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Blow off valves "mythbusted", also, BOV on a NA car...

Thanks for the link.

Pretty entertaining, I haven't seen those guys before, going to have to check out some of their other videos.
 
I don't fathom how there could be any myth here. On any forced induction engine there are going to be times that you don't want boost. When that happens there are two options, you either vent the excess pressure, or let the air stall in the intake tract.
On an NA engine, there is never any pressure to vent. A blow off valve will have the same effect as adding a pencil sharpener.
 
Looks like they showed, despite their premise, that aftermarket blowoff valves do provide a performance enhancement.
 
I might be retarded, but I don't think those guys tested what the engineer actually said. He didn't say it gave more power. What he said was that saving some of the pressure rather than venting all of it reduced LAG because you start from maybe 3psi instead of 0. All their numbers showed was peak power, which has absolutely nothing to do with the throttle lag that guy talked about.


Ok I have idea. Instead of using some complicated spin up and down kinda deal, why not have a small tank that stores pressure? Instead of waiting for a turbo to spin up, it would just open the valve and boom instant boost. Boost comes from the tank, and the turbo feeds the tank. It's actually how a battery backup system works in electrical systems....
 
GasX said:
Looks like they showed, despite their premise, that aftermarket blowoff valves do provide a performance enhancement.
Click to expand...

uh where? The stock Blowoff Valve is fine but if you add boost, or tune for boost to hold longer or w/e then you need a bigger valve to handle the pressure.
 
ShawnD1 said:
I might be retarded, but I don't think those guys tested what the engineer actually said. He didn't say it gave more power. What he said was that saving some of the pressure rather than venting all of it reduced LAG because you start from maybe 3psi instead of 0. All their numbers showed was peak power, which has absolutely nothing to do with the throttle lag that guy talked about.


Ok I have idea. Instead of using some complicated spin up and down kinda deal, why not have a small tank that stores pressure? Instead of waiting for a turbo to spin up, it would just open the valve and boom instant boost. Boost comes from the tank, and the turbo feeds the tank. It's actually how a battery backup system works in electrical systems....
Click to expand...

They did show the plot and pointed out the line for the stock unit. It was clearly leaking boost at higher RPM. The aftermarket units were not.
 
DivideBYZero said:
They did show the plot and pointed out the line for the stock unit. It was clearly leaking boost at higher RPM. The aftermarket units were not.
Click to expand...

That doesn't show throttle response though, which is what Shawn was complaining about.

It does however show that "an old valve with leaking valve seals" sucks. That should be common sense.

It also shows that if a factory valve is rated at 10 psi, it will vent any boost you generate above about 10psi by remaping the ECU.
 
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