removed was the wire mesh?? do i have to reset the computer err something? any help would be appreaciated