Boost pressure is measured at the intake manifold. Without porting and polishing, (polishing is a bad idea anyway) any given intake manifold pressure will flow the same CFM through the six intake ports and into the cylinders. CFM is a measure of flow, and flow is flow, no matter how the path is configured, or what the driving force is. This means that for any given pressure flow is constant - the higher the pressure, the higher the flow and vice versa. If the intake manifold pressure is 9 psi, it doesn't matter if that 9 psi came though a turbo with an intercooler or a twin screw supercharger - it is what it is. Today's turbos do build power earlier, but this is a result of lighter impellers (which spool up earlier) or better fan designs (which move more air at lower RPMs). Once again, for any given restriction (resistance) the same pressure will produce the same flow no matter how it's produced. In the case of our Mustangs, for the constant intake manifold size, increased pressure will result in increased flow - it's physics.
< Message edited by MdnytRider -- 2/25/2007 5:04:11 PM >
Hey Mdnyt. I was hoping someone would put it in simple terms like you did. I would say almost exactly the same thing. However, the parasitic draw of a twin screw sc is more than that of a turbo if only slightly more in the higher revs. So RWHP/RWT yields are obviously a bit different or less in the case of an xc. Personally I like turbo's on others cars but not on mine. Too much plumbing for me. Mine is definately going to be boosted with an xc! Simple, direct, clean and it looks and sounds great too!
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mdnyrider 8ccd3gro is correct in what he posted about CFM it does matter, if one flows more CFM than the other it will produce more power an example of this is when the Paxton Novi 2000 first came out it outflowed in CFM Vortechs high end unit (at that time) and produced more rwhp and rwtq on the same car/motor. So the CFM a head unit can flow does matter.
< Message edited by Krazer -- 2/25/2007 5:57:38 PM >
Boost pressure is measured at the intake manifold. Without porting and polishing, (polishing is a bad idea anyway) any given intake manifold pressure will flow the same CFM through the six intake ports and into the cylinders. CFM is a measure of flow, and flow is flow, no matter how the path is configured, or what the driving force is. This means that for any given pressure flow is constant - the higher the pressure, the higher the flow and vice versa. If the intake manifold pressure is 9 psi, it doesn't matter if that 9 psi came though a turbo with an intercooler or a twin screw supercharger - it is what it is. Today's turbos do build power earlier, but this is a result of lighter impellers (which spool up earlier) or better fan designs (which move more air at lower RPMs). Once again, for any given restriction (resistance) the same pressure will produce the same flow no matter how it's produced. In the case of our Mustangs, for the constant intake manifold size, increased pressure will result in increased flow - it's physics.
you are oversimplifying my friend....what you seriously think that 9psi on an ati would produce the same numbers as the 9 psi on this turbo setup if it werent for the parasitic loss? so you really beleive 100 ft lbs is lost to parasitic loss....? btw a twin screw replaces the intake manifold, just so you know. There are many, many other factors here that you are not accounting for.
Absolutely flow characteristics matter - and this is part of what accounts for the large difference between RPMs of max HP for different power adders. But for any given RPM, 6 psi at the intake manifold (where boost is measured) is the same CFM to the cylinders no matter who's doing the boosting.
< Message edited by MdnytRider -- 2/25/2007 8:15:15 PM >
Why do you need a bypass valve? The best kept secret in forced induction is the little known bypass valve. This small valve, when properly installed between the supercharger and the air throttle body, allows the supercharger to become extremely efficient in terms of economy and parasitic power loss. Our M90 supercharger uses less than 1/3 of 1