MmSadda

iTrader: (2)

You're just gonna drop the AFM out of your intake? This isn't gonna end well...

VacavilleFC

i don't think you guys get it, your just wasting money, theres basically no difference in horsepower and your mileage is most likely worse, and you've wasted money

i mean really guys. mazda probably spent several hundred million in R&D on our cars. do you really think that some home rigged intake is gonna be better???
theres a reason for every single thing on our item on our cars and the materials there made from.

look how small the opening is on the headlight cover, its nowhere near the diameter of the intake tube. that means it's restricting air not helping. also if you look around theres a wind tunnel diagram showing that area is low pressure, so no air is actually being pushed into it.


it may look neat and seem like a cool idea, but it's really not gonna be as efficient as stock. also any metal used to make the cold air box is gonna defeat the purpose because metal will got hotter than the oem black plastic

Roen

iTrader: (2)

Everyone incorrectly refers to the aerodynmaic diagram. At low speeds, air is being pulled away, but at higher speeds, air is still being pushed through the headlight vent.

The stock airbox is a restriction on intake flow, not the filter, as there is a big pressure drop before and after.

Cone filters "suck" better but better depends on if it is sucking hot air or cold air.

Most good cold airboxes are made from heat resistant ABS plastic.

cold, dense air, shielded from hot engine bay air + better performing filter equals improvement.

Now, whether or not that improvement is justified by the $$$ is another story.

well uhhh

CAI's are pointless on n/a 7's. You would be much better off spending the time to matchport the intake IMO, and if you have the tools or can borrow them it will be next to nothing as far as cost.

Roen

iTrader: (2)

I would agree, it's pointless for the average NA owner, a K&N drop-in will get you 80-90% there.

For some NA racers in stock or near-stock classes though, it's a must-have.

RotaMan99

This gave me a stable power output. Can't tell you what was gained but its better than the "filter in the bay" setup I had before. Between the 2 setups this one I can feel an increase. Now an increase from the stock setup I have no idea.



Click on the links below for more pics...
http://midnightgray.net/images/cai3.jpg
http://midnightgray.net/images/cai1.jpg

The stock airbox is restrictive. Not talking about the filter element. The snorkle will also pose a pressure drop. The stock intake is ok for an engine thats near stock. If you have the OEM exhaust there is no reason to upgrade the intake. If you have a high flow exhaust than a intake "could" help but will be more helpfull on ported engines.

Look at this thread..
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/airflow-measurements-stock-airboxes-730260/

Changing out the stock paper element for a K&N will also do nothing for you on a stock engine. There will be no pressure increase swaping the filter.

The airflow in the box will be cooler than in the engine bay reguardless of how the metal transfers heat. Now I know you will say something about using aluminum pipe for an intake and say the air inside the pipe is getting heated up. Are you right? To a certain degree but will it make any difference at WOT with 280-300 CFM flowing through it? Not one bit. The heat can't transfer fast enough to make a difference.

HAHAHA. The stock intake is the best intake for our cars I guess. Thats funny. Now if you were compairing a cone in the engine bay with the stock intake, the cone in the bay would still have the least amount of pressure drop but would get less dense air. How about going with a "cold air" or some may say "Ambiant air" intake which if its not so convoluded like most, it will outperform the stock intake by far.

Whizbang

your afm should be flat

RotaMan99

What if the outside air is cold? The arguments between which is more actual to say, AAI (Ambiant Air Intake vs Cold Air Intake) is just rediculous. Never say the are is not cold because its cooler than the engine bay and if its 30*F or 50*F its cold enough.

I get that a lot yet I have not had a single issue with the volt readings at all or the performance of the engine. At idle which is the point at which the flapper is more prone to movment by vibration or gravity, the volts are the same as if it was level. The only thing that I have noticed is that at idle the volts may jump up or down a tenth or couple tenths of a volt due to the idle vibration. Will reving the engine, that specific vibration goes away and the volts are as steady as can be.

