boost gauge in an NA vehicle???
#1
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boost gauge in an NA vehicle???
I have a boost gauge still in place from when I had an FI system that I ended up removing(long story). The gauge reads directly off the intake manifold. My question is this:
In a normally aspirated vehicle, can I use the boost gauge as an indicator of throttle position. More specifically, when the boost gauge is reading 0 psi (no vacuum), can I assume that the throttle plate is wide open?
In a normally aspirated vehicle, can I use the boost gauge as an indicator of throttle position. More specifically, when the boost gauge is reading 0 psi (no vacuum), can I assume that the throttle plate is wide open?
#2
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Assuming that '0 psi indicated' = 1 atmosphere = 14.7psi, that's backwards. I think that boost guages indicate the difference between manifold pressure and atmospheric pressure (or at least 14.7psi).
In a NA car, the faster the air flowing through your manifold, the lower the pressure is going to be. It's not actually possible to have 0psi indicated in a NA motor; the cylinders create a vacuum when they go down, which sucks air into the cyl via the throttle body. this means that if the car is running, you will have a negative manifold pressure reading.
If this is all correct, you could do some trial and error testing (or find a smart engineer) and figure out what vacuum level indicates what throttle position. I would assume that WOT = lowest indicated psi.
Or it could turn out that I'm totally wrong, so take it for what it's worth.
In a NA car, the faster the air flowing through your manifold, the lower the pressure is going to be. It's not actually possible to have 0psi indicated in a NA motor; the cylinders create a vacuum when they go down, which sucks air into the cyl via the throttle body. this means that if the car is running, you will have a negative manifold pressure reading.
If this is all correct, you could do some trial and error testing (or find a smart engineer) and figure out what vacuum level indicates what throttle position. I would assume that WOT = lowest indicated psi.
Or it could turn out that I'm totally wrong, so take it for what it's worth.
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Originally Posted by Speedracer
I have a boost gauge still in place from when I had an FI system that I ended up removing(long story). The gauge reads directly off the intake manifold. My question is this:
In a normally aspirated vehicle, can I use the boost gauge as an indicator of throttle position. More specifically, when the boost gauge is reading 0 psi (no vacuum), can I assume that the throttle plate is wide open?
In a normally aspirated vehicle, can I use the boost gauge as an indicator of throttle position. More specifically, when the boost gauge is reading 0 psi (no vacuum), can I assume that the throttle plate is wide open?
#4
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Originally Posted by 510dat
Assuming that '0 psi indicated' = 1 atmosphere = 14.7psi, that's backwards. I think that boost guages indicate the difference between manifold pressure and atmospheric pressure (or at least 14.7psi).
In a NA car, the faster the air flowing through your manifold, the lower the pressure is going to be. It's not actually possible to have 0psi indicated in a NA motor; the cylinders create a vacuum when they go down, which sucks air into the cyl via the throttle body. this means that if the car is running, you will have a negative manifold pressure reading.
If this is all correct, you could do some trial and error testing (or find a smart engineer) and figure out what vacuum level indicates what throttle position. I would assume that WOT = lowest indicated psi.
Or it could turn out that I'm totally wrong, so take it for what it's worth.
In a NA car, the faster the air flowing through your manifold, the lower the pressure is going to be. It's not actually possible to have 0psi indicated in a NA motor; the cylinders create a vacuum when they go down, which sucks air into the cyl via the throttle body. this means that if the car is running, you will have a negative manifold pressure reading.
If this is all correct, you could do some trial and error testing (or find a smart engineer) and figure out what vacuum level indicates what throttle position. I would assume that WOT = lowest indicated psi.
Or it could turn out that I'm totally wrong, so take it for what it's worth.
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Wide open throttle should show some vacuum but only a little. The intake tube is not large enough to eliminate all vacuum. Max vacuum would be at throttle closed position....so theoretically you could use your vacuum amount on the boost gauge to relate throttle position. Max amount-min amount = total amount of vacuum. Half that amount on the gauge would be yor 50% throttle position.
#7
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Originally Posted by 510dat
Well, that'll learn me!
So what are you going to use this for, anyway?
So what are you going to use this for, anyway?
Infact, one could argue that if you are seeing atmospheric pressure at WOT in any given area within the intake system, you really can't improve on that part of the intake system. This would hold true from the the filter all the way into the intake runners. Does this make sense?
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#8
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Originally Posted by Speedracer
I basically want to use the boost gauge as a "throttle position gauge" in conjunction with my Nitrous system. It is dangerous to run nitrous on anything less than WOT, and although there is a WOT switch in the system for the nitrous activation, the boost guage can act as a monitor for WOT. With my Nismo intake, I do see full atmospheric pressue in the intake manifold at WOT. I suspect a boost gauge, or manifold pressure guage, which is, in effect, what the gauge is in a NA vehicle, can be a good measure of intake restictiveness. The least restrictive intake system should give atmospheric pressure at full throttle.
Infact, one could argue that if you are seeing atmospheric pressure at WOT in any given area within the intake system, you really can't improve on that part of the intake system. This would hold true from the the filter all the way into the intake runners. Does this make sense?
Infact, one could argue that if you are seeing atmospheric pressure at WOT in any given area within the intake system, you really can't improve on that part of the intake system. This would hold true from the the filter all the way into the intake runners. Does this make sense?
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