1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

Open breather or cold air intake

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Old Feb 18, 2004 | 01:02 PM
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Question Open breather or cold air intake

What is better a cold air intake or an open breather???
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Old Feb 18, 2004 | 09:39 PM
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Dont understand your question. Open breather, as in no filter? Thats VERY bad.
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Old Feb 18, 2004 | 11:14 PM
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well a open element like a k&n cone or something like that will allow more cfm to get used but if its just hanging out in the hot engine bay your sucking in a lot (cfm wise) of hot air. the best thing is to have a open element that has a fresh air/cold air feed so your getting more and colder air. i did this with a 300z scoop and some rubber door weather striping on the base of the stock airbox.... .so it sealed to the hood and the scoop was feeding it outside air
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Old Feb 19, 2004 | 11:07 AM
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Ram Air!!!....If you can manage it. I'm working on forming it for my Vehicular unit. Figuring on using the scoop for more than just looks. Some friends suggested a shaker hood and I had to laugh...*shrugs* But Like I said I suggest Ram air. if not... Cold air.
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Old Feb 19, 2004 | 01:20 PM
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There are two different things at work here that you might want try - 1) cold air intake, and 2) ram air intake.

Cold Air Intake (CAI) is designed to isolate the intake system (air filter, box, etc.) from the hot underhood temperatures that normally occur during hard driving or hot outside air conditions (summertime in AZ). The density of air changes with temperature, so the higher the temperature, the less dense the air. The less dense the air is, the less fuel you can mix with it at 14.7/1 (air/fuel mixture) to remain in perfect balance, and the less fuel you can mix, the less power you can make by burning fuel.

In short; the more dense (cold) the intake charge, the more fuel you can mix, and the better it will combust to generate horsepower.

CAI systems use either insulators or shields to keep hot underhood air from where it can contaminate the air intake system. This is usually supplemented by a free flowing air filter to help with air volume.

Ram Air Intake (RAI) systems are designed to use the forward motion of the car to stuff more air volume into the intake. This uses the inertia of the air in front of the car to help 'stack-it-up' and build up a bit more pressure than if you use a static air source (like under the hood). RAI requires something on the front of the car, preferably in clean, non-turbulent air that scoops the air into the intake for carbs, or into the Airflow Meter for EFI cars. While you're not getting anywhere the positive pressure of a turbo or supercharger, the Ram Air effect effectively pushes an overall positive air pressure in front of the air filter, which helps to get air through the filter and on to the rest of the intake system to burn. Ram Air induction has been used on aircraft for a long time, and on cars going back to the 60's muscle cars.

The best installation, IMO, would be a Ram Air inlet that's attached to a Cold Air source, i.e., you're forcing air into the airbox from somewhere outside the car, while also insulating the intake from hotter air under the hood. (See my full-size pics in the signature line to see my Ram Air, CAI setup...)

With either of these systems, you still need an air filter, since any particles that make it into the intake will need to pass through the engine without causing problems. Rotary engines need very clean air to maintain service life and performance. HTH,
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Old Feb 19, 2004 | 02:25 PM
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Where are the pics of your intake setup?
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Old Feb 19, 2004 | 02:47 PM
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Click on the picture and you'll be taken to the fullsize screen which slows the NACA duct that's mounted into my passenger side headlight lid.

This NACA duct is built to strip airflow from a smooth surface without disrupting the airflow over the inlet, much like you would find on an airplane so that the air isn't turbulent behind the scoop. This duct then flows fresh ram air under the headlight lid, past the interface under the hood and runs directly into the EFI airbox that's mounted to the AFM on my SE.

The installation was performed using all stock air tube parts for the in-between duct, and uses the stock rubber adaptor from the inlet air pipe to the airbox - this preserves the stock appearance, and only required cutting of the metal mount and rubber dam that's behind the headlight lid to prevent water from being blown into the engine bay. By cutting this metal mount and the rubber piece, I created a channel for the air to flow into the airbox, on top of my K&N filter, and then down to the AFM and intake piping.

When you squat down and look into the NACA duct (with the lids down, lights off), you can see the K&N filter. This gives the most direct and shortest path of airflow to the AFM and also gives good wet/dry performance. In the rain (rare in AZ), I have my headlights on to help with visibility, so the rainwater is blocked off from entering the intake. Water is able to run down the inside of the front valance where it drains to the ground. When sunny, I just leave the lights off and enjoy the benefits of knowing that my engine is getting cooler air from the front of the car.

