Alright so this post might not have any real useful outcome but i want to see what everyone else thinks.

So I have the Greddy Type RS on my Eclipse, and its not that i dont like the sound that it makes. I just like the sound of the Type S alot better. So i was sitting here thinking about how they work. My theory is that the whistle that you hear from the Type S comes from some flow of air over the nossel (like blowing air over a bottle). The Type RS has little holes cut into the nossel so im thinking that those holes eliminate the whistle. So what i will attempt to do is try to make my Type RS whistle. So, if anyone has any other theories or ideas i would like to hear them.

 

well if you unscrew the horn on the type-rs wouldnt it be almost identical to the type-s? i'm not sure on the exact dimensions of the bov but i would assume they are very similar

 

thats what i was thinking

 

yea take that piece off that screws on and see if it changes.

 

let me know what happens because i want to get a type s but i have a type rs just sitting around.

 

you shoulda asked this question a few days ago and i could have tested it for you, now i'mback at school and can't, if it sounds the same as a type-s with the horn off that would be pretty interesting

 

ok... if i take off the horn piece i think that it will just sound like random air because it has no track for the air to go out (I will still try it though). Also, that screw on the top of the Type RS is adjustment for the spring inside the BOV itself. And if i take it off or out it will just let all my boost pressure out.

Im thinking of maybe somehow covering the holes in the horn piece to possibly allow for the air to "whistle out". I will give the horn off a shot, but any other suggestions would be awesome too. Thanks

 

At that point I think it might 'whoosh' out like the TurboXS BOV's

 

also i think the rs has a slightly larger valve allowing it to flow more air, giving it more of a whoosh than a whistle.

 

this is interesting i wanna know also, I bought an Rs cause the greddy site said improved sound. Why do companies always chage things that are so popular, like they are just toying with us......
well any ways I wanna know I might even buy another BOV I.e. a type S

 

The Type S has a slightly larger valve (not comparable to the Tial though) and does make a more 'airy' sound than the S.

I just switched BOV's and my system evacuates pressure noticibly faster now.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by T3mp3sT &raquo;</TD></TR><TR><TD CLASS="quote">The Type S has a slightly larger valve (not comparable to the Tial though) and does make a more 'airy' sound than the S.

I just switched BOV's and my system evacuates pressure noticibly faster now.</TD></TR></TABLE>

is this with the rs or S?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Dstretch33 &raquo;</TD></TR><TR><TD CLASS="quote">

is this with the rs or S?</TD></TR></TABLE>
Sorry
The RS has a quicker evacuation time than the S.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SOHC50shot &raquo;</TD></TR><TR><TD CLASS="quote">ok... if i take off the horn piece i think that it will just sound like random air because it has no track for the air to go out (I will still try it though). Also, that screw on the top of the Type RS is adjustment for the spring inside the BOV itself. And if i take it off or out it will just let all my boost pressure out.

Im thinking of maybe somehow covering the holes in the horn piece to possibly allow for the air to "whistle out". I will give the horn off a shot, but any other suggestions would be awesome too. Thanks </TD></TR></TABLE>

have you seen the type-s?? it just has the outlet on the bov no specialpieces or anything just a threaded hole and it gets that high pitched noise... as for the boost leaking out at the adjustment screw, it wont thats not where the boost pressure goes to through the vacuum line...

 

yea ive never seen the Type S close enough to examine it, so im not really sure what you mean by a threaded hole.. And i to correct what i said before, i know the pressure wont come out of the adjustment screw hole. I was saying if i take the adjustment screw out, the valve in the BOV would be constantly open and it would not function properly.

 

if you take the adjustment screw out the valve wont be open it just wont hold as much boost, it will still function without the bolt there. AS for the threaded hole part you know on the type-rs how you can unscrew the horn on the discharge outlet? If you take it off it looks the exact same as a type-s which just has a threaded discharge outlet/hole

 

you are wrong. boost pressure will escape through the adjustment hole. it is doing it on my turbonetics raptor BOV. where i used to have 7 it will only hold 4 now. thats why im going to get the greddy anyway.

 

Ok if you have the adjustment screw all the way in the bov will have a very hard time discharging and in turn holds more boost, now if you take it all the way out there is less tension in the spring letting the bov either bov easier or actually be pushed open by the boost pressure on the opposite side of the valve... you are wrong

 

and just for reference:

 

Keep in mind that the BOV is vacuum activated....


gosh.

 

Alright well that makes sense. Yea i see what your talkin about now with the threaded horn/outlet (thanks for the pics, i suppose my lazy *** could have looked that up myself, haha). As for the adjustment screw i just assumed that because i had it all the way out when i got it, the car idled like crap and it wouldnt build boost, i thought thats what i was trying to convey (less tenstion=easier for the valve to open).. whatever the case im gonna run a few experiments today so i will let you guys know how it goes.. lets hope i can get that biatch to whistle~



thanks for the input

 

Alright well.....

My theory was that a majority of the whistling/churp of the type S was due to something similar to blowing over an empty bottle. I thought this because if you look at the outlet of the Type S its a cylinder shape, and when the air leaves the BOV it moves out in such a fasion that it gives the signature Type S sound. The Type RS has a horn shaped outlet with holes drilled into it. And my theory is that it doesnt churp or whistle because of that design.. So i ran a few experiments to see if i could get it to sound like the Type S.


Experiment 1
I removed the blue horned piece from the BOV itself to see if it would do anything. Results: Nothing, the type RS noise (whoosh) was still present and if anything it was less intense.

Experiment 2
I covered the horn piece with a 2in section of the old recirculation tube. I did this because i wanted to see if i could mimic the cylinder desigin of the Type S. Reults: same noise....

Experiment 3
i moved the adjustment screw all the way out (car stalled) and close to all the way in (I could barely get it to release pressure =no good)

So-- i think that because the end is shaped like a horn it will not whistle.. so once i get back down to school i will see if i can fabricate a threaded cylinder to replace the horn outlet..

any more suggestions or ideas on how to help that would be awesome.
thanks

 

The adjustment bolt and the vacuum signal are both on the top half of the diaphram, it won't create a vacuum if the bolt is gone. 99accordvtec is right...

 

my type-s worked without the screw, the hole got stripped and i ran without it and it still blew off...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Dstretch33 &raquo;</TD></TR><TR><TD CLASS="quote">this is interesting i wanna know also, I bought an Rs cause the greddy site said improved sound. Why do companies always chage things that are so popular, like they are just toying with us......
</TD></TR></TABLE>

i seriously doubt greddy redesigned it BOV solely on the sound. i love BOVs just as much as anyone else but really sound isnt that important and shouldnt really be considered in its performance. the bigger RS valve flows more air, yes it changed the sound but it also increased the performance of the BOV.

tial uses a huge 50mm valve because it flows a huge amount of air and i think thats why you see them the most on race cars. i say as long as the BOV is doing its job and eliminating compressor surge and reducing lag then cool go for whatever sound you want. but dont be mad at greddy for making a better performing BOV just cause it doesnt sound the same as it use to.