My BOV seemed like it never wanted to open at the right time so...I just took the entire BOV apart from top to bottom and cleaned that shaft and put new grease on it and put it all back together..its opening and closing alot better now but still seems to open alittle late but I dont know if I have it adjusted right...sometimes it doesnt make any noice and some times it whistles like crazy...

If i give it light gas and shift I hear a second of deap growling noise like air rushing back threw the blower than instantly the BOV opens and flutters air out ??

Is there a chance that shaft is Seized up ?? the action of the BOV is very simple movement and after I cleand it it worked really well...now it seems to be doing the same thing

any words of wisdom is appreciated

-matt

 

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-matt

 

adjust it. It must be more tight than loose if its not letting out air until after the fact! Try it really loose , then try it really tight, then try it in the middle. It takes driving , testing , getting out on the side of the road or in a parking lot and popping the hood and turning a screw over and over until you are comfortable with it. If none of that works maybe its broke. how old/miles are on the bov?

Try reving the motor and getting the bov to release air as soon as the rpm's start to decline. Oh, did you ever get your belt ligned up right, what was the problem with that?

 

The dayco was messing it up somehow..I popped on my Fennner Drive pulley and now it seems to be fine

-matt

 

That is strange. The dayco should work fine. I assume your blower works right with no oil leaking. I sent my V1 off last week. I hope I dont have the same luck as you on that one. Do you have any washers between you mounting bracket and the chain drive case?

 

NO the dayco met the braket too far OUT from the engine that means that the post is too large for the dayco or the dayco had not enough inlet space between the rib and the bearing....Get it ??

It was off so bad it started to wear on the belt without even really boosting with it...the car ran for about 10 min....I have to say though that the dayco and Fenner look exactly the same...but for my car, didnt line up...idleing and reving the car up with the dayco in, you can see it on an agle onto the alternator...

Im buying a Fenner Drive pulley for a backup soon
-matt

 

oh well, atleast you figured it out. I dont think your bov issue is nothing other than just adjusting the screw. I used to mess with mine all the time. The sounds you described and functions is what happened to me when I tried a hks bov. It doesnt release much air unless your boosting. So on downshifts it would remain closed and give a jerky response to the car. Sounded mean as hell when I reved it up though. I would think you need the bov screw just a bit more than 1/2 way . Man, I hope you figure out whats wrong so you can get out there and represent that fast max!

 

Well I adjusted it so that the screw is just touching the plate to push down on the spring, (very loose) and ran it like that..Im gettin a fluttering up top and a whistle after I close the throttle off....the more I tighten it down the less air that is being released...Im still not gettin a clean woooshhh sound from the Greddy Type S...is just sounds fluttering...flutter flutter flutter....

it seems the screw does nothing...

I am hearing that compressor surge every once and a while from air going back threw the blower....momentarely, until the BOV opens...

Im thinking I need a new BOV...

-matt

 

i have the turboxs type h, opens up every time. has something like 8 huge holes for the air to come out. no compressor surge there.

 

Another valid question is, What is this paticular BOV (Greddy Type S) suppose to sound like ??
a) What will a normal Functioning BOV on a S/C Application typically sound like ??
2a) Full boost shift ?
b) Slight throttle then shift ?
c) Coming out off of boost ??

-matt

 

each bov sounds different.

 

matty- the greddy is supposed to give a whistle sound. I would suggest trying to tighten it to alittle less then half. Do you have any air coming out at idle with your current adj.?

The eclipse in fast and f 1 has a greddy bov.
I have never heard one on a maxima with sc. It sounds bad A$$ on my friends eclipse runing 22psi

 

it should be a slight whistle until u hit full boost. I couldnt get it to make much noise until I made any decent type of boost - I was told it's just because of the way that the sc builds boost and thats how come it doesnt blow off till mid rpm's

 

yea its letting air out at idle...when I start it up and the cars cold, it lets out alot...I have the set screw jsut touching the plate thats inside, and not really tightened down at all...

After I warm the car up the BOV is definetly letting air out....if I rev the car, and Look in the BOV, it definetly is opening

Im worried about the air going back threw the blower noise...I was told thats compressor surge and it could cause the Blower to fail ?? I do hear air rushing back towards the blower but not much

-matt

 

You probably want to tighten the bov just a bit so there is still air coming out at idle. You are running 10psi so I know you should have it tighter than you do. I know the blitz is rated to hold up to 18psi and I am running 10psi so.. Another thing that is affected by how tight you have the bov is your throttle response/ acceleration. Try tightening the bov until no air comes out at idle then loosen so some comes out and try that.

