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Location:
Balranald
Registered:
May 2002
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Blow Off Valves
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Thu, 21 October 2004 02:50
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Before you start paying me out no I am not a rice boy....but I do want a Blow Off Valve for my car and yes I do want it to make a noise not a plumb back one but no I don't want one that sounds like a rice boy from the Fast & Furious.
How can you buy a Blow Off Valve and know what it's going to sound like before you buy it and fit it?? The websites should have sound files so you know what you are buying....I know Turbosmart does but that is all and I don't like the sound of any of them.
I would like to know the sounds of different types and then choose the one that sounds the best and not stupidly over loud.
There are millions of different types out there and I'm confused.
I live in a small country town and have the only turbocharged car except for one other stock XR6 Falcon so I can't talk to people around and hear others.
I have seen the cheaper $150 ones for sale...are they worth getting??
Cheers
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I supported Toymods
Location:
Adelaide
Registered:
July 2004
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Re: Blow Off Valves
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Thu, 21 October 2004 03:45
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I bought a cheapo one off ebay for $40, its a pooey monza type one, but its small and it does the job and its not overly loud 
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Location:
Inside a giant turbo (syd...
Registered:
June 2002
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Re: Blow Off Valves
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Thu, 21 October 2004 04:07
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i run a bosch black plastic bov that was $50... its plum back but sounds sweet! you dont have to plum it back ofcourse.....
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Registered:
May 2002
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Re: Blow Off Valves
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Thu, 21 October 2004 04:17
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I have had two types of BOV mounted in 3 different ways
1st was the classic Bosch BOV plumbed back, it was almost silent in operation.
2nd was the same Bosch BOV venting to atmosphere, it let out what I would consider a low to medium level classic pssshhhhh sound. It wasn't too loud but the sound was there and could be heard outside the car, this worked very well.
3rd and current BOV is a GFB one that works fine but is considerably louder than the the Bosch one was. The sound doesn't bother me as I don't do laps and look like a tool  .
As far as I am aware the only type of BOV that are distinctly different sounding are the super sequential type (HKS) (I like this style as it sounds like a WRC cars BOV). Most just make the classic psshhh noise to varying degrees.
The "flutter" noise that some peoples cars have is NOT a BOV noise (despite what some think), it is compressor surge due to not having a BOV or having too much spring tension in the BOV so it is not even opening or is opening late. The people who want the "mad" flutter noise created by compressor surge should get that "mad" pinging noise that some finely tuned machines have as well  they both do wonders for your car.
Good luck with it mate, must be hard when you can't just head down to your local car hang out place and find a car with a BOV you like the sound of and just ask them what they are using.
Cheers.
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Location:
Inside a giant turbo (syd...
Registered:
June 2002
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Re: Blow Off Valves
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Thu, 21 October 2004 04:28
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hows your brothers corolla wagon coming along? when i was down there it looked like it was going to be a monster 
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Registered:
May 2002
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Re: Blow Off Valves
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Thu, 21 October 2004 06:31
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hows your brothers corolla wagon coming along? when i was down there it looked like it was going to be a monster
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The wagon was on the road briefly making ~205rwkw (on the same dyno mine makes 170rwkw). It was then taken back off the road for a full respray in a nice bright metallic blue (Ford XR8 blue to be precise) and a full engine rebuild as it was a 2nd hand engine of unknown km's and it needed a freshen up. It is not far off being finished and should be a wild little wagon perfect for loading up with the shopping and boosting on home .
We plan on a trip to WSID once it's done along with a few other 4AGTE powered vehicles (mine included). I will let you know when we are heading up if you are keen to meet up. Should be some good 4AGTE grudge matches 
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Location:
Inside a giant turbo (syd...
Registered:
June 2002
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Re: Blow Off Valves
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Thu, 21 October 2004 06:45
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yeah he did my aw11, and i saw it in blue when i picked it up, had a chat to him about. It will surely be a wild wagon!
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Registered:
May 2002
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Re: Blow Off Valves
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Thu, 21 October 2004 06:57
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Yeah the engine bay would have been painted in the blue when you saw it, it has since been panel beated and will have the exterior painted in the next couple of weeks.