Whizbang

my logic on it is that something that opens a small flap based on the pressure differences might find itself working differently when the weight of the flapper itself is acting against the air trying to come in.

t24todd

iTrader: (7)

simoncbrr1 makes a bad *** vented headlight cover...sorry simon im 90 percent done with cutting all the metal to make it sit flush then ill post pics likei said i would..check into it guys hhas a thred on his cover with pics onhis car just search vented cover and look for the name..

VacavilleFC

OEM- heatsoak isn't an issue as long as the car is running. but once you shut it off the tubes heatsoak to over 130. so it's not a big deal if you just drive your car to work and it sits for 8 hours then you drive home, but for errands and anytime the car is gonna be shut off for less than a couple hours your intake air temps are 120+ for a good half hour. now with aluminum it could possibly get even hotter than that unless you wrapped it up. aluminum might dissipate that heat faster also.

now the other benefit of your setup is the fact that the aluminum tube has a completely smooth interior finish unlike the ribbed stock setup. meaning the air might flow through it with less turbulance. but really the most restrictive part of anybodies setup is the afm, it has a much small diameter than any of the connecting tubing

isn't the stock intake an ambient air intake?? it draws in from the high pressure area in front of the radiator aslong as you have the cooling tray still installed

if putting an aftermarket intake on the car actually worked, wouldn't AEM,MUGEN,INJEN etc. make a CAI for 7's? but they don't and never have, that makes me think that even with money for real R&D they can't find a setup that out performs stock


i do like your setup though it's much cleaner than alot of peoples.

RotaMan99

Heat soak is always an issue no matter what intake you have. Once you have high velocity airflow through a proper cold air intake its not going to matter much.

I do agree that plastic reduces heat soak though.

It takes its air from all the abundance of air leaks in front of the rad. There is no direct air pressure at the intake inlet. If you removed the cooling trays you be able to raise the air pressure in front of the air inlet but may reduce the cooling efficiency.

They also make short ram intakes that suck in less dense air. Do you see any easy way of installing an aftermarket true CAI on our cars without modifing the chassis? I don't. Its would be LOTS of money to invest in designing one and there is not enough demand to make cheap kits for the rx7. Just because the major fast and the furious brands don't make it doesn't mean it doesn't do anything.

thanks for the compliment

I agree. holding the AFM verticle does have a large effect on performance but not anything noticable the way I have it.

crazyasu

The position of the air flow meter position also can cause hesitations; this only applies to the 1986-1988 FC's that use the flapper-door type of air flow meter - this does not affect the later 1989-1991 FC's which use a sliding-cone air flow meter. If you twist the air flow meter so the flapper door swings up/down, then gravity can help or hurt the action of the flapper door itself - this leads to hesitation problems!

The proper position of the air flow meter is with the black, plastic "cover" facing up. The upside-down position is the metal, "ribbed" side facing up. The air flow meter should be positioned in either of the two abovementioned positions to prevent any hesitation problems.

Roen

iTrader: (2)

um, i think he knows that.

copying and pasting from the stickies doesn't earn you any kudos.

7fold

lol

crazyasu

The FC3S is designed with a very restrictive air intake system. Even when replacing the stock, panel-type air filter with a freer flowing unit (i.e. K&N drop-in), only a very small amount of power can be freed. The restriction is not with the air filter itself but with the stock air box.

To eliminate the restrictive, stock air intake design, you can switch over to a cone-type air filter. For 1986-1988 FC3S you need a cone filter adapter mounted to the front of the stock air flow meter; we, at FC3S Pro, offer our own airflow meter adapter that is cast aluminum unit that has a 3" O.D. inlet to fit all universal cone filters that is typically sized with a 3" I.D. outlet. For 1989-1991 FC3S, no adapter is needed - the sliding-cone air flow meter can directly use any cone-type air-filter can clamp down to it's 2.5" OD inlet.

