Tim Skelton, Ported Eaton, Heat generated
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Joined: Feb 2001
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From: San Antonio
Originally posted by BMWBig6
You state: "the blower is a positive displacement pump that takes a fixed volume of ambient air per revolution and the mass air flow is determined by the induction into the blower and the "mass"will not be affected by anything downstream of the rotor."
So if mass "is determined by induction to blower" and "anything downstream of the rotor will not affect mass air flow," then by your logic the intercooler or anything else downstream CAN'T make it pump more air. Yet you claim it does! Get your story straight, which is it?
Here we go again: "but, the intercooled application reduces temperature and pressure for the exact same mass of air...so you still get the same mass"
You contradict yourself by saying "in a non-intercooled application it will pump less air than an intercooled application everytime." Again, which is it? (Note: I'm technically not debating you, since you haven't made clear what side you're arguing yet.
)
So which is it?
"The pressure drop because of less resistance of the air flowing through the intercooler makes it easier to pump,"
or
"intercooler will allow a higher velocity than a non-intercooled?"
You state: "the blower is a positive displacement pump that takes a fixed volume of ambient air per revolution and the mass air flow is determined by the induction into the blower and the "mass"will not be affected by anything downstream of the rotor."
So if mass "is determined by induction to blower" and "anything downstream of the rotor will not affect mass air flow," then by your logic the intercooler or anything else downstream CAN'T make it pump more air. Yet you claim it does! Get your story straight, which is it?
Here we go again: "but, the intercooled application reduces temperature and pressure for the exact same mass of air...so you still get the same mass"
You contradict yourself by saying "in a non-intercooled application it will pump less air than an intercooled application everytime." Again, which is it? (Note: I'm technically not debating you, since you haven't made clear what side you're arguing yet.
)So which is it?
"The pressure drop because of less resistance of the air flowing through the intercooler makes it easier to pump,"
or
"intercooler will allow a higher velocity than a non-intercooled?"
yes , mass is determined by the inducton into the blower .....fact, MAF
cant change it...nothing downstream of the blower will change the mass....fact...
You do not change the mass of the air. You increase the density by pumping the same mass at a higher pressure. but the mass is the same as it was as it passed the MAF......
The supercharger can only change the air DENSITY. It will not affect mass......mass in equals mass out...... The "mass air flow" sensor MAF will do exactly what it says,..... tell the ECU how much mass of air per unit of time is entering the engine. To do that accurately, the ECU needs to know air velocity, temperature, pressure, and cross-sectional area at the point of measurement .........mass will not change.....the intercooled apples to apples S/C engine allows the compressor to move a greater, more, (higher volume) mass of air for the work it does per unit of time....
Time for an example....... the volume of air flowing into an engine for two different trucks, an intercooled and a non-intercooled . For both we will use a volumetric efficiency of 0.85. For both the engine is turning at 5000 rpm. What is the volume of air it is using?
volume, in cu.ft per minute = 5000 x 231 = 334.2 cfm
1728 x 2
This is the same for both the intercooled and non-intercooled will be moving 334.2 cfm of air all the way to the the cylinders at 5000 rpm.......... the mass of air flowing is not the same for each.
lets say the temp at the blower discharge or galley in the non-intercooled engine is 250 deg F and its has 19 psi boost. What is the mass of air the engine is using?
Absolute temperature = 250 deg F + 460 = 710 deg R
Absolute pressure = 19 psig + 14.7 = 33.7 psia
n (lbs/min)= 33.7 psia x 334.2 cfm x 29 = 42.9 lbs of air per minute (ideal)
10.73 x 710 deg R
lbs air per minute actual = lbs/min ideal x vol. eff.
= 42.9 x 0.85
= 36.4 lbs air/minute
now take the same apple and intercool it, intercooler changes density to say a discharge temp of 130 deg F at two lbs less at 17 psi boost.
Absolute temperature = 130 deg F + 460 = 590 deg R
Absolute pressure = 17 psig + 14.7 = 31.7 psia
n(lbs/min)= 31.7 psia x 334.2 cfm x 29 = 48.5 lbs of air per minute (ideal)
10.73 x 590 deg R
lbs air per minute actual = 48.5 x 0.85 = 41.3 lbs air/minute
MORE lbs/min of air (41.3 to 36.4 ) with even less boost because of the "intercooler will allow a higher velocity than a non-intercooled"
now port the same blower, and improve blower efficiency and if the motors VE can keep up.........
