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View Full Version : SR20 Compressor surging


Rapier46
01-26-2009, 12:25 PM
My sr has always done it, and i need to fix it. It has a blitz blow off valve installed. i have one on my skyline to it's a pretty distinct sound. I've switched bov's and played with them alot. Can't get them to blow off. The one on skyline works for sure. Even through adjusting all the way both direction of the screw, nothing changes. maybe some sort of blockage? what else could be causing this. I may have to throw in my boost gauge to see what exactly it is boosting at. and the controller to see if it changes anything. any ideas?

Sleepy240
01-26-2009, 12:30 PM
My first idea is grow a pair of balls and stop worrying about compressor surge...

But to answer you question other than the adjustment screw there really isnt a whole lot you can do with the BOV. When I did run a BOV my blitz had a problem with low boost, anything less than say 7lbs, but it held fine up into the low 20's. My guess would be your boosting is either way to low or the adjustment screw isnt working properly. If I remember correctly you could unscrew it to the point where it would blow off at like the slightest amount of throttle but thats when I ran into issues at a high psi, and had idle issues.

4x4le
01-27-2009, 04:31 PM
Your bov's vac source isnt hooked up to the middle barb on your throttle body is it? It wont work properly there and the only thing you should hook up to that is your boost controller or directly to your waste gate. The middle barb gets its boost source from the cold pipe side of the throttle body flapper. I made the mistake of hooking it up there one time and I got surge all day at a drift event. It actually even broke the flapper on my throttle body.

Mister.E
01-27-2009, 04:49 PM
check your vacuum lines. if your vac source isnt working correctly, or at all, the valve isnt going to work properly.

http://picsftw.com/up/VacDiagramSmall.jpg

fliprayzin240sx
01-28-2009, 06:56 AM
^^^If you look at the Throttle Body above, make sure its hooked up to one of the 2 ports on top of the TB. The one below isnt really a good vacuum source since its before the TB butterfly. If the TB is close, that source gets 0 psi. You only get vacuum/pressure out of it when the TB is open.