I saw this black nissan silvia on streetfire.net

http://videos.streetfire.net/search/...BD037591D4.htm

and it has the hks ssqv. The dual shudder sound after the bov goes off, seemed to go on for longer than you would normally hear. What would make this sound like this or does anyone know how that would work to get it to do that?

i have the hks bov its just a loud whistle. that silvia is crazy though

yeah i have heard clips before of just the really loud wistle, but can you get it to shudder a little? because i have heard that if you let off the gas slowly after spooling up it will do that. i was just stunned at how long that shudder was on the silvia?

You need to be running HIGH boost for that.

I didn't watch the video, but it sounds like you're describing compressor surge...

I have a knock off hks bov, and it sounds exactly like that. No matter how i adjust the bov it will always shudder like that. At lower boost i'll notice that you mainly hear it shudder but at higher boost i get the sharp blow off, followed by it shuddering.

yea if i let off the gas slowly it will shudder, but quick and its a sharp whistle

I can shudder mine at certain rpms by letting off slowly. I would recommend the purple whistle insert for anyone dumping to atmosphere. I willl have my purple insert for sale here shortly because the previous owner had it set up to vent....and I want to do it right.
On a side note anyone know if I will notice a difference when I change over? Smoother power curve?

2nd post of same thread...

it sounds more of a chatter when recirc'd.

The HKS Super Sequential Blow-Off Valve (SSQV) is a dual stage pull-type relief valve. Unlike typical push type blow-off valves, the SSQV will not leak under any level of boost because the boost pressure in chamber "C" keeps the valve closed against its seat (Diagram 1). The SSQV releases excess boost when there is a pressure alteration in chambers "A & B", not by the rate of boost pressure or vacuum in the line. This ensures a quick valve response and complete closure during idle. Many competitors use a push-type blow-off valve design with a large valve to accommodate high boost / high horsepower applications. These large valves react slowly and require high pressure to open, and are not able to activate and prevent compressor surge at light-load conditions. On the other hand, smaller, fast reacting push-type valves do not discharge the airflow capacity required for high horsepower applications and tend to slowly open and leak as boost pressure overpowers the spring. For maximum performance, the HKS SSQV incorporates both a small primary valve for ultra quick activation, and a larger secondary valve for additional discharge capacity. The SSQV is engineered to initially open the small primary valve at light throttle and load conditions (Diagram 2), then sequentially opens the secondary valve for additional relief capacity under high boost and load conditions (Diagram 3). The SSQV is constructed of polished billet aluminum, which ensures long-term durability and a high luster look. The mounting base utilizes a circular mounting flange that combines with a C-clip snap ring and O-ring gasket to insure an excellent seal. The triple-fin discharge port design produces a powerful, unique and aggressive blow-off sound.

The HKS SSQV is available in vehicle specific kits or as a universal unit for custom applications. Vehicle specific HKS SSQV kits come complete with all mounting flanges, brackets, and miscellaneous hardware for an easy installation. For Universal SSQV applications, weld-on flanges are available in steel or aluminum for custom installation.


Hope this helps!

that car has major compressor surge, that's why the sound lasts longer than normal

Compressor surge, or he has the spring set super soft and its just staying open.

so does the chatter/shudder go longer if you set the spring really soft? and for those who responded saying their hks does the shudder, at what psi is this happening?

honestly, i couldnt tell you what psi exactly(right now i have boost creep)but around 4k rpms when i let of slowly

I have been messing around with mine and that shudder is most likly from highboost and still being in gear. If the throttle closes and the turbos still spinning the pressure in the piping/bov and the vaccume in the rear of the bov will work against each other becuase of the way HKS set up the outlet, causing the Cha cha cha cha chaaaa sound. I modified mine to take care of this and its works ALOT better. The only problem im working on now is a rought idle a few seconds after blow off. I have a few ideas to take care of that though.

