Ok I just ran some numbers for my plans on the cold air intake that I am making.

I measured the stock AFM opening and found it to be 3" by 3.5" the total area of that rectangle is 10.5"(L X W) Now I plan on using 2.75" pipe but I have found that it is less area than the square shape in the AFM. I measured the area of a 3" diameter pipe and got 7.06"(Pi X R X R) I punched out the numbers for 3.5 inch and got 9.62" and a 4" pipe would be 12.56" square. Is this a majore problem? I mean does the round pipe designe flow better enough to make up for the difference in size?

I don't want to make an intake that is too small for a good HP gain.

Santiago

 

I dunno. Get one of these and see what happens

 

Are these things really bad?

 

This first thing you should do is learn to use a ruler...

The AFM opening is 2.5" x 2", which is about the same area as a 2.5" pipe. This doesn't really matter though, because no matter what the size of the AFM, the bigger the intake pipe, the less the restriction it causes. Make it as big as possible, aiming for a minimium 3".

 

oh ****!!!

lol I soooo botched the damn messuring lol. My bad Ok it will work then.

 

I'm going to disagree with this. The bigger the pipe, the less velocity for a given amount of air. This means less momentum. A smaller pipe would allow for more momentum due to higher velocity, but also creates more drag at higher airflow numbers due to the higher velocity increasing drag at the rate of the square of the airspeed. As you can see, what you need to do is size your pipe for the airflow rate. The intake pipe is just like the exhaust pipe, where larger isn't necessarily better.

You can flare the front of your intake pipe a little bit like NZConvertible mentioned if you want to make a bellmouth inlet duct (aka intake trumpet, horn, or velocity stack) directly behind the air filter. However, the aspect ratio of the flare is pretty critical and may or may not increase performance. Plan on lots of trial and error.
http://naca.larc.nasa.gov/reports/1948/naca-tn-1785/

As for the round to square transition, your main concern is going to be smooth flow through the transition. If the air has to ram into flashing, bends, ridges, etc., as it transitions from the round tube to the square AFM it is going to incur a terrible drag penalty. See my post here about the HKS adapter, which you will see transitions well and also maintains a uniform cross-sectional area fairly well:
https://www.rx7club.com/forum/showth...hreadid=197293

 

I wonder if velocity is really such a big deal, considering the air is going to slam into the AFM and then head into the accordian style stock intake tube. I would imagine that those things combined do quite a number on airflow...

 

I plan to also make a replacement mandrel bent pipe for that peice aswell but I am going to have to look at all the bends in it and see if it is worth it to make.

 

how about the AEM v2 intake, seen some dyno numbers on some of those pretty neat man make alot of power for just an INTAKE , but anyways how about mimicing those... with alot of math im sure you can find out the right combination.... if youve seen the v2 intake youll know what im talking about

 

got any links?

 

www.aempower.com i think thats the link

 

Well they don't make an intake that I could find for the FC.

Santaigo

 

well why dont u use the stock intake, put a cap on top of the AFM. u can use a universal bracket(which is made for Mazda) to attach the cone filter on the front!! this is a easy way to mod ur air intake!! it only cost like $50 USD from ur local import performace shop(if acceptable). u can also put a plexiglass wall like thing around the filter in the corner of ur engine bay(where the filter ends) to simulate a cool air box!!

a friend did that to his work just as good he says. =p

 

jgrts20

This is a real cold or cool air intake not like the ones we all usually have with the box. this will lower temperatures quite a bit gaining performance. Plus this will eliminate the need for a box. And it will cost just about what all the others cost but it will be cool air not warm air like the ones we all have.

Santiago



PS- YOU DO NOT HAVE TRUE DUALS

 

I agree with the wave tuning (like the AEM) on the intake piping. I've been racking my brain on what the proper sizes would be for a car like ours, but still not sure yet. Can't wait to see what comes out of Factoria de Santiago !

PS- About time someone said that Santiago

 

lol LMAO!!!!!


Our Proper name is "AZ-Tech Rotary" Hopefully my friend can get our website up for us soon

Santiago

I kinda looked into the V2 intake thing but I don't know how the formula works.