blow off valves

which blow off valves make the sound that kind of spuders when blowing off like.. psh-psh-psh-psh but really fast. Also what type of blow off is the best type, piston type or spring type? thanks

please don't get a bov just based on it sound. If you just want that, go with one of the electronic bov noise making things and don't waste the money on a turbo. The Tial and HKS are nice bov's, if you want a nice pshht, the greddy type s isn't bad. But the Tial under high boost sounds mean as hell.

"please don't get a bov just based on it sound."

Why else do you think hes asking?

I know why he asked, and i gave my reasoning for why I said what I did. So pretty much what your telling me is most of you just care about what your car sounds like vs. how it performs?

nope i dont care if my blow off valve sounds like a bunch of howler monkeys beating on the cage at the zoo as long as it does what its designed for proficiently.
I didnt answer him because it sounded like he just cared about the sound.
That and the psh psh stuff made me crack up and press the back button. :iceslolan

Are you sure that psh psh psh psh sound isnt just turbo lag? I dont know much but thats my guess.

Originally posted by hondaturbo
Are you sure that psh psh psh psh sound isnt just turbo lag? I dont know much but thats my guess.


the release of presure during closed throttle has nothing to do with turbo lag......

Originally posted by V00D00
nope i dont care if my blow off valve sounds like a bunch of howler monkeys beating on the cage at the zoo as long as it does what its designed for proficiently.


LOL, exactly.

Originally posted by V00D00
"please don't get a bov just based on it sound."

Why else do you think hes asking?

off topic but your sig doesnt make sense, cars with exhaust are louder when they're driving with strain on the engine (in gear with your foot on the gas) than in neutral. so if they're driving along and you hear a loud noise its just because he has exhaust, not because he's revving at you.. i like the drawings though, they're good.

The flutter sound your hearing is LACK of a BOV, most likely compressor surge. It's a BAD thing, and you don't want that. Although it does sound cool. :-P

I only use HKS or Tial BOV's. Personal preference, when in doubt, stick with companies that know their shit. GReedy, HKS, Tial. etc.

i think his question is perfectly legit. most any bov made by a reputable company is going to function well if its placed correctly...i would ask about the sound as well. although his 'example' did make me laugh. just my $.02 :D

Position of the BOV doesnt matter when it comes to the performance of the BOV.

Actually there are BOV's that make that fluttering sound that he describes, that sound probably isn't compressor surge. The fluttering sound is a result of sequential blow off valves. I don't think the make really matters, as long as it is a sequential setup.
The sound of a turbo without a BOV isn't so much a fluttering like he describes, but a high pitched, whirring sound. I have to agree that you shouldn't buy a bypass valve solely on the sound it makes, buy one that suits your needs.

High pitched whurr? WTF?
Everyone, as your homework for today, disconnect the vacuum from your BOV today and drive down the street, spool up, and release. Please describe this sound to the class when you return.

End yourself. Sequential BOV's (made specificly by HKS IIRC) sound nothing like compressor surge.

re: position of the BOV, youre supposed to put it as close to the intake manifold as possible because thats where the pressure builds up. and yes, of course do some research and make sure youre getting a good performer, but i just re-read an article in SCC last night where they tested about 20 of them, and pretty much all of them performed the same. there was one...i think it might been the Blitz SS one, where they said it was the "catcall" of the bunch, meaning it didnt perform as well as the others but looked and sounded better. and they hailed the gen 1 DSM as a good standby. ill check on the catcall later

If your buying a BOV from a well known company, its more than likely gonna perform well. So why not get one that sounds and looks good? My Vortec bypass valve makes the stuttering sound that 4drcivic first described. Followed by a cool whistling sound from the breather. Its a pretty loud release, much louder than say a Greddy BOV, and the whistling sound that follows is kinda neat.

Well, to all of you that made fun of the question. I did not even refer that i was getting a BOV becasue of the sound. All i was asking was which BOV made a certain sound, becasue i had seen a Teg Type-r and his BOV was a fluttering type sound and i had not heard that before. Try to read before you comment in stead of bashing somebodys question. Anyway, thanks for the help.

