Boost and Boost relief valve?

[whatabudro]

What pressure are you seeing on you boost guage at WOT in your highest chip setting?

If you are seeing above 20 or there abouts if I recall, the PCM will "De-fuel" the motor in an attempt to lower boost/power to protect the motor. So you will loose power. The boost relief valve "blows off" some of the boost to the Map sensor (not actually blowing off boost (air pressure) to the motor) to fool it and keep the engine from De-Fueling.

Hope that helped some.

Where do we find out what the programming is on the map sensor. If you are correct about 20lbs then I do need one. I have never had a CEL on my truck and I thought that was the main purpose of the relief valve. But if I'm defueling above 20lbs then I'm LOOSING horsepower and that sir is unacceptable. I'm seeing 23 lbs of boost on 1-2 shift and 27-29 on 2-3 but I don't set off a CEL.

 

[Fire1]

I can not remember the exact boost number that de-fueling occurs, but I think that is the ball park. Mine would set the SES light without the relief valve. I peak in the 25 psi area.

Well on edit it appears to be the 25psi area. See the link below.

HERE

 

[whatabudro]

I can not remember the exact boost number that de-fueling occurs, but I think that is the ball park. Mine would set the SES light without the relief valve. I peak in the 25 psi area.

Well on edit it appears to be the 25psi area. See the link below.

HERE

I may buy one in the future since the price is right, but since I don't have an SES I think I'm not defueling. Budro

Are you coming by on Sunday?

 

[roosterdiesel]

.. but since I don't have an SES I think I'm not defueling.

When I had my BRV removed while chasing boost leaks, I would only set the light when I kept it at 26psi+ for sustained amount of time. Flashes over 25 wouldn't set it.

I had to disconnect the red tube at the WG to achieve this since my WG is set to open at 24lbs. I don't recommend running this way but if you want to find out what it feels like, try it.

 

[whatabudro]

When I had my BRV removed while chasing boost leaks, I would only set the light when I kept it at 26psi+ for sustained amount of time. Flashes over 25 wouldn't set it.

I had to disconnect the red tube at the WG to achieve this since my WG is set to open at 24lbs. I don't recommend running this way but if you want to find out what it feels like, try it.

So I might be defueling without a CEL?

 

[roosterdiesel]

So I might be defueling without a CEL?

No, I don't think you are. You will know when you defuel.

Boost dropped off to around 10lbs for a moment then back up, then I lifted. This is on my truck, I've read where other trucks acted different.

 

[Fire1]

Are you coming by on Sunday?

I talked to Bill earlier. My truck is still at Prestige . I may or may not get by in the wifes Explorer though. What time and where you at exactly? PM me.