hey all, I have a b series 6262 setup, precision 46mm gate, topspeed performance ramhorn manifold.

with the wastegate boost pressure source at the compressor housing, the wastegate will not open, just hits boost cut.

however, with the boost source from the intake manifold it opens at the spring pressure (15psi)

also, the bov will work fine using compressor housing as a source.. anyone know what this could be? I've never really seen it to where the wastegate will not open at all from that source.

one more thing, with the source at the intake manifold, it does open at 15 psi, yet creeps to 19.6! this would be normal for a 38mm but for a 46mm on a t4 thats a little crazy!


in for input, thanks!

 

I think you are totally confusing yourself...

The source from the compressor housing is boost-only or atmospheric.. it's incorrect to hook your blow off valve to it. The BOV needs a vacuum and boost source, so that will be the intake manifold and nowhere else. If your BOV is somehow opening, it is simply due to compressor surge, and there is enough pressure to prematurely pop the blow off valve open.

If your wastegate is not opening by getting the source from the compressor housing, you may want to check if the fitting is blocked, or if the hole is drilled all the way through the housing.

Make a new opening/fitting on your intercooler pipe (right from the turbo), and run the line to the wastegate. That should help with the boost creep issue you are having. That's only if you are unsure that the outlet from the compressor housing is blocked or not.

 

yes i am aware that that is a bad source for bov, it was simply to test it. i will look to make sure that my compressor source is open but i am 99% sure it is, could having a 90 deg fitting on it become a restriction enough to stop from opening?

 

took fitting out, and it is drilled through, but only seems to be about a 1/8" hole drilled through but the port is bigger, however i'm using 1/8 npt fittings so should suffice correct?

 

why not just plug the port up and use a vacuum source from the intake manifold or t off the bov line

 

i can do this, but am experiencing boost creep with that source. hence why I am further troubleshooting the compressor housing source because I feel it will be more accurate.

 

While this really shouldn't be the case, could possibly be too much turbulence in the compressor housing to get a good feed off of it. Try getting a boost source a few inches down the hotside pipe instead.