DIY: Removing VFAD
01-31-2012, 09:46 AM
#127
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Take the time to read the whole thread.
Then you'll see that its not worth it to remove the duct and the VFAD can simply be bypassed if that is what you desire.
And when I say bypass... I'm simply saying you can prevent the valve from closing to keep it open at all times.
Keep in mind, the valve is closed at lower RPMs simply to keep the engine noise down.
Bypassing the valve will only increase the sound coming from the intake... nothing more.
Then you'll see that its not worth it to remove the duct and the VFAD can simply be bypassed if that is what you desire.
And when I say bypass... I'm simply saying you can prevent the valve from closing to keep it open at all times.
Keep in mind, the valve is closed at lower RPMs simply to keep the engine noise down.
Bypassing the valve will only increase the sound coming from the intake... nothing more.
02-26-2012, 11:38 AM
#128
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So to my understanding, if I want to just bypass the vfad all I need is a valve cover, but since the vfad is closed at lower rpms does that mean I need to rev the engine above 5500rpm then remove the vaccum hose? Can someone clarify this? Or will it be ok to remove it while the vehicle is off?
02-26-2012, 02:08 PM
#129
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Also cube, no you do not need to rev the engine while you are disconnecting it. You just disconnect the little hose from the throttle body and cap it with a vacuum cap. Then do something with the hose you removed, its covered somewhere in this thread. When you first drive your car and go over whatever rpm opens vfad fully, it will stay open.
02-26-2012, 05:43 PM
#130
I tried both. The disconnect vacuum line, then finally took the whole mess out. I pulled it out chasing lower intake temps. I was running 15 to 25 degrees above ambient air temp with the vafd system in, with it out, intake is now only about 10 to 15 degrees higher. On the highway, I will get down to 7. Yeah, I know the inside temp gauge is a little hokey, but I watched it for a week or so before the mod. Lower air intake temps are a good thing. Next step is duct to suck air out of the grill opening, with appropriate attention to bugs, rocks and water, of course.
06-15-2012, 01:57 PM
#131
Am I the only one that doesn't notice an increase in sound or a difference in feel with the VFAD bypassed? Windows down and some romping below 5,000 RPM. I capped off the vacuum nipple on the upper intake manifold with the rest of the system remaining. I am fully stock (with consideration of removing the airbox baffles and having a K&N drop in). This makes me question whether or not removing the whole VFAD system will make a difference on top of what I've done.
Either way. I plan on installing a duct in place of the VFAD. But I would like to know if others think that with only the VFAD bypassed (not entirely removed), there is no difference in feel nor sound.
Either way. I plan on installing a duct in place of the VFAD. But I would like to know if others think that with only the VFAD bypassed (not entirely removed), there is no difference in feel nor sound.
Last edited by SayNoToPistons; 06-15-2012 at 09:03 PM.
06-16-2012, 08:22 PM
#132
Removed the VFAD as a whole today. The sock duct, valves, and all the vacuum lines.
I also made my own duct instead of chopping the VFAD to fill in the space where the airbox inlet is now expose to. I extended the duct forward and down a bit to pick up some fresh air also. Used an L-bracket to secure the sheet metal duct to one of the predrilled open holes that was for the plastic shield which was removed. Everything is painted black, and even used one of the philips head push clips to mount the bracket to the body. Looks totally stock. Spent about 5-6 hours, mostly due to fabrication of the duct itself.
All in all, it is most definitely louder and deeper. Not AEM/MS and K&N hot air intake loud, but most definitely louder than stock and the Revi set up. No difference in feel, as I tried not to have a placebo effect take hold of me
. Sounds great at any large amount of throttle opening at any RPM below 6000.
I also made my own duct instead of chopping the VFAD to fill in the space where the airbox inlet is now expose to. I extended the duct forward and down a bit to pick up some fresh air also. Used an L-bracket to secure the sheet metal duct to one of the predrilled open holes that was for the plastic shield which was removed. Everything is painted black, and even used one of the philips head push clips to mount the bracket to the body. Looks totally stock. Spent about 5-6 hours, mostly due to fabrication of the duct itself.
All in all, it is most definitely louder and deeper. Not AEM/MS and K&N hot air intake loud, but most definitely louder than stock and the Revi set up. No difference in feel, as I tried not to have a placebo effect take hold of me
. Sounds great at any large amount of throttle opening at any RPM below 6000.
Last edited by SayNoToPistons; 06-16-2012 at 08:24 PM.
06-22-2012, 09:12 AM
#133
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I have a AEM c.a.i, while my car was into mazda having the engine replaced they must have snapped off the vfad host and now right at the nipple there is just a bit of plastic and the nipple itself. is there anyway i can close this ? as it is not long enough for a cap or a hose.
06-22-2012, 11:53 PM
#135
Just thinking out loud.. but can anyone point me in a certain direction with this??
The way i figure it, the tiny holes in the center grille barely do anything for the rad, as i think it gets most of its air through the lower portion.
If i were to create a duct that completely used up the space of the grille and have it feed into the intake, (after i delete vfad) would that make it more efficient than the RB duct?
or am i taking too much away from peter(rad) to give to paul(intake).
