Modifying the Stock Air Intake System

[norwood1026]

Hi Everyone,

I just completed this mod (one and two) and I have to admit that I do notice a difference i n the way the car preforms, esp getting on the freeway :-)

I personally feel that the last mod makes the most difference.

[Sleezer1533]

For those of you who have removed the MAF screen, have you noticed a drop in MPG. Ive dropped from 24.2 to 21.1 since this mod. Coincidence?

[goldstar]

Actually, in my vehicle the mods have resulted in a small but noticeable drop in fuel consumption which is to be expected from the reduction in pumping losses attributable to the lowering of negative pressure in the induction system.

You report a 3.1 mpg drop after removing the MAF sensor screen. That's a rather incredibly large drop to find from a mod that functions to reduce intake restriction. I certainly can't account for your results and as far as I know no other modifier has reported this outcome.

I'm mystified as to why this occurred considering the physics involved here. My only advice is to replace the MAF sensor screen as soon as possible to restore your previous level of fuel consumption.

Sorry that this didn't work out for you.

Happy Motoring!

[Sleezer1533]

Well im not calling it a MAF problem just yet. My plugs are starting to kick the bucket so Ive got some new ones on the way. Ill see what happens after that, if that doesnt fix it, I guess put the screen back in, if i can find it ... im sure its laying around the garage somewhere :p

[norwood1026]

For those of you who have removed the MAF screen, have you noticed a drop in MPG. Ive dropped from 24.2 to 21.1 since this mod. Coincidence?

To be honest I haven't noticed I end to tip into the throttle a bit more sence I've done this mod so mine might suffer some.

[Drive323]

What are peoples experiences with removing the snorkel all together, up to the air box? The engine would take in warm air but there would be less restriction wouldn't there?

[goldstar]

I wouldn't advise it. Removal of the snorkel would produce less intake restriction but any gain would probably be eliminated, or even overridden, by the ingestion of hot underhood air.

Check out:

http://www.wihandyman.com/forum/showthread.php?t=995

http://www.wihandyman.com/forum/showthread.php?t=47990

Racing Beat was involved in the modifications that resulted in the 2001 MP3 at the request of Mazda R&D. RB was provided with a 2000 model for test and evaluation purposes and directed the development of the suspension components used on the MP3 and later the MSP.

As part of the project, RB attempted to design an improved induction system for the MP3. Here is their comment:
"An intake duct utilizing a K&N cone filter was produced for the car, and it got close to production when Mazda discovered that, due to its narrow range of operation, the engine management system could not tolerate drawing warm air from the engine compartment. It was not possible to design a filter system that drew truly cool air in the time available. This aside, obtaining measurable improvement with this type of intake was proving to be a challenge."
Reference:

http://racingbeat.com/FRprotege.htm

MP3 Parts Development section

Consequently, the production MP3 utilized the same induction system as all other Proteges with the exception of the 2003 MSP. Essentially, what Mazda was saying is that due to its restricted operating range, the MAF sensor and IAT sensor, in conjunction with the PCM, could not provide the correct A/F mixture when ingestion occurred at the elevated temperatures and reduced air density provided by underhood air. Obviously, emissions would also be negatively affected.

Happy Motoring!

[talltim]

Noticeable increase for me by just cuttin out the spot for more cold air. worthwhile mod!

[goldstar]

talltim, welcome to CP. I'm glad to hear the mod worked well for you.

Happy Motoring!

[smokstac]

And here I was thinking that the little place there was a nice convenient bolt/nut holder when doing engine repairs

I'm going to have to try this soon if I can find another plastic piece before I move.

[justin700]

goldstar,
Just a quick question.

Im from Australia, where the air is quite warm (: Will this make much difference?
Would you also recommend creating a scoop with the horizontal grill support or simply removing it like you have done? Like in this air intake mod?

http://www.themazdaforum.com/showthread.php/2607-Cheap-custom-made-ram-air-intake

And what are your thoughts on the modding within the 'snorkel'?

Thanks for any help

[goldstar]

Welcome to the Forum.

justin700, thanks for your interest in this mod. I was not aware of the reference that you posted. Apparently, the creator of that reference was not aware of me, or my work, either.

