Horrible Compressor Surge

[BoostedTT91]

I am running a Tial BOV and Bullseye Power t3/to4B H-3 and when i am driving its fluttering like crazy underload like going up a hill before i hit boost and if i mash the throttle down to get into boost it will go up to like 5-8 psi and then flutter like crazy and wont let me boost any higher. Now that i am running a SMIM and have 21psi of vaccumm im thinking that the spring in the BOV isnt strong enough and that is causing all this. Can someone confirm this or have any other diagnosis? Also at idle my BOV is 1/4 of the way open which is most likely cause of the spring not being correct, but im really thinking that im gonna still have this surge after the spring change. Some people are telling me that this turbo is prone to surge which i dont see how its not possible to fix it. Its a brand new turbo and i dont have money to buy another one so is there anything i can do?

 

[Gstclipse69]

What spring are you running in the tial? I run a 7psi spring in the tial with 22psi and have no flutter/surge issues.

 

[JusMX141]

Also at idle my BOV is 1/4 of the way open which is most likely cause of the spring not being correct, but im really thinking that im gonna still have this surge after the spring change.

Surge under acceleration isn't the fault of the BOV. As long as it has a good boost source (from the manifold) then whatever pressure is pushing against it from the piping will be loading the diaphragm from the top in addition to the spring.

The BOV really should be open slightly at idle- the throttle plate is closed at idle but the turbo is still turning even though it's not generating boost.

 

[BoostedTT91]

yeah i know the bov isnt causing the surge. There is a 8 spring in there now which is supposed to be ran with -14 to -17 inHG of vaccum and im going to replace it with the 10 spring.

Why would this turbo be surging like that so badly? i cant even really hit any boost without having to let off because it surgest like crazy. Is there any fix for it?

 

[bling5tatus]

Is it a possibility that your turbo is pushing the bov open? I had the opposite problem, my tial had a 11 pound spring in it, and it was causing comp surge at low boost levels, because the boost wasn't overcoming the amount of spring pressure in the BOV.... if your turbo (and I don't even know if this is possible, but it sounds like it could be) is pushing a lot of air even at low boost levels, it could possibly be pushing the bov open due to the spring being too weak for your setup.

 

[DirtyBirdRacing]

Hi,

I think I agree with bling, it sounds like your turbo is forcing the valve open. Are you sure the vacuum line going to your BOV is ok, aka no large holes or rips? The line might be leaking so much boost air that its only able to provide a couple of pounds of pressure to the BOV to keep it shut.

Bill