Ok, so understand the concept of the blow-off valve and what it does just from reading a little in the past few minuets, but what is the difference in different blow-off valves? Do they make different sounds? Some have better proformance than others?

I am mostly intrested in the sound, I am about to buy an FD probobly, and it will be my first turbo-charged car, I dont know what sound I am looking for exactly, but knowing that some sound different than others and maby a small explenation of that would be nice

 

What would be nice is completely up to you. A manufacturer didn't say "Hey, this sounds like ****, let's put it on the market!"

And a BOV is a BOV... but I'd probably keep away from the eBay ones...

 

i wish mine made NO noise at all. I hate that it draws everybodies attention from a mile radius. not to mention as soon as the cops here it they want to pull you over. The stock one works great!! leave it be imo... But if you absolutly need to here yourself let off the gas then you can just take the hose from the BOV going into the airbox and vent it to the air. Then you'll here a loud whoosh.

 

Well, to be more specific (I started watching some videos and found a bunch of higher pitched whistling sounding BOV's)

I would like somthing that has a bit of a deeper tone. More like a KSHHHHHHHHHHHHHHHHH! sound than a TSIIIIIII!!!

 

Trust me a BOV was the first thing I wanted to put on my car when I just got it.

Yes it sounds cool etc to begin with but as time goes I found myself going back to the stock BOV which is pretty much what I have now despite having 2 different BOV just sitting on my shelf collecting dust which in hindsight I probably should have used that money for something else.

 

They give you 60 horses.

 

If you install an aftermarket BOV, or vent the stock one at atmosphere, it can get a little annoying if you drive the car a lot. I dont drive my 7 very much, but when I do, the BOV sound gets a little tiring after a while.

Just food for thought..

 

The stock air bypass valve (also known as a "BOV") has that sound that you are looking for, if you were to vent it to the atmosphere.

 

I read somewhere here that having a BOV closer to the throttle plate is best because it lets the air off immediatly as the throttle plate closes.

but then i read that its best near the turbos, something about letting the air let off when it get back to the turbos which allows for less lag when the air has to be pressurized in the IC piping or something along those lines.

eitherway i have no idea xD

anyhow, if you want a woosh, try the stock BOV and if that doesnt do it, look into a GReddy Type RS

 

Um...huh? Pressure doesn't care where it gets released. If it did, then the FD's fueling system (which only reads manifold air pressure) wouldn't work.

 

heh dont look at me man, thats what i read here, i aint sure whats what either xD

 

yea there has been some discussion here about the best location. normally unless you're redoing the entire system, the stock bov is all you need.
the main argument being the throttle since thats where the pressure begins or before the intercooler since it doesnt waste any already cooled air. that being said, i don't know nearly enough to say which is better for sure.

 

Just a couple things:

1. BOV sound is also dictated by the amount of boost the car is running. i.e. a BOV is going to sound different on an RX7 running 10 PSI of boost verses one running 17 PSI.

2. Aftermarket BOV's can offer some performance advantages over the FD stock unit. The afermarket BOV's typically have stronger springs. This allows the boost to build quicker and make the turbos more responsive. There are people around who can modify the stock BOV to add a stronger spring which will give a similar result.

3. When picking a new BOV, it's just not as simple as "I want that one". Not all BOV's have car specific flanges. This means they are expecting the BOV to be mounted to a universal flange which is welded onto an intercooler pipe. The stock intercooler piping is plastic so you can't do any welding there. If you are working with the stock IC piping, you need to get a BOV which has a "kit" for the FD.

 

so venting the stock BOV to atmosphere has no ill effects? if thats the case, the only purpose for the stock one is to silence that noise.?

 

Well, the purpose of it venting into the airbox is to suppress the noise, yes. The FD uses a MAP system, not a MAF like some other cars (i.e. DSM's). In this case, there is no issues venting the BOV to atmosphere.

 

I heard somewhere its best to filter the stock BOV if its vented to the air, is this true?

 

Ok, this is really good to know.

During my research last night I came across a particular blow-off valve that was based around performance, and particularly allowing the engine to bypass the turbo system until the turbo kicked in ( I believe this is what he was getting at anyways.)

I couldnt find the exact video that I watched, but those of you who know alot about BOV's probobly already know about this one, or at least know if it is any good. It's the Synapse Synchronic BOV. http://video.google.com/videoplay?do...arch&plindex=4

From the sounds of it to suit my needs all I need to do is re-route the stock BOV to the atmosphere, and then I should be good, but this discussion is intresting, and if anyone knows a good post on how to reroute it (if it's even difficult) that would be great.

 

I can't see any reason why... air doesn't go back in, only out...

 

I just got to take a look at one of the sinapse engineering synchronis BOV's last night.

THat thing looked top quality (construction)

It was brand new in the box, with agreddy flange, but I was amazed at the percision in which this piece was made.

Now lets just wait and see how well it performes. lol

 

Yea, I am really really intrested in how well this particular BOV performs. As soon as you get some more info please post.

 

pettit vented mine to the air... it sounds great

 

On some cars, a blow off valve helps control boost level. So replacing the stock blowoff valve is part of tuning it for higher power. The sound is a non-performance aspect. Most people who buy BOVs I think place higher priority on sound anymore.

FD's use different boost control methods and therefore don't benefit from an aftermarket BOV. If you want it for the sound that's fine, but there isn't a performance benefit.

Dave

 

like Mahjik mentioned... same BOV will sound different when u run higher psi.

aside from that, different type of BOV design will sound very different as well. for example Greddy RS and HKS SSQ have valve design, where Blitz use cylinder design. valve design tends to give u a higher pitch or bird chirp sound when u run lower boost.

some BOV like the HKS gives u optional inserts u can buy that will alter the sound as well. normal HKS insert gives u a high pitch chirp, where their purple flange gives a whooppssshhhh sound...

if sound is all you care about, i would just close the BOV recirculating back to filter and just vent it to atmosphere and see how you like it first. stock BOV is already quite loud.

IMO, if you pick from a reputable brand... just choose the look you like and make sure it comes with a flange/fitting that fits ur stock rubber hose.

 

I don't run a BOV


car is so damn quite during shifts, and I find it quite responsive too...still breaking in the new engine/transmission/turbo so I don't have any redline shifts.

flame on

 

Yea, from the sound of it my best option, and probobly the sound I am going to like the most, is going to be from the stock one, by just re-routing it.

I think I mentioned this somwhere earlier in the thread, but is it heard to re-route it? Do I need to get somone at a shop to do it, or is it simple enough that I could do it?