Rate this: Blow off valves (1 Viewer)

[seremify007]

Sexy or not?

 

[Optimus Prime]

flutter sound is compressor surge...
blow of valves are a necessity.

 

[seremify007]

I'm asking more in general whether people think they are or aren't cool considering there are some guys who purposely get a much louder atmo ventilated BOV... or worse, some people buy the fake BOV speakers and fit it to their car *shudder*

I personally have my stock BOV and it's already quite a bit loud... but I do like the sound. Not sick of it yet

 

[Optimus Prime]

my mates 300zx the BOV is louder than the exhaust...
Nothing compared to my neighbour whose S14 has an external wastegate though.

Edit: and I know wastegates and BOVs are not the same thing, but yeah, holy fuck.

 

[Phantomeureka]

Favourite bov would be the tial Q 55mm

 

[hungwell1337]

its douchey, but better than a turbo tip

 

[Optimus Prime]

Oh and my opinion (and my friend agrees too) it's really annoying but necessary.

 

[hvf26]

theyre useful in venting excess boost so it helps in not damaging parts
but if theyre too loud theyre so douchey...

 

[Optimus Prime]

when you're running 18psi it's hard to make them quiet though

 

[seremify007]

when you're running 18psi it's hard to make them quiet though

I'm pushing 19psi (stock) and I agree it's a bit loud, but it's nowhere near as loud as some people who use aftermarket.

Mine isn't too noisy: YouTube - Injen SRI + GReddy Informeter Touch on Evo X MR (AUDM)
... but then this is from inside the car.

 

[Havox]

If the loudness is a necessity then its fine, but if its a done up Excel then its douchey.

 

[hvf26]

I'm pushing 19psi (stock) and I agree it's a bit loud, but it's nowhere near as loud as some people who use aftermarket.

Mine isn't too noisy: YouTube - Injen SRI + GReddy Informeter Touch on Evo X MR (AUDM)
... but then this is from inside the car.

nice car dude haha, saw the skid pan vid

 

[Optimus Prime]

I'm pushing 19psi (stock) and I agree it's a bit loud, but it's nowhere near as loud as some people who use aftermarket.

Mine isn't too noisy: YouTube - Injen SRI + GReddy Informeter Touch on Evo X MR (AUDM)
... but then this is from inside the car.

smaller engine plus stock is like 16 on an evo?

edit: also your bov is shit and not doing its job because its too quiet, flutter is compressor surge.

 

[Havox]

edit: also your bov is shit and not doing its job because its too quiet, flutter is compressor surge.

Noise isn't everything...An Evo is a no compromise track car and I'm positive Mitsu engineers know what they're doing especially when it comes to turbocharging. They'd at least know a lot more than you do and what is appropriate/necessary for their flagship beast.

 

[seremify007]

smaller engine plus stock is like 16 on an evo?

smaller engine? no idea what u're referring to but stock is 19psi.

SS-T boost varies dependant of mode you are in.

1.3 bar in Normal
1.5 bar in Sport
1.7 bar in Super Sport with it spiking into 1.8 at times.

Manual is fairly consistant with the SS-T with max boost.

You have to remember, the 4B11 is a fairly serious engine from factory. Four bolt crank cap on each journal, semi-enclosed deck, forged Mahle pistons, chunky conrods and a strengthened crankshaft. The stock engine reads like a 'built' engine. Why do you think we can take the car from 217kW to 275kW with just an ECU tune and a rear muffler modification. Thats all!

Source: Kijima, Evo X stock boost - JDM Style Tuning Forum (he works for TMR Australia)

Note: (approx from Google)
1.3 bar = 18.9 psi
1.5 bar = 21.7 psi
1.7 bar = 24.7 psi

edit: also your bov is shit and not doing its job because its too quiet, flutter is compressor surge.

...as for the BOV being too quiet... it isn't venting to atmo since it's a compressor bypass valve so u are correct. either way though, it's stock mitsu and does the job. the fluttering sound is coming from the intake rather than the bypass but it's still a bit noisy on the outside of the car.

 

[Optimus Prime]

its a great sports car, yeah, but its still a road car too, and the bov is somewhat quiet because noisy ones are annoying. Just like stock exhausts are relatively quiet. Flutter sound is compressor surge, that's all there is to it. No doubt that they have reasoned that that level of it is acceptable without shortening the compressors life.

Noise isn't everything...An Evo is a no compromise track car and I'm positive Mitsu engineers know what they're doing especially when it comes to turbocharging. They'd at least know a lot more than you do and what is appropriate/necessary for their flagship beast.

I'm not disputing they know what they're doing, but as you said they choose what is appropriate not what is absolutely the best performance.

 

[Havox]

its a great sports car, yeah, but its still a road car too, and the bov is somewhat quiet because noisy ones are annoying. Just like stock exhausts are relatively quiet. Flutter sound is compressor surge, that's all there is to it. No doubt that they have reasoned that that level of it is acceptable without shortening the compressors life.

Yea, shouldn't be a problem then. Just the sound of the compressed air going through the intake, hitting the throttle and going back through the turbo. As long the pressure surge and backflow isn't too high then there shouldn't be any ill effect on performance or durability. Like you said, the engineers have already taken this into account

 

[seremify007]

At the end of the day, the car is designed for road use as well as track use- these factors have already been considered when they tuned the engine at the factory. Whether or not that still applies once you get the 270kW+ ECU tunes is another matter.

Anyway I'm not planning to go for an aftermarket BOV. Last thing I need is more attention. Currently considering dewinging it.