bvillarreal

Ok so when I am not under full boost and let off or shift my turbo surges really bad but under boost my BOV blows off but my turbo also surges while and after it blows off. Any ideas?

dpetro1

how about you start with providing info on your setup including what engine, turbo, bov. how much boost you are running/ etc.

prelude760

Compressor surge occurs in two forms. The first is the standard one that everyone normally thinks of and which sells aftermarket blow off valves. This form of surge is not as deadly or damaging as manufacturers will lead you to believe and no matter what, NO blow off valve will entirely eliminate this surge entirely. There are too many variables present that alter the dynamics of the air traveling through your system. Even Tial and Synapse BOVs will display that well-known flutter sound quite often.

The second form of compressor surge is what is experienced under acceleration. This will harm your turbo exponentially faster than the first from I described. This can be combated by running an Anti-Surge compressor housing or a larger A/R turbine housing if Anti-Surge compressor housings are not available. It doesn't sound like this is what you have. Here is a quick demonstration of my Supra with my old Precision 68mm that surged pretty bad:

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

Reid

anavrin

Hmm I didn't hear any surge from that clip?

bvillarreal

have a b16 with ssqv on 8 pounds on an ebay 50 trim

TheShodan

iTrader: (14)

Check to make sure you have a strong vacuum source, and there aren't too many "Tees" off of anything . that's really all we can say based upon the information given.

mr.speaker

You can clearly hear the surge in that video. My setup does that as well with a gt35r at 3/4 throttle and sometimes full throttle when I get on it out of the powerband. Don't focus on the BOV flutter sound, focus on the spool that sounds like it's shuttering, that is true compressor surge.

mr.speaker

Fast forward to 50 seconds to here the surging.

http://www.youtube.com/watch?v=nCj6Spwl1CU

ScorpionT

Same.

Doesnt sound like it.

Ive heard surge inside and out of a car, and thats what it sounds like. Its very distinct, unlike the Supra video.

I doubt the 68mm would surge that bad in a Supra, coming from a Supra with 67mm, 71mm and 76mm billet turbos that have zero surge. The 67mm had a non ported shroud and it was fine, and several people I know will say the same about their cars.

bvillarreal, you simply have BOV flutter, nothing more.


Edit:
This is what real surge sounds like in-car.

Turbo-LS

iTrader: (4)

If you listen to the supra video very closely and turn the volume on PC way up you can hear the surge.

darkvader0

Hmm... I'm glad this came up this morning. I've been meaning to ask about it.

I get throttle-lift surge all the time, but I credited it to my driving style. I do a lot of freeway driving and high-boost acceleration in 5th gear. Sometimes I "gently" lift off the throttle and simultaneously hear BOV and fluttering tyle compressor surge. From all I have read in the past, this is nothing to worry about.

But sometimes when it is REALLY cold--like this morning--I will go full throttle in 5th gear from ~3300RPM (~65MPH) and spike to 30psi by 3800RPM. When this happens I hear (and feel) a terrible fluttering from the turbo/engine. Could this be the "real" damaging type of compressor surge? I assumed building that much pressure at such a low RPM would put the turbo below the surge line. This is a GT3076R on a 2.0L B18C.

Don't mean to threadjack; hope my input helps clarify for the OP.

TheShodan

iTrader: (14)

This second video was more apparent.

But is really the point of this thread to find every video that may or may not have specific sounds of surge or should we just all stipulate that for the sake of argument the OP has displayed it. What's next? Let's help him solve this by making a series of checks.

bvillarreal

I dont think its BOV flutter because it is a brand new BOV and doesnt that happen when springs wear out in the BOV? Just askinnn

ScorpionT

The first part sounds like BOV flutter, the second does indeed sound like surge, especially if you can feel it. What turbo/compressor cover are you running?

BOV have a tendancy to flutter at light throttle lift, even brand new.


For those curious, here is a video that really demonstrates BOV flutter:
http://www.youtube.com/watch?v=sXakq1Qr6zI

Coming from a Supra, I know the sound well and the difference is clear. Light to mid-throttle lift gives flutter, heavy throttle lift dumps the BOV open.

TheShodan

iTrader: (14)

BOV flutter can easily occur w/ new units.

mr.speaker

New BOV's flutter as well. Actually they probably flutter more since the spring is new and stiff. When they're worn they usually leak. If you have an adjustable spring you can try adjusting it, but it might still flutter because you have to make sure it can hold the boost. Basically what I'm saying is, it might sound normal under full boost, but may still flutter under low boost or part throttle situations.