Also putting the adjustment screw all the way in will help the flutter or surge and cause this.

hereitcomes said:

Compressor surge, or he has the spring set super soft and its just staying open.

Click to expand...

You can't adjust the spring on the real SSQV's

On old hks ssqv's you could, they took the bolts off on the new ones. I've seen this mis-info spread a couple times on these forums, next person's getting a warning for it.

Mine flutters, but only at low boost, on high boost it releases much faster. You can hear mine do both in this video as it transitions between the two different valves inside the ssqv.

http://www.youtube.com/watch?v=Um4Wxf6yurs

mavisky said:

On old hks ssqv's you could, they took the bolts off on the new ones. I've seen this mis-info spread a couple times on these forums, next person's getting a warning for it.

Mine flutters, but only at low boost, on high boost it releases much faster. You can hear mine do both in this video as it transitions between the two different valves inside the ssqv.

http://www.youtube.com/watch?v=Um4Wxf6yurs

Click to expand...

No, not on any model SSQV could you adjust the spring tension. The adjustment knob was for the travel of the diaphram inside the blow off valve. When messing with it you would change how far the diaphram would travel which limits movment of the valve. Since the ssqv works becuase of pressure alterations, which we have read so many times the screw was just there so we could "tune" to what amount of travel we wantd to inner valve to have.

Oh I gotcha, I read it as there was no adjustment on the bov at all. As many of the knockoffs have an adjustment screw back there still while the new HKS's don't have one any more. I was always under the impression that the screw adjusted that backing plate and compressed the spring when turned in thereby increasing tension on the diaphragm, but the pictures and descriptions aren't very clear on that.

mavisky said:

Oh I gotcha, I read it as there was no adjustment on the bov at all. As many of the knockoffs have an adjustment screw back there still while the new HKS's don't have one any more. I was always under the impression that the screw adjusted that backing plate and compressed the spring when turned in thereby increasing tension on the diaphragm, but the pictures and descriptions aren't very clear on that.

Click to expand...

Oh ok I understand, Sorry. Anyway I though that also, untill I took alook inside the one I bought that was bad. Turns out theres 3 chambers and the 2 rear ones are what do everything. The fluttering comes from the valve not opening far enough/having the adjustment screw to far in. I have spent the last 3 weeks messing wiht the bov trying new things to make it work even better than before I I finally have it. well 98% done.

Heres what I did.

1. eliminated the one way seal between the 2 rear chambers
2. gave the middle chamber its own nipple
3. tapped the intercooler piping for the middle chambers pressure source.

I made a diagram but my computer is acting up I will post it later on.

Heres the real thing as of today....all thats left is a valve that acts like a MBC comming off of the nipple in the middle of the vac line from the IC piping to the middle chamber.

ALso do you guys thing the dual nipples on the rear chamber are fighting each other or working together? My question is do you think I will have better flow with just one vac/boost port on the rear chamber. Thanks guys. The Sqv responds GREAT I just have a small idel issue with no brether between the sqv and the IC piping vac line. Tell em what you guys think

WTF kind of blow off valve is that? Do I really see 3 separate vacuum lines going to it?

Here's the single nipple with adjustment bolt ssqv that I have.



The newest ones are identical to mine, but with no adjustment screw on the back. That is not an actual HKS unit. Alot of the ripoffs I've seen have the vacuum port on the bottom instead of the tip like this one pictured here.



You can see in this picture that my real hks unit (the older 2001 model) has an all black adjustment screw, HKS on the outside of the bov, and the nipple above the adjustment screw.



and another older picture of my car with the bov facing the other direction.

Yea My adjustment screw was black also and my brass nipple was above it but I spun the rear case so I could make more room for the the nipple and as for the adjustment screw I took it out and put the extra nipple on there to get better vac/boost responce..but im starting to think one would be better than the 2 in the rear.

I have another real HKS SSQV on the way to me just incase something goes wrong here with this one, but so far the only problem Im having is idle related. Ill letyou guys know how it turns out.