31 psi Video
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Originally Posted by Smearin
Well Psi absolute is Psi guage and atmospheric... psig + atmospheric pressure (14.7 or 15) = psia or absolute psi... psi guage is pressure within the system.. which I think is what you're talking about..
Absolute pressure is the total system pressure starting from zero (total vacuum).
Gauge pressure is referenced to zero from the local atmospheric pressure conditions. Its a differential pressure gauge that displays the difference of atmospheric pressure (local) from the higher pressure such as manifold boost or fuel pressure. A port in the gauge body allows atmospheric pressure to zero the gauge.
Absolute pressure gauges are not referenced to atmospheric pressure.
On a F150 lighting.(I used to own one) There are MANY mods you can do that lower you boost but increase your horsepower.
Ported head drop your boost.
Cams drop your boost.
Headers drop your boost.
All increase your horsepower.
A truck that runs on 15psi of boost may now run at 11-12psi after cam/head/longtuves but will make 60-70 more hp than before.
So the motor with less boost is more powerful. So yes boost is not the only thing to consider. Say 2 guyz have the same truck, both with the same supercharger and one has all of these mods that drop you boost and they both have a kene bell with the same pulleys. The one running higher boost is the weakest because he is more restricted than the one with those mods that free up the flow.
Check this thread out.
http://www.nloc.net/vbforum/showthre...ght=boost+drop
Ported head drop your boost.
Cams drop your boost.
Headers drop your boost.
All increase your horsepower.
A truck that runs on 15psi of boost may now run at 11-12psi after cam/head/longtuves but will make 60-70 more hp than before.
So the motor with less boost is more powerful. So yes boost is not the only thing to consider. Say 2 guyz have the same truck, both with the same supercharger and one has all of these mods that drop you boost and they both have a kene bell with the same pulleys. The one running higher boost is the weakest because he is more restricted than the one with those mods that free up the flow.
Check this thread out.
http://www.nloc.net/vbforum/showthre...ght=boost+drop
Last edited by jfman; Sep 7, 2006 at 02:10 AM.
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Originally Posted by jfman
A truck that runs on 15psi of boost may now run at 11-12psi after cam/head/longtuves but will make 60-70 more hp than before.
So the motor with less boost is more powerful. . . The one running higher boost is the weakest because he is more restricted than the one with those mods that free up the flow.
So the motor with less boost is more powerful. . . The one running higher boost is the weakest because he is more restricted than the one with those mods that free up the flow.
The truck running 15 psi on stock cam/heads/exhaust is only getting maybe 8 psi in the cylinder before compression. The truck running 12 psi after cam/head/headers is getting 10 psi in the cylinder. So, even though the gauge reads lower, the boost pressure, as measured in the cylinder, is actually higher. If you were to continue to improve the cam/heads/exhaust, the pressure in the intake and cylinder may eventually reach unison (11 psi boost and 11 psi in the cylinder), but both numbers will still be well above zero.
I suppose by your logic, you could improve the cam/heads/exhaust enough to obtain 15 psi positive pressure (psig) in the cylinder with 0 psig in the intake manifold???
I also have a Lightning BTW.
Originally Posted by engineermike
Everything is right except for the conclusion.
The truck running 15 psi on stock cam/heads/exhaust is only getting maybe 8 psi in the cylinder before compression. The truck running 12 psi after cam/head/headers is getting 10 psi in the cylinder. So, even though the gauge reads lower, the boost pressure, as measured in the cylinder, is actually higher. If you were to continue to improve the cam/heads/exhaust, the pressure in the intake and cylinder may eventually reach unison (11 psi boost and 11 psi in the cylinder), but both numbers will still be well above zero.
I suppose by your logic, you could improve the cam/heads/exhaust enough to obtain 15 psi positive pressure (psig) in the cylinder with 0 psig in the intake manifold???
I also have a Lightning BTW.
The truck running 15 psi on stock cam/heads/exhaust is only getting maybe 8 psi in the cylinder before compression. The truck running 12 psi after cam/head/headers is getting 10 psi in the cylinder. So, even though the gauge reads lower, the boost pressure, as measured in the cylinder, is actually higher. If you were to continue to improve the cam/heads/exhaust, the pressure in the intake and cylinder may eventually reach unison (11 psi boost and 11 psi in the cylinder), but both numbers will still be well above zero.
I suppose by your logic, you could improve the cam/heads/exhaust enough to obtain 15 psi positive pressure (psig) in the cylinder with 0 psig in the intake manifold???
I also have a Lightning BTW.
Of course there comes a point where you cant or dont want to have too much flow to drop boost. I bet completely removing the headers would increase flow and drop the boost but have a negative effect on performance.
I was just showing that higher boost doest not necessarely equate to higher HP. Other things have o be taken into consideration.
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Originally Posted by jfman
How can you measure boost, in the cylinder, before compression ?
Of course there comes a point where you cant or dont want to have too much flow to drop boost. I bet completely removing the headers would increase flow and drop the boost but have a negative effect on performance.
I was just showing that higher boost doest not necessarely equate to higher HP. Other things have o be taken into consideration.
Of course there comes a point where you cant or dont want to have too much flow to drop boost. I bet completely removing the headers would increase flow and drop the boost but have a negative effect on performance.
I was just showing that higher boost doest not necessarely equate to higher HP. Other things have o be taken into consideration.
This is why I tried to stress that you have to compare the same engine configuration when talking boost. If you've done head porting and whatnot and saw a loss of pressure on the gauge but picked up power then try driving the supercharger faster to bring the level back up to where it was before. You should be able to stay detonation free at that level and pick up even more power due to the increased airflow.
The misconception is that a lower reading on the gauge somehow cost power. Of course it didn't.
