It's not necessary. I had one on the BOV for awhile, but it kept blowing it off (no pun intended). Eventually I just realized that the BOV is a one way valve which only lets air out, and then shuts, meaning no air ever comes back in, making the filter pointless and actually a restriction. It will occasionally spit a little bit of oil out, but it's never made a mess on mine.

 

Get a TurboXS H-RFL. I got one and it's the loudest i could find for a FD. Sounds similar to a HKS. At low boost it sounds like a puff of air, but at full throttle it's a sharp pitch that'll definitely turn heads. I biught it and had the Muffler shop weld me a small adapter to it. I'd say go with either this or the HKS only.

 

My HKS SSQ isn't blowing loud.
I can only hear it when I'm going WOT and it's not that loud. My friend has the same one on his Supra and it's a lot louder than mine. It's loud when he revs in neurtal. I can't here mine when I rev in neutral. Is my BOV set too tight? It came w/ the car.

 

It probably depends on the location of the BOV. I'll bet if you open your hood and rev the car you'll hear the BOV very well. Close the hood and it will be quite muffled.

If you want to hear the BOV more, you'll need to have it mounted where the sound can escape a lot better. Not sure where that would be in the cramped FD engine bay.

My Apex'i BOV is loud as hell with the hood open. The hood closed up, it's just another BOV.

However for me, I can't hear sh*t at WOT over my exhaust.

 

My $0.02:

Just vent the stock valve if you want the BOV sound. The stocker works very well for the stock twins, and is decently loud.

Also, my experience is to stay away from the Apexi BOV. I had one, but I took it off when I found out that it WAS LEAKING UNDER BOOST. I gained 1 psi switching back to the stock valve. I took the Apexi valve apart after I discovered it was leaking, and I can see why it leaked...there seems to be too much clearance between the piston and the bore..it can't make a good seal so the boost just blows right past the piston and out the vent.

 

the reason being that he is most likely running higher boost levels than you. if he is anywhere near BPU (or better) levels, he is pushin 17+ psi.

boost level and air flow (relative to the size of the turbo(s)) makes a world of difference in the sound that a BOV puts out.

i have heard the HKS SSQV blow-off valve on RX-7s running <12 pounds of boost, and it honestly sounds like a very ***** little chirp...kinda annoying if you ask me. but i have heard the same BOV with the same insert on Supras running 17+ pounds, and the sound is much louder and much more aggressive.

 

bov sounded pretty nice for the PRICE...LOL!!

but i LOVE my BLITZ so much better.....
the HKS and GREDDY are tooo PLAYED out....

 

Actually My bov soudns differet at 12 psi.
yes it is an apexi. and i do think apexi one works better than any other one in market.. (better than single chamber)

I really don't care about sounds of BOV.. as long as they do their work...

 

oh yea.. apexi has 4 holes.. instead of 1

 

you can hear my blitz bov in the link below in the middle of the page (#15 the white FD). Some of the FDs have their stockers vented. You can easily hear the sound differences. With my second gen blitz supersound bov (with the new adapter), I don't even need to boost in order to make a sound. Turn up the volume, listen to all of them and hear for yourselves...

dyno videos

 

Just curious, what are the reasons you prefer the Apexi over other valves? Why do you feel it's the best?

 

Man, just vent the stock bov or get a nice quality bov like the Tial. The only thing you can benifit from a bov with stock twins is the sound. Just vent the stock for free and see if you like it, if you dont come back for more advice. If you come back my advice will be get a Tial, its a very good high quality piece that wont leak.

STEPHEN

 

Question:

Since my car is bone stock. If I do the stock bov mod, will it hurt or alter the cars performance in any way?

I used to have a '95 eclipse w/ a blitz bov, but it actually helped hold boost, considering that the stock bov leaked after 12psi.

So if the stock bov mod doesnt hurt, I'll go ahead and do it once I get off work.

 

I just removed the small 2 inch hose connecting the bov to the airbox, and I have a few questions:

I've got the hole in the airbox covered with a small bottle cap wrapped with electrical tape. it works but i wouldnt trust it for very long. what works the best for plugging up this hole?

Someone was talking about doing something with the crv hose up a few posts, could someone explain to me whats going on with that?

Oh, btw.. It sounds nice. Its not really really loud at all, but then again I am almost completely stock. I've already scared a few people too

 

It won't change anything other then the sound of BOV (it'll just be a lot louder). That's it, vent it open and enjoy.

 

I can see the bottle cap... but I don't know the part its hanging from. Its right above the airbox next to the airtube.


chris

 

It's plugging an air nipple on the air box. The hose that went on the nipple connected the Air Control Valve (ACV) which is now gone.

 

quote from rx7 store.

"high-response unit for use on a wide range of applications. Rather than relying on the vacuum chamber alone, the Twin Chamber Blow Off Valve harnesses boost pressure in a second chamber to assist in opening the relief valve"
I'll say twin chamber is better than single.

 

Here are two pictures of mine. It says K&N on the little filter (which made me think it is a K&N) but it may not be. I don't know enough about them to tell you for sure, it was installed by the previous owner.




-Charlie

 

Right...that means that Apexi designed their BOV so that it uses Boost to hold the door closed, and vacuum to open it up...

The twin chamber design assists the spring

 

Well, I don't like the Apexi because mine leaked boost, but maybe that's just my bad experience. If you like yours, then that's cool. Still, if I were you, I'd at least check to make sure that yours doesn't leak like mine did. It was my opinion it leaked because the design was bad, rather than my part being faulty.

As to the design, I'll agree that a twin chamber design is better than a single chamber design, all other things being equal....but the real question is, "are all other things equal?" For example, how much does the piston inside the Apexi weigh? If Apexi's piston in their BOV assembly is heavier than in other BOVs, then the gains of the twin chamber design are negated by the heavier piston. I'm not saying the Apexi piston is heavier or lighter, because I don't know, but I am saying that simply being a "twin chamber design" doesn't tell the whole story. It could be all marketing hype rather than actual performance. For me, I'm simply not convinced unless I see an objective test of various BOVs, showing that Brand A is truly better than Brand B.

 

where ur bov leaked boost?

oh yea.. whats the point of putting lil k&N filter on BOV??
to catch oil??

 

On mine, it leaked out the vent holes.

My car was completely stock then. With the Apexi BOV, my boost pattern was 9-8-9. With the stock BOV, it was 10-8-10.

When I removed the Apexi, and blew through it with my mouth, I found some air was getting through. Just try to blow through it and see if you can...or better yet, if you have a way to pressurize it to 10 psi while it is off the car, that would be the best. If air leaks through, then you are loosing boost.

 

I don't have any boost problem on mine...
did u tight that bolt (end of BOV) all the way?

 

Yes. It had nothing to do with the spring tension. Remember, I could blow through the thing with my mouth...there's no way I could blow hard enough to compress the spring, even if the spring tension bolt was set to full soft.

The problem with mine was that there was too much clearance between the piston and the bore...so boost would just go around the piston and out the vents. That's why I think it's more of a design issue. Maybe Apexi has changed their design so that there is less clearance now, or maybe mine was mis-machined, but mine leaked around the piston for sure.

You should still check to make sure that yours isn't leaking, even if you don't see a problem with your boost. Then you would KNOW that yours is working right. What would it hurt?