SnyperZ

iTrader: (10)

After installing my kit and experiencing heavy compressor surge I did a little research. Tial BOVs come standard with an 11psi spring. Our cars require a 9 psi spring. They base spring pressure on the hg's you pull in your car. The only options are 7psi, 9,11 and 12. Our cars don't pull enough Hgs to run a 12 or 11psi. The bov should fully open and stay open upon upon engine vacuum and as soon as you apply throttle and it losses vaccum it should close.Im going to replace my 11psi spring with a 9 and see if it eliminates the surge and if not ill step down to the 7 spring. I do NOT want any shaft play in my new turbo..even though at 4psi im not really hurting the turbo yet. Also just so theres no confusion..the amount of boost you run has NOTHING to do with the spring pressures needed for your car. The vacuum your car pulls is what compresses the spring and opens the valve to let air out..if the spring is too strong the vacuum wont be strong enough to open it up to let boost out forcing it back out throuh the turbo.

UpRev

iTrader: (5)

There is no standard Tial 50mm BOV. When a retailer orders them they have to specify what spring to order them with.

Here is the Tial PDF showing what spring to use for the Hg your car pulls.

http://www.tialmedia.com/documents/w3_tial_bov50_sp.pdf

UMW350Z

iTrader: (18)

what is this surge you are talking about? I don't notice anything odd about my PL kit

SnyperZ

iTrader: (10)

If you dont specify which spring they send you an 11lbs spring.

SnyperZ

iTrader: (10)

When you let off the gas your blowoff valve should make a solid release sound..not "flutter".

IIQuickSilverII

iTrader: (13)

flutter isnt surge either



running that softer spring will help

SnyperZ

iTrader: (10)

Thats correct..however if it sounds like a rattle snake..then chances are you getting light surging..(like I am) My BOV doesnt even move when I start the car..im hoping dropping down from the 11 to the 9 will fix it..if not then the 7 def. will.

UMW350Z

iTrader: (18)

hmmm...mine makes that noise only on light load...didn't know that was a bad thing.

When i am fully spooled, it is a solid PSSSHHHH. If i am juuust about into boost and let off or just get into boost at let off, it will flutter. Still not normal?

http://www.youtube.com/watch?v=NQAcVgKPXG4

makes this sound like this car in the vid...light load it does what this car does....full boost it blows off solid like this car too

IIQuickSilverII

iTrader: (13)

yes flutter its oK... HKS ssqv has been doing it for over 10 years and i know cars that have that flutter sound after over 50k miles with a 18 year old engines. You clearly said on light load, so its not surge... so by taste.. if you cant take it use a softer spring, but its fine..I personally think it sounds pretty cool

UMW350Z

iTrader: (18)

Is it safer not to have any flutter at all....i keep seeing all these youtube videos of Tial vs Synaptic BOV's and I am a newb to BOV's period

SnyperZ

iTrader: (10)

Yes, its best not to have any at all. I ordered a 9psi spring and im gonna see how much of a difference it makes..if theres still some ill go down to the 7 and let you know.

UpRev

iTrader: (5)

Synapse Engineering BOV and WG > *

Not going to lie, the guys at Synapse are really damned smart, I've sold their product for a while and never had anything but praise from customers on their parts.

Flutter is never a good thing, just because some people have it and their cars last a long time doesn't mean it's right. Even if it's just for driveability sake and not to stop shaft movement on the compressor, why not just use the better parts?

SnyperZ

iTrader: (10)

I agree..even though it might not hurt the turbo for 50k miles..its still not the way the unit was designed to work. It has to be chosen with the right spring or its never going to work 100%. The bovs only purpose is to relieve pressure in the intake..to prevent surge, blowing couplers and in extreme cases bending TB blades.

IIQuickSilverII

iTrader: (13)

Tial parts are some of the best in the industry and in this case with the PL kit best out of any other turbo kit out there...
I never said flutter is a good thing either... but its not necesarly bad, you can get really picky if you want, but fact remains you could go 50+k miles with out any issues from the flutter..no shaft play......and depending on your taste it sounds pretty cool too
In any case the this is a spring issue, since mark cant take the flutter sound i dont doubt that it will be taken care off with the spring . I just i rather have a strong bov that wont leak at full throttle pulls 8-10+psi ...
I dont think you will assume that the synapse BOV will not flutter if you put too strong a spring too right?

Mark, btw when are you going to get tuned?

UMW350Z

iTrader: (18)

Just to clarify, the flutter noise is coming from the air going back through the turbo (cavitation), or the rapid opening/closing of the BOV?

SnyperZ

iTrader: (10)

Ok, Its not that I can't TAKE it, its just that its not functioning properly. You say 50,000 miles with no problems..why not 100k? Its a small issue that shouldn't be there. Also, the weaker spring will NOT cause it to leak at all.

Basically..at idle the vacuum compresses the spring..and when you eliminate vacuum the spring expands again closing the valve..now with the 7lbs spring... Its not going to open or leak if you boost past 7psi..think of it this way..vacuum compresses the spring..and then when you go into boost..say you run 20psi..you have that 20psi of pressure ON TOP of the 7psi(so 27psi all together) holding that valve shut tight. So theres 20psi pushing up on the valve from the pressure in the pipes and theres 27psi pushing down to hold it closed...so which ones gonna win?

SnyperZ

iTrader: (10)

Both and I experienced it so anyone saying its not...I can feel the air coming back out of the compressor.

IIQuickSilverII

iTrader: (13)

sure if you plan on keeping you stock block fo 100k miles...
i have set to see a member go over 50k boosted miles on the stock motor(vq)....

i think miaplaya is close to that at some point but not sure if he even has his Z anymore

SnyperZ

iTrader: (10)

And that reason that happens is because the vacuum alone cant open the BOV fully to let the air out..the sound you hear is the pressure from the charge pipes trying to relieve themselves by forcing their way out..and of course not ALL of the pressure will be relieved through the valve so it goes back out the way it came.

SnyperZ

iTrader: (10)

Im in the process of getting setup for my build..I thought id be ok with 4psi....and the excitement is over..I need 15-20 for street driving. One thing ill tell you is I can dead hook on 4psi in first(weird) and it just goes. I raced a friend of mine last night with a 463whp fwd talon..and I gave him a spankin until the end of 4th and that was from a first gear roll.