BOV sound and what compressor surge sounds like and some more information .

[Ranger498]

member synapse
made this vid
"Updated video of Honda S2000 turbo with Synapse Synchronic Blow-Off Valve. There's no diaphragm in the BOV, it is fast acting and uses a piston and Synchronic geometry. You can also hear what compressor surge sounds like, drive by's with the BOV, and ........."


click here for vid

[95jza80tt]

intereresting

[95jza80tt]

after watching the video a second time and paying more attention and trying to understand how this bov works i am a bit confused here.. so the guy says that there is no diaphram and its a piston actuator controlled by vacuum.. when there is boost pressure present the valve is held close by that pressure but when there is vacuum present (off throttle) it opens the valve.. so when not under boost the valve remains open? and thats what it seems on the video as well.. so in my case since i am still just bpu running with the factory maf on if this is used in a vent to atomosphere manor then this would stall out my car, unless used in a recirculated manor.. the appeal of this went down a notch.. call me a ricer if you will but like most others i love the sound of my bov vent to atmosphere.. still interesting in design though..

[chris_k]

It looks to me, as well, that this BOV is open at idle, or any vacuum conditions. This means it can only be used by MAP cars, or if MAF sensor is put between BOV and the intake manifold. Even if MAP computers are used, VPC or MAP ECU or others, the car needs to be retuned after this BOV valve is installed. I also believe the car using this BOV would be more sluggish in creating boost, the split second before boost can close BOV.

[cord4530]

Yes, the BOV is definitely open at idle. Someone may want to mention that to the guy, as the poor S2000 is ingesting a bunch of unfiltered air at idle/part-load conditions. You would want/need to run this as a bypass valve, or put some sort of filter on it. And with the filter, it may not vent as well.

The other thing I didn't like was that they only showed the valve under no-load conditions. My BOV hardly opens when free-reving like he was doing in the vid. What would be really nice would be to see some video of the valve when the car was on a dyno building some boost. Boost pressure on the back side of the piston tends to keep it closed. I'm wondering what will happen when there's 20 psi of pressure on the back side. It certainly opens (heard in drive-by) but higher boost will make it open a lot slower.

I also don't see what's new about this BOV. I always classify BOV's as either diaphragm or piston types. To me this one looks just like most piston types. The good thing about piston types is that they have VERY good flow. But they also have more inertia, so they usually open slower, and don't react to the smaller fluctuations.

[cord4530]

Originally Posted by 95jza80tt

<snip>
call me a ricer if you will but like most others i love the sound of my bov vent to atmosphere.. still interesting in design though..

FWIW, I have one of the HKS SSQV units that I run recirculated sometimes, and open sometimes. The BOV definitely makes more noise (high pitch whistle) when vented to atmosphere, but it's still makes planty of noisy when used with the recirc kit.

[synapse]

Guys, thank you for your input. We had a discussion going on this over at Previous discussion if you want to check out some of the same concerns that others have.

I'm clipping and pasting here a little too. But basically this BOV is a pull-type BOV, so it will stay shut with boost pressure in the intercooler pipes alone. If you watch the vid and see that I made compressor surge happen by disconnecting the vacuum line to the actuator of the BOV because it stayed shut under boost. This is different from other BOVs because it uses a patented new actuator geometry. There are 4 different, unequal piston areas. This BOV even has built-in overboost protection, by using one of the piston areas to open the BOV to limit boost pressure if your wastegate sticks shut, or your signal line breaks, or boost controller stops working. I also want to clarify that there is a spring in the assembly. If you are Engineering inclined, you can read about the actuator geometry here Synchronic Actuator Technology

This BOV was designed from the outset with two settings, Economy and Race. The video only showed the economy setting in order to demonstrate how fast the valve actuated at FULL valve travel. The economy setting utilizes the maximum amount of piston area against the spring = valve is open at idle. Race setting was designed to keep the valve closed at idle.

When running the Economy setting, you have to either filter the BOV if you are discharging to atmosphere, or reroute it back into the intake pre-turbo and after the filter. With MAF cars, between the MAF and the compressor inlet. It is the economy setting because it is a setting that has less intake restriction. If you ever watch yourself cruising the freeway at 70 mph, you are mostly running around at 10" of vac on a flat road. Someone mentioned earlier that it looked there was better throttle response with this BOV. It is because in the normally open condition, the engine can rev faster from full vac to 0" since you are bypassing the restriction of the intercooler, piping and compressor. The Synchronic Wastegate works the same way. With both of them in place, the engine can have the throttle response of an NA motor by eliminating restriction on both intake and exhaust.


I honestly didn't expect it to actuate this fast, when I first designed it, I was too caught up with other calculations. I'm starting to think that the config you see in the video is the best performing setup, so long as you filter the BOV or recirculate to the intake.

With legacy BOV designs, you usually want the BOV shut at idle, because you can't reliably predict that it will actuate fast enough to shut the minute you close the throttle, without having a ton of spring preload on the valve that is. But then you get into the problem of excessive spring pre-load limiting valve travel. Which is why you guys have experienced with push type valves that if you crank down on the spring too much, the BOV barely opens and it whistles. What I'm telling you, is that this thing actuates fast enough that you don't have to crank down on the spring. And you get the benefit of improved throttle response from full vac to 0" because the valve is in a normally open config.

