When you look at the blow off valves (BOV) and bypass valves (BPV) on the market today you see many examples of the same thing with little to no innovations. For those of you that aren’t aware, BOV’s and BPV’s are valves that vent pressurized air in the tract between the turbo and the throttle body. This prevents the turbo from suddenly stopping or slowing as those can cause unwanted bearing wear on the turbo. A BOV vents this pressurized air into the atmosphere (into the engine bay). A BPV vents that air back into the intake just after the mass air flow (MAF) sensor. Venting back into the intake allows the ECU to correctly meter that air that it has already accounted for. Many times when venting to atmosphere you can get a momentarily rich condition because the ratios are off.
We were talking about innovation though, the last great innovation in valve technology for turbos was probably years ago with pull type valves like the SSQV from HKS. Many years have passed since then and not much has changed, outside of the few valves that partially vent to atmosphere and route the rest back to the intake tract. Typically now you just see one copy after another of someone else’s idea. SURE, it can be hard to innovate in the blow off valve market but we were convinced there was something exciting we could do.
We speak often about your ideas sparking our innovative minds, this project was started by just one of those customer suggestions. We started with a customer submission of using wave springs that led us to design a new valve design to reduce the size and weight of the moving parts.
Key Features of the upcoming patent pending CorkSport Blow Off Valve:
Reduction of spring height 
With the use of a wave spring we are able to reduce the spring height by 50%. The traditional spring sits at 40mm and the CS wave spring sits at a 20mm height. These springs both provide the same force and will move the same distance before experiencing coil-bind.
Reduction of piston size
Because the spring is 50% smaller we are able to reduce the piston and still maintain the same amount of movement. As you can see, just changing to the wave spring we were able to decrease the piston by 33%!!!
What does that all mean?
The reduction in mass is all well and good, but just being smaller isn’t the only benefit (even though that is pretty cool). With the force (F) being the same and the mass (m) decreasing by 33% we can see how the mass relates to acceleration (a) in the formula F=ma. Rearranged, this becomes a=F/m. This means we have accelerated the actual speed of the valve, which means the valve is able to react much faster than a larger valve with a traditional spring (33% faster!) Because the blow off valve is a safety feature to protect the turbo from premature wear, this increase in acceleration can help increase the longevity of the turbo and the system as a whole.
What does all this innovation look like?
With the reduction in the size of these key parts, we can reduce the body size. This can be especially helpful in situations with airboxes, custom turbo and intercooler kits or even in universal situations where space is at a premium. Below you can see a comparison of similar BOV’s, the spring chamber on our design is significantly smaller but the function is not lost; in fact, we improved it!
To maximize flow, we pushed the piston area out to ensure a larger venting area, this reduces the time it takes to vent the air and allows larger turbos to vent more efficiently. As a blow off valve, this certainly pushes the envelope, we think we can find even more applications for this kind of innovation. We are very proud to be able to offer things for the Mazda market we helped create and will continue to engineer parts that push the scene for you.
should integrate a 90 degree vacuum nipple on it
i see what you did there lol.
SURE, it can be hard to innovate in the blow off valve market but we were convinced there was something exciting we could do.
Excellent – someone finally has a reason for me to contemplate replacing the factory BPV that was already performing as expected for my application. Anything to prolong turbo life is a win in my book.
Rad. Wanted to pick one up for my 12 MS3, I’ll wait til yours is out!
How about sound? What I’m looking for is no sound, personally I try to keep it as quiet as possible.
You guys always have awesome ideas! I love that the piston area is increased for better venting, which means longer life for my turbo. This is definitely the only BOV I want. I’m CorkSport to the soul! This is next on my list 🙂
2009 MazdaSpeed3 GT with CS Stage II Intake, CS Turbo Back Exhaust, CS Short Shift Plate, CS LED Lighting Kit. And loving every mod <3
aahhhhhh I see what you did there Corksport, “SURE, it can be hard to innovate in the blow off valve market….”. Can’t wait to get this
Is the fatigue life of the wave spring similar to that of the coil? Similar S-N curves?
….just curious.
Sounds like great innovation! However, I would match up the BOV’s in your pictures to be in the same positions…
Please make this fit and finish for a 2010 Wrx, I love my Mazda but my Wrx is my pride and I love your products!
Now the question a lot of us want to ask…do you have a video of where we can hear how this sounds??
Colour me excited.
So this is not a BPV, correct?
I can’t wait to get one and try it out.. I’m still running the stock valve right now. 😉
Your picture says “Factory BOV,” but it’s a BPV. Minor point, but it contradicts your earlier explanation of what each one is.
What it is the part # of this corksport BOV ????
If you could release this BOV with an SRI packaged deal I’d be all over it. I’ll be ordering your stage II SRI soon.
what is the expected release date and Part Number?
Awesome idea! Can’t wait for this to come out. I haven’t changed the oem one on my ms6 cause I heard its better then all the rest on the market. Defiantly gonna get this. Keep up the “great work”
Will you be releasing this bov as a package deal with your fmic, like you do with the hks and greddy?
This is the first product I’ve seen that would make me consider replacing the BPV (you meant BPV in your article right?) on my MS3. For a daily driver with just a couple power addons, there isn’t a lot of need to replace the BPV; but if it enguages faster and can prolong the turbo life, then I’m all for it.
Can’t wait to see the finished product and the final cost.
As you mentioned there’s a huge difference between a BOV & BPV. Per the pic of your product it looks to be a BPV but your calling it a BOV and not even saying its a “Hybrid”. So if its “true” BOV then that wld mean no air recirculation which we know our Speeds don’t like unless your running a Guardian Angel. So my question is this, BPV, BOV or Hybrid???? I look forward to another well engineered CorkSport product, Thank You!!!