Blow off Valves or BOVs

Let’s talk about a less common ricey modification but probably one of the most heart breaking. The blow off valve.

Blow off valves can only be equipped with turbocharged vehicles. Turbocharged cars typically come equipped with more performance than there base model counterparts. Some owners of turbocharged vehicles decided to equip their vehicles with what is called a blow off valve. In some but not all circumstances, this can be considered a ricey mod. Some modern turbocharged vehicles come stock with some sort of atmospheric venting for positive boost pressure. The sound of that venting is called “blow off”. If the vehicle is factory equipped with an atmospheric vent, allowing it to make more noise by replacing the valve has no performance gain and literally only makes it sound different.

Almost all turbocharged vehicles do not come from the factory with an atmospheric venting system, instead they are equipped with what is called a recirculating valve. The purpose of this is to not waste the positive pressure by “blowing off” into the atmosphere, but to take the pressure and reuse it to help the performance of the car. The real heartbreak comes when a vehicle that is equipped stock with a recirculating valve is replaced with a blow off valve for the purpose of having a more aggressive sound. A few different negative things happen to the vehicle when the owner does this without having proper supporting modifications. First off, in any application atmospheric blow off will reduce spool time in-between shift, therefore reducing the performance of the car. Secondly and more importantly, if the vehicle is equipped from the factory as “MAF sensed” most vehicles ECUs or engine control units will compensate for the loss in pressure by adding or reducing fuel to the air coming in therefore skewing the air to fuel ratio. As any mechanic will tell you, having the incorrect air to fuel ratio can cause a variety of symptoms ranging from fuel consumption, to reduced performance, and even engine failure. To correctly install a blow off system and have it be considered a performance upgrade, you must first spend multiple of thousands of dollars installing or upgrading a turbocharger on your vehicle. This concludes my personal opinions as to why blow off valves are considered ricey.

If you’re interested in what a blow off valve sounds like, check out this video below!

Annnndddd if you’d like a little giggle or are interested on what a fake one sounds like, check out this video!

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