Your right, sequential BOV's don't sound like compressor surge, and compressor surge doesn't sound like the fluttering he described. Read through this (http://www.rsphysse.anu.edu.au/~amh110/Technical_pages/blow_off_valve.htm), in it is this Cars and trucks without a vent valve emit a high shrill-whirr sound, as the compressor back cuts the air. Listen to a turbo truck between gearchanges. Also, it is not only the HKS sequential BOV that makes that sound; at a rotary shop I worked in for experience, we installed a custom turbo setup on a 2nd gen Rx-7 that used dual bypass valves. These bypass valves made this sound. Think about it, why would compressor surge make a fluttering sound? The air flow from a compressor is constant, not punctuated, therefor the sound would also be constant rather than puntuated like a fluttering. I think you are thinking of a different sound.

Do you have a turbo/bov? Please remove the vacuum hose. Drive around.

Thanks.

Actually yes, I own a First gen Rx-7 with a TII swap, and my Neon is turbocharged (not factory of course). While my turbo setup on my Neon was still in it's beginning stages I didn't have a blow off valve. Not a pulsating or fluttering sound was ever evident. I did, however, observe the whining sound I have already described. Please explain to me why compressor surge would make a pulsating sound. I can explain why it wouldn't.

Here's why it wouldn't
The air from the compressor follows the plumbing to the throttle body, when throttle is released, the throttle boddy closes. The air from the compressor backs up against the butterfly valve, through the plumbing, and puts back pressure on the compressor. This pressure on the compressor wheel creates an audible whining noise as the compressor is struggling to maintain it's correct forward motion.

Here's the only way it would
The only reason a steady stream of air would make a pulsating sound is if the air was being vented out in a pulsating fashion, or something was periodically interfering with the air stream. The venting would be a blow off valve, but what could be interfering with the air stream in such a way as to create a pulsating noise? The air usually (I say usually because sometimes bypass valveless systems will encounter enough pressure to stop the compressor wheel, or turn it the opposite direction)never actually forces its self back into the compressor (if it does it will destroy your turbo far quicker than the simple back pressure on it), the air being forced out of the compressor stops the air trapped by the throttle body from actually backing into the wheel, and reversing it's direction. Think about it, to create a pulsating noise, something needs to be pulsating, I can't think of anything that would pulsate in a bypass valveless system. The pulsating noise could, however, be created by a blow of valve, pulsating as it releases pressure.

U R DUMB. Period.
stop talking.

The air backs up and STOPS The motion of the turbo as it is forced backwards. Creating the wonderful sound of compressor surge. Sounds like SHH SHH SHH, PS. This DOES destroy your turbo. Causes the thrust bearings lots of stress and boom, they die.

Thank you, please drive though.

Actually, you should learn how to read, I did say that it will kill your turbo. And compressor surge doesn't always result in the compressor wheel stopping. You still haven't explained WHY surge would cause a pulsating sound. Why would a stopped compressor make a pulsating sound?

So far the only explanation I got from you is "[I am] DUMB PERIOD"

Growl. Why are people on this board so impossible to make understand...

Compressor SURGE, it stops the tubo gradually, the air gets chopped up from the wheel, and flutters out of the intake.

http://natoubb.turboford.org/Forum11/HTML/000383.html

They explain it similarly.

I'll find some more. Hell Im looking for a god damned wave file...

By the way, in situations where the surge is great enough to stop or reverse the impeller, generally the impeller blades are at high risk. Although you ARE right about the bearing damage that occurs, the the damage to the shaft is what is ftal to the turbo (no bearings, the shaft doesn't last long).

Holy shit? Could this be another one?
Yes.

http://www.mrtrally.com.au/forums/topic.asp?TOPIC_ID=7802

STFU Noob.

In my experience, the sound is not a slow fluttering like the one described in this thread, but an extremely quick one, which would be a whirring sound. The fluttering he (4drcivic) is describing, is far slower than what you are thinking. BOV flutter happens about 5-6 times per second in a syncronious way, the whirring sound of surge is far quicker and in my opinion isn't a flutter at all, but a whirring.

I will try to find a sound file of the BOV flutter that I am picturing, and once you hear that you will understand, as it can in no way be mistaken for surge.