That was my car for about 5 years with a 2TG I fitted to it. Hence my outdated logon (ke382TG).
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Location:
cambo
Registered:
May 2002
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Re: Blow Off Valves
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Thu, 21 October 2004 09:46
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my BOV is a tial, and it sorta makes a puring fluttering sound, sorta like compressor surge. this is only when i change gear and there is none or little boost. when i back off at higher boost, say 15-20psi its more of a woosh sound. and before anyone says the fluttering is my BOV not opening causing compressor surge at low boost its definately not. the BOV opens FULLY.
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Location:
Brisbane
Registered:
July 2002
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Re: Blow Off Valves
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Thu, 21 October 2004 09:56
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whats wrong with the stock one.. i can hear mine fine for a plumb back stocko.. maybe thats because of the pod...
but why?
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Registered:
May 2002
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Re: Blow Off Valves
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Fri, 22 October 2004 01:37
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my BOV is a tial, and it sorta makes a puring fluttering sound, sorta like compressor surge. this is only when i change gear and there is none or little boost. when i back off at higher boost, say 15-20psi its more of a woosh sound. and before anyone says the fluttering is my BOV not opening causing compressor surge at low boost its definately not. the BOV opens FULLY.
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Just to offer some advice (and a minor performance gain of better low boost response between gears if you choose to take the advice).
The Tial BOV is a sweet bit of gear and uses the common BOV design in which there is a piston inside the BOV housing. The chamber on one side of this piston has a tubular line that runs to the manifold allowing both boost and vacuum to be created in the chamber. This side of the piston also houses a spring (adjustable in pre-load).
The other side of the piston will see atmospheric pressure through to boost.
Now the only noise this type of BOV can make is that of air escaping when it opens, this is the woosh or psshhh or hiss you indicate you get at 15 - 20 psi. The fluttering noise can not be created by the BOV as to do this it would have to be opening and closing at a rapid rate or "pulsing" (think about it for a second and it will make sense). Now that you have thought about that do you see what I am saying?? In between your gear changes even after only spooling up the turbo a small amount one side of the BOV piston is seeing vacuum, the other side is seeing boost, so unless the vacuum is fluctuating a great deal then there is now way for the piston to be opening and closing at a rapid rate to cause the fluttering noise.
But this is easy to rectify and will help keep your turbo spinning a touch longer and hence less time to bring it back on boost between gear changes
Now I don't know where you have your BOV located but I will assume it's nice and close to the throttle (no problem if it isn't but this is the ideal location). Now with a neat BOV like you have (and most others these days) it is possible to adjust the spring tension (or purchase a different spring rate) to have it set up for your particular vehicle.
The simple thing to do in order to remove this "fluttering" noise at low boost gear changes (I am 99.9% confident you can get rid of it) is to just back off some of the preload on the spring. If this is already at it's minimal preload adjustment then a slightly softer spring is in order (sounds like it is only just a tiny bit too much preload though).
The only other reason I have seen for this flutter on low boost gear changes is that some cars have had such a long line from the manifold to the BOV that the minute delay this causes in allowing the BOV to respond causes a small amount of compressor surge before the BOV is able to open.
The ideal is to have no compressor surge at all, and don't worry about the BOV "leaking" if the sping is set quite soft, it won't happen
If you decide to have a play around with it let us know how you go, it's free performance to unleash (even if it is only a small amount )
Oh yeah, I am happy to repost this in the Tech section to gain some input from others too if need be.
Cheers.
[Updated on: Fri, 22 October 2004 01:40]
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Location:
Melbourne
Registered:
November 2003
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Re: Blow Off Valves
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Fri, 22 October 2004 03:29
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Ahh, so the flutter is compression surge? Didn't know that.
viagra_cressida, what engine are you running? As I understand it if you have an AFM and go for a venting BOV, then you can cause damage to your engine and lose performance due to the injectors flowing too much petrol once the throttle snaps closed between gears (or any time for that matter). I think HKS and a few other brands get around this by having hibrid BOVs with both a plum back and venting BOV in one that lets some pressure out in to the air, while moving enough air back into the intake piping to stop your AFM from getting confused.
