compressor surge
02-24-2007, 11:43 AM
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compressor surge
someone please help. my blow off flutters when i shift, well it sounds like the blow off, i think its compressor surge which means the blow off isnt opening all the way or not at all. how can i fix this? where should i connect the vaccum line off the blow off valve? all pointers and help is greatly appreciated, oh by the way its single cam
02-24-2007, 11:45 AM
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Re: compressor surge
any source off the intake manifild.
are you sure that it is a problem? some BOVs just sound like that naturally under low airflow conditions.
are you sure that it is a problem? some BOVs just sound like that naturally under low airflow conditions.
02-24-2007, 11:47 AM
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02-24-2007, 03:45 PM
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02-25-2007, 07:46 AM
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Re: compressor surge
02-25-2007, 09:45 AM
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Re: compressor surge
Flutter is pretty normal, it depends a lot on where the BOV is on the intake piping. It's just BOV oscillation, and it happens when the vac signal to the BOV is changing when the BOV is venting pressure, and also because the BOV spring and the air pressure (another spring) aren't really damped at all. It's a kind of feedback. If the BOV is fairly large for what you need, pressure can be vented quick enough that you get a feedback loop like that, because there really isn't anything to damp it. There are a lot of things that can affect this, intake length, size, vac line bung location, intake manifold volume, etc.
Does it only do this when you close the throttle completely under boost, or just partially close it? If it really is compressor surge, it would vary alot depending on boost, load, etc., so the surge flutter would change a lot under different conditions. BOV flutter is usually fairly constant in frequency, which will be the combination of factors that make it oscillate (resonant freq).
Now that I've bored you to tears, give some more information.
Does it only do this when you close the throttle completely under boost, or just partially close it? If it really is compressor surge, it would vary alot depending on boost, load, etc., so the surge flutter would change a lot under different conditions. BOV flutter is usually fairly constant in frequency, which will be the combination of factors that make it oscillate (resonant freq).
Now that I've bored you to tears, give some more information.
02-25-2007, 09:53 AM
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Re: compressor surge
Flutter is pretty normal, it depends a lot on where the BOV is on the intake piping. It's just BOV oscillation, and it happens when the vac signal to the BOV is changing when the BOV is venting pressure, and also because the BOV spring and the air pressure (another spring) aren't really damped at all. It's a kind of feedback. If the BOV is fairly large for what you need, pressure can be vented quick enough that you get a feedback loop like that, because there really isn't anything to damp it. There are a lot of things that can affect this, intake length, size, vac line bung location, intake manifold volume, etc.
Does it only do this when you close the throttle completely under boost, or just partially close it? If it really is compressor surge, it would vary alot depending on boost, load, etc., so the surge flutter would change a lot under different conditions. BOV flutter is usually fairly constant in frequency, which will be the combination of factors that make it oscillate (resonant freq).
Now that I've bored you to tears, give some more information.
Does it only do this when you close the throttle completely under boost, or just partially close it? If it really is compressor surge, it would vary alot depending on boost, load, etc., so the surge flutter would change a lot under different conditions. BOV flutter is usually fairly constant in frequency, which will be the combination of factors that make it oscillate (resonant freq).
Now that I've bored you to tears, give some more information.