By the way, I think your personal attacks are ridiculous, and you should be the one to shut the fuck up. This is a forum, where differences of opinion are to be voiced, not silenced. Asshole.

Opinion? It's fact fucktard.

http://www.grc.nasa.gov/WWW/OptInstr/piv/images/figure11.gif

Look, here's a NASA graph of surge on the larger gas turbine engines... now, how could THIS sound like a flutter???

I just don't know.

Firstly, factory blow-off valves reduce noise. Reduce noise? - aren't blow-off valves the ones that make the pppsssssht! noise on gear changes? Yes they do when the valves are vented to atmosphere, but all factory blow off valves are of the recirculating type, where the exhausted air goes back into the intake after the airflow meter. What these valves do is reduce the bbrrrrrt! noise of the compressor blades whirring into a dead-end of a shut throttle...

The quote is from here (http://www.autospeed.com/cms/A_0046/printArticle.html)

Here they describe the sound of surge as whirring as well.

And this comes from that same article...

And if you've got a turbo car, you're sure to have been told that a turbo timer is a good idea. You know, to give time for the turbo to cool down and so stop frying the oil in the turbo bearing after you switch off. Well, I think that turbo timers are a total waste of money. I'll go further - they also make your car easy to steal.

Two things, the nasa link, could you also link me to the text informing me of what kind of turbine that is, what size it is, and what speed it moves at. I am not questioning the validity of the link but in order to answer your question I need to know about the turbine.

Also, here's a NASA graph of surge on the larger gas turbine engines... now, how could THIS sound like a flutter??? I never said that surge sounded like a flutter, that was you.

You didn't include his reasoning So why are they a waste of money? If your car has a water-cooled turbo (all turbo cars of recent times), the heat build-up in the bearing after switch-off isn't so terrible - the water transfers the heat away. The use of synthetic oil also reduces the likelihood of oil coking - and all turbo cars benefit from the safety of running a synthetic. And finally, if you've been driving your car hard, exactly what is the problem in sitting in your car for a minute or two while it idles? You can then let the engine cool down for as long as needed - and it doesn't cost you a cent. He isn't saying that the function of turbo timers is a waste, just payin for a timer to do something that you can do yourself.

That was sarcasm. :)

Another thing your friend in his article says...

Despite the belief to the contrary, some turbo car performance parts do little. Like all generalities, the following doesn't hold true for all cars - just for most.

Firstly, turbo blow-off valves. Basically, in lots of cars they do nothing for performance. For the uninitiated, a blow off valve vents the pressure build-up that occurs between the turbo compressor and the shut throttle blade on gear changes and when the throttle is suddenly closed. If you believe the publicity, this prevents the turbo slowing and also stops a pressure wave attacking the compressor.

Okay, but there are a few problems with the theory. When the throttle is closed there isn't much volume of exhaust gas being produced to keep the turbo spinning anyway. The result? - the turbo slows pretty quickly when the throttle is closed - with or without a blow-off valve. But don't many cars have factory-fitted blow-off valves? They do - and you need to read the workshop manuals to find out why they are used.

?? WTF?? He's a quack!
Yes the turbine slows, and yes you do lose some boost, BUT if you have surge, once you get back on the throttle you have 0psi, with a BOV You now have (in my case 6psi) from the before gained 10, so hence, it helps performance.

This guy knows shit about turbochargers.

NASA LINK:

http://www.grc.nasa.gov/WWW/OptInstr/piv/compressor_surge.htm

I'm gonna have to agree with you on that one, suggesting a turbo system without a BOV is pretty stupid, I hadn't read that far into the article. Anyways that isn't the point, I am simply trying to find people who describe the sound the same way as me. Still workin on that nasa stuff.

Another fun thing to mention. from my understanding, and my turbo builders' synthetic oil fucks up turbo seals, makes them last half as long... go figure.

Really? I'll have to check that out, I had never heard that. Interesting, I'll look into that, thanks for the advice. Synthetic help avoid coking, but I didn't know about the seal issue. I'd have to say that you got me on the nasa turbine. I stick with my opinion, and somehow I don't think I am gonna change yours, call it a draw?

