ok, i've gone threw 2 greddy bov. one greddy type R i perchesed from hurlysurf in florida. i installed it on my rx7 with the modified stock bov pipe. it never made the signature noise for me. i traded my friend my greddy type R, for a brand new greddy type RS. i installed it on my 2.5 inch custom front mount intercooler piping near the throttle body. and i still have no signature sound. my friend who now has the R bov has the signature sound so i know it wasnt a defect. but he also has a very slighly larger turbo. "stage 1" upgrade to stock turbo by BNR i believe.

yes it is functional. and it does work. i dont experience what i think is called "turbo surge" when it backs out the front of the turbo and makes that shuttering noise. i dont have that. the bov is functional. you can feel the air come out if i rev it at idle. (sometimes if i push it hard enough)

under load at 6psi (stock) at about 6krpm it will make a puff noise. but not even like hks. just a light puff noise. but i dont take it up that high because i currently have an issue leaning out(installing fuel pump soon). so i am always watching while i get on it. and as soon as i see dangerious numbers i let off.
i have reached psi of 10 and even 15 at a spike and i still have never heard the signature noise.

so i would assume my issue is that its because my turbo? but heres the catch. hurleysurf had a stock turbo on his engine. i saw a video with his vert making the signature greddy bov sound...


WHAT AM I DOING WRONG!
heres a picture of the supply for the bov's vaccume

 

Did you set the BOV spring tension properly? sounds like it may be set to high... and the BOV is only opening very briefly/momentarily. Since you traded with your friend who was using the BOV with a larger turbo - and they were probably running a higher boost pressure (amirite?) they may have had it set with a high spring force.

Other than that I can't really come up with any logical answer to why it is not making the signature sound anyone else?

PS: I see an EVIL s4 AFM there! avoid those like the plague

 

Not to get off topic, but does your AFM have a Decepticon logo on it?!

 

i dont know it matters

But I didn't start hearing my BOV untill I got a downpipe + exhaust

i suppose that has to do with that fact that when I got those, I was going up to 12 psi instead of the stock 6psi

 

i wouldn't run the vaccume line that far. but thats just me. other that, if your turbo blown? is your filter clogged? the spring tension on the Bov?

 

Also don't want to get off topic, but you should think about getting a bigger radiator if running the front mount IC. Especially in texas. I had trouble keeping mine cool with the stock rad in WA.

 

I have the Greddy Type-S. With the stock turbo and s4 AFM, it will make a very light (and wussy sounding) puff noise unless the engine is under significant load (holding full boost usually). At WOT it will make much more of a "wooooosh."

Interestingly enough, when I went standalone with a big turbo (AFM removed) the sound of the BOV change completely, with a more of a fluttering sound when I let off under higher boost (10+ psi).

and what's this about the "evil s4 AFM" ? You know people have dyno'd in the mid 300s on that evil AFM...

 

isnt flutter the tall tale sign of compressor surge?

 

i have set it to all the way loose to half tight. and as far as what psi he was running 6-10psi he was getting the sound. i ran 10psi for a while. he currently IS running 12psi, but the fact of the matter is that it was making the signature noise for him at 6 or 10psi

i have a 3'' exhaust to a 2.5 racing beat revII exhaust with an open intake.
stock location usto be right there and i had no difference. i'll change the location of that. but i dont know exactly what would be the best spot. i have pretty much all on my tb usable.

i had a lil bit of a problem then used water wetter. it works. i dont drive it when its that hot. so i dont have issues

hehehe.. yeah... unless you have the kind of bov that does flutter.. which greddy isnt one of them

 

Yes.

 

i suggest you get your type r back, much better.

 

are you sure your building boost? have you tested this?

how does the car idle?

 

yeah. i am postive i am building boost. i have a boost guage and a greddy profect b spec II that i read off of.

there is no vaccume leak but the car idles a tiny bit rough. the idle is a little rich using my LC-1 to read that. i have a full block off plate kit so i would assume the slighly bumpy idle is due to that.

would even the smallest of vac leak cause this silence in bov?

with all my block off plates i am sure i MIGHT have the smallest of vaccume leaks. its possible. though unlikely.


edit: i am talking to SirCygnus right now and we're talking about boost leaks/vaccume leak. i belive it may be the issue.

 

Yes, but does the car turn corners and experience G-forces on the dyno? No.

