Tech_Greek

Alright,

So here's the 4-11-3921-39249101. I own a Thunderbird LX and there's a piece on it called an Air Silencer on the intake which basically makes the LX a CAI in its true form stock.

I looked under the front of my car and I noticed that the intake goes from the box through the open air and back into the engine bay.

Now pinky pondered for a few minutes and I came up with two theories;

1) The air passing upon the plastic tube causes the pipe to cool down and causes the air inside to theoretically cool down. I don’t see how this would work with plastic, maybe aluminum or some other form of metal would work but I would also drill little holes all throughout the middle of it to still allow cold air to charge the air coming from the engine bay.

2) They did this because it rains like Godzilla over there in Japan land and major floodage would hydro lock the engine (which I've never heard of it, but anything’s possible).

Now, the intake under the shroud is essential three pieces.

- - \ The first - being what you see next to the battery.

I took the first piece off and left the other two on, the results, an indistinguishable sound and a good increase in power far beyond what I expected.

Alright, now this sounds crazy but normally at 96 MPH in fourth gear my rev buzzer goes off and I shift now I'm shifting at 115 MPH to fifth. Call me crazy but this is VERY TURE, I don't know how but something happened and it worked.

I'll test out the rain but I doubt it will matter considering that my Thunderbird has the same setup and I never had a problem with rain.

First, I unbolted the shroud (6 x 10MM Bolts)

Then I removed the bolt on the first piece of the intake (10MM too, may have been a 9MM).

Next I had to remove the battery out of its spot just high enough so I could pull the piece out beneath.

Put the battery back and take her for a run. If anyone else wants to try this and give any feedback that would be great. I know the sound of it when you press the gas (if you've got a lot of feedback from the fan it's hard to hear unless you're up high in the MPH range) is great.

Thanks,
Tech

LongDuck

Well, what you're describing has been hashed over here many times over the past several weeks. It would seem that a lot of us have been looking to CAI ducting to help get cooler air into the intake to help with combustion, and some others claim that it's a complete waste of time.

I believe that it's a good thing to do, a fun project, and where I live in the desert - a few degrees cooler is a good thing. So keep reading...

You're looking at the intake ducts on an 85 SE-EFI. I know this because my 84SE-EFI has a very similar system, but that front plastic pipe doesn't go all the way over to the other side on my car - never did. Mazda made that change in the 85 cars due to water flooding when the 84 cars got into water deeper than the front lip of the airdam (stock). When this happened, it cause water to fly up and into the intake tube that only protruded about 12" across the front of the radiator (not all the way to the other side). In effect, the flow of air cause water to suck into the tube, go into the airbox, flood the air filter, and if enough water got in, it drained to the bottom of the 'elbow' leading from the AFM to the TB. When this happened, no air could get past, and the car wouldn't start.

I tell you this story because I saw it happen first-hand.

The 84's design was so that you had a CAI intake from the factory. Mazda recognized that drawing air from in front of the radiator and A/C condensor would be cooler than drawing from the exhaust side of the engine block, so they built the airbox intake to draw air from that pipe that you describe. I would think that after more than a few owners drove their 84's through puddles and ended up parking them for a week until it evaporated, that Mazda then took the stock tube, extended it to the other side of the radiator bracket, and made a hole right next to the battery.

Even drawing air from behind the battery (on an 85SE) was cooler than drawing it from the exhaust side, and, you didn't have to worry about water getting into the system.

I have since modified my own CAI/RAM intake from a Mariah headlight lid, and think it works out great. I wish you luck in your project, and give you kudo's for using your technological mind to figure out why Mazda did what it did. You've earned your callsign!

Pics of my intake:

Tech_Greek

Hey!

I'm not the only one with Fireball coils and Tokico Shocks/Struts.

So, I thought about the whole rain issue, if you've got a hole behind the battery then essential you've still got the opportunity to let water come into the engine, it just has a harder time.

Now, I've made a diagram to diagnose my problem even more.

Now, theoretically, you've now got two places to draw air from, the whole (engine bay) and the air from out side. So, now, if the force of the suction coming from the engine is more than the suction of the hole then technically the hole could act as a filtering agent almost to suck rain in (nice engine wash?) because unless you're flooring it through the rain (which is a bad idea in the first place) the suction of the intake isn’t strong enough to suck that water in there.


AND if you drive through a river of water then you shouldn’t be driving in the first place, and since the first thing any driver does when hitting a puddle is to let off the gas and control the steering wheel and feather the brakes then I don’t see too much suction coming from the pipe?

Nice setup, I wanted to do that but I had the big bulky air box, I wanted to give it a (I know this sounds ricey) aluminum look/polished look from the intake manifold back to the actual intake.

I took what spraypainted in red is off; if she starts to act weird in the rain from this I'll put it back on and break the bad news! :P

LongDuck

The rain concerns that you have don't seem to be a real problem in my experience. When I designed my system, I kept that in mind, but since I live in the AZ desert, I don't have to deal with rain very often at all. When it does rain here, though, I needed a method to ensure that I wouldn't be drawing in water with the air which would soak and block my air filter.

If you notice in my setup, the RAM lid has an NACA duct on the top, which gives a direct path of flow through to the stock airbox. This retains the correct and factory air filter, which has been replaced with a K&N. Given this direct airflow path, however, I needed to be sure that the channel which I created wouldn't carry water, so 2 things were built into the design;

1) The stock duct was cut to re-direct the airflow from my RAM intake, and the bottom was cut at an angle to expel any water that would be at the bottom,
2) I understood that if the rain was heavy, I would need to open the headlight lid, thus shutting off the RAM inlet, and the engine would then be drawing air from behind the lid.

With the headlights up, you still get a CAI effect, but the RAM has been disabled. This helps to keep RAM water from coming in with that air, and I've never had a problem regardless of how heavy it's raining here. In fact, I don't flip the lids up unless I have to run my wipers at medium speed and I've never had a problem with Airfilter soaking or performance.

With the lids down, you can put your hand in front of the NACA duct at idle and feel the air being drawn up the duct - rev the engine even slightly, and the force of air being drawn in is impressive. I am certain that this is the shortest path to the airbox if you want to still use the stock filter location.

All in all, a fun project, and unique. HTH,