The way i figure it, the tiny holes in the center grille barely do anything for the rad, as i think it gets most of its air through the lower portion.
If i were to create a duct that completely used up the space of the grille and have it feed into the intake, (after i delete vfad) would that make it more efficient than the RB duct?
or am i taking too much away from peter(rad) to give to paul(intake).
06-23-2012, 12:42 AM
#136
The AC condenser and rad feed off of air from both the grill and bottom chin portion. Using the whole grill as a duct area wouldn't be very wise at all.
Would it feed more intake air than the RB duct? Yes, obviously due to higher volume. Would it make a noticeable difference? No. Is it worth it to sacrifice the efficiency of our already weak cooling system for a giant duct that won't make a noticeable difference? Um... Most definitely not.
Would it feed more intake air than the RB duct? Yes, obviously due to higher volume. Would it make a noticeable difference? No. Is it worth it to sacrifice the efficiency of our already weak cooling system for a giant duct that won't make a noticeable difference? Um... Most definitely not.
Last edited by SayNoToPistons; 06-23-2012 at 12:47 AM.
08-18-2012, 12:00 AM
#138
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You really just need to cap the nipple behind the throttle body.
This is the "beginning" of the vacuum line for the VFAD.
Attachment 136611
Autozone sells a pack of vacuum caps of various sizes.
This is the "beginning" of the vacuum line for the VFAD.
Attachment 136611
Autozone sells a pack of vacuum caps of various sizes.
Anyway, with the throttle still on, I pulled this line. It is the line that traces back to that small plastic box.
The "stock" size for the vacuum cap seems to be a 3/16. If you want to go tight for peace of mind, use a 1/8 cap. 7/32 is too loose.
08-26-2012, 07:00 PM
#139
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I've noticed some strange behavior with my 8 lately. I decided to go through a checklist of things that I can address myself to make sure I don't waste a trip to the dealership for something j could fix myself.
The symptoms are as following. It has very hard starts. I still need to upgrade my starter to the '06 + version. Once started, it runs great. Although, if I drive it for more than 10 minutes, city or highway, it starts to lose power, and run a bit rough. Regardless if I drive it for 5 min or 30, if I shut it off, it will not start again. It has to sit for at least 15 minutes before it will start again.
So far I've done the following to narrow down the possible culprits. I've replaced the coils, wires, and plugs, all NGK, cleaned my air filter (K&N), run seafoam from the vacuum line, and checked my vfad for possible blockage or other problems.
When I got to my vfad, is when I became really confused. After seeing the pictures you guys have posted, mine looks nothing like them. It's pretty much just a pipe that mates with the air box on one end, and has a fabric tube with an open end on the other. There isn't a second opening at the end where the airbox mates, or is there any hardware on the side, which is what I assumed to be the actual vfad.
Were there any models made like this? Or is it possible that the previous owner replaced it with a cheap aftermarket part?
I went to take out my cat and inspect it as well, but didn't have the correct tools, so that will have to wait for another day. Is it possible that the loss of power could be due to a clogged cat, once it heats up from driving? I can't tell if the car won't start because its flooding every time I shut it off, and needs to sit for a while to clear out, or if the cat is clogged, and needs to cool down before it will start.
It's a 2004 gt automatic.
I appreciate any feedback, as I'm lost at the moment.
http://I45.tinypic.com/fcmaf7.jpg
The symptoms are as following. It has very hard starts. I still need to upgrade my starter to the '06 + version. Once started, it runs great. Although, if I drive it for more than 10 minutes, city or highway, it starts to lose power, and run a bit rough. Regardless if I drive it for 5 min or 30, if I shut it off, it will not start again. It has to sit for at least 15 minutes before it will start again.
So far I've done the following to narrow down the possible culprits. I've replaced the coils, wires, and plugs, all NGK, cleaned my air filter (K&N), run seafoam from the vacuum line, and checked my vfad for possible blockage or other problems.
When I got to my vfad, is when I became really confused. After seeing the pictures you guys have posted, mine looks nothing like them. It's pretty much just a pipe that mates with the air box on one end, and has a fabric tube with an open end on the other. There isn't a second opening at the end where the airbox mates, or is there any hardware on the side, which is what I assumed to be the actual vfad.
Were there any models made like this? Or is it possible that the previous owner replaced it with a cheap aftermarket part?
I went to take out my cat and inspect it as well, but didn't have the correct tools, so that will have to wait for another day. Is it possible that the loss of power could be due to a clogged cat, once it heats up from driving? I can't tell if the car won't start because its flooding every time I shut it off, and needs to sit for a while to clear out, or if the cat is clogged, and needs to cool down before it will start.
It's a 2004 gt automatic.
I appreciate any feedback, as I'm lost at the moment.
http://I45.tinypic.com/fcmaf7.jpg
Last edited by Daed99; 08-26-2012 at 07:11 PM.
08-26-2012, 07:11 PM
#140
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There isn't a second opening at the end where the airbox mates, or is there any hardware on the side, which is what I assumed to be the actual vfad.
Were there any models made like this? Or is it possible that the previous owner replaced it with a cheap aftermarket part?