When a car with a flapper style AFM turns corners it is affected by the forces and gives an incorrect mass air flow reading. making a bit of a problem with A/F ratios!

Hence, it is EVIL and a crap design, and a big inlet restriction!!!



But yeah... anyway back to topic. Have you inspected/overhauled the valve? I suspect something may be wrong with it.

We can note the facts:

- The valve worked before (on another car) with desired sound
- The valve operates in your car - you can feel the air that is vented
- The spring tension is set correctly/sufficiently low
- Your car is making sufficient boost according to two guage readings

The fact that the valve is venting pressure correctly, would lead me to believe the valve or flute which the air blows through to achieve that signature sound is faulty. I would remove it and open up the entire valve and inspect all of the parts.

Chuuuuuurrrrssss

- Luke

Oh and are you running a stock ECU? - if so, might have a problem with your oxygen sensor being disconnected there :P

 

i was waiting for some one to note the o2 sensor. yeah. heard that it didnt matter to be disconnected it only helps highway mpg. that is a bad sensor so i didnt hook it back up after swap. i have a wideband sensor to watch .

you may have skipped over the fact that i have had 2 different bov . both greddy. one type S one type RS. the type S is on my friends rx7 and working perfectly fine. that one i did take apart to inspect because i thought the same thing.

 

I'm gonna chime in here.

I have her old Greddy Type S and running a BNR Stg.3 w/ ~15psi. I'm pulling the vacuum line from a nipple on the front (by the alternator) of the intake manifold. I have a T there for my boost gauge. Can't see the T but here's a pic.



I do get the Greddy "whoosh" with a slight flutter. I have the spring tension adjusted so that it blows off above 4psi but not below that. Reason was that it was leaking when it was set looser. Adjusting that was the only mod I made to it other than when I received it from her.

 

heh. aw. how cute. its still red!
but yeah... i could have sworn you said it had a wistle to it. but in any way its making more noise on your fc then it did on mine. and sorry jason its stage 3. i couldnt recall what stage you were running..

 

hook up your wide band's narrow range output to the ecu.

you should have a narrow range output to simulate the narrow range voltages.

 

yep. i have 2

also i found this write up about the greddy type S bov about how it requires 22'' of vaccume to open but if you use only one of the 2 springs it could require 12'' or 8'' of vaccume to open

http://forums.evolutionm.net/showthread.php?t=24611

 

so i played with the bov today. i went to take out one of the springs but i couldnt get 3 of the allen head screws to come off . stripped or some odd size. so i abandond that idea.

i played with the tention setting of the screw and at about mid strenght i got it to wistle. its a long wistle.. not like its ment to sound. very long wistle but only if i didnt build more then a tiny bit of boost it wouldnt sound at higher rpm or higher psi.
so i am thinking that its already open. but that still doesnt make any sence at all... i hooked it up to my air compressor and it does NOT leak at 15psi.

oh ya. and my hesitation went away. apparently it was not holding when the spring was set to as soft as it could be. go figure... so now there is no hesitation!!

 

i got my hesitation to go away by tightening the bov.

i also got the bov to squeek after reducing the amount of fuel under boost with my crappy SAFC. i now have a quiet long squeek noise all the time i am even close to 0psi. if i am really getting on it i cant here it but i would assume its cuz my exhaust is loud. the bov does not increase in sound with increase of load and rpm

i have a lead on my issue. i believe its because i am running to rich under boost. 9 a/f is what i see under boost and thats very rich. i reduced it as much as i could with the SAFC to roughly 11s. and since i have done that it has been more consistant with its sound.

a friend believes that there is not enough cfm/energy from the exhaust because the EGT is to low because of the engine running so rich. the hotter the turbo the more energy there is and the more CFM can be made out of the turbo apparently.

 

you dont find blow off valve annoying?

wait till you have it working for about a month.

 

oh yes. i know. they can get annoying.

my bf's hks sounds nice and the type rs should sound similar so i think i'll be ok

 

I have a greddy type S as well

boost 8-9 psi on my FD.. it barely makes a woosh

I can't hear it with the windows down only up..

I think it's due to the design.. they have a large opening and require alot of air to move through them before they make any noise..

when I crank up my boost to about 15psi i expect the noise will change significantly..

 

it could be that you do not have enough pressure since you are on the other side of the intercooler.

Mine and other just have theirs after the turbo.