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

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Dai Yoshihara’s 350Z before loading for Abu Dhabi.

One thing we didn’t like about the Synchronic valve was that we felt it was partially designed to compete with other BOV’s on the market on a visual basis.  Many people buy BOV’s for looks and the Synapse part was impressive looking, a big heavy chunk of impressively machined billet aluminum about 10x overbuilt in our opinion.  We personally don’t care what a component looks like, only how well it works and we did not like the bulk and weight of the valve.

The Synapse Synchronic mounted on the Z’s charge pipe using the optional weld on fitting.  The Synchronic can also directly replace other BOV’s on HKS, Greddy, Tial and Turbonetics flanges.

We actually ended up using the Synchronic valve instead on Dai Yoshihara’s car that we were installing a modified JWT turbo system on for a Forumla D event in Abu Dhabi. The larger displacement engine with twin turbos could use a high capacity BOV.  When tuning the car on the dyno we were able to learn firsthand how useful the stepped piston could be for tuning the valve to the car’s needs.  The Z uses a mass airflow meter and we set the valve up to recirculate because of this.  Sometimes having the BOV recirculating causes some driveabilty issues especially when using a big valve like the Synchronic, but we were confident that its tuneabilty would enable us to be rid of any issues that might arise.

Read about it here!

We first set up the valve with the valve’s return spring loose and both substrates on the valve active.  Synapse recommends this initial set up as a starting point for most cars. When starting our dyno pulls sometimes a resonance would set up in the change pipes where boost would start to build when the valve would still be open due to partial intake manifold vacuum.  The rapid onset of boost would cause the valve to slam shut.  When the valve shut, the virtual length of the charge pipes would become long again and a vacuum would start in the intake manifold opening the valve.  This cycling had something to do with the natural frequency of the charge pipes and caused the engine to buck violently.

GTI’s Costa Gilamas fabricated this awesome part to merge the charge pipes from both turbos, the BOV bypass and the MAF all in a very tight area.  The air from the BOV is directed away from the MAF so as not to screw up its readings.