DIY: Better Flowing Intake Box (Similar to RB Intake Box)
11-05-2007, 06:18 PM
#28
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also does anyone have a part number for a K&N airfilter cone style that will fit on the stock piping?(Gotian im taliking to you)
Last edited by Rx8urZ; 11-05-2007 at 06:20 PM.
11-05-2007, 08:42 PM
#29
there are few members who have the set up, IM trying to design a more improved version of it, to block the heat better instead of just using the upper part of the box to block the heat. On the hot days it isnt really affecting the car, but i would rather block as much heat as possible.
Basically what I did was, I removed the lower portion of the box, removed the mouth inlet and screens and put a cone filter where the inlet is, now that its just the tube. I used a filter called power adder since they give you 3 different size adjustments (which the 2nd one will fit on the tube). So now I dont have to worry about the VFAD, I only spent 30 bucks for the filter, and 10 minutes of my time, and the engine sounds a hell of alot louder that it makes people think I have heavily modded the car.
I also track the car at autocrosses and it runs the car cooler than the airbox does in my opinion. (I've touched the intake tube after the runs just for the hell of it and my set up made it feel cooler.)
I will snap a pic for you either tonight or tomorrow.
Basically what I did was, I removed the lower portion of the box, removed the mouth inlet and screens and put a cone filter where the inlet is, now that its just the tube. I used a filter called power adder since they give you 3 different size adjustments (which the 2nd one will fit on the tube). So now I dont have to worry about the VFAD, I only spent 30 bucks for the filter, and 10 minutes of my time, and the engine sounds a hell of alot louder that it makes people think I have heavily modded the car.
I also track the car at autocrosses and it runs the car cooler than the airbox does in my opinion. (I've touched the intake tube after the runs just for the hell of it and my set up made it feel cooler.)
I will snap a pic for you either tonight or tomorrow.
It's basically a highly modified version of the stock air intake box and the REVi Ram Air Duct
11-06-2007, 12:24 AM
#31
I must point out that this does not make the stock intake perform like the RB intake since it doesn't deal with the single biggest problem in the stock box. That would be the bell mouth inlet on the air intake tube behind the filter. You'll notice that the bottom is cut off. This is because it hits the air filter. However this isn't good for flow either. RB's intake has a full bell mouth. It's just inside the filter.
Now saying all that, no intake gives much of a power gain so whether or not an aftermarket intake is money well spent is a subjective matter that each person has to make on their own. If keeping the stock airbox is your preferred method then I see no reason not to take the walls out of it. At least it's free!
11-06-2007, 01:09 AM
#32
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renesisse3p:its nice that you actually post directions for the stock airbox mods.
so for those all with confidence in stock airbox performance for free, here are some other things i have gone even further on to improve and mimic getting an aftermarket intake(without sacrificing filter exposure to more dirt and debris) while being able to fly by under cops radar!
-air pulse damper: its right on the intake flexpipe and only needs a phillips to loosen the hose clamp. remove it. and for those that have a better way of blocking it...do it. but i used a brake fluid bottle cap that happens to be sized right and shoved it in there...
airflow should flow right on thru since the "damper" is now blocked off and turbulence is now none existent.
-flexpipe mod: go to any of your local hardware store and buy a sheet of your thinnest aluminum sheet plate. make sure to get a pair of aviation snips( metal snips, or sheet metal cutter) now go back home and remove your intake again, measure the circumference of your intake tube from the box. cut out all the material you need to be able to roll the piece up and shove it in the flexpipe over the ridges.
done! now put it back.
cheap intake, stock look! hp gains? who cares? its just engineering out the b.s. resonance and restrictors that manufacturers have to undergo from noise regulations.
i got to warn those who wants to free up some flow though. it does make the intake whistle noise on light throttle more noticeable since now its less restrictive. but then again... whats the purpose of vfad? variable fresh air duct???.... only reason why it may switch from a short duct to a long duct under more vacuum demands is mainly to keep suction noise level down to a minimal if ran under only the short one.
so for those all with confidence in stock airbox performance for free, here are some other things i have gone even further on to improve and mimic getting an aftermarket intake(without sacrificing filter exposure to more dirt and debris) while being able to fly by under cops radar!
