blow off valve
blackcloud
blow off valve
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From: arizona
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From: 21791
that is NOT a blowoff valve. that is used on 7.3 powerstrokes mainly. it is designed to bleed off excess pressure in the MAP line to prevent the MAP sensor seeing an "unsafely high" boost level and throw a code, sending the engine into defueling mode. they do not make a sound over the engine, but i believe there may be a slightly audible hiss if you took away all other sounds. no "psschtt" sound of a blow off valve on a gasser. the reason you don't need a BOVC on a diesel, is that there is no throttle plate that closes when you let off the throttle. therefore there is no need to vent the pressurized air between the turbocharger and the throttle plate. the air just keeps moving in the cylinders.
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From: arizona
Originally Posted by strokin_it7.3
that is NOT a blowoff valve. that is used on 7.3 powerstrokes mainly. it is designed to bleed off excess pressure in the MAP line to prevent the MAP sensor seeing an "unsafely high" boost level and throw a code, sending the engine into defueling mode. they do not make a sound over the engine, but i believe there may be a slightly audible hiss if you took away all other sounds. no "psschtt" sound of a blow off valve on a gasser. the reason you don't need a BOVC on a diesel, is that there is no throttle plate that closes when you let off the throttle. therefore there is no need to vent the pressurized air between the turbocharger and the throttle plate. the air just keeps moving in the cylinders.
ok i see and that sounds true, but the 04 and up PSD do have a throttle plate that closes .
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From: 21791
no, early 03 models have the throttle plate that only closes to help the EGR system. it closes somewhat to allow the exhaust a less-pressurized path to the intake manifold. the throttle plate does not close every time the throttle is let off. it's not the nature of a diesel. the speed is controlled by the amount of fuel injected, not the amount of air injested that is fuel-rich.
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More Turbo
Joined: Sep 2005
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From: arizona
plate or no plate ,why
Originally Posted by strokin_it7.3
no, early 03 models have the throttle plate that only closes to help the EGR system. it closes somewhat to allow the exhaust a less-pressurized path to the intake manifold. the throttle plate does not close every time the throttle is let off. it's not the nature of a diesel. the speed is controlled by the amount of fuel injected, not the amount of air injested that is fuel-rich.
check this out looks like you were right. I have a 03 and found this.. I wonder if this is why , when I let off after hard acceleration I some times get a turbo bark sound( some type of pop off valve letting off do to this....)
https://www.ford-trucks.com/lc/lc.php?action=do&link=http%3A%2F%2Fwww.backglass.o rg%2Fduncan%2Fps60_manual%2F
cool huh. why did this loose it ? after
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From: MI
Originally Posted by chadjones99
I wonder if this is why , when I let off after hard acceleration I some times get a turbo bark sound( some type of pop off valve letting off do to this....)
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