Is there a BOV that harmlessly make flutter sound?

[supraturbo_mk3]

I know it sounds ricey but I like the sound, is there a BOV that makes that sound without it being bad for the turbo??

[87hilux7mge]

as in a flutter sound like...? instead of a constant pulse or pressure relief sound, it pulses up and down?

ive never heard of one being made to do that. that is the sign of an improperly operating BOV as far as ive heard/researched.

[supraturbo_mk3]

Well I don't mean exactly a flutter but I like when the sound pulses

[87hilux7mge]

yea, same deal, not good as far as i have heard.

if you are talking about the sound that the R34 skyline makes in 2 fast 2 furious in the beginning b4 the race (sorry only reference i can think of right now) then yea that is not a good sound. the spring is most likely worn out and is bounced off the limit and rebounds multiple times.

that car actually used to be here in spokane, went to spaldings auto first, then was bought by the local tech college and restored.

anyway, no, i dont think there is one that will do that safely, it would slowly cause compressor back surge, putting pressure on the bearings and inlet turbine, wearing them out prematurely.

[supraturbo_mk3]

Yeah I know the effect's of compressor surge....It blow up a friend of mines turbo either that or he didn't give it enough time to cool down before shutting engine down...He wouldn't know the difference so couldn't give exact details

[cre]

The characteristics of failure from oil coking (from not letting a turbo cool a bit before stopping the oil flow) and from compressor surge are very different.... if you have a mind to do an autopsy. If he wanted to know what killed it your friend could have found out.

I'm glad everyone knows what it is and why it sounds that way... The only way you're going to get that sound without the oscillating manifold pressure and erratic valve behavior would be to add more piping with a mechanism to create the effect (I'm thinking copper pipe and ball bearings, reliefs cut in the pipe above the ball bearing's resting point).

Keep in mind that at low pressures (where it's more likely to occur) isn't always going to cause a problem, it depends a lot on the rest of the system and the health and design of the turbo. The reason you hear a lot of highly tuned cars make that sound it that the BOV is intentionally tuned that way. This allows for a slight increase in responsiveness while shifting but once the system starts bossting past what they consider to be a critical level it will open properly and the flutter sound will stop. Some people do it just for cool points though. A lot of high end race cars employ multiple BOV's each set at a different flow and trigger pressure. A small BOV used at lower boost levels to bleed just enough to reduce surge but leave enough pressure for a quicker return to positive pressure after the shift, then another large unit to dump at higher pressures. I know, an even quieter solution isn't what you're looking for... sorry.

[cre]

I love this show and amusingly enough this is all covered pretty well (although basically).

http://www.youtube.com/watch?v=Z_fG_...feature=relmfu

Just thought I'd share.

[supraturbo_mk3]

lol Thanks for the video! Actually some useful info in there too.........I have a question, I bought a turboXS RFL it can vent to the atmosphere and recirculate at the same time. At the moment I have it venting to the atmosphere only and I still have my stock BOV hooked (Because my car is sitting) and I hooked it up to make sure it works properly......What are if any effects should I expect if I were to drive it like that while I wait for my IC piping?

[supraturbo_mk3]

Originally Posted by cre

The characteristics of failure from oil coking (from not letting a turbo cool a bit before stopping the oil flow) and from compressor surge are very different.... if you have a mind to do an autopsy. If he wanted to know what killed it your friend could have found out.

I'm glad everyone knows what it is and why it sounds that way... The only way you're going to get that sound without the oscillating manifold pressure and erratic valve behavior would be to add more piping with a mechanism to create the effect (I'm thinking copper pipe and ball bearings, reliefs cut in the pipe above the ball bearing's resting point).

Keep in mind that at low pressures (where it's more likely to occur) isn't always going to cause a problem, it depends a lot on the rest of the system and the health and design of the turbo. The reason you hear a lot of highly tuned cars make that sound it that the BOV is intentionally tuned that way. This allows for a slight increase in responsiveness while shifting but once the system starts bossting past what they consider to be a critical level it will open properly and the flutter sound will stop. Some people do it just for cool points though. A lot of high end race cars employ multiple BOV's each set at a different flow and trigger pressure. A small BOV used at lower boost levels to bleed just enough to reduce surge but leave enough pressure for a quicker return to positive pressure after the shift, then another large unit to dump at higher pressures. I know, an even quieter solution isn't what you're looking for... sorry.

I see what your saying....When driving my normal, (low boost) my old 95 GS-T would flutter a little (not very loud) but at high boost my greddy type S would sound normal but my supra doesn't do that at all and I miss it lol