To make a long story short I bought a fully built Evo 9 that has the synapse diverter valve fully recirculating to the engine. The car sat for a couple of years before I bought it from
The previous owner. The car is an animal at 400whp on a mustang dyno fully built by cbrd. The car drove perfect for a month. The other day I boosted first and second gear hard and then pulled into my driveway. I let the car cool down for 30 seconds and started to notice that the idle went from a solid 1000 RPMs like it usually is and started revving on it's own up to about 2000 to 3000 RPMs I thought that was odd I went to sleep and woke up the next day and drove to work and noticed that the diverter valve instead of making a large Skoff noise like it usually does between shifts was making a fluttering noise and it feels like I lost over 100+ horsepower I ended up taking it to a shop and they checked all of my intercooler piping and vacuum hoses none of which seem to be leaking which leads me to believe that The problem could possibly be inside of the valve itself has anybody had any issue with this synapse diverter? If so let me know what you think from what I told you!

 

The Synapse BOV is easy to take apart to inspect, I would presume the DV is as well. Have you considered simply taking it apart to look at the insides?

 

The early Synapse DV has a coule of design flaws.
1) The investment cast housing cracks along the join line causing a leak above the digaphram. This causes lower boost on throttle and poor blow off on lift off.
2) The inlet and outlet pipes can crack and break off the main housing. The slots that allow the three fingered clamps to hold the adapters in place weaken the investment cast pipe walls . This often results in cracks and breakage of the metal around the clamping slots. This usually happens on the high pressure inlet side creating a boost leak. It can cause an explosive failure on high boost - ask me how I know

If you find either of these problems I recommend contacting Synapse Engineering over the phone. They recently released a new housing which fixes these problems. Once you get hold of them, (keep trying) they are very helpful. They sent me a new housing for free so long as I paid the shipping!

Good luck with your issue.

 

yes, its 6 little bolts on top of it, very easy to take apart.

 

Thank you so much guys for your help! I will take this valve apart asap and contact these guys.