I have Greddy TT's with a Blitz DD Bov, and have tried everything to try to get rid of compressor surge. I took everything apart cleaned it and oiled it up, made sure the vacuum source is good, played with the spring tensioner. Nothing seems to work and I keep getting that "psht-psht-psht" sound instead of the "whoosh" sound. Right now I'm only running stock boost too, at 1-3lbs I get a "whoosh" sound, but at 5+ lbs I get surge....

Any remedies aside from adding extra bov's or going to a bigger size bov?? Any input great appreciated!!!! I need to fix this before I can turn up the boost

 

I was under the impression that most turbo guys get compressor surge under vac. In your case the only thing that ive ever heard about surging over 4psi is that your turbo is...dammit, i wanna say bearings are wearing out but not sure. Dont take what i say too extreme, but from what ive heard, it not good at all to have compressor surge during boost, in vac its ok, or normal.

 

?? I meant I hit 5+lbs and when I let off the throttle the BOV goes "psht-psht-psht" aka the fluttering sound aka compressor surge... dunno how else the turbo would be spinning backwards under boost? Is that even possible??

I don't want to run two bov's since I can barely stand the blow off noise off of one now.... I'd just rather listen to my wastegates and exhaust anyways

 

Are you sure that is surge?

 

hey man, what kind of BOV do you have, you can take it apart and take out one spring if you want to only run low boost. that will solve your issue.



see if it is open under vaccum??

if not then take out a spring or check the vaccum lines.

 

I'm pretty sure its surge, its not the smooth bov let off sound that its supposed to be that I get at 1-3lbs, with the normal "whooooosh" noise. My BOV doesn't have two springs, just one, so no go there... I think only the Greddy RS has that? Maybe the Tial too... Vaccum lines are clean and I don't have any leaks.... I feel like this now

 

i think you just need more boost, more boost and more timing makes everything better...

 

Maybe I have the same problem. Sometimes when I build boost and let off I hear 2 woosh type sounds right after eachother.

 

Mine was always interesting. I used to get woosh at low boost like you said, then it would flutter at mid-level boost 3-5 psi, then at full boost 8 or 9 psi it would be a full on woosh again. Never really knew what it meant....this was a HKS ssqv btw.

 

sound normal to me!

When on the dyno, I hopped on Jeremy's creeper and use a "listening device" to see where these extra "whooshes" were coming from. I was certain that I had a leak somewhere.

NOPE! It is compressor surge......The extra whooshes were air coming back out of the greddy mushrooms.

remember that the biggest pressure buildup is between the turbos and the intercooler. The intercooler is designed to be a restrcition, so that it can divide up the air and cool it properly........if an intercooler flowed really well, the air would pass through too quickly and not cool down enough.....

anyway, the best thing is to put a BOV on each pipe leading to the intercooler.

 

I have used a Blitz BOV before. Why dont you try a different one. They should still vent normally at low boost.

 

Very Very weird, I just tried that today, ran it up to 7.5lbs and added just a little timing and some fuel, guess what? I don't get the nasty surge "psht-psht-psht" noise anymore??!!?? Any explanation though??

Only thing is though now I get the double "whoosh" noise like Thawk is talking about at just below positive manifold press. like around -3 to 0 when I let off.... anything above is good go though. Maybe these noises are normal though??? Am I just being too paranoid about comp surge?? My opinions are being based on what I've heard out of the few greddy's I've ridden in, and what my TN kit sounded like before.

 

Well at -vac from what I have heard compressor surge is normal. I own an srt4 and im running 22psi right now, and anything under 1psi will surge. And from what everyone tells me, as long as it dosent surge after you let off after building boost then its ok. You should be fine, but its werid that your symptoms for surge were a little backwards, surging after letting off at 5psi...and normal at 1-2 psi...

 

The turbos don't have bearings

 

Yeah they do, just not ball bearing.

 

just spinning the greddy by hand, they easily spun as well as my turbonetics ball bearing unit. of course a 100,000 rpm, who knows what the difference is?

 

They are called bushings, not bearings. They are more reliable than Ball Bearings because they can't fall apart like ball bearings can.

 

Actually I have heard people call them journal bearings, but bushings could work.