We Test Synapse Engineering’s Synchronic Blow Off Valve and DV Diverter Valve


Due to the responsiveness of the piston design, the Synchronic valve can be tuned to eliminate fluttering, boost dumping and other driveability issue that are usually just accepted on a turbo car as normal.  When cornering where you have to finely modulate the throttle, the Synchronic valve shines.  Its fast action also helps reduce boost fall off during shifting.  In their benchmarking testing, Synapse has found that their valves are the fastest responding valves on the market by far, responding to changes in vacuum signal in mere milliseconds.

We Test Synapse Engineering's Synchronic Blow Off Valve and DV Diverter Valve
A few years ago we asked Synapse to come up with a BOV with all of the functionality of the Synchronic in a compact non ricey and lightweight package.  They responded with the Synapse DV.  The DV is small, here it is compared to the stock EVO IX DV.  The DV is one third the size of the Synchronic BOV.

Not being constrained by the flex in a diaphragm, the Synchronic BOV’s control valve has a much higher lift than other valves as well, allowing for more flow.  This eliminates surge and keeps the turbo speed high during shifts, even when tuned for maximum driveabilty. You have to experience the difference to really appreciate what a well tuned BOV can do for smoothness and throttle response.

We have been ribbing Peter for a few years about the size and weight of the Synchronic BOV.  Don’t get us wrong, it’s not just Synapse but pretty well all of the BOV’s on the market  that are big and heavy chunks of billet because we feel that they are largely designed to impress when the hood is popped.  We used to think it was funny that a big ricey BOV was the first mod that many people with a turbo car would buy.  We presumed that these people wanted to show off their mod so the industry made really custom looking valves of excessive size and penility because of this.

The thing is, we felt that BOV’s didn’t need to be like this. We didn’t want a ricey chunk of billet under our hoods, we wanted function.  We started to bug Peter about making his valve with all of its functionality in a small, compact and light package that we could put on our turbo race cars.  Well Peter listened and delivered with the Synapse DV valve. The DV valve’s outsides tightly package against the proven Synchronic stepped piston insides which have been redesigned to package in a much shorter dimension while still keeping an impressive amount of lift.  The DV is small and light but still has the same impressive flow and response as the big Synchronic.

We Test Synapse Engineering's Synchronic Blow Off Valve and DV Diverter Valve
The DV’s valve is much larger than the stock EVO part which is actually pretty big for a factory part.

Another interesting feature of the DV is that it is reversible and can be installed in a push or pull position, Push meaning that boost pressure helps push the valve open and Pull meaning that boost pressure helps hold the valve shut.  In either position the valve will not leak until over 60 psi of boost pressure is applied but push or pull has an effect on how quickly the valve closes which changes the tuning characteristics. For instance,  when the valve is in pull, it is the fastest closing.  This is good for throttle response and part throttle driveability.  However push works better with some tuning if you are trying to tune out some compressor surge, your car has a MAF and is prone to stalling on throttle lift or if you are running a car with a MAF and are venting to atmosphere.


  1. Hi Mike. I am looking at purchasing the Synapse DV BOV for my R32 GTR project car. I was just wondering the technology used by Synapse is still market leading or has there been improvement by other makers?

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