Compressor surge!!!!

[slayer_699]

So I have a greddy type s bov. I adjusted it many different positions but I ALWAYS have compressor surge. A week ago everything was fine. I went everywhere from the Loosest position and it still surged. If I boost up past 5 psi then It does compressor surge folowed by a slight pssss... Shouldn't it go psss only like it used to? Is it just a worn bov? Bov age is unknown. Was on when I bought the car.
Thanks everyone!

 

[ramsack]

It's the BOV bouncing open and shut. Just because this happens doesn't mean air is being forced backwards across the turbo, thus not compressor surge. Compressor surge is when the turbo is working hard, the engine can't digest that much air, and the turbo can't continue to compress air, so the ability of the compressor to compress air breaks down completely, and the air flows backwards until the turbo can once again compress air (too high of a pressure ratio, and cavitation).

 

[Tiki2777]

You don't know physics

Quit trolling because you're sad you don't have a DSM.

 

[phantom_19]

From the moment i read this I knew it had to be vacuum related. I had the same problem with my Greddy RS. It was not getting good vaccum

 

[ramsack]

Nope, it's not surge. It's the BOV bouncing open and shut. A extremely sensitive BOV will queef or fart instead of fluttering.

1. The BOV opens
2. The pressure drops while the turbo is still spinning
3. The BOV closes
4. The turbo is still spinning so it creates pressure again
5. Goto #1

Pressure propagates in waves. It takes time for the pressure wave of the BOV closing to reach the turbo and start the compressor building pressure again. That pressure wave again takes time to reach the BOV and force it open. The spring in a BOV slows this process down. Only a free-floating BOV with a minimal amount of spring, just to close it when the car is turned off, will not flutter or queef/fart. Also, a 1" hole is plenty big to drop pressure significantly instantly, and thus air does not get forced backwards across the turbo.

If you do not have a BOV at all, it will indeed surge, because there is literally nowhere for the pressure to go while the turbo is still spinning. Flutter is not surge, it is oscillation of pressure waves acting on the mechanical parts of the BOV and compressing system.

 

[GRAVEDIGGER]

You have no idea what your talking about. WTF When was the last time you even worked on a car? The fluttering sound is NOT just from the BOV's diaphram. It is a combination of air going BACKWARDS THROUGH THE TURBO and the diaphram having trouble opening.
Surge is surge whether its in boost or during a shift or whenever the throttle plate closes (air going backwards).

Quit trolling because you're sad you don't have a DSM.

This is wrong! ^^^

It's the BOV bouncing open and shut. Just because this happens doesn't mean air is being forced backwards across the turbo, thus not compressor surge. Compressor surge is when the turbo is working hard, the engine can't digest that much air, and the turbo can't continue to compress air, so the ability of the compressor to compress air breaks down completely, and the air flows backwards until the turbo can once again compress air (too high of a pressure ratio, and cavitation).

This is right! ^^^

Nope, it's not surge. It's the BOV bouncing open and shut. A extremely sensitive BOV will queef or fart instead of fluttering.

1. The BOV opens
2. The pressure drops while the turbo is still spinning
3. The BOV closes
4. The turbo is still spinning so it creates pressure again
5. Goto #1

Pressure propagates in waves. It takes time for the pressure wave of the BOV closing to reach the turbo and start the compressor building pressure again. That pressure wave again takes time to reach the BOV and force it open. The spring in a BOV slows this process down. Only a free-floating BOV with a minimal amount of spring, just to close it when the car is turned off, will not flutter or queef/fart. Also, a 1" hole is plenty big to drop pressure significantly instantly, and thus air does not get forced backwards across the turbo.

If you do not have a BOV at all, it will indeed surge, because there is literally nowhere for the pressure to go while the turbo is still spinning. Flutter is not surge, it is oscillation of pressure waves acting on the mechanical parts of the BOV and compressing system.

This is also right!^^^

http://www.dsmtuners.com/forums/tur...mpressor-surge-bov-flutter.html#post152509644
http://www.dsmtuners.com/forums/new...ekend-got-compressor-surge-around-3500ft.html

 

[necrotopsy]

greddy makes shitty BOV's if you ask me.
i had a type RS and if it was loose enough to not flutter, then it leaked at high boost, and if it was tight enough to not leak, then it fluttered at low boost.

horrible BOV's....

 

[GRAVEDIGGER]

greddy makes shitty BOV's if you ask me.
i had a type RS and if it was loose enough to not flutter, then it leaked at high boost, and if it was tight enough to not leak, then it fluttered at low boost.

horrible BOV's....

I agree... I always hear of people having problems with them.

 

[ramsack]

Toyota MR2s have excellent BOVs. The more boost you run the tighter they hold. They don't operate on a spring principle to keep them shut, they operate on the principle of surface area and force. They are some of the quickest-reacting valves. I have no idea what they can be had for anymore, but I got mine for like $30 shipped a couple years ago. I still have it sitting waiting for a car, along with my old HID fog lights.

 

[laserspeeddemon]

Just an FYI on a push-type BOV a constant vacuum helps keep the valve open and not do the "flaflaflaflalfalfalflaflaflaflaf" sound. This is why a uninterrupted vacuum line is important.

 

[ramsack]

Just an FYI on a push-type BOV a constant vacuum helps keep the valve open and not do the "flaflaflaflalfalfalflaflaflaflaf" sound. This is why a uninterrupted vacuum line is important.

Yes! And to add, one with plenty of inner diameter. There's a reason there is a specific nipple on the intake manifold for the BOV and that it's thicker than most. ID of the hose should be 3/16" - 1/4"

 

[slayer_699]

I pass through every day on my way to work.

Nice. We'll have to get together sometime andvu can give me some pointers for upgrades!

 

[Jorgen]

Glad you figured it out, thanks for posting the fix even though it made you feel a little silly. Threads like this often end with no result because the op is too embarrassed! Lol