greddy type s bov

Okay so I got my slightly used greddy type s bov in a trade for a that walboro 255 I had laying around. I really needed this because I was tired of driving around boosting like ten psi on my stock bov. Anyway, I throw the sucker on there and notice that it needs some adjusting. Searching back over the past threads I found one that related to a dsmtuner thread about adjusting the greddy type s.

I tried this and adjusted and tested the results. Now as soon as I started my car I checked my vac because at this time I had also just installed brand new U/ICP piping. Now my normal vac reading is 18 so I noticed that it was running at 15 psi so I got out checked all my new piping connections tightened again and made sure everything was secure. So I got back in and the same thing. I decided to go for a small test drive. I drive it around the block trying to build as much boost as possible the bov seems to work alright I don't notice any loss of boost like a boost like but what did happened was strange. On my way up to boosting to about 17psi at about 15psi the car jumped, or stuttered/hesitated for a second and then continued boosting.

Now my question is what could have caused this and and do you think it may be related to my low vac or my bad tuning of this bov? From the thread on dsm tuners it talks about turning it soft until the plunger opens up well I cranked that thing as far soft as I could go and I didn't get it to open up at all. Anyone had any experience adjusting this bov's that might be able to give me a tip? Also anyone know what that hesitation/jump might have been?

i know that sometimes the turbo cars will "shutter" under boost for a few seconds because of bad plugs, but i'm not sure if that's what your case is or not. kevin had a great answer to a bov question a couple weeks ago. look back a few pages in the threads and you might find it.

Are you sure it wasn't fuel cut? Althought it's more of a brick wall than a shuttering.

here's the method I use for dialing in greddy BOV's

adjust it as tight as it willl go, then loosen it a few turns

Take it for a spin, build max boost and let off, it will "flutter"

Loosen it a turn and build max boost again" If it flutters, loosen it again, keep doing this turn by turn until it doesn't flutter

this is the hardest setting you have before it opens prematurely

From your post it seems you have it set too soft, the BOV is actually opening before max boost hits which causes one hell of a boost leak which makes your turbo work too hard, and fuel trims go out of whack, easily describes that "Stutter" and the car tries to compensate for the out-of-whack fuel trims.

Alright so I was adjusting my blow off valve and I got it to blow off and it doesn't flutter at all now. Anyway. So I'm driving along and the car is still doing the same thing with the stuttering under boost. Also the other day I happened to look in the review and see that the car was blowing out white smoke out of the exhaust.

Also I am getting strange vac readings. They keep fluctuating from 17-19 psi. Before I had a steady reading now it fluctuates. Sometimes it'll start at 19psi and I can watch it drop to 17psi. Any suggestions?

My vac is usually 18-20 with A/C off, and 16-17 with it on.

My vac is usually 18-20 with A/C off, and 16-17 with it on.


I have no A/C and it never flucuated before this.

have you performed a boost leak test?

From the thread on dsm tuners it talks about turning it soft until the plunger opens up well I cranked that thing as far soft as I could go and I didn't get it to open up at all. Anyone had any experience adjusting this bov's that might be able to give me a tip? Also anyone know what that hesitation/jump might have been?
I had the same problem, I took my type-s apart and relized both springs were in there so I took one out and it worked great

here's the method I use for dialing in greddy BOV's

adjust it as tight as it willl go, then loosen it a few turns

Take it for a spin, build max boost and let off, it will "flutter"

Loosen it a turn and build max boost again" If it flutters, loosen it again, keep doing this turn by turn until it doesn't flutter

this is the hardest setting you have before it opens prematurely

From your post it seems you have it set too soft, the BOV is actually opening before max boost hits which causes one hell of a boost leak which makes your turbo work too hard, and fuel trims go out of whack, easily describes that "Stutter" and the car tries to compensate for the out-of-whack fuel trims.

I did this and it still flutters at lower boost but at my max boost it doesn't flutter. Is it still suppose to flutter at lower boost?