One word of warning about using the cone-style air filter: caution must be exercised to keep hot air produced by engine heat from entering the intake to a minimum. The air filter ends up sitting in a very hot engine bay. The FC3s does not lend itself well to a "cold-air induction" system well - it is not easy to plumb a big enough opening into the front of the engine bay without cutting heavily into the car itself.

Roen

iTrader: (2)

wow......is this the stickies or fc3spro.com?

I would seriously like the mods of this section to tack off 2 posts from crazyasu's post count for copy pasting, instead of introducing original ideas, but that's my opinion.

well uhhh

i could be wrong but i believe that's plagarism or however you spell it... i don't even think he used any of his own words. on another note, why is it so easy for people to get all caught up in silly arguments about a topic that has been beaten to death? I like how this thread went from recommendations to who's e-***** is bigger. im not trying to offend anyone but it just seems silly to me that people spend time on these threads when they could be helping people. /end thread

VacavilleFC

lol thats hillarious

actually i just was out working on my car and realized one mod i did to my intake that i forgot to mention. i removed the silencer/air chamber off the side of the snokle and made a block off plate. it sits right on top of the fan shroud and almost looks like a small paintball hopper molded onto it the back of the intake snorkle. i did this mod along time ago because i used to own i wrx and it had silencer chamber big enough to hold a gallon of water, just removing it and putting an elbow in gave it alittle oommph but also a great intake sound. i thought it might help on my car also... not saying it's relevent to but it's something i forgot to mention you can do

RotaMan99

Key word in bold. Word is used instead of the word will

satch

iTrader: (1)

With all this argumentative talk and analysis of which air intake is the best I don't understand why no one on this board has attempted something very simple to see if there are better methods for getting cold air into the engine. Seems to me that on a stock setup that if the air intake passage located on top of the radiator had an extension which would bring it downward and through the plastic engine shield mounted to a scoop similar to a dust pan of all things that this would solve the heat soak problem once and for all while at the same time increasing the amount of air into the stock intake. This is one of my projects in the waiting. The only real downside I forsee is the air would probably have a greater concentration of dirt or particulate matter thus the air filter would need to be cleaned and or replaced on a more routine schedule.l

RotaMan99

Good luck with that.

Your still dealing with a very restrictive air box. Putting more bends into the stock snorkle will only produce more pressure drops. Putting the snorkle in direct way of pressure is a great idea as long as you can eliminate the air box and direct plumb it to the TB with or without the AFM.

Even a dirty air filter is not very restrictive with the amount of CFM our engines injest. Read up on air filter restriction. Yes you are right though. My air filter picks up a lot more sand and dust than before but is better than anything I have see in a while.

Search. There are many ways people of done it. Some are so convoluded that they have actually lost performance, especially on turbo engines some have lost pressure designing a "CAI" with lots of bends.

Roen

iTrader: (2)

Straight shot is the best obviously.

That being said, my idea is just to build a cold airbox surrounding an APEX'i or a K&N cone filter, and make an opening on the right side just big enough to fit an extension of the stock snorkle through.

I may also use a NACA duct on the headlight cover with an extension tube on the bumper side of the box as well. I would only do this for a track car, as at an autocross, the car would be moving too slowly for air to pass through the duct. Worse case scenario, the duct could be pulling air out of the box!

RotaMan99

The only problem I see with air boxes is that sealing them 100% is almost impossible unless you use silicone or seam sealer on the bottom of the box with some thick foam at the top of the box to all the air to only come from the available area you have decided on.

I wonder about this. For low pressure to occur the airflow has to be forced to change direction to increase its speed so if you have the air duct which is a"gap" in the upward incline, this should reduce the low pressure and you should have a higher than usuall pressure at the NACA duct correct?

This goes the same for a turbo hood scoop. some say it does nothing because its in a "low pressure" zone but having that in the way of the airflow will disturb the airflow which should increase the pressure at the point..... correct?

Morondongon

I liked how you did that... have you thought about insulatint it to keep the hot air out...