 

Whats some ?? if I tighten it soo much it doesnt seem like any air comes out up top after I hit full boost and shift....

I dont think I understand the reason for tightening ....My understanding is that you want the MOST air comeing out so all that air isnt escaping back threw the blower....right ??

I really should go onto a stretch on a road someone where and F around with the settings

-matt

 

if it isnt tightened enough then you wont hit full boost because the bov will leak too much air. If it is tightened too much - then you dont blow off enough air and it surges @ the compressor.

The idea is to just find that medial point where it is still venting some air at idle, but not having any compressor surge. If the bolt is backed out to where it isn't doing anything - and you're SURE its surging - then the diaphragm may be damaged or the spring in the bov is malfunctioning. Compressor surge is a deep phuuuggmmm sound - hard to explain though. You could try tightening it and seeing if the sound you heard before gets worse in order to make sure that it is compressor surge... just a thought

 

The sound I am hearing is If I go outside of the car at idle and cover up the BOV Outlet hole and rev up the engine and let it come back to idle, the sound of air rushing back out the blower and out the filter is that noise I am hearing..

I have had my BOV apart twice already and the Diaphram looks fine..no rips or tears in it at all

-matt

 

Yeah, I had that noise. Nothing I did fully got rid of it until I installed a Vortech Mondo bov - largest bov in the free world. The little bovs we typically use are too small to prevent the Vortech blower from surging if you have a small pulley.

 

well it sounds like im getting compressor surge at low rpms then. Should I tighten the screw on my BOV (Blitz). I rev it in N and at redline a lot of fluttering is coming out the filter on the BOV but there is the same amount of fluttering coming out the filter on the SC'er. Guess I'll try tinkering with it after work tonight.

 

Tightening it makes it worse. You want the bov to open as much as possible under manifold vacuum.

In the case of superchargers it's really only a sound issue. I don't think SC's are susceptible to bearing damage from surging like TC's are, because of the belt preload. And being coupled to the engine, surging by itself won't slow the blower down appreciably.

 

thanks a lot for the insight, I've still got a lot to learn

 

I have the blitz bov. At low rpms I get some surge, like a deep humm/wooosh. When I get some boost the air comes out the bov. If you were running 5psi you would not need it as tight as when you are running 10psi. Think of it as the more psi the more you have to tighten the screw in order to hold in the air. Mine releases small amount of air at idle. To tune this I usually rev motor from engine bay. I try to match the decrease in rpm with the release of air from the bov. If I were to rev my motor to 2500 rpm's it will release alittle, if I rev it to 3000 rpm's the bov releases all the air. Its really trial and error. I do see a mondo bov in my future!

 

I was looking at Vortechs Race Bypass Valve, looks something like this...

I dont paticuarally like the Polish/Polish look...I like the Blue/Anodized one
The Race bypass valve flows 320CFM at 8 Psi instead of the Mondo being 600CFM at 10psi...

I would like to upgrade to a good Blow off valve but I cant decide between the Race Valve from Vortech or the HKS SSQV....I like the Vortech because I Have heard it on Pauls car and it sounds amazing...the race valve is $230 and Ill be able to use the same mounting spot as my greddy...
The Mondo from Vortech needs a different flange

 

this would be a good one if you are running a z32 maf that is before the compressor.

 

Mardigrasmax had that bov when he was SC'ed.

 

which one of the vortech bov's would be better for a 10-13psi setup?

 

I messed with my BOV (greddy Type S) and I only get it function properly when the screw it just getting resistance on the plate (Fully Loosened)


yea its the same one Paul has...

I think the smaller BOV like the Greddy Type S arent good for our setup for gettin NO compressor Surge...(growwlll after letting off the gas)....I think the Mondo or the Race type BOV are a better choice

Mondo is for rated for 600CFM at 10psi
Race Type is rates at 320CFM at 8psi
*that doesnt mean you cant use the Race Type BOV for >8PSI...

-matt

 

my turbos xs is rated to hold 25psi

 

will the turbo XS fit the flange I have for the Blitz?

 

I dont think it does

 

mine was welded on. don't have pics just yet.
steve