-air pulse damper: its right on the intake flexpipe and only needs a phillips to loosen the hose clamp. remove it. and for those that have a better way of blocking it...do it. but i used a brake fluid bottle cap that happens to be sized right and shoved it in there...
airflow should flow right on thru since the "damper" is now blocked off and turbulence is now none existent.
-flexpipe mod: go to any of your local hardware store and buy a sheet of your thinnest aluminum sheet plate. make sure to get a pair of aviation snips( metal snips, or sheet metal cutter) now go back home and remove your intake again, measure the circumference of your intake tube from the box. cut out all the material you need to be able to roll the piece up and shove it in the flexpipe over the ridges.
done! now put it back.
cheap intake, stock look! hp gains? who cares? its just engineering out the b.s. resonance and restrictors that manufacturers have to undergo from noise regulations.
i got to warn those who wants to free up some flow though. it does make the intake whistle noise on light throttle more noticeable since now its less restrictive. but then again... whats the purpose of vfad? variable fresh air duct???.... only reason why it may switch from a short duct to a long duct under more vacuum demands is mainly to keep suction noise level down to a minimal if ran under only the short one.
11-06-2007, 01:12 AM
#33
I will make a DIY on the removal of the VFAD when I have the time The only thing that sucks are my pictures, I have only a cell phone to take pictures with so the quality might not be so great.
ALSO! I will be making my own REVi imitated duct I believe that there's already a DIY on it but I'll be including that one in the VFAD removal DIY that I'm going to make
It's going to be similar to this: https://www.rx8club.com/series-i-do-yourself-forum-73/diy-home-made-cold-air-intake-69081/
I have a question on the VFAD though, if I were to disconnect the VFAD, will there be a CEL? Is there a way in fooling the ECU that the VFAD is still there? Please post back, thanks in advance
The only thing that sucks are my pictures, I have only a cell phone to take pictures with so the quality might not be so great.ALSO! I will be making my own REVi imitated duct
I believe that there's already a DIY on it but I'll be including that one in the VFAD removal DIY that I'm going to make It's going to be similar to this: https://www.rx8club.com/series-i-do-yourself-forum-73/diy-home-made-cold-air-intake-69081/
I have a question on the VFAD though, if I were to disconnect the VFAD, will there be a CEL? Is there a way in fooling the ECU that the VFAD is still there? Please post back, thanks in advance
Last edited by Spinning Sushi; 11-06-2007 at 01:21 AM.
11-06-2007, 01:29 AM
#34
Hmmmmmm.........
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Happy to be wrong here but doesnt the VFAD serve a purpose at lower RPM? Not saying there aren't gains to be had, but I am guessing with the VFAD removed, depending if you go a long or short intake length you may end up with lousy idle.
11-06-2007, 01:34 AM
#35
Many people on this forum removed the VFAD to free up airflow. I believe that the VFAD is only there to make your car sound quiet, a resonance device. It basically lesson the noise created by the suction when you're at low RPMs. The flap basically closes off the large intake intake piping on the VFAD when you're at low RPMs and then it opens the large pipe when you're at high RPMs. It's highly restrictive in my opinion.
The only real question is how to prevent the CEL from showing up after the VFAD is removed?
The only real question is how to prevent the CEL from showing up after the VFAD is removed?
11-06-2007, 01:52 AM
#36
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^^theres a blank clip on your stock air box for the vfad connector to clip into when you delete it. and no cel's should come on unless you did something wrong or didn't bother to clean up your mods and have it plugged up correctly.
