I have a RevHard stage 2 set at 5psi on a b16.

When letting off the gas while boosting, I don't necessarily hear the characteristic chirp of the vortech BOV, instead, there is a flutter which I'm assuming is rebounding air against the turbo.

Is it true that some BOV's don't work as well under low boost conditions? Other than the fuel management that comes with the RH, I don't have anything else, and I'm loathe to turn up the boost without the hondata to get the BOV to work correctly. Of course, I also want my BOV to work correctly!

Any suggestions? I'm not sure how to adjust the BOV. If anyone has pointers, I'd love to hear 'em!

 

where did you hook up your bov vacumm line?

 

It's usually that some BOV's don't work well under high pressure as some do not let out the excess boost fast enough. My HKS makes a big woosh and a flutter sound when I shift around 1-5PSI, over that though it lets out more of a high pitch chirp. Also, I would advise not boosting hard until your car is fully tuned and your certain that your A/F ratios are correct. Get the Hondata, you'll save yourself time, money, and headaches down the road if you do.

 

Sadly, I didn't hook it up, the shop that installed it did. From a quick glance, it appears to be tee'd off a vacuum line from the intake manifold. Interestingly there are quite a few tee's back there. I wonder if too many things are being tee'd off of one vacuum line. I'll take a couple pics to illustrate the point.

How many locations are there that can be used to tee off of? Damn, I wish I could have had this installed with myself as an assistant.

Thanks again for any help!

 

my HKS does the same thing .

 

What is "boosting hard"? 5psi seems to be a relatively small amount, although, yeah, any boost can kill an engine.

The a/f ratio from the lightshow autometer gauge certainly doesn't show anything being lean, but I know that's perhaps the most unreliable way to determine that. Plugs were changed for a cooler set of NGKs. Timing was retarded a bit for the colder weather.

I have a couple of other questions which I'll post as seperate topics...

 

I've got a JDM blitz bov that came from Japan (100 bucks off ebay)...really nice condition and came with the tube that let me run my piping perfectly. Im using
a T25 and HF manifold and I get the characterisitc snake / hiss sound and the
whoosh noise at the same time. I've tried everything except moving the vacuum line to the brake booster hose (larger black hose over the brake booster)...has anyone done this? I have a brand new turbo and have so far run it for about 500 miles.....with the surge unfixed

Jason

 

i have the same problem with my greddy type s. It definately blows off if i let go of the gas pedal right away (like sudden) it'll flutter a lil (turbo) then blow off a bit. If i let go of the gas slowly then I can hear it blow off with no fluttering sound. It only flutters if i hit around .45 bars...if it does only say 1 or 2 psi there is no fluttering what so ever....

Could that fluttering sound be the turbo despooling as I've heard it? The bov is adjusted accordingly and the spring was even taken out of the bov as Mase suggested.

 

The "fluttering" is compressor surge. A result of your bov not opening enough (or not at all) to release the pressure when you let off the gas, or no bov at all. Loosen up the bov adjustment screw and see if that helps. Be careful not to loosen it too much as it may then leak under full boost. Also, try different vacuum sources. I had to try a couple different sources before the fluttering was finally minimized, the vac source you use will make the most difference. Atleast in my experience. HTH.

Justin

 

Once I loosen up the bolt a bit, how can I tell if the BOV is leaking under full boost? Would I simply not reach full boost, or is there some other consequence?

Thanks for your help, guys!

 

My Bov screw at the top is barely in...enough to hold the screw in and
from falling out. Last resort is the brake line vac source. I'm sick of
messing with it and hear hisss hisss from my turbo...

 

Don't feel bad guys this happens to alot of people. I have a blitz DD that releases boost fine at high rpm and not at low. The boost doesn't really matter especially since im only running .35 bar. The screw is barely in and that did help, but i would get that flutter which indeed is compressor surge. I know this because the bov sound and the flutter sound come from different sides of my car due to the location of the turbo and bov, so it is easy to tell the difference.

Getting more and more pissed off about this, I decided to take matters into my own hands. I knew another vac source was not going to change this so I took out the spring and cut it just a little shorter like one coil. I fired up my beast and surprisingly there was a noticeable difference in sound. So I did this process a few more times until I was happy. Now the compresor surge is gone and i can still hit full boost... actually even faster now. I get a nice whoosh sound at closed throttle from 0-.35 bar. And if I run more boost I will just tighten the screw. Before at idle the valve would be shut and if i throttled the car the valve would open and shut slowly. Now the valve stays open at idle and if i throttle the car it will slam shut fast and open fast. To be this means that under boost the valve shuts easier because of less tension on the top of the piston, and upon letting off the throttle the vac can pick the piston up more quickly.

it worked for me, but make sure you only cut a lil at a time until you are satisfied. By the way i posted this topic like 4 times before and had to figure it out for myself.

All engines are different and suck vac. pressure differently. For example I have seen some talon/eclipses w/ the same bov and they are louder than mine at idle when just revving it up w no load doesn't make scense, but whatever works.. works

 

mine kinna flutters then blows off? and is it horrible if it does it when you don't boost? like mine flutters if i let off the throttle while i'm still under vac.

 

Y'know, I'm not even too sure I actually know what the Vortech BOV sounds like when blowing off. Maybe it is doing its job and I just can't tell because of the fluttering (which still isn't good). Anyone have a sound clip of their vortech?? Does it give that quick *tshew!* sound? or is it more like the *sighing* that some other BOVs sound like?

Thanks for the feedback, spooled b16. Come the morning, I'm going to see whether I can loosen it enough to minimize fluttering while minimizing boost leakage. If I have to resort to spring trimming.... well, I'll cross that bridge if I get to it!

 

My greddy type-s fluttered a lot before yesterday. I'm running 5 psi on a stock D16Z6. I took apart the BOV and took the center spring out (there are two, one inside the other) and now everything is great. No fluttering or rattle snake sound, just a nice clean tsshhh when I shift under full boost, and a little shhhh when i let off in partial boost.

 

M-EJ1, that sounds a lot better. I'm glad you have yours working for you.

I loathe the Greddy Type-S with a passion. ~$100 for a piece of fake chrome and purple obscenity that sounds like a bird being raped. No thanks.

My current Bosch standard ($30, w00t) makes a pronounced yet not loud whooshing sound. They come in a variety of spring tensions, depending on the vehicle they were manufactured for.

 

Damn... my greeness is shining through. When adjusting the bov, I notice there are two components that could be adjusted:
1) a bolt
2) ...and a nut surrounding that bolt.

The bolt is what really needs to be adjusted, right? The nut surrounding the bolt is intended to tighten up th bolt to prevent it from loosening even more. I'm assuming this since loosening the nut by itself totally didn't seem to make sense or do anything. I was expecting a steady tension as the spring would push against "it".

Thanks guys... help a grease monkey n00b out!

 

yah... the nut is just a locking nut to keep it from slipping. don't worry i have the same prob w/ surge... mine is set real tight because my TB butterfly is bent and it sucks at idle. When I get my new TB i should be able to set it how i want. A tip for BOV adjustment i saw on h-t a while back was to have someone go in the car and hold it at like 3500rpms... and u go under hood and loosen the bov all the way and then gradually tighten it until it doesn't leak at those rpms... then just do it a lil tighter to make sure.