BD Blow Off Valve

[hasselbach]

Installed a BD BOV today because my sps 66 was barking at full throttle between shifts.



Wow, pretty cool, completely eliminated the 'wham wham wham' when I shift. All you hear now is 'phist' and no more barking.



Not too hard to install, other than finding a proper feed off the drive by wire throttle, but thanks to Matt400, that's all taken care of now.



I highly recommend one to anyone that is pushing the boost to the limit and doesn't like to bark their turbo.

 

[BIG BOB]

I like mine also! Oo.

 

[mattymac]

How about some pics and some install info on the BOV!

 

[Mad Bomber]

I like mine also! Oo.

Hey Bob is that BOV the one that is on your truck you were planning on leaving stock. LOL

 

[hasselbach]

BOV Pictures

Ask and you shall receive... I can get these a few hundred cheaper if anyone is interested through my supplier. PM me for details.



BIG turbo? This is the ticket!

 

[AK RAM]

That looks like a shiny new piece of charged air tube. Did the BOV come with an all new tube from the intercooler to intake horn or did you have to weld a fitting on for the BOV to attach to?

 

[hasselbach]

That looks like a shiny new piece of charged air tube. Did the BOV come with an all new tube from the intercooler to intake horn or did you have to weld a fitting on for the BOV to attach to?

My truck came with a silver pipe, so no, its the stock pipe. I may chrome it later (helps make the truck looks faster )

 

[JCleary]

Does it chirp like a BOV on a ricer, or is it just a rush of air?



Some of the ricer BOV's have a horn on them (like the intake horn on a Weber carb) and they sound sweet!



Either way, I think I'll get one for my truck, as I need a big turbo soon...

 

[hasselbach]

Does it chirp like a BOV on a ricer, or is it just a rush of air?



Some of the ricer BOV's have a horn on them (like the intake horn on a Weber carb) and they sound sweet!



Either way, I think I'll get one for my truck, as I need a big turbo soon...

MOre like a truck airbrake releasing,,, it sounds great.

 

[jwilliams3]

So if its dumping at say 50+psi, isnt the turbo going into an overspeed condition?

 

[hasselbach]

So if its dumping at say 50+psi, isnt the turbo going into an overspeed condition?

The valve is pressurized from the manifold, so the only time it released is when the throttle voltage is reduced quickly, (meaning the exhaust flow is reduced) and since the whole intake tract is pressurized with no exhaust flow, it tries to flow backward since the turbo has stopped spinning. The valve to the BOV opens, dumping the pressure on the top side of the BOV, which allows the pressure on the lower part to overcome a spring, and blowing off pressure before it can bark the turbo... Works great.

 

[jwilliams3]

Cool. Bet it sounds good.

 

[Tomeygun]

<----------------------- Very jealous! - I have wanted a BOV ever since the TST twins flash, Bark city with most turbos

 

[SRadke]

The valve is pressurized from the manifold, so the only time it released is when the throttle voltage is reduced quickly... .

This makes perfect sense but how does that help you with the "barking at full throttle between shifts"?



-Scott

 

[RustyJC]

... since the whole intake tract is pressurized with no exhaust flow, it tries to flow backward since the turbo has stopped spinning...

With all respect, you might want to do a search on "turbocharger surge". There's far too much rotational inertia for a turbocharger rotor to "stop spinning" during surge. Since the turbocharger compressor is a dynamic (versus positive displacement) compressor, it is subject to flow reversal if it crosses the surge line on the head/flow map - that's the "barking" you hear.



Rusty

 

[Tomeygun]

This makes perfect sense but how does that help you with the "barking at full throttle between shifts"?



-Scott

You dont lift throttle between shifts do you?



Bad-bad boy

 

[hasselbach]

With all respect, you might want to do a search on "turbocharger surge". There's far too much rotational inertia for a turbocharger rotor to "stop spinning" during surge. Since the turbocharger compressor is a dynamic (versus positive displacement) compressor, it is subject to flow reversal if it crosses the surge line on the head/flow map - that's the "barking" you hear.



Rusty

I didn't mean exactly that the turbo spun backward, but when the drive pressure drops the turbo slows down quite a bit, and if you have say 50 psi in the intake track, its going to seek the path of least resistance, or head back to the compressor side.



The BOV vents off this surge of air before it hits the turbo.



I love it so far, it works great, and no more bark-bark.

 

[SRadke]

You dont lift throttle between shifts do you?



Bad-bad boy

Who me? If you lift the throttle the tires'll stop spinning, we don't want that to happen now do we.....

 

[JasonCzerak]

You dont lift throttle between shifts do you?



Bad-bad boy

He's not shifting fast enough.

 

[BIG BOB]

Unfortunately, the BOV only helps when you let off the throttle very quickly. For those of us that have Auto's, the up shift from 3rd to OD under WOT will still get the momentary turbo bark.