To begin with, I don't think that the mean ambient air temperatures are much different between Australia and the US. In any case, the warmer the ambient air temperature, the warmer the underhood temperature and the greater the heating of the intake duct components, particularly during idle, stop and go, and low-speed driving conditions. Therefore, anything that provides cooler air at the induction system inlet should be beneficial to power output. For more information on the relationship between intake air temperature and power output, go to:

http://www.wihandyman.com/forum/showthread.php?t=995

http://www.wihandyman.com/forum/showthread.php?t=47990

Air Scoop
I had toyed with the idea of utilizing a scoop at the air inlet similar to the one described in your reference but rejected the idea because I thought water might be ingested into the air inlet during heavy rain storms possibly leading to destruction of the filter or even worse, hydrostatic lock. Since I have the 6 drain holes taped up in my system, to ensure hot underhood air won't be drawn in (and to maintain any ram effect) there would be no place for water to exit before reaching the filter or the engine itself.

I believe one of the features of my mod is that although the air inlet is located in a high pressure area, forward facing and subjected to some ram effect, it is in a relatively protected location. In all the years that I've been running like this, I have never experienced any water in the induction system regardless of the severity, or duration, of the rainstorms I've driven through. Nor have I ever ingested any appreciable amount of road debris (stones, etc.)

Notwithstanding the above, a scoop would probably enhance the ram effect for increased performance and it's also quite possible that I'm wrong in believing it would cause water ingestion to occur. This is purely an empirical question and if you want to try it you're on your own. If you should build a scoop, please let me know the outcome. For more information on the relationship between ram air and power output, go to:

http://www.wihandyman.com/forum/showthread.php?t=2921

Modifying the Fresh-Air Duct ('Snorkel')
Obviously, some kind of duct is required to convey ambient, high pressure, induction air to the air filter box. Simply removing the snorkel would cause a decrement in performance over stock, to say nothing of affecting the emission system adversely, because it would lead to the constant induction of hot underhood air.

One alternate possibility is to remove the snorkel completely and run a hose from the air filter box down into the wheel well similar to the way CAI systems such as Injen or K&N are configured. This leads to two potential problems. The first is the possibility of hydrostatic lock when running through high standing water, although this could possibly be minimized by using the shortest possible length of intake tube projecting into the wheelwell. The second is the possibility that a negative pressure exists in the wheelwell meaning that the air inlet is placed in an area of less than atmospheric pressure. Even if the pressure in the wheelwell proves to be at atmospheric, one would still lose any potential ram effect.

Since I've not looked into modding the snorkel myself, there isn't much I could say about it. I do have a spare snorkel myself and have intended to take it apart and examine it but have not yet done so. I do know that it's internally configured to act as an induction noise silencer but that does not necessarily mean it has impaired flow characteristics. The only way to determine this would be to modify one similarly to that described in your reference and compare the before and after results. Again, since I have not done this, you'd be on your own here, also.

Incidently, the hanging down piece mentioned in your reference, from which the poster cut out pieces to glue into the snorkel, is a Helmholtz resonator and either functions as an intake noise silencer/or as a device to enhance low-speed torque. At this point I'm not sure which function it serves but if it's the former, since it's connected in parallel with the system (not inline) and it can't affect performance adversely, there's no need to remove it; if the latter, removing it would be detrimental. That's why I left mine in the system. If pieces are cut out of the resonator, make sure it's sealed back up again as otherwise it will draw hot air into the induction system and destroy its function as a resonator whatever purpose it serves.

I hope this discussion answers your questions sufficiently but if not, don't hesitate to get back to me.

Happy Motoring!

[1Mazda323Fan]

Just a quick interjection here, fellas. Goldstar brought up a good point; if you're going to fabricate a cold air intake that places the filter element close to the ground in the wheel well area, water ingestion is a very real problem. If you decide to go this route, buy one of these: http://www.google.com/imgres?imgurl=...:0&tx=24&ty=34. It's a bypass valve. Mount it after the filter, and if water gets into the intake, the valve closes off, allowing the water to drain back out while still drawing air in through small vents in the side.

[justin700]

Thanks for the speedy reply goldstar!
Ill be doing the first cut out mod the weekend. Do i physically need to remove the structure to cut the hole? Or can I just cut it while its still bolted in?

Are there any other mods that you would recommend for a 1.6L? Im on a tight budget so the cheaper the better. Just trying to get my baby running nice before i get my license (:

[goldstar]

You're welcome.

It's not necessary to remove the grill assembly in order to cut out the horizontal section under the snorkel air inlet. I was able to easily remove the unwanted material with the grill in the car (see post #1). It would be a good idea to cover the portion of the radiator adjacent to the cutting area with a cloth to keep plastic bits out of the radiator, however.

Considering your limited budget, and on the theory that every little bit helps, a free-flowing exhaust system, iridium/platinum spark plugs, non-OEM spark plug wires such as NGK Blue or Magnecor), and a true synthetic engine and transmission oil should provide you with a small but noticeable boost in performance.

Good luck carrying out your mod and let us know how it turns out.

Happy Motoring!