[cord4530]

Originally Posted by synapse

Guys, thank you for your input. We had a discussion going on this over at Previous discussion if you want to check out some of the same concerns that others have.

I'm clipping and pasting here a little too. But basically this BOV is a pull-type BOV, so it will stay shut with boost pressure in the intercooler pipes alone. If you watch the vid and see that I made compressor surge happen by disconnecting the vacuum line to the actuator of the BOV because it stayed shut under boost. This is different from other BOVs because it uses a patented new actuator geometry. There are 4 different, unequal piston areas. This BOV even has built-in overboost protection, by using one of the piston areas to open the BOV to limit boost pressure if your wastegate sticks shut, or your signal line breaks, or boost controller stops working. I also want to clarify that there is a spring in the assembly. If you are Engineering inclined, you can read about the actuator geometry here Synchronic Actuator Technology

There was some good info on your site. And congrads on getting a patent too! That's tough work. I was looking over the PDF on that link and thought you did a nice job of explaining how the system can work, and its use as a pressure regulator. As a fuel regulator, that's a pretty powerful piece of hardware.

I did have some more questions about the BOV though. And if some of this is secret, I understand too. I'm curious how many ports are connected, and to what sources. I'm guessing that one port is connected to manifold pressure (post throttle). One port is going to be connected to the IC piping (pre throttle). One is connected to atmosphere (or turbo inlet).

Have you considered making a test bench for the valve? It would be interesting to see how the valve worked under different scenerios (without having to depend on the engine/turbo system).

Also, is this designed to fit in the same holder as the HKS SSQV? Do you have a rough idea how much these are going to cost?

[Ranger498]

interesting BOV

im wondering what if any others cars have you tested it on ?
and how does it compare to the others on the market ! tial ,hks ect.........

[cord4530]

Actually, looking in your original thread on Honda-tech there's a good animation of the valving and connections.
http://www.synapseengineering.com/pr...tion-small.gif

[synapse]

Originally Posted by cord4530

I did have some more questions about the BOV though. And if some of this is secret, I understand too. I'm curious how many ports are connected, and to what sources. I'm guessing that one port is connected to manifold pressure (post throttle). One port is going to be connected to the IC piping (pre throttle). One is connected to atmosphere (or turbo inlet).

Have you considered making a test bench for the valve? It would be interesting to see how the valve worked under different scenerios (without having to depend on the engine/turbo system).

Also, is this designed to fit in the same holder as the HKS SSQV? Do you have a rough idea how much these are going to cost?

Thanks for the input Cord. Nothing's secret, in fact I want anyone that is Engineering inclined to digest how it works and derive their own applications, come up with their own derivative patents, and we go license it together. So ask away.

There are 3 main ports used in the standard configurations.

Config 1-Vac to port with small piston area, boost in intercooler piping actuates piston area internal to the BOV. So the actuator is actuating based on the amount of boost in the IC pipes too. Smaller piston area, less pull on the spring, so it is designed to keep the valve closed when in Vac.

Config 2-Vac to both ports that pull the valve open, and then the permanent one mentioned above. More piston area means more pull on the spring, so the valve stays open in Vac and you bypass the intake restrictions of the IC, Turbo and piping.

Config 3 (untested so far)-Config 1, but the 4th port which has a much larger piston area than config 1, is connected to a solenoid, when your ECU determines that you are producing excessive boost, it opens the BOV like a pop-off to limit boost. This is more of a safety mechanism, and for the road racers, will allow you to finish the race even if your WG goes out on you.

The Synchronic BOV also has interchangeable flanges, so in the video you see an HKS flanged config, but we'll be making flanges to accomodate the various BOV's that are out there.

[Ranger498]

Originally Posted by synapse

The Synchronic BOV also has interchangeable flanges, so in the video you see an HKS flanged config, but we'll be making flanges to accomodate the various BOV's that are out there.

wow now that is a sweet idea this will save lots of time when and if a person decideds to switch ..make sure to make one for the tial mounting flange


this unit seems likea great item when it comes out ..so what willbe the price range on it ?

[JoeThaMan]

To me, it appears to be similar to the Bosch bypass valves that have been used for years, but with a different design and without a 'recirc' nipple on it. The bosch valve is similar to the stock one used on MK3/MK4 (open during vacuum conditions) but larger, around 1" to 1.25" depending on which valve you get and different springs and valves. They usually connect post turbo and and pre-turbo so that air doesn't have to travel through the intake/intercooler tract before it gets to the throttlevalve, so it just bypasses everything straight to the throttlebody which increases throttle response in most cases. Under boost it closes so that boost is not bled back pre-turbo and when the intake manifold goes from positive manifold pressure to vacuum, the valve opens and bypasses the compressed air back into the intake pre-turbo reducing compressor surge. Also, how the valves are installed is that the valve closes towards the intake (pre-turbo) so if the vacuum reference hose does pop off, boost pressure doesn't push the valve open. If you do a google search for "Bosch Bypass Valve" you'll find several different test and product info pages. You can also get them from $35-$65 depending on which one you want.

[makipsee]

not to kill everything this is acting just like a normal BOV aside for the 3 ports. a bov can simply be adjusted to work just like this just loosed up the BOV and u will see the valve open as u loosen it and it would actully help with when the TB closes and open quicker. as soon as the TB opens on the video it closes, just like then he pulles off the source line it closes b/c theres no vacuum present so then the TB opens theres no more vaccum present so it closes. but thats my $.02