blackeg

i recently switched turbos from a 60-1 to a 57 trim. now im having some issues with compressor surge. i took off my bov (greddy type s, the real one) and the valve moves. i softened the hell out of it with the adjuster screw on top. i also shortened the vacuum source to the bov.

when i shift, it will sputter and surge a lil out of the intake, and about half a second later i can hear the remainder of the air going out of the blow off valve. what else can i try?

HiProfile

I'm almost thinking its just how the type-s bov works, or rather, sounds. I have the same issue where it has the surge-like "chu chu chu" if I let off slowly. Has the usual butteryfly sound when I go from 100% to 0% throttle. Once this ice age leaves wisconsin, I plan on trying incorporating the lower nipple too.

Basicly that nip feeds the lower half of the diaphragm. Top nip gets vac/boost, bottom gets boost-only. This way the valve opens much easier. The only issue may be the max PSI your BOV can take before it leaks will become less. When the bottom nip sees boost, you have only the spring keeping it shut. At that point you could increase the spring pressure.

FYI when I tested my charge piping, my real type-s held 18psi before I heard it leak. BUT neither of the ports were connected, nor did I try increasing the spring pressure. When I do try for 20psi, I want to hook the BOV to a small MAF sensor hooked to my SSI-4. No guessing wether it leaks or not at that point

blackeg

yeah ive had the boost up to 19 psi before with it working ok. now im only running low 10-12psi due to the cold *** roads and no traction.


im interested to see how connecting the bottom nipple work out. ill hope for a thaw, but i dont think its coming....

turbo97coupe

iam almost sure its just how the bov sounds/operates on low boost cause mine did the same thing on two different setups then i bought a rs with the same turbo setup and it didnt do it

Dartanian

Connecting the lower port eliminated any surge I was getting. Give it a try, it will make a difference.

blackeg

just curious, where did you get the vacuum source from for the bottom nipple?

Dartanian

I tapped right into the flange.

VtecnTurbo

if i remember correctly the bottom port is to be used when you have an electronic boost controller. if you are getting surge you can get a weaker spring for your BOV.

blackeg

ok im gonna try and hook up the lower nipple. i think my alternator is crapping out on me and its about to be 20 degrees every day, so it might take me a while