I will have some new pics added to my signature line once I get them off the camera - I get a lot of requests from people wanting to see my engine bay with the color matched RB strut brace. HTH,
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Old Feb 19, 2004 | 06:01 PM
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Thumbs up

Thanks alot that really helps a bunch I have always seen that hole in the top of the headlight but never knew quite what it was. could you mabye put some pics of the inside the engine bay?? thanks again!!!!!
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Old Feb 19, 2004 | 10:45 PM
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Uploaded a new picture - this may be big, but should give you an idea of what the Ram Air Intake looks like on my SE:



And, another head-on shot, just for grins;

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Old Feb 20, 2004 | 01:06 PM
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thanks and where did you get the headlight cover intake at??
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Old Feb 20, 2004 | 01:36 PM
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Not Your Babies Daddy
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He probably had it fabricated... *shrugs*
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Old Feb 20, 2004 | 04:13 PM
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www.mariahmotorsports.com

Mariah makes some pretty cool parts, but be prepared to wait for them. I was on-hold for about 8 months waiting for my rear deck to be finished. They said it was due to moving their fabrication shop, but after doing some research, I found out this is pretty standard wait time for them.
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Old Feb 20, 2004 | 04:18 PM
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I like the splitter you added to the xenon airdam. How far back does it extend?
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Old Feb 20, 2004 | 04:30 PM
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Back to the bottom edge of the standard lower valance. My thinking was that this gives a smoother flow of air in the front of the car, and also helps to 'bottle-up' some of the intake air that would otherwise be lost. I have removed the stock lower splash panel to aid in maintenance, and do not see increased engine temps without it.

I had thought about adding a full bottom panel for the rest of the car, to be suspended between the lower edges of the sideskirts, but quickly decided against that due to the increased hassle whenever I'd want to work on anything under there - which is occasional.
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Old Feb 20, 2004 | 05:11 PM
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That's pretty darned spiffy, if I may say so. (The intake system and the car!)

How do you like your suspension set up with RB springs and blues? Decent highway ride and good cornering?
(I ask because I have Tokico springs and they are hard as rocks-I'm considering RB springs for the front)
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Old Feb 20, 2004 | 06:22 PM
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WOW! that is a sweet looking engine bay! I love the matched color strut tower brace, its pretty sweet.

oh, and that intake is awsome too! does the plastic tube pice immedatly behind the headlight come with the cover from mariah?
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Old Feb 20, 2004 | 08:23 PM
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The plastic piping that carries the cold air is actually a stock 84 SE air intake pipe that used to extend across the car from the right front (behind headlight bucket), along the front of the radiator and end about 3/4 of the way across. This was likely to help with a stock 'cold air' intake at the time, but Mazda found in the 84's that this actually caused 'scooping' of any water that entered the front intake to go right into the intake system and flood out the AFM - no kidding.

The previous owner drove through a 4"-5" wash and the car sucked up enough water in the intake to render it useless for several days until they could figure out that water had pooled in the lower air intake pipe.

As for the suspension, I am very happy with this setup (RB springs, Koni stabilizer bars, and Tokico Blues) because it is firm enough to keep the car feeling planted to the ground, and also lowers about 1/2" more from stock - just enough to get the right look with the wheels and not impact daily driving with speed bumps and occasional potholes. While stiff, it does let the car corner very flat and the Tokico's are a cheap upgrade for good performance. If you're going to replace springs, I'd do the whole set - RB sells theirs as a kit so that the rear is matched to the front. F+R stabilizer bars help to flatten cornering, and the rear bar is adjustable; you move a link across the bar to whatever setting you want, and then tighten it down. This doesn't require pre-drilled holes in the bar, so it is infinitely adjustable for most of the effective lever arm. I'll have to get some pics of that this weekend.

Highway ride is very comfortable, especially on the rubberized road surfaces that they use here in Phoenix (AZ), and since it never snows, the roads are always in pretty good shape. I only have to watch out for curbs with the front airdam, since I have the splitter installed to break free from it's pop-rivet mounts if it ever gets bumped, and no matter how hard you try, it will eventually get pushed into a curb.
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Old Feb 20, 2004 | 08:53 PM
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When my AFM was stuck i found ICE in the bottom of my intake pipe and AFM. Truth to LongDucks statement.
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Old Feb 20, 2004 | 08:55 PM
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Hey LongDuck, how does your car run when you have your lights up? Notice a difference at all?
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Old Feb 20, 2004 | 10:31 PM
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No noticable difference in performance, but I also don't drive as fast at night because I can't see as far.

Part of the fun of the modification is that it's a custom installation. Even if it doesn't add horsepower, I know that it's getting outside air that HAS to be cooler than what's under my hood on a 115 F day in Phoenix summertime. Plus, it appeals to the pilot in me to have a NACA duct on the front of my car.

I have driven it in heavy, driving rain (no pun intended) with the lights up and there wasn't a problem with soaking the K&N filter - I was concerned about that when I first made the mod. Works great, and keeps out the rain just by flicking the light switch or the headlight cleaning switch on the dash (aka the 'airbrakes' - headlights...).
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