What kind of BOV?

[stillmatic]

I've been meaning to ask this for a while now.. Does anyone know what kind of BOV they use in those Best Motoring videos? It sort of sounds like a horse ... Also, is it called a blow off valve or shut off valve?

[aleph1]

The valves they have are set very "loosely" I believe, and most BOV make that flutter sound when set like that. I would think it would be bad for performance, but these major japanese tuning companies set the BOV like this...why??

[02_silver_wagon]

Here is a website with BOV sound clips. Personaly I think the RFL and Forge sound the best. Here it is

[andrave]

what sort of horse sound? that "chii chi chi" that you hear in some is compressor surge...

[WDRacing]

Sweet, I love compressor surge, how do I get that???

[aleph1]

Uh, it only makes the sound when they are off throttle...so I dont think it can be compressor surge...eh?

[stillmatic]

what sort of horse sound? that "chii chi chi" that you hear in some is compressor surge...

It just sounds like a horse humming... The second "HKS SSQV Clip (full sound effect)" from the 935motorsports link almost sounds the same, but still not quite like the ones in those japanese videos.

[SHIEF]

I believe, if you are talking about that Supra fluttering, I think that it's the Blitz bov.

[3rD GeAr]

most of them resemble my blitz dd bov and i even get that wonderful compressor surge sound. The bov only sounds real loud like that at high boost though.

[stillmatic]

Okay, this is the sound I'm talking about:http://members.aol.com/s132fortysx/bov.mp3

[02_silver_wagon]

WHAT KIND OF BOV IS THAT? It should horable.

[SHIEF]

I also like that bov, just because it doesn't sound like a SSQV, or a Greddy because those are so rare :rolleyes

[aleph1]

Some people actually buy BOVs for their performance. :rolleyes

[creophus]

You're right. It does sound like a horse! Please don't tell me you like the way that sounds. I like the "whoosh" sound personally.

[stillmatic]

WDRacing is right. The sound does come from a compressor surge. You can achieve the same sound by using a compressor that doesn't match with the turbo or run a lot of boost without a BOV.

[aleph1]

Well, considering these cars are finely tuned. I doubt that its a compressor mismatch. I know they run high boost, but no BOV?? Why? and how would it make external noise?

[stillmatic]

Compressor surge is extra air that didn't make it to the intake, so instead it comes out through the turbo. This happens when you don't have a bov to release the pressure.

[aleph1]

how can it "come out" through the turbo? The only way I can think of is out of the filter.

[stillmatic]

I don't know anymore. Now someone is telling me that it could be a BOV... Some say it's an HKS bov, some say it's a Blitz..

[aleph1]

I still stand by my statement that it revolves around the setting on the BOV itself, most likely mixed with high boost. Personally I think the BOV is fluttering so it doesnt let ALL the boost out, similar to WRC settings, so they still have some compressed air still left in the piping/compressor so when they let off the throttle and come back it doenst have to build as much boost. Ive heard both the Blitz and SSQV. I HIGHLY doubt the HKS unit is capable of this sound. The Blitz is a very common design and could pull it off. I think it has less to do with the brand of BOV and more by the TYPE. Greddy, Blitz, possibly Apexi could all do it me thinks...

[stillmatic]

I think it's compressor surge but no one really knows for sure..

Here's a guy who had the same fluterring sound:http://www.automotiveforums.co....html

[aleph1]

AH! It is surge, and the noise DOES come out the filter...lol Good job stillmatic!! FINALLY ITS SOLVED!

[WDRacing]

I thought we said that already??

[SHIEF]

So to get this "surge noise" you could just adjust the bov to not open fully or not allow it to flow as much air, right?

[aleph1]

Well you guys said it was surge, but no one really pinpointed it. Compressor surge is like a general solution, but nobody said the noise comes from out of the air filter...which is weird but true.

[Chingon]

Ok, so I had to contact the knowledgeable friends of teamfc and this is what one of the members said about pro's having this issue (made total sense):

"Its not that they like it (surge) but take 25psi motor with a bov that doesnt like to be under 15psi (hard springs valves). So If the bov is built to operate over 15psi if you hit the gas and build 13psi then come off theres not enough pressure to hold the pisont on the valve open and you get surge, If you watch the cars they dont surge off of straights only when there on the throttle for short amounts of time.

Statik"

[aleph1]

Hmmm that does make sense now that I think a bit more about it. Cuz if you play those Mazda videos, the one with the weird noise in particular you cant hear the BOV (normal PSHHH sound, as in the second vid) at all, which leads me to believe that the sound is from the BOV itself.

Plus, in reference to what that guys quote says, its true that the japanese D1 cars and such make this sound even when on throttle very little, hardly enough to build significant boost. This is a very interesting conversation...to me at least...I like learning. =)