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From: Colorado
Originally Posted by andereck
For clarification you're defining absolute pressure incorrectly by referencing gauge pressure.
Absolute pressure is the total system pressure starting from zero (total vacuum).
Gauge pressure is referenced to zero from the local atmospheric pressure conditions. Its a differential pressure gauge that displays the difference of atmospheric pressure (local) from the higher pressure such as manifold boost or fuel pressure. A port in the gauge body allows atmospheric pressure to zero the gauge.
Absolute pressure gauges are not referenced to atmospheric pressure.
Absolute pressure is the total system pressure starting from zero (total vacuum).
Gauge pressure is referenced to zero from the local atmospheric pressure conditions. Its a differential pressure gauge that displays the difference of atmospheric pressure (local) from the higher pressure such as manifold boost or fuel pressure. A port in the gauge body allows atmospheric pressure to zero the gauge.
Absolute pressure gauges are not referenced to atmospheric pressure.
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Originally Posted by Smearin
I dont know where your getting some of this stuff from... but absolute pressure is guage pressure + atmospheric pressure.... 0 psi on a guage is equal to atmospheric pressure which is 14.7psi .. The absolute pressure scale registers zero at a pressure which cannot be further reduced.... Well you must refernce further that your talking about pressure in a confined system... which could only be measure with psig .. since there is no absolute pressure... being seperated from the atmosphere..
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BUILT engine that Actually uses 31 psi thats not a diesel. Ive seen 1 this whole thread 1895 hp car . I didnt start this to hear about losing psi from head swaps, cams, headers etc. TOO mANY 1,000RWHP cars running 20 psi and the engine is consuming it . so if you have a 90+ vol eff engine, add 31 psi say around 30 rwhp per psi increase you should gain 930rwhp on top of the na power.
500rwhp Na
+ 31 psi 930 rwhp or about 190 percent increase
1,430rwhp
500rwhp Na
+ 31 psi 930 rwhp or about 190 percent increase
1,430rwhp
Last edited by cws T/A; Sep 7, 2006 at 05:52 PM.
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From: Colorado
Originally Posted by andereck
Seriously I don't understand why you can't comprehend absolute pressure, but I don't care. You talk a bit in circles and this subject matter just doesn't matter as long as you're not the one doing the tuning on someone's car and you need to understand how a map sensor works.
Im just explaining some things... obviously that you dont know... He's some reference andereck... pick up a book.. units that measure... I use my refridgeration book since there is alot in there.... and read..
Im done.
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so do you guys think more people will be pushing big power (over 1500bhp) when the warhawk block becomes avaliable???
will the come a point when simply tring to package bigger and bigger turbo(s) becomes the problem? C4's are having that probelm!
thanks Chris.
will the come a point when simply tring to package bigger and bigger turbo(s) becomes the problem? C4's are having that probelm!
thanks Chris.
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I know this thread was completely hi jacked but holy knowledge batman... keep going fellas. I love reading about turbos.
What you were guys were saying was kinda the way I thought how it worked... but the exact physics of it? I was way off. haha Had no clue!
Could this be sorta right from what you guys are saying?
20psi is 20psi... but 20psi in a V8 is obviously flowing better assuming Mods are equal (Full boltons, turbo, etc...)
Because if the bores/stroke are very similar on both motors, but the V8 has 4 extra cylinders... the 20psi on the V8 is just pushing more air, correct? Or not at all?
QUESTION: Where is boost being measured? If heads/cam/intake mani/exhaust can lower boost... where is the reading coming from? Unless... the air flowing through the motor is just that much quicker. That the setting used before/after the mods can no longer keep up with the air flowing. Sorta like having less load on the turbo so it's just producing less boost?
So basically after every air moving mod you should have to turn the boost up a little to make what you were making previously?
What you were guys were saying was kinda the way I thought how it worked... but the exact physics of it? I was way off. haha Had no clue!
Could this be sorta right from what you guys are saying?
20psi is 20psi... but 20psi in a V8 is obviously flowing better assuming Mods are equal (Full boltons, turbo, etc...)
Because if the bores/stroke are very similar on both motors, but the V8 has 4 extra cylinders... the 20psi on the V8 is just pushing more air, correct? Or not at all?
QUESTION: Where is boost being measured? If heads/cam/intake mani/exhaust can lower boost... where is the reading coming from? Unless... the air flowing through the motor is just that much quicker. That the setting used before/after the mods can no longer keep up with the air flowing. Sorta like having less load on the turbo so it's just producing less boost?
So basically after every air moving mod you should have to turn the boost up a little to make what you were making previously?
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From: Colorado
20psi in a ls1 is diffrent than a i-6 supra motor... You have more space to fill with air... you would be flowing alot alot more air than that motor...
.
Heads and cam and etc can get better hp out of lower boost because it is flowing the air more efficiently than non ported heads... diffrent intake, etc..
.
Heads and cam and etc can get better hp out of lower boost because it is flowing the air more efficiently than non ported heads... diffrent intake, etc..
HIGH BOOST 8 CYLINDERS
http://videos.streetfire.net/categor...44012be3a5.htm
http://videos.streetfire.net/categor...3d00aca26d.htm
http://videos.streetfire.net/categor...177c41a18d.htm
Ls1 with 8 turbos http://videos.streetfire.net/categor...39014820ef.htm
http://videos.streetfire.net/categor...44012be3a5.htm
http://videos.streetfire.net/categor...3d00aca26d.htm
http://videos.streetfire.net/categor...177c41a18d.htm
Ls1 with 8 turbos
http://videos.streetfire.net/categor...39014820ef.htm Last edited by cws T/A; Sep 23, 2006 at 08:38 PM.
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From: Australia
Originally Posted by Vortech GTO