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Joined: Feb 2001
Posts: 1,394
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From: San Antonio
Originally posted by Tim Skelton
now that is a sweet setup,.Of course, air flow directors can actually work, if specifically designed with a particular engine, inlet manifold and air ducts in mind. They can be used to direct air into shrouded areas, around obstacles, or to reduce unwanted turbulence., but most are just an obstruction .......BTW...BMWBig6, this setup wont work so cancel the trip to Home Depot....
reminds me of air flow straighteners; air flow turbulence inducers; vortex generators; air catalysts micro turbo supercharging;
the miraculous $9.95 mini supercharger;
the “incredible device the oil companies don’t want you to buy”;
the "device Europe has known about for years, now available in the US"; air ionizators; fuel line magnets; fuel catalysts; fuel oxygenators; fuel line heaters; and the controversal plasma booster spark intensifier, whistles that glue to the top of the bumper to create an ultrasonic noise to chase away the deer from roadways, sticker that you buy for $12.50 from one of those police benevolent societies which allow you to get out of speeding tickets free
just busting your ***** BMWBig6 I know you were not out the door to home depot
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Joined: Feb 2003
Posts: 1,294
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From: Colorado,
Excuse me for asking a dumb question
I never was good at math or spelling.
I am trying to get a picture in my head of the enormity of what you are calculating.
Just for a start, how many cubic feet of air = one pound of air?
Now I am trying to picture in size what you said about @5000 RPM
Can you give me a demension of size for a block of air that goes threw the engine in one minute? Like X high by X long and X wide.
The other thing on my mind is the 14.7 absolute.
I know that is at sea level. What would that convert the whole thing to where I live in colorado at 5k feet and typicaly drive to 10,000 ft.
Instead of 41.3 and 36.4 I am guessing it would be 38 and 33 or something.
I kinda thought the SC was the big equalizer up here but I guess it is still a straight line comparison for power loss with or without.
Thats why they only sell 91 octane and you can advance your timing more here also.
I never was good at math or spelling.
I am trying to get a picture in my head of the enormity of what you are calculating.
Just for a start, how many cubic feet of air = one pound of air?
Now I am trying to picture in size what you said about @5000 RPM
Can you give me a demension of size for a block of air that goes threw the engine in one minute? Like X high by X long and X wide.
The other thing on my mind is the 14.7 absolute.
I know that is at sea level. What would that convert the whole thing to where I live in colorado at 5k feet and typicaly drive to 10,000 ft.
Instead of 41.3 and 36.4 I am guessing it would be 38 and 33 or something.
I kinda thought the SC was the big equalizer up here but I guess it is still a straight line comparison for power loss with or without.
Thats why they only sell 91 octane and you can advance your timing more here also.
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From: DETROIT, (formerly Eaton County, Michigan)
Originally posted by Brian@SCT
[B]
I was waiting for someone to bring this up. I've seen this several times in both lightning and cobra. You can see by the amount of oil and the color of the intercooler fins on the front and rear that there is an imbalance of airflow. [b]Somewhere at home I have some real clear pictures I can post showing shiny triangles in cobra intercoolers where the airflow was not balanced thru the whole I/C.
rotor fill is a big deal. Also, there's another thing not discussed. The radiuses of the outlets. Air is going to flow better if they are not sharp like factory.
So we have three factors that impact the result. One is the enlargment of the bottom of the casing to make more effective use of a larger area of the IC. The second is opening up the inlet area to allow better airflow into the rotors. The third is the changing radiuses around the case inlets and outlets to increase airflow.
All three of those are important. That's why there's skewed results from all of the different porting companies. Some do one or two of the three, and naturally the price is going to vary based on the work done.
Brian
[B]
I was waiting for someone to bring this up. I've seen this several times in both lightning and cobra. You can see by the amount of oil and the color of the intercooler fins on the front and rear that there is an imbalance of airflow. [b]Somewhere at home I have some real clear pictures I can post showing shiny triangles in cobra intercoolers where the airflow was not balanced thru the whole I/C.
rotor fill is a big deal. Also, there's another thing not discussed. The radiuses of the outlets. Air is going to flow better if they are not sharp like factory.
So we have three factors that impact the result. One is the enlargment of the bottom of the casing to make more effective use of a larger area of the IC. The second is opening up the inlet area to allow better airflow into the rotors. The third is the changing radiuses around the case inlets and outlets to increase airflow.
All three of those are important. That's why there's skewed results from all of the different porting companies. Some do one or two of the three, and naturally the price is going to vary based on the work done.
Brian
Would a different I'C design balance out the air flow?
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From: Mobile, AL
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Joined: Oct 2001
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From: SE Mich
Sorry man but, the relationship between pressure and velocity does not go like that. There relationship is when pressure increases velocity decreases and vise-versa.
In a GEN2 S/C intercooler system the higher the pressure the higher the velocity when that intake valve opens. It's a simple function of delta P (Assuming greater cylinder fill can be achieved with higher psi output of the blower)
Rich