It's a 2004 gt automatic.
Were there any models made like this? Or is it possible that the previous owner replaced it with a cheap aftermarket part?
It's a 2004 gt automatic.
12-11-2012, 04:15 AM
#141
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I don't have a Vfad..Just a FAD.. 05 GT AT.. After lookin at it Im interested in gettin it more air to breath since its Buried Behind Bumper Near Headlight.. Any thoughts as to Cuttin in the 350z Duct just in front of it,Since the FAD opening is sittin right there?
Last edited by Shoreguy926; 12-11-2012 at 04:48 PM.
03-04-2013, 03:36 AM
#142
Non-Savant Idiot
I recently removed my VFAD (along with the airbox baffles) and WOW!!!! 
It made a huge difference! The car actually sounds like the kind of car a 19yo would drive. Granted I'm not one of those "I want my engine to wake the neighbors!!!" types, but I wanted the car to purr just a bit more. This definitely did the trick. Hopefully soon I'll be doing this mod to my airbox, https://www.rx8club.com/aftermarket-...ke-pics-42631/, or something like it, in lieu of the almost $500 REVi system. I also am trying to find a way to the intake opening somewhere else. I am considering Racing Beat's ram air system. I don't know if "ram air" actually works but I like the idea of intaking cooler air, as opposed that dead space behind the bumper where it is being sucked now. However, I am hesitant to spend $150 for that duct so I may be fabricating my own, so we'll see how that goes. 
It made a huge difference! The car actually sounds like the kind of car a 19yo would drive. Granted I'm not one of those "I want my engine to wake the neighbors!!!" types, but I wanted the car to purr just a bit more. This definitely did the trick. Hopefully soon I'll be doing this mod to my airbox, https://www.rx8club.com/aftermarket-...ke-pics-42631/, or something like it, in lieu of the almost $500 REVi system. I also am trying to find a way to the intake opening somewhere else. I am considering Racing Beat's ram air system. I don't know if "ram air" actually works but I like the idea of intaking cooler air, as opposed that dead space behind the bumper where it is being sucked now. However, I am hesitant to spend $150 for that duct so I may be fabricating my own, so we'll see how that goes.
03-07-2013, 09:37 AM
#143
I recently removed my VFAD (along with the airbox baffles) and WOW!!!! It made a huge difference! The car actually sounds like the kind of car a 19yo would drive. Granted I'm not one of those "I want my engine to wake the neighbors!!!" types, but I wanted the car to purr just a bit more. This definitely did the trick. Hopefully soon I'll be doing this mod to my airbox, https://www.rx8club.com/aftermarket-...ke-pics-42631/, or something like it, in lieu of the almost $500 REVi system. I also am trying to find a way to the intake opening somewhere else. I am considering Racing Beat's ram air system. I don't know if "ram air" actually works but I like the idea of intaking cooler air, as opposed that dead space behind the bumper where it is being sucked now. However, I am hesitant to spend $150 for that duct so I may be fabricating my own, so we'll see how that goes.
It made a huge difference! The car actually sounds like the kind of car a 19yo would drive. Granted I'm not one of those "I want my engine to wake the neighbors!!!" types, but I wanted the car to purr just a bit more. This definitely did the trick. Hopefully soon I'll be doing this mod to my airbox, https://www.rx8club.com/aftermarket-...ke-pics-42631/, or something like it, in lieu of the almost $500 REVi system. I also am trying to find a way to the intake opening somewhere else. I am considering Racing Beat's ram air system. I don't know if "ram air" actually works but I like the idea of intaking cooler air, as opposed that dead space behind the bumper where it is being sucked now. However, I am hesitant to spend $150 for that duct so I may be fabricating my own, so we'll see how that goes. 
03-09-2013, 05:09 AM
#146
Non-Savant Idiot
Yes, I'm wondering why that's a no? 
Like I said, Mazda designed the car to be quiet for the everyday driver (perhaps who would want an engine with a sporty note to it). I, being the 19 year old that I am, really see no point to this. I drive what I consider to be a sports car and want it to sound like what it is. (Which is not an overly obnoxious, loud monstrosity that we all know and hate.) 
Like I said, Mazda designed the car to be quiet for the everyday driver (perhaps who would want an engine with a sporty note to it). I, being the 19 year old that I am, really see no point to this. I drive what I consider to be a sports car and want it to sound like what it is. (Which is not an overly obnoxious, loud monstrosity that we all know and hate.)
04-20-2013, 01:51 PM
#148
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I removed my vfad about a month ago and it sounds much better, but i wondered can the actual vfad solinoid be removed as there is a blank socket on the airbox which the harness plugs into making a very neat install
10-13-2015, 04:40 PM
#149
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Ram air
Just a couple comments on the vfAd removal-do it! I took mine off my Brilliant Black 2007 manual with great results.I put on the Revi and ran it through the stock box which I gutted.A nice k&n filter lives there now.The more air the better!I have a Borla exhaust with the original cat.The other mods are opening up the oil cooler vents in the wheel wells and throttle body bypass.The car is much more responsive-especially over 35-40 mph.It loves the cold 50 degree air blowing into it here in Southern New Jersey.
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