Gfb Bov

[gilto]

Hi guys,

Ok so I have this GFB Hybrid BOV which is like a 3-in-1 valve. You can have it full-atmo, 50/50 or fully plumbed-back.

I have experimented with all 3. BTW mine is an auto running 15psi...

When revs are high and the foot comes off it's fine....gives a loud and snappy WHOOOOOOSH!

Problem (for me) is when the revs are low.....say between 2000 and 3000 under light acceleration and you back off it give the TU TU TU TU TU TU sound. It was cool at first but it's becoming annoying. My car is a sleeper and under normal driving acceleration (2000 - 3000rpm I don't want any noise.

I only want noise when I am hammering it.....not driving to the shops and back if you know what I mean.....I want the TU TU TU TU TU noise gone....

Is there something I can do regards spring etc? I wound the adjustable spring to the softest level and it still does the TU TU TU TU....

(When I put on the twin trumpets to full atmo it was SO LOUD!!!! haha pretty funny!)

[benjam]

How does it sound at full plumb back? I have the GFB stealth and have been playing around with it for awhile. You should have the spring on the softest setting. Some cars that have an AFM, softest setting can cause problems like exhaust back fire, but XR6T's don't use one and softest is fine. If you increase the spring pressure your TU TU noise will be even more. The TU TU TU TU TU noise at low revs, is the air moslty backing up and causing cavitation on the turbo impeller blades. It isn't escaping the BOV fast enough. I was getting the same sound on mine with a harder spring setting. You are probably still getting some TU TU TU etc at full atmo, but the Pssshhh noise drowns it out.

So you could perhaps get a softer spring, GFB make them. But the main problem is that the standard crossover connections for the BOV are tiny and the increased airflow with more boost just is too much. I've been considering modifying the crossover and using something like a 35-38mm weld on adapter and piping to suit, or another crossover like and AVO one (if they answer my PM hehe). My GFB on full atmo goes Pshhhh shhh shhhh shhhh and lasts for about 1.5 secs, where I want to air to come out much faster and short period like you hear WRXs and EVOs. They have BOVs that bolt on directly to the intake so have bigger adapers standard, because they run more boost standard.

Or you could get Plazmaman piping and ask for bigger adapters to suit. Or you could get a turbosmart adapter, but then you can't have plumbback as the BOV connects near the turbo on that one. I've been looking for something that allows my BOV to sit in the standard location just so it doesn't stick out like the proverbial.

Ben

[turbo.vixen]

im no mechanic but dont they have a adjuster screw for harder or softer, maybe its set to soft and needs to be tightened?

[gilto]

Thanks guys,

Yeah that makes sense...maybe I should try the softer spring first and then if it still does it have my connector enlarged. I have plazmaman piping already but the exit weld on the pipe is the same size as standard I think?

Shouldn't be too much of a problem for them to take it off, cut a hole and put a larger diameter weld on there.....

I'll let you know how I go with the soft spring.....

[Dillz]

On the GFB I think you can tighten the spring so it will only vent under high boost but I don't think this will get rid of the surging under low boost.

[Shaky Bones]

well the tu tu tu tu is compressor surge so I wouldn't want much of it at high revs and boost

[Guest]

What airbox setup are you running? If the intake pipe is relocated to the standard battery position, you'll have to live with the tu tu tu sound... Or decrease boost.