compresor surge?

[ilovemy420a-t]

what exactly is it and how do you make it stop what is its effects

 

[gofer]

Compressor Surge Wiki

 

[JusMX141]

That Wikipedia article is a little vague on the description of compressor surge within a turbocharger....if your turbo surges under boost or when you cut the throttle it will eventually harm the unit, but will not cause you to crash into the Hudson River.

What are your symptoms, O.P.?

 

[gorf]

My understanding of what compressor surge is when your turbo pushes more air than your engine can swallow. Either because of restrictions in the intake piping, manifold or valves are too small for the amount of air flow the turbo is pushing.
What are the symptoms? I'll let some one else answer.

Sorry not trying to hijack your thread, but my problem may shed light on yours:

Justin, it has been suggested that I have surge due to my stock intake manifold. 20g, 264/272 cams, 2.5 inch intercooler piping, 1g throttle body, stock 2g intake manifold, synapse BOV. At 20lbs no problem, at 25 lbs it sounds like the bov is blowing open and I start to get some knock. The synapse bov can not blow open.
How many lbs of boost have you seen someone run with a 20g and stock 2g intake manifold?

 

[GsXdSmKingGsX]

YouTube - True Compressor Surge

 

[JusMX141]

Justin, it has been suggested that I have surge due to my stock intake manifold. 20g, 264/272 cams, 2.5 inch intercooler piping, 1g throttle body, stock 2g intake manifold, synapse BOV. At 20lbs no problem, at 25 lbs it sounds like the bov is blowing open and I start to get some knock. The synapse bov can not blow open.
How many lbs of boost have you seen someone run with a 20g and stock 2g intake manifold?

We've run up to 25psi with my buddy's 2G using a Frank L5 20G and BC0101 (272/272) cams without a surge issue. Stock intake manifold, although he did have a 1G throttle body (60mm). Jeff didn't feel the stock head bolts would take much more, so the boost stopped there.

Honestly, the only cars I'm seeing reports of compressor surge with stockish-sized turbos (Small 16G's and such) are all 2G's using the stock intake manifold. Starting to wonder myself if that's the restriction.

 

[gorf]

We've run up to 25psi with my buddy's 2G using a Frank L5 20G and BC0101 (272/272) cams without a surge issue. Stock intake manifold, although he did have a 1G throttle body (60mm). Jeff didn't feel the stock head bolts would take much more, so the boost stopped there.

Honestly, the only cars I'm seeing reports of compressor surge with stockish-sized turbos (Small 16G's and such) are all 2G's using the stock intake manifold. Starting to wonder myself if that's the restriction.

Thanks for the reply. I have a 60mm TB also. I have picked up an Evo 3 intake, I'll report back after it is installed.

 

[99gst_racer]

I ran 30 psi on a 50-trim at around 47 lbs/min on the stock 2G intake manifold and TB, and I never had surge issues. The factory 2G IM may kill your VE up top, but it should ever cause compressor surge.

I've noticed that surge is best controled with the throttle. If you build boost, and slowly ease off the throttle, the closing throttle plate will create a large enough restriction to create compressor surge. Keep in mind that the BOV will only evacuate the charge piping once the intake manifold plenum sees a vacuum. So, when you're slowly easing the throttle plate closed, the BOV won't naturally react, so pressure builds, and you get some harsh compressor surge. The solution is to completely lift the throttle to purposefully open the BOV after every hard boosting session.

This is the main reason why cruise control doesn't work well with medium and large frame turbos. The cruise control system opens the throttle plate as if the car was still running a quick-spooling, small, stock turbo. It open quiclky and a far greater percentage than it needs to with a larger compressor. This results in the system building more boost than the cruise control system is used to seeing at that particular throttle percentage, which also results in the car acellerating quicker as well. When the CC system senses this, it quickly eases the throttle plate closed again to prevent further acceleration. The IM plenum never sees vacuum during this, therefore the pressure in the charge piping has nowhere to go except for back into the compressor wheel. And it's very violent.

I LOVE cruise control, but could never use it because of this, so I eliminated it.

 

[1gdsmftw]

im an idiot ik...i coulda sworn compressor surge was when the bov was set to soft and air was pushed in hard enough to spin the turbos blades the opposite direction?

 

[99gst_racer]

im an idiot ik...i coulda sworn compressor surge was when the bov was set to soft and air was pushed in hard enough to spin the turbos blades the opposite direction?

It happens when the compressed air in the IC piping "backs up" into the compressor wheel due to some sort of restriction.

 

[ilovemy420a-t]

my car dosent sound anything like that video but everyone keeps telling me its surging but it runs and boosts fine maybe ill try and post a vid of it in a bit

 

[1gdsmftw]

my car dosent sound anything like that video but everyone keeps telling me its surging but it runs and boosts fine maybe ill try and post a vid of it in a bit

do u have a aftermarket bov?

 

[beachbum2185]

cant bov's make a flutter noise if theyre set too soft?

 

[1gdsmftw]

if its set to stiff it will flutter from lack of air being recirculated if its set to soft it will make a surging sound

 

[JusMX141]

cant bov's make a flutter noise if theyre set too soft?

They'll make the sound if they're too stiff. If they're too soft, the worst thing that will happen is they'll open the entire way on vacuum (like they're supposed to).

 

[1gdsmftw]

does your car sound like this????

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

 

[beachbum2185]

if its set to stiff it will flutter from lack of air being recirculated if its set to soft it will make a surging sound

ahhh i see. im still a noob, but im learning

 

[1gdsmftw]

as am i! ive only been around turbo dsms for maybe a year now but have been into dsms for damn near 8 years

you learn quick dude trust me

 

[ilovemy420a-t]

i have an hks ssqv i believe but my car sounds almost identical to the vid posted

well its pretty close but after watching the vid again mine dosent sound so harsh its alot louder and softer sounding but is it harmfull if it is a compressor surge???

 

[1gdsmftw]

loosin the bov a bit then your restricting the turbo its bov flutter

 

[99gst_racer]

but is it harmfull if it is a compressor surge???

Yes, very. Surge is a turbo killer. It causes shaft play which will quickly have your compressor wheel rubbing against the compressor cover and whinning. I lost an old v-trim this way.