Compressor Surge?

[badgsx]

Im confused about the exact meaning of this term. I've heard that when a bov doesnt release all the way and the air is forced back into the turbo thats surge. Which makes it sound like a bov valve problem. But I've also heard people say that differnt turbo's are known for compressor surge which sounds like a turbo problem. Which is it? Or is it both? The reason Im asking is I just put a turboxs bov on my car and when I let off the gas at partial throttle the car bucks hard. Is that compressor surge? At full throttle when I shift the bov works fine. Its only at low boost when I let off the gas the car jerks forward then back. Any idea's? The bov has 2 washers in right now. Thanks.

 

[1993eclipseGS]

'Compressor surge is when you are under boost, you let off the throttle, the throttle plate closes and that pressure in the pipe has to go somewhere. The bov is there to detected the throttle plate closely, and let the pressure escape from the upper ic pipe back into the intake of the turbo. If your bov is not functioning properly, it will stay closed and not release this pressure, so the pressure wave finds it's way back to the turbo, causing compressor surge. '

Edit: Is your bov the Turbo XS Rfl? Is your bov vented?


Rob.

 

[badgsx]

No its the H34 vented back into the intake.

 

[doug]

I have the same BOV-- try lubing the piston with some grease. Helps with the flutter a lot. At 2 washers, you shouldn't really be having any flutter.

 

[Liquid Illusion]

'Compressor surge is when you are under boost, you let off the throttle, the throttle plate closes
Rob.

that would be incorrect try again

 

[ryanjay21]

When the turbo is boosting, there's pressure in the charge pipe that connects to the intake manifold through the throttle body. On a manual transmission vehicle, when you shift, you close the throttle. When the throttle closes, that pressure has nowhere to go, so ... it bounces back into the turbo, which stops the turbo blades from spinning and causes compressor surge. <--- That last part is actually what compressor surge is.

 

[kpt4321]

that would be incorrect try again

Yeah, he's incorrect IF YOU ONLY READ HALF THE SENTENCE.

If you read the whole thing, he's right on.

 

[kpt4321]

For the record, the technical explanation for compressor surge is when the airflow across the compressor wheel is less than it can support at the current pressure ratio. As such, the turbo tries to flow too much air, and some if it runs backwards through the compressor.

This can happen on spoolup with a large turbo, and under lift-throttle conditions as mentioned.

 

[NOSLO2PT0]

Or, in laymans terms, your turbo spools up too fast. The cause of this is too small of a turbine wheel/housing, mated to too large of a compressor wheel. The exhaust side spools up too quickly, and the comp. side fills up with air so fast, it has nowhere to go but backwards. Usually happens right before the point of full boost. Frank 4's and a few Red's (with the right combo of parts) have been known to have compressor surge.

 

[badgsx]

So it can be a turbo problem or a case of the bov not functioning properly. Ok I think I get it. Thanks guys.