When is the stock "BoV" no longer good?

[Fubar231]

When they go bad!

No im kiddin, i put a 57trim ct26 on my car a few weeks ago, and boosting 10 psi right now, waiting for suprasport to get some more 550's then im ordering those, got a lex afm, walbro installed, no afpr yet. Should be ordering the AFPR this weekend if all goes well, but back to the question, when is the stock recirc valve start failing? 10psi? 15? I plan on getting a new one soon but injectors and afpr are way more important than a recirc valve right now.

To throw this out there mods are as follows:

2.5in hard pipes, spearco replica, 57 trim ct-26, walboro 255lph, safc neo, apexi intake, tms downpipe to blitz nur spec no cat, cooleze intake hard pipe, cometic headgasket and arp studs, Boost/EGT/Wideband, i think thats about all engine/performance wise. Least all thats coming to mind.

 

[Mastapip]

I can't say as to what psi they are good for, but I'm planning to upgrade mine when I get the hard pipes and intercooler upgraded...

So since you have hard pipes I'd suggest going ahead and upgrading.

 

[easternguy2005]

I started hearing turbo flutter between shifts and that was enough for me to do the bosch upgrade. That was at 12 psi.

 

[89supra7mgte]

What else will cause turbo flutters? can a worn turbo create this? or boost leak?

 

[Bootymeat]

What else will cause turbo flutters? can a worn turbo create this? or boost leak?

Turbo flutter is compressor surge. Which means the fins are spinning backwards, this could be caused by a faulty, worn, or improperly set blow off valve. Get a good name brand blow off valve and have it recirculated, otherwise you're going to have idle problems, ect.

 

[Fubar231]

What do you guys think about the TurboXS RBV Type 25?

Also, how good are the bosch ones? I asked on a local forum to see if any vw/audi guys had one laying around but that was a no go.

 

[Poodles]

Turbo flutter is compressor surge. Which means the fins are spinning backwards, this could be caused by a faulty, worn, or improperly set blow off valve. Get a good name brand blow off valve and have it recirculated, otherwise you're going to have idle problems, ect.

Wrong... It's cavitation of the turbine, it's NOT spinning backwards.

More boost usually doesn't make a stock BOV "go bad" it usually just doesn't flow enough.

 

[Bootymeat]

Wrong... It's cavitation of the turbine, it's NOT spinning backwards.

More boost usually doesn't make a stock BOV "go bad" it usually just doesn't flow enough.

I have searched that word "cavitation" and it seems to only relate to marine pumps and water pressure. I appreciate the correction, the more I know the better off I am. However, if you take compressed air, force it into plumbing, and assuming you have no Blow off valve, the air goes one way, out of the turbo. Some turbos such as the T51R have options for anti-surge housings to prevent late BOV reactions.


I'm not trying to argue, I just wanna understand man. If the compressed air is going out of the turbo, what is the compressor wheel doing? Surging speeds instead of spinning backwards? So in other words the air is being chopped up and forced out the intake of the compressor?

I would like to learn more about this, because I have heard so many opinions. Search "True compressor surge" on youtube. It shows a skyline MASSIVELY surging

Here : http://www.youtube.com/watch?v=nCj6Spwl1CU

 

[Poodles]

The surging is the compressor stalling and causing shockwaves (like cavitation) and can cause terrible damage. The anti-surge housings are to stop "true" compressor surge (like in the video), not to replace/help BOV reactions. True compressor surge is a different animal than the "surge" from a BOV not functioning.

 

[easternguy2005]

That TurboXS RBV looks nice. The OEM blowoff was fine on a c-26 but once I moved to a larger turbo and brought the boost up a touch it would flutter. With more ambitious plans in mind I did the bosch upgrade for about $70 total. Never looked back again. There's a "how to" guide around that made it easy.
There's a difference in the Bosch valves in that one has a metal part inside and the other doesn't.
The flutter is caused by letting go of the accelerator, the moving air has nowhere to go suddenly and "bounces" against the compressor wheel momentarily. The OEM looked fine to me upon inspection.
If it wasn't making that noise I wouldn't have done any replacement.

Call around the import aftermarket places - it fits a saab.

 

[BOOSTEDSUPRA]

holy shit!!! lol. thats baaaad surge. this just happened on mine, lol. popped my damn boot off and was the LOUDEST thing ive ever heard, lol.

poodles.... nice detail in description! :bigthumb:


and i think all the hair on my body stood straight up and ran for there little lives at "turbo spinning backwards"...... OMG how bad would that be!!!!! :icon_eek:

oh and i have heard that the stock bov starts to give out around 10 to 14 psi depending on age of it and set up. but i dont know for sure.

 

[dmiller]

im all stock and just added and hks intake and i started having flutter at stock 7psi. im getting an hks bov and recirculating it.

 

[supra90turbo]

What's a stock BOV?

 

[IJ.]

LOL @ something doing 80,000+ Rpm stopping and spinning backwards.... :nono:

 

[Bill UK]

SAAB Blow-Off-Valve

 

[GrimJack]

In all my time with Supras, I've only ever seen ONE stock bypass valve that was still functioning. Take off the old one and try to blow through it - chances are you can, and that means it's toast.