For MAF (mass air flow sensor) type vehicles, the problem with installing a blow off valve is that once the valve opens and releases the compressed air the car will stumble because the pcm has already released fuel for the air that it thought was flowing into the engine.
So, to use a blow off valve on a MAF car correctly, you really need to plumb the air from the blow off valve back into the engine. What you would do, is take the air from the blow off valve and route it back into the engine AFTER the mass air flow sensor.
We’ve now started carrying two components that will help Cobalt turbo owners with installing a blow off valve.
1) Anti stall kit – this allows those of you who want to vent to atmosphere to use a Synapse bov and make it so that the Synapse will not allow unmetered air in during vacuum conditions. This will work well, however it will not solve the problem of the car running really rich after the pcm sends out fuel for the air that has been measured by the MAF sensor.
2) Recirculation fitting for Synapse blow off valve – this is the perfect solution. Install this fitting on the blow off valve and then plumb the air back into the air tubing AFTER the mass air flow sensor. You would typically add on a 1 inch rubber hose from the synapse blow off valve to the intake hose tubing.