Compressor surge?

[Blitzeclips]

I know what this is, but I'm not sure how to diagnose it, if that makes any sense. I'm assuming it's leftover charge after the TB plate closes, and it reverts back to the turbo. This would probably create a pa-pa-pa (almost backfire) noise, but I'm not sure.

Whenever I'm coming down from boost my car loves to gargle and almost make the backfire sound, almost like a sequence of mini backfires that you can hear and feel.

I was going to back out the screw on my BOV about 3/4 of the way, maybe it's relieve the pressure needed for the piston/flapper to open. But then again, I'm not sure if compressor surge is my issue or not.

I'm new to boost, so I don't know what surge sounds like at all. I'm just making assumptions because I kind of understand the concept. So I'm creating what I would believe to be compressor surge...

Who's had it? How can you tell if you have it? What is to expect of it? Slower spool? No BOV at times?

 

[BigRand]

Pressure surge sound you will know....just go find a best motoring video of the drift king's S15, and you'll know. Its the coolest sound in the world until you remember what its doing to your turbo.
Its a loud fluttering sound every time the throttle plate closes and w/ no BOV.

It also happens when the BOV is set too tight for the amount of air being thrown back fromt he TB.

I wish I had time to find you a sound clip, so you could eliminate a possibility or come to a conclusion.

 

[Blitzeclips]

Pressure surge sound you will know....just go find a best motoring video of the drift king's S15, and you'll know. Its the coolest sound in the world until you remember what its doing to your turbo.
Its a loud fluttering sound every time the throttle plate closes and w/ no BOV.

It also happens when the BOV is set too tight for the amount of air being thrown back fromt he TB.

I wish I had time to find you a sound clip, so you could eliminate a possibility or come to a conclusion.

I wish I could post a sound clip but I can't. I DO hear a loud fluttering whenever I shift. It's not the BOV. But I assumed it was just my WG opening. You don't hear the BOV until you actually build boost, so the wastegate would be the pressure release when not boosting, to an extent.

If you can Rand, post a clip. I just want to be sure I know what sounds like.

 

[totaleclipse_05]

I can hear my BOV go off when I'm not in boost. If you have the vid "The Fast and the Furious", I believe towards the end when the supra lines up with the charger, when he slows down you can hear compressor surge. Should sound the same if that is what is wrong with your car.

 

[BigRand]

Here is a link of what it sounds like

its in the second part of the video not the engine dyno part.

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Click here to see Video

 

[TalonESIT]

You'll know the surge, like rand said, because you will hear the flutter during boost. Sure you can hear your BOV w/o boosting, but it won't flutter, unless your BOV is really tight! What is leading you to believe it is compression surge anyways? Did you adjust your BOV recently?


"Pa pa pa" or your popping from backfire happens for a completely different reason. That sound is usually due to a component in your fuel or exhaust set-up. Sorry for being so vague.

 

[Blitzeclips]

Okay, I watched the video and... I definately don't hear that on my car. That was a sick ass set-up though. What was that a sr20det or ka24?

Talonesit- Yeah I originally have heard the pa,pa,pa, which I assumed was just unburned feul, thats why I was scaed it was surge for a moment. This is the first turbocharged car I've owned so I didn't know exactly what it sounded like.

I don't know what it is I'm hearing then. The surge definately isn't it.

What's lag sound like? Lol. Sorry for being so vague guys...

 

[TalonESIT]

Do you mean "boost lag"? Boost lag is not a sound as much as it is a feeling. Boost lag refers to the reaction time for your turbo to spool. If I were to stomp on my gas pedal, how long does it take until you feel your turbo kicks in. Boost lag doesn't sound like your problem either. Are we still going off that "Pa pa pa" noise? Or did something else occur?

 

[BigRand]

After reading your first post again, and checking out your mod mod list, that 3" test pipe is probably the reason your not used to hearing that gargle sound. It usually happens when you let off the gas coming down from 6000rpms or so.

I think it might also occur when you start to build boost a little, and then you don't give it much thorttle but still make the rpm's rise, then let off. (just shooting off ideas)

I"m used to hearing that sound when I had headers for my NT, I still heard it a little when I went turbo and took out the cat, but not so much any more......or maybe I'm just used to it.

 

[greenmeanie99]

Don't mean to Hijack this thread but my turbo had serious compressor surges I have the HKS and there isn't any way to adjust the spring and it is normal tension compared to my previous BOV. I have some boost leaks think thats why its surging?

 

[Blitzeclips]

Don't mean to Hijack this thread but my turbo had serious compressor surges I have the HKS and there isn't any way to adjust the spring and it is normal tension compared to my previous BOV. I have some boost leaks think thats why its surging?

Don't worry about it man. I'd backoff on the screw at the top atleast to the point where its almost at the thread ends... That screw adjust the spring pressure when air releases from the charge pipes. Either that, or take it apart and check for damage to the diaphragm. My buddy had the HKS SSQ BOV on his STi for a couple months, then it mysteriously stopped working. We took it off and apart, low and behold we found the diaphram bent bad enough for jamming. So, the OEM BOV went back on..

I believe you may find some springs to fit the BOV at a hardware store, I've had a couple buddies do this and the difference was night and day.

I don't see why a boost leak would attribute to the compressor surge. Of anything, it would actually help it. You don't want charged air reverting back to the turbo. That is what damages it the most. So a leak of this air would become beneficial and decrease the pressure built..

Or just buy a new BOV. Assuming that's the problem, of course.