If you think about it..
A stock filter was designed to be perfect for that car..

So if you add a high flow, the car still only needs X air to run at its peek preformance... so the other air is going to waist.. unless you have tuned the motor and added aftermarket products that now it can use that extra air..
I dont know, this is pretty much coming out of my ass..
but it makes sence..


aswell, your filter doesnt regulate how much air flows into your intake.. your air flow meter does.. so there can be tons of air going through the filter, but if your AFM isnt letting it by, its not going anywhere..

StinkyFatPig, you are correct, that did come out of your back side. The stock intake system on nearly all cars is intended for the most saleable balance between quite and powerfull. In addition, the AFM does not control intake, it meters (measures) it. The throttle body controls the engines ability to inhale within the limits of the other existing components. A greater mass air charge will always allow for more power (assuming enough fuel is available). The reason most intake mods don't see much improvement at first is simple. A cone intake increases the volume of available intake charge, but if the temp rises too much, the decreased mass due to thermal expansion (I've been out of school too long to quote the exact physical law) will reduce the total intake charge mass to or below that of the stock intake system. Cold air boxes overcome this by insulating the intake charge from the heat of the engine bay.

ohhh, so thats why i havent noticed anything after i put on my cone filter.....i was wondering what the deal was...:p:

I think the cone itself does increase gains. BUT i think that the hot air in the compartment lowers if not overcomes the gains. Get a CAI under the panel away from the heat and maybe you'll see a few HP.

yeah i think im gonna buy the mariah CAI box, ive tried to make my own, its hard!

Most people seem to have figured out it's the higher air temp that negates most of the gains of a pod filter. Unless there's some way of ensuring only ambient temp air is sucked in you're loosing potential performance, and worse, increasing the chance of detonation, particularly on a turbo. Remember most of the air entering the engine bay comes through the radiator, so it's far too hot.
I posted this a while ago:

...a duct of at least 3" diameter pulling air from the front of the car and directing air to a pod filter cut off from the engine bay by a shield is an excellent idea, as the more ambient temp air the filter inhales, the more power the engine will make. The lower temp of the air will be detected by the air temp sensor in the airflow meter and the ECU will then calculate the higher mass of the colder air. More air mass means more fuel injected, and more air and fuel means more power...

...assuming 20ºC air with 60% RH, heating this to 40ºC (typical underbonnet temp) drops its density from 1.19kg/m3 to 1.11 kg/m3, a drop of 6.7%.

This would be approximately how much power you'd lose! I've measured temps much higher than this in the engine bay, so it's probably even worse in some situations.

damn, now that i've found this out, my #1 thing to get is the Mariah Cold Air Box, i should be geting it within this month, so maybe i'll make a writeup on how to simmer up your own creation similar to this one with dimentions and all! because i've tried to make my own or make one someone else made a writeup on, but its too hard, and not one freakin writeup i've seen has the dimentions.....so this will be a first!

for those n/a guys that made their own, what materials do you guys use to make the box? it's just basically make a box that fits, and secure it, right?

Light gauge aluminium sheet is perfect. It's easy to get, easy to work with and it looks good.
First get a bit of cardboard, trim it to a rough shape (but bigger than you need). then trial fit it to work out where you need to trim. Repeat this process until you have the shape you want, then use it as a template to mark out the aluminium sheet.

Couldn't you just build a cold air intake box for yourself by cutting down (and cutting circles out of) a plastic battery housing box from Murray's?

someone posted pictures a couple months ago (I forgot who) of the cold air box he made out of aircraft aluminum and a piano hinge. after he got tons of requests he started mailing out templates for it, and the templates and instructions absolutely kick ass

here is my take on what you originally saw. most cars have the most restriction in the exhaust or are equal in restriction between the intake and exhaust. even if the exhaust manifold is decently designed you have cats and restrictive mufflers to deal with.

so you slap a cone filter that can flow better on there. your engine can breath easier but can't exhale any easier, so no gain. now you also have that filter sitting in the hot engine compartment, as was previously said. so you are not really pulling anymore air through, due to the still restrcitive exhaust, and you are now breathing hot, less dense air. so of course, you are going to see a drop in power (but you gain the cool cone filter honk). cold air box will help some but basically bring you up to stock as the engines ability to pull in more air lies in a free flowing exhaust. that is why you here of upgrading the two as a unit. even gran turismo upgrades the two together. moral of the story is upgrade the exhaust first or get both together. and cold air is good air. :)

Every month i go to the local store and check out Import Tuner... I check out the power pages and not once have i ever seen a cone filter upgrade decrease horsepower. There are atleast 72 examples that im talking about because ive only been reading it for 2 years and it has usually shown an upgrade of 3-5hp and 10-15 on forced induction cars.

This is how I have dealt with the hot air!

https://www.rx7club.com/forum/attach...&postid=776583

https://www.rx7club.com/forum/attach...&postid=776585

I can't say whether or not the original installation of the filter made a noticeable difference. I did however notice an increase in performance when I made that modification to the intake. You need cool air! I bet the people who have lost horsepower after adding a cone filter were in the summer months. I can't see how changing the filter could lower power over the stock intake unless the outside temps were very extreme.

mariah cai box
 

You guys are talking about getting this mariah cai box. where are these available. Internet?

Tim

here

http://www.mariahmotorsports.com/

Archive anyone? :)https://www.rx7club.com/forum/showth...threadid=95492

Note that he had some minor exhaust mods.

I purchased the cold airbox and the NACA headlight cover. The only thing about the airbox its made out of firberglass and it has the original look of fiberglass. I painted the cold airbox engine black paint and I think it looks good that color. I also added a grill to the opening of the headlight.
I did not notice a diffrence in performance when I installed these.
Afterwards I also installed the bonez high-flow cat and I can hear and feel the difference.

Al
87 "Beatup" N/A :cool:

o damn, thanks for the archive i wanna do the intake swap now...

Samps:
How's cooling with just that single elec. fan and the stock rad? Where are your temps?

Temps stay at half way on the crappy stock gauge. But this car is only driven for fun so it never sits in traffic or even driven slowly around a mall parking lot. I probably could get away with running without a fan. Otherwise it cools just fine. :)

Hey, thanks for the props.

All must kneel in the presence of the Exhalted Air Box Master!

I replaced my stock intake with a cone filter and I did experience a perceptible increase in low-end response. When I created the (beautiful) air box, the difference was even more positive.

https://www.rx7club.com/forum/attach...postid=1288970
https://www.rx7club.com/forum/attach...postid=1288983
https://www.rx7club.com/forum/attach...postid=1288986

Guess i'll revive this thread from the dead. I saw a picture of a headlight with a vent that leads directly to the intake, where can I find one of these things?

Does anyone have some measurements that they would like to share, im going to build a cold air box myself...
HAPPY NEWYEAR---KIM