please read the thread in it's entirety before posting questions, thank you

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i already took the vfad off... and loving it. I was just wondering if i should put the foam and nose support back in. is there any good reason to have these back on? will my bumper sag if i leave the nose support off? thanks

 

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?

 

Foam and nose support? I assume you mean your crash bar lol? I am pretty sure you wanna keep that... Refer to this https://www.rx8club.com/rx-8-discussion-3/rx-8-totalled-car-wash-229628/ to see why it may be a good idea.


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.

 

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.

 

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.

 

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 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.

 

Some sort of rubber plastic plug that looks like a screw with a head. Reason for that is so it doesn't get sucked in.

 

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 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.

 

+1

thanks for the quick solid answer!

this is why we think out loud

 

Took me a while to figure out that no disassembly is needed to reach that nipple. I started taking off the throttle body and snapped an air connector.

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.

 

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

 

https://www.rx8club.com/specific-per...3/#post4303031

 

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?

 

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.

 

No.

 

No?

 

No to the bold sentence on the quoted text, that's what SayNoToPistons meant

 

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.)

 

ok. im gonna get dawg for this, but im more of a visual learner. does anyone have a video of doing this?

 

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

 

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.