2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

Cold Air Intake

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Old 01-09-11 | 06:42 PM
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Cool Cold Air Intake

Hey everyone, we'll I've been looking everywhere to find a decent cold air intake but I have no luck in finding the whole system, specifically the piping. All I find in websites, even ebay, are short ram intakes. I don't mind if the brand is generic, I'm just looking for the piping as I will change the filter to a high performance one after. So I'm wondering where can I find some? Or where did you all, who use cold air intakes, find them? Thanks, much appreciated.

-Damon
Old 01-09-11 | 06:53 PM
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no such thing as cold air intakes

and here is mine. its really nice. designed to get air from outside the engine bay


also you can try this
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/my-custom-air-box-937217/

just sticking pipe and a filter won't gain hp and most likely you will loose power. I have a K&N filter like this in my stock air box
Old 01-09-11 | 07:43 PM
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I wish the previous owner kept his old air box.

its the best way to go. but if you can make your own with a headlight cover inlet, that would be good as well
Old 01-09-11 | 07:43 PM
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Hmmmm.. I see. Thanks Alex, I think I'll try the custom air box.
Old 01-09-11 | 11:50 PM
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Your car comes from the factory with a "cold air intake". The supposed "cold air intake" is common among the Honda owners because their cars are typically not real sports cars and many of them were designed with an intake that pulls air from above the hot engine. These Hondas require a convoluted snorkel in order to fix the problem, and the aftermarket vendors come up with all kinds of misleading names for this, such as "cold air intake" or "short ram" intake.

If your car is a non-turbo model, then the stock intake will work just fine for street driving. You can use a drop-in K&N filter if you like, but its main advantage is the long service life and not so much its performance aspect. If you are serious about performance in a non-turbo model then you would want to completely replace the stock intake system with an individual throttle body setup with a custom air filter and inlet ducting. The Mazda RX-7 Competition Preparation and Service Manual has directions for this, but keep in mind that you are looking at a minimum of $2,000 for such a project.
http://www.nocoastmotorsports.net/Ma...tionmanual.pdf

If your car is a turbo model, then the stock air box is adequate for a completely stock engine, but it starts to become a restriction as the car is modified for more power. Modified turbo cars are better off with a custom air box. A simple cone filter will also work, but the more it is ducted away from the hot air the better. Try to not make the common mistake of making the ducting or tubing so convoluted that air is getting restricted and reducing performance. Just keep in mind that there are two main factors that affect performance: temperature and pressure. Using heat-resistant material in the intake system will obviously help a bit, but don't worry about it too much as the air moves so fast that even aluminum will not transfer much heat. The way to determine the effectiveness of your custom setup is to test the car on a dyno and compare the performance with the custom intake connected vs. disconnected.

Cone filters will fit directly on the stock AFM of the S5 cars but will require an adapter for S4 cars. For sizing a K&N cone filter, you can use my stupid formula which I think is less stupid than the other guidance you will see on the internet: Horsepower Potential = Filter Media Area square inches * 4.53. When in doubt just use the next larger size filter, as this will not hurt anything and the filter will not get dirty as fast.

Cork Sport sells a filter kit with a carbon fiber-looking air box:
http://www.corksport.com/autoexe-ram...tem-32284.html
Old 10-20-11 | 02:01 AM
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Damn that Corksport filter kit with the box seems quite expensive.
$680 just for the filter and the box.
Do you guys think it is worth it?
Doesn't even come with piping for further back past the MAF.
Old 10-20-11 | 02:13 AM
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Originally Posted by lyoryl
Damn that Corksport filter kit with the box seems quite expensive.
$680 just for the filter and the box.
Do you guys think it is worth it?
Doesn't even come with piping for further back past the MAF.
wtf hell no lol. i think that autoexe intake works only if you get air from the hole where the windshield wiper funnel goes into and the little hole where the wires for the headlights go through. for $680 i can get so much more stuff to improve my cars performance

Last edited by NatAsRex7; 10-20-11 at 02:16 AM.
Old 10-20-11 | 08:44 PM
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Old 10-20-11 | 09:04 PM
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Instead of (in essence) duplicating the stock airbox, why not move the filter to where the "cold" air is?
Like this.
Old 10-20-11 | 09:09 PM
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^^ thats a neat idea... but what "cold air" is there? if your looking for "power" take the box out, and just slam a filter on air meter.. not hard

Edit.. even with all these mods. i dont think any will help as much as somehow taking that vein meter, and going mass air flow... any ideas on this???
Old 10-20-11 | 09:22 PM
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^^^ COLDER than air intake.
Old 10-20-11 | 11:36 PM
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Originally Posted by slow_Fc3s
^^ thats a neat idea... but what "cold air" is there? if your looking for "power" take the box out, and just slam a filter on air meter.. not hard
Nope, not hard at all.
No very effective either.

In discussions of this type, "cold air" is generally accepted to mean ambient air, unheated by the radiator/exhaust/oil cooler, etc. So "cold" is a relative term.

While slamming a filter on the AFM is seductively easy (and keeps Weapon R in business), your incoming air has been preheated by the rad and is therefore less dense (and way less desirable) than air sourced from a different area.
This is why people (and a few companies) go to the trouble of duplicating the stock airbox and piping in the air from the washer rez location.
I figured my method was probably just as effective and a whole lot simpler.
Old 10-21-11 | 03:31 AM
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I had nothing when I bought the car, so i went to pepboys and bought a $20 cone and installed it
How's that guys
Old 10-21-11 | 10:09 AM
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As far as heat is concerned for the intake take a look at this first:

-Exhaust manifold /header sitting right under the intake piping / manifold and heating them up.

-Radiator and rad-hoses heating the stock airbox up which is only about 5 cm away.

-Lower and upper intake manifold sitting right ontop of the engine and getting heated by it and the exhaust.

Stock airbox might be a good ambient air intake but (!) that thing is very restrictive.
Just take a look at all those bends and wrinkles before the air reaches into the TB. Thats not an intake thats a labyrinth.

Ever touched the stock intake tubing after a long drive ? On my NA S4 you won't touch it unless you want to burn your fingers. Air filter too.

For the lulz I once installed a temp sensor right onto the stock piping 15 cm before the TB. Temp at that place was 2,5 times hotter than outside temp. The air just traveled past the drop in K&N air filter and its already 2,5 times hotter. Thats not bad...

Steven
Old 10-21-11 | 08:44 PM
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ahahaha +1 on 7dusts pics
But anyway, I've had better luck using heater-ducting + PVC pipe and fabricating one. Cheap and effective!
Old 10-21-11 | 08:47 PM
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Oops double post!

Last edited by w0ppe; 10-21-11 at 08:50 PM. Reason: Double post
Old 10-21-11 | 10:35 PM
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I really admire clokker's intake. I thought of using his idea, but chose a different route.

I did some ducting of my own in the link below. I still need to extend the TID and box off the filter. My temps appeared to be slightly lower after installing the duct. Can't wait to box out that damn engine/radiator heat.

My cone filter ducting.
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