Until I make a video of my compressor surging. :D

Stay tuned. Cheers. :comprage1

I'll try to get some sound files of mine, and if the Rx-7 with the BOV flutter comes in, I will get that too.

Originally posted by Cronic
Another fun thing to mention. from my understanding, and my turbo builders' synthetic oil fucks up turbo seals, makes them last half as long... go figure.


how can that be??? All turbo cars are suposed to run on synthetic.....on the evo for example they recomend mobil 1 supersyn.....why would they recomend the wrong oil on a new car.....they would end up with the cost of repairing it....

Ball bearing turbos are slightly different. I believe that is why they recommend it. Everyone recommends synth, it's just NOT the way to go on FI cars.
Although everyone has a different opinion. I have friends that run NOTHING but synthetic in they're DSM's. Most of them do have ball bearing turbos, however.
Since I have a full Crower head, and David Crower says to me, "Do NOT use Synthetic." I won't use it. :) Regardless of my turbo.

I have no personally seen Synthetic make turbo seals go bad. *shrug* Since my turbo builder provides my warranty for my turbos, I'll go with what he says. :)

I hear the Blitz SS (stands for Super Sound), looks really nice, and has a pretty loud PSSSSHHHH!!!.
:tongue:
Go look it up on the Blitz's website.

Originally posted by 4drcivic
Well, to all of you that made fun of the question. I did not even refer that i was getting a BOV becasue of the sound. All i was asking was which BOV made a certain sound, becasue i had seen a Teg Type-r and his BOV was a fluttering type sound and i had not heard that before. Try to read before you comment in stead of bashing somebodys question. Anyway, thanks for the help.

i made the first reply. I didn't mean to sound like i was making fun of you. There are alot of people i know that only buy things for the way they sound or look and not based on how they perform.

actually the blitz super sequential bov is the one i was talking about earlier. the "catcall." it looks sweet, and it has different inserts to make it sound different, but it didnt perform as well as the rest

which BOV's can u NOT hear for like a sleeper?

i dont think its possible... but mebbe. ive never heard of it though. maybe if it was just a really large diameter so it didnt whistle/whoosh as much..

One that has been router into the intake, 1g DSM's and 2g dsm's are great. I ran 17psi through a 2g for a while.

Originally posted by funkdaflex1
which BOV's can u NOT hear for like a sleeper?

Tial, my bov does not sound loud untill under high boost around 1bar and up

good stuff good stuff im gunna have to pick me up one of those so i can start winning some money...... no one ever wants to race cuz my car is turbo....

Originally posted by Cronic
One that has been router into the intake, 1g DSM's and 2g dsm's are great. I ran 17psi through a 2g for a while.

Well, that is surprising. The second gen DVs would leak after about 15PSI. The first gen DVs could hold a lot more boost.

ok, I have a couple of questions. on my turbo, there is an internal wastegate, and on the compressorside, there is a line that runs to a vaccum canister looking thing, then out of the canister there ids a long bar that opens a diaphragm on the exhaust side. so Im guessing when the compressor side gets past a certain point of boost it opens it up, is that right?

also on a BOV, is the way it releases the pressure by when your throttle plate closes and the turbos still spinning compressing air, your piping has more pressure than usual and it opens up just by poressure, like dop you tighten a spring or something to adjust it? and anyone know what old MX6 turbos boost was. cuz I have seen a mnifold that was supposedly from an MX6 that matched the flange one my IHI turbo, I dont necesarily know its form an MX6, but the wastegate isnt adjustable at all so I wanna see if it is gonna be too much boost or not enough, maybe just right. if it is too much or too little, I could just get an external one and wire the internal one closed right?

What you described is the wastegate actuator.
It opens up at a set psi, either with a diaphram, or a spring. Some are adjustable.

There are a few types of BOV's push types, and pull types are ones' Im familar with, they all work off the vacuum from the TB, once it reaches vacuum, the BOV opens and releases pressure. The push types are succeptable to leak because they can be pushed open from high boost. (15psi+ usually)

To use an external gate on a turbo that has internal stock, the wastegate port must be welded shut.