You can safely put venting BOVs on engines with a MAP sensor though.
I'm not sure if there is ANY advantage to running a venting BOV or hybrid over a plumb back on an AFM engine other than a wanky sound. Somone with more experience wanna clarify that for me?
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Registered:
May 2002
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Re: Blow Off Valves
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Fri, 22 October 2004 04:16
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I'm not sure if there is ANY advantage to running a venting BOV or hybrid over a plumb back on an AFM engine other than a wanky sound. Somone with more experience wanna clarify that for me?
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Performance advantage/disadvantage of plumback Vs vent to atmosphere BOV = none. Vent to atmosphere if you want the sound louder or if plumbing it back into your intake is too much work for you.
Correct call on the overfuelling between on boost gear shifts of AFM cars when a venting to atmosphere BOV is used. The severity of this problem seems to vary from car to car though from what I have seen (partly dependent on how much air the BOV can dump in its puff).
Some people don't seem to mind a small puff of smoke (unburnt fuel) and a backfire to get the pssshhh sound from there BOV on an AFM car, I personally wouldn't do it.
Just be aware that the supersequential BOV's do have a different sound (not a flutter though), which is hard to describe. The only example of this type of BOV that I can think of that lots of people have probably heard is it sounds like the BOV on a WRC car (when you can hear it over the antilag ). I have only seen a few cars on the streets with these types of BOV, I wouldn't mind one but they are pretty expensive.
As a side note I went for a spin in a friends car the other night and his BOV wasn't venting unless he absolutely gunned it. He is going to be fitting a lighter spring, the compressor surge was very loud and it doesn't do your turbo much good either.
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Location:
cambo
Registered:
May 2002
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Re: Blow Off Valves
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Fri, 22 October 2004 06:31
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ke382TG, thanks for your feedback its greatly appreciated.
i understand its not my BOV causing the fluttering, cause when i got the hood up and i jab the throttle (no load on engine so turbo doesnt even move) when i back off it opens completely but no sound cause theres no boost.
due to the fact that my BOV is slightly open at idle when i was at GCG to get some gaskets i asked about a replacement spring for my BOV as i was under the impression it was not adjustable and they informed me there is NO replacement spring for my tial BOV, only for tial wastegates.
so if i open up the BOV, can i close it up again easily? i assume theres a seal of some sort i just hope it can be reused.
also i should mention BOV is right before throttle.
how is the spring adjusted? is there a screw or is/can it be adjusted by shims? i understand that i may not gain much performance from adjusting it but everything helps when i have to wait till 5000rpm for boost 
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Location:
Brisbane
Registered:
July 2002
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Re: Blow Off Valves
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Fri, 22 October 2004 06:35
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he's running 1jz jzz30
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Location:
Melb, Victoria
Registered:
April 2004
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Re: Blow Off Valves
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Sat, 23 October 2004 08:38
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guys i'm running gen2 3sgte with afm. i have a sw20 mr2 factory bov. i wanna put it on but its a real pita trying to plumb it back (due to my intake setup). are these bov any decent, or should i go aftermarket? will this bov plumbacked with a pod filter make any differnt noise?(mr2 owners???) thanks
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Location:
Balranald
Registered:
May 2002
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Re: Blow Off Valves
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Sat, 23 October 2004 12:52
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Thanks Jag....I haven't been able to get online much lately....thanks for the responces everyone.
Yeah I have a JZZ30 Soarer and I like the sound of the stock BOV especially when I take out the air cleaner...not that I do this much 
I like how it has the flutter of compressor surge. I would like this but a bit louder and all the time. Should I just get a pod filter and then have more power too??
How much are they and where do I get them and what are the best types?
I live in a town of 400 people 100k's from the nearest shop of any sorts (we have a take away shop here and 2 servos and a school...that's it) so it's hard to talk to anyone about stuff like this. So all the help on here is needed...thanks
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Location:
Brisbane
Registered:
July 2002
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Re: Blow Off Valves
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Sun, 24 October 2004 12:13
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just get a pod.. i doubt it will raise power at all over a good filter.. but your noise will be better, try shield it from heat though
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