BPV Question

[rjspeed]

Striker
Thanx for all the help I really appreciate it as this is my first turbo car. Do you have any pics as where to mount the BOV so that it will be loud? Also what is the price difference between the two BOV's and where can I order them at?
Thanx again
Ryan

 

[KyRaceFan]

Which is louder HKS ssqv or Greedy Type S? I take it that there is no aftermarket BPV available?

HKS is louder... its a sharp whoosh
Greddy Type S is like a whistle.. go listen to the BOVs from F&F..thats a greddy BOV being used on most of the cars.

If you get hardpipes made,like the ones im getting done, then you just have them weld on the appropriate flange. The HKS type h rfl comes with the flanges ready for weld. HKS does too, but i think its extra

 

[YuYuRena]

the "flutter" or "gobble" is compresser surge.

I wouldn't say it's a compressor surge. Trust me, I have seen compressor surge on a larger "scale" and it's something that FAA doesn't like. Plus if it's a compressor surge is what's causing that sound, then everyone's compressor wheel would be shot by about 3k miles.

 

[rjspeed]

Is the HKS SSQV a short psht noise or a longer one? I know it depends on how fast you shift but even on a slow shift some BOV give off a very short psht instead of a long pshhhhhhhht.

 

[girth]

I have no scientific proof, but I'm quite certain that the flutter is caused by the turbo's compressor wheel surging and stalling. This surge and stall does not really harm the turbo because its compressor wheel is so tiny and because it is running such low boost pressure. All turbos make this sound to some small extent (you just can't always hear it), but a perfect BOV can eliminate the compressor surge and stall effect. On high boost engines (which the MSP most certainly is not) the compressor stall can damage the compressor wheel due to its increased inertia and can even unwind the compressor wheel from its shaft - which is why most "racing" competition turbos use a left-hand threaded shaft.

Try blowing into a fan and you'll get a similar sound. Air is hitting the turbo's compressor blades in the wrong direction.

 

[KyRaceFan]

when shifting fast, the HKS is a very quick high pitched shriek.
The greddy type s is usually a longer whistle...

 

[Striker187]

rjspeed - no pics, sorry. but just think about putting it somewhere close the outside of the car to maximize what you'll hear. those who choose to go this route generally put it near the intercooler. but from what i've always heard is that the rule of thumb is to place the bov close to the throttle body (quicker pressure? i dunno...). don't get me wrong, a bov placed near the throttle body will sound plenty loud.

there's really not that much of a difference in price. maybe $20. shop around, the greddy can be had for about $180 and the hks $190-210. if you wanna know what the hks will sound like, visit www.blowoffvalves.com. they have plenty of recordings of the hks....it's a favorite among supra owners.

girth - if it is compressor surge, why would tuned cars, such as the cars i mentioned above, have it then?

 

[girth]

girth - if it is compressor surge, why would tuned cars, such as the cars i mentioned above, have it then?

Were they recirculating or blowing off to ATM? If blowing off, then I'd say their pressure relief screw was not adjusted perfectly (one of the reasons a BOV can be a pain in the arse). If they were recirculating, then I'm not sure ......... how big of turbo and how high of boost were they running? All of that factors into it. Personally I think nearly all turbos make this sound, just on different levels of "audibleness" (is that a word? lol)

 

[Striker187]

i'm pretty sure they were venting. just seems weird that the tuner would leave it set with compressor surge. these clips i saw were taken from best motoring vids (except for the is300...you'd think tuners would have their car perfectly set before letting them be driven by the testers.

 

[girth]

I agree that it is odd. And by no means am I an "expert" on the subject -- all of those guys with those cars are probably far more knowledgable than I am on the subject. Flat out, we need a turbo expert to get on this board.

 

[Sparkz28SS]

the "flutter" or "gobble" is compresser surge.

true true......



and you can try a bigass BOV,it willl help it for the most part.It helped out on my Z28...the flutter may not always be audible ...but it will never go away...

 

[girth]

true true......



and you can try a bigass BOV,it willl help it for the most part.It helped out on my Z28...the flutter may not always be audible ...but it will never go away...

I concur.

 

[Striker187]

i wonder if the flutter will still remain when i get around to changing out the bpv....then i could make like a tuned jdm monster waaaaapshh, psssh, psssh, psssh!!!