Thoughts on external blow off valves on a direct fuel injection system

[Mo-mo]

So I had a long drive yesterday and let my mind wander so I didn't fall asleep or race anyone who looked at me funny. Anyway, from what I understand a GDI engine is similar in ways to an EGR system on a diesel, minus the big ol filter and 1000+ degree temps. So with the essential recycling of air via the EWG, causes carbon build up over time. My question is, if you run external BOVS, would that lower the amount of carbon on top of the valves?

 

[D.J.]

So I had a long drive yesterday and let my mind wander so I didn't fall asleep or race anyone who looked at me funny. Anyway, from what I understand a GDI engine is similar in ways to an EGR system on a diesel, minus the big ol filter and 1000+ degree temps. So with the essential recycling of air via the EWG, causes carbon build up over time. My question is, if you run external BOVS, would that lower the amount of carbon on top of the valves?

Huh,

The BOV blows off filtered air...
The OEM diverter valve blows off the same air, but blows it into the intake pipe rather than to atmosphere.

How would that affect the amount of carbon on the valves?

 

[RM7]

The PSSSHHH sound comes from removing factory intake silencing. My subaru PSSSHHHed all day long when I put a short ram intake on it...with the stock BOV.

 

[D.J.]

The PSSSHHH sound comes from removing factory intake silencing. My subaru PSSSHHHed all day long when I put a short ram intake on it...with the stock BOV.

Exactly,

But to the OP, how is that in anyway related to carbon on valves.

 

[Mo-mo]

Huh,

The BOV blows off filtered air...
The OEM diverter valve blows off the same air, but blows it into the intake pipe rather than to atmosphere.

How would that affect the amount of carbon on the valves?

I was assuming that the air was the same for each. Instead of blowing out the excess air it's put back to be re used. Again I'm used to semi trucks so if there is a difference feel free to correct me.

 

[Saschaversum]

The PSSSHHH sound comes from removing factory intake silencing. My subaru PSSSHHHed all day long when I put a short ram intake on it...with the stock BOV.

What is the intake silencing you are mentioning? Are you saying i can remove some sort of dampening material in the intake area and get more turbo sound?

 

[Saschaversum]

The PSSSHHH sound comes from removing factory intake silencing. My subaru PSSSHHHed all day long when I put a short ram intake on it...with the stock BOV.

Do you mean removing the recirculation hoses from the diverter?

 

[oddball]

So I had a long drive yesterday and let my mind wander so I didn't fall asleep or race anyone who looked at me funny. Anyway, from what I understand a GDI engine is similar in ways to an EGR system on a diesel, minus the big ol filter and 1000+ degree temps. So with the essential recycling of air via the EWG, causes carbon build up over time. My question is, if you run external BOVS, would that lower the amount of carbon on top of the valves?

No.
The turbo blow off system and the EGR system are totally separate. The EGR is much further down the intake path and on the engine side of the throttle body, while the BOV is between the turbo charge outlet and charge inlet. There's only fresh air swirly around the charge side of the turbo.

EGR is an emissions things and has been around for 30+ years on all engines. A small amount of exhaust gas is allowed back into the intake to be burned again with the fresh air and fuel. This helps reduce emissions. There's fairly sophisticated control on when this is enabled and how much. Has nothing to do with the wastegates. Non-turbo cars have it too - it's an EPA requirement.

 

[Devin]

What is the intake silencing you are mentioning? Are you saying i can remove some sort of dampening material in the intake area and get more turbo sound?

If you replace the air cleaner with something open you can hear the turbos. I can hear them a little bit with the Takeda boxes and leaving out the plug.

 

[Kazz]

Anyone that's worried about carbon on their valves should be running a quality oil catch can. Period.