Don't try to be smart, both of you, I know how to read. My gauge and my maft are showing similar numbers so what gives? Obivously the boost is off, though 14.7 plus 7 gives about 21-22 psi, but I'm not sure if thats correct way to calculate it.
vacuum?
- Thread starter black89t
- Start date
Not trying to be smart, but the physics doesn't add up. Science lesson follows:
- Std atmospheric pressure at sea level is 29.92 in/hg...yes it varies, but for this we need apples = apples.
- Vacuum is a reduction in pressure to the point where it equals zero.
- A perfect vacuum results (pretty much only in space)...this would be expressed as vacuum = -29.92 in/hg
- On a vacuum gauge, it would read ~30
- It is not possible to go less than zero where gas pressure is concerned...how can you take anything else away from nothing?
What you are saying is your motor is pulling a near perfect vacuum (29 in/hg). I'm not sure how you have the electronics/gauge hooked up or calibrated, but you can see how both of us would say that's impossible
- Std atmospheric pressure at sea level is 29.92 in/hg...yes it varies, but for this we need apples = apples.
- Vacuum is a reduction in pressure to the point where it equals zero.
- A perfect vacuum results (pretty much only in space)...this would be expressed as vacuum = -29.92 in/hg
- On a vacuum gauge, it would read ~30
- It is not possible to go less than zero where gas pressure is concerned...how can you take anything else away from nothing?
What you are saying is your motor is pulling a near perfect vacuum (29 in/hg). I'm not sure how you have the electronics/gauge hooked up or calibrated, but you can see how both of us would say that's impossible
Exactly. Although I don't expect everyone to understand the ocean we all live at the bottom of on a level guys like us do they at least ought to learn the basics.
Dumbo: the simple explanation is you're using a gage of insufficient resolution...
Dumbo: the simple explanation is you're using a gage of insufficient resolution...
So if 2.6kpa is 29inches, then it is NOT impossible, correct? I don't believe there was a way to calibrate the MAP for the maft pro. jetjock, your saying I cannot clearly differentiate between 29 and 30inch correct? Very possible.
Do you atleast see why I think this is accurate, plausible, and possible being both my MAP, and mechanical gauge are showing very similar numbers AND with the engine off IIRC my map read 101kpa, and I can throw a rock into the ocean from where my car was usually parked when I stay down in BC.
So if I can't make out the difference between 29 and 30inches on my mechanical gauge, but my MAP confirms 29inches, decel. 24inches, idle(jdubs math) it is possible, technically?
In a few months...I will confirm.
I can show you the only video I have that shows this, but I don't know how to post one up here.
Do you atleast see why I think this is accurate, plausible, and possible being both my MAP, and mechanical gauge are showing very similar numbers AND with the engine off IIRC my map read 101kpa, and I can throw a rock into the ocean from where my car was usually parked when I stay down in BC.
So if I can't make out the difference between 29 and 30inches on my mechanical gauge, but my MAP confirms 29inches, decel. 24inches, idle(jdubs math) it is possible, technically?
In a few months...I will confirm.
I can show you the only video I have that shows this, but I don't know how to post one up here.
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dumbo;1309801 said:
I can see pulling 24 in/hg during decel...that is possible. There is no way on this planet you can pull 29 in/hg during decel...re-read my post above and think about it. Near perfect vacuum with an internal combustion engine?
I can see why you would think it is given your gauge/MAFT readings, but it's not possible. There is something amiss with your sensor or the calibration.
You're still missing the point. Not only is that kind of gage not accurate at deep vacuum levels but even if it were there's no way the engine could make 29 inches of vacuum. Understand we're talking in a strict technical sense here. For uses such as determining engine health what you have will work fine but only in the relative sense. Jdub and I simply want you to understand two things: 1) It's impossible to achieve more than 30 in/hg on Earth and 2) Your engine (nor anyone else's) can't make anywhere close to it and that includes 29. It only appears that way because the instrumentation being used is so rudimentary. So is the engine. It is, after all, little more than a air pump and a poor one at that.
jdub;1308376 said:
so i ran the truboost up direct and i still got 22 in/hg. i guess thats just all its gona pull. i'm not really going to worry about it. but i'm still open to any thoughts.