We recently have had 2 turbo failures due to bad or slow reacting blow off valves. One car had an old BOV that just stuck shut - it killed a turbo in 1 hour.

The second car had a Tial 50 hooked to a slow responding vacuum source. It worked, but was slow to open. You could rev the motor, hear it surge 2-3 times and then see the BOV open.

This the what it did to the inside of the turbo from all the compressor surge -









The result was an obvious lack of power and heavy smoking out the exhaust.


So, today or whenever you get a chance, go outside, pop your hood and watch your blow off valve. It should open as soon as the motor comes off a quick rev and should be fluttering at idle.

If you here any surge try a couple of things before buying a new BOV.

Check the vacuum line going to the BOV and make sure it isn't crimped, but or in a bad location.

Spray some lube on the actual valve and see if it reacts quicker.

Adjust the hardness/softness of the BOV and see if it helps.

Replace a stiff spring with a softer one (11psi to 9 or 7)


If none of that helps and you still suffer from surge, it is time to start looking for a new blow off valve before you have to buy a turbo!

 

the failiure you posted doesn't have anything to do with the bov, the damage would have been done to the other side of the thrust bearing....

what turbo is this out of

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TiAL &raquo;</TD></TR><TR><TD CLASS="quote">the failiure you posted doesn't have anything to do with the bov, the damage would have been done to the other side of the thrust bearing....

what turbo is this out of</TD></TR></TABLE>

Bingo.

 

Good write up regardless of what side the damage was done to the bearings. I just did that little test of yours and my bov is slow reacting. The BOV stays completely shut when the car is at idle and when i rev the car up quick it stays shut until the revs are already coming back down and almost at idle and then it opens. Soooo what do you think a "slow" vacuum source or a different size spring? Let me know. Don't worry tial i still love you guys i just wanna get this figured out so i don't ruin my turbo.

 

Tial -

This is a 3251 Precision unit...if you don't think surge did it, what would you say caused it? I am very interested in the answer becuase we would hate to have this happen again.

The turbo sits perfectly flat - the only known cause we could see was surge pushing and pulling against the thrust. Once we moved the vacuum source the BOV worked great.

 

where was the vacuum source?

 

I am not sure actually, but it wasn't strong enough, or so we thought. I would love to see what everyone else thinks could have caused it, becuase it certainly did a number on the turbo.

 

i just dont see a bov not working doing this.
i have a freind who runs no bov on his gn.
its been this way for 5 years, constantly surging.
he just wants his turbo die so he has a reason to
buy a bigger one. that looks like an oiling issue
to me.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CarterRace.com &raquo;</TD></TR><TR><TD CLASS="quote">Tial -

This is a 3251 Precision unit...if you don't think surge did it, what would you say caused it? I am very interested in the answer becuase we would hate to have this happen again.

The turbo sits perfectly flat - the only known cause we could see was surge pushing and pulling against the thrust. Once we moved the vacuum source the BOV worked great.</TD></TR></TABLE>
non screwed down 270* thrust bearing, too much boost, it lifted and boom

 

10 psi is too much? That seems odd, we have never seen another one do this. I'll take your word for it tho.

 

Looks like a oiling issue?

 

How would an oiling issue cause sideways pressure on a thrust tho? Seems to me it would be surge that could do that? Maybe not ?

 

i also noticed something wierd with my Q. when I put a filter on my turbo there is a slight surge right before a clean blow off. if i run no filter it blows off clean. wierd...

 

you DO know that some factory turbo charged cars dont even come with a BOV right?

i HIGHLY doubt compressor surge put THAT MUCH force on the turbo. especially when you said your only running 10psi.

 

Well we all know that surge will damage the turbo and not running a BOv will also cause damage.I am just wondering how long was the car running with the bov like that for it to cause this problem.I also highly doubt the Tial BOV did that but nothing is impossible either way this is the first time I have heard of a tial valve not working properly.

 

well in the UK there are plenty people running 30+ psi on garrett gt30 t3/t4s etc on different cars and no damage, its on a different car but i cant see how it makes a diif

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CarterRace.com &raquo;</TD></TR><TR><TD CLASS="quote">10 psi is too much? That seems odd, we have never seen another one do this. I'll take your word for it tho.</TD></TR></TABLE>

2 Years and counting with no BOV and i still haven't had a problem.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Blind-Fashion &raquo;</TD></TR><TR><TD CLASS="quote">

2 Years and counting with no BOV and i still haven't had a problem.</TD></TR></TABLE>

thanks! at least someone here knows what theyre talkin about.

BOV isnt REQUIRED. yes it helps, yes the turbo may last longer.

but NO the turbo isnt just gonna go BOOOOOOOM instantly if you dont use one.

 

I have also seen a good number of setups without a bypass or blowoff valve who have not had any issues for longer periods of time... from low hp stock or lightly mod'd turbo cars to wild drag cars. they are not killing turbos left and right like this.

to kill a turbo in per say an hour as the OP suggested... I would say there was another issue besides an old sticking brand whomever bov.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by siblues &raquo;</TD></TR><TR><TD CLASS="quote">Well we all know that surge will damage the turbo and not running a BOv will also cause damage.I am just wondering how long was the car running with the bov like that for it to cause this problem.I also highly doubt the Tial BOV did that but nothing is impossible either way this is the first time I have heard of a tial valve not working properly.</TD></TR></TABLE>

in the case of the tial bov reacting slowly... the valve was working properly, its sounds like the use and installation of it was not on par. which is I think what the OP was saying when he described possible contributing conditions to such a problem.

 

i too have heard this happening. happened to running925, tony, and his turbo is now on its way out the door.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Blind-Fashion &raquo;</TD></TR><TR><TD CLASS="quote">

2 Years and counting with no BOV and i still haven't had a problem.</TD></TR></TABLE>

I am there with you, no BOV here no probs. Joe Simpsons didn't run one neither did John Ferguson/James Innes on their race car, you can't just let up on the gas though full throttle lol

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote"> It should open as soon as the motor comes off a quick rev and should be fluttering at idle.</TD></TR></TABLE>
I disagree on it fluttering at idle, it should keep shut on idle and open during boost in the charge pipe and a strong vacuum source. Mine stays shut 100% on idle and works just fine when I close the throttle, no compressor surge whatsoever.

 

Is there any specific reason why some of you guy's dont run a bov?Just curious.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Blind-Fashion &raquo;</TD></TR><TR><TD CLASS="quote">

2 Years and counting with no BOV and i still haven't had a problem.</TD></TR></TABLE>

No BOV on what ?


But thinking a bov causing that damage... LOL, and you guys are a shop??? You dont have to have a BOV... anOn top of that having a malfunctioning one is more likely going to LEAK boost than not open and "[freak] something up".

Jesus wept.


Modified by extralargenog at 4:05 PM 5/14/2008

 

that bearing to me looks more like oil starvation, or shutting down the car without letting the turbo cool down.

check the oil feed and returns for blockage.

its been said in this thread numerous times. you do not NEED a BOV on a turbo car.

it HELPS. but it wont grenade a turbo like what you have pictured