11-06-2007, 02:03 AM
#38
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^^don't just remove the vfad duct. remove the whole assembly along with it!
you will need to go to the auto store to get some vacuum caps(blind caps) to do it right. the whole vacuum lines be removed along with the small diaphragm behind the airbox and tubes under it as well. and plug up the vacuum tube from the manifold with the blind cap.
regarding cel's, nothing should come on from deleting vfad. the blank clip slot on the stock airbox for the vfad connector led me to believe that maybe certain models aren't equipped with vfad. hence why the blank clip spot is there.
you will need to go to the auto store to get some vacuum caps(blind caps) to do it right. the whole vacuum lines be removed along with the small diaphragm behind the airbox and tubes under it as well. and plug up the vacuum tube from the manifold with the blind cap.
regarding cel's, nothing should come on from deleting vfad. the blank clip slot on the stock airbox for the vfad connector led me to believe that maybe certain models aren't equipped with vfad. hence why the blank clip spot is there.
11-06-2007, 02:13 AM
#39
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renesis3p: if you haven't already done so, now is the time to get things to prep for a clean delete with your car looking like it came out the factory like that... remember to get those vacuum caps from the auto store before starting!
and after so... take the whole airbox out as a complete assembly. and follow the vacuum lines to the intake manifold. there will be a metal tube and a diaphragm on a bracket iirc...take all of those off and throw it in the fireplace. j/k.
anyways, just remember to follow all tubes hidden under the airbox trace to the manifold vacuum nipple. thats where you'll need the vacuum cap.
if you're ghetto and don't mind mickey mouse, then cut a piece of the tube and shove a screw in it and use that as ur vacuum cap.
and after so... take the whole airbox out as a complete assembly. and follow the vacuum lines to the intake manifold. there will be a metal tube and a diaphragm on a bracket iirc...take all of those off and throw it in the fireplace. j/k.
anyways, just remember to follow all tubes hidden under the airbox trace to the manifold vacuum nipple. thats where you'll need the vacuum cap.
if you're ghetto and don't mind mickey mouse, then cut a piece of the tube and shove a screw in it and use that as ur vacuum cap.
11-06-2007, 11:10 AM
#41
The Professor
You guys do know that removing the VFAD won't gain any power, right? Not worth it in my opinion if your staying with the stock box, espically if you want to sell the car later.
That and adding a cone filter to the end of the accordion is the absolute worst intake idea for the RX8. They had a filter like that, it was called the K&N typhoon version 1, and it dynoed like 8hp less than stock. So they nixed that idea and came up with the version 2.
Generally if it is cheap and easy on this car, its either not doing anything or its hurting performance.
That and adding a cone filter to the end of the accordion is the absolute worst intake idea for the RX8. They had a filter like that, it was called the K&N typhoon version 1, and it dynoed like 8hp less than stock. So they nixed that idea and came up with the version 2.
Generally if it is cheap and easy on this car, its either not doing anything or its hurting performance.
11-06-2007, 01:51 PM
#45
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i just did this diy a few minutes ago and i might say for not costing anything its worth it. Removing the screens was simply easy, the hard part was getting the intake off and on.
from what i can hear:
whistling noise like if i had an intake
louder at upper rpms
smoother acceleration
for costing nothing its worth doing it
from what i can hear:
whistling noise like if i had an intake
louder at upper rpms
smoother acceleration
for costing nothing its worth doing it
11-06-2007, 01:59 PM
#46
Power!!
The complete intake horn and removing the screens are the two pieces that have actually been proven to make more power.
Everything else I've heard here is a guess in terms of making more power.
Everything else I've heard here is a guess in terms of making more power.
11-06-2007, 02:07 PM
#47
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i wouldn't say removing the two screens gives you more power, but it gives you the sound and better airflow to the car
Im getting a kn drop in filter tomorrow so hopefully it will finally sound like i have an after market intake. Ill post my results with the filter and the removing of the screens in this thread tomorrow
Im getting a kn drop in filter tomorrow so hopefully it will finally sound like i have an after market intake. Ill post my results with the filter and the removing of the screens in this thread tomorrow
11-06-2007, 06:04 PM
#49
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I have the K&N filter, and while the sound didn't change, it did get louder. Not OMG YOU GOTZ INTAKEZ!! loud, but it's loud enough that I can't hear the stock exhaust above 4000rpm. Under 4000 I didn't really notice a difference.
11-06-2007, 11:07 PM
#50
Power!!
I didn't make it up. Racing Beat tested it and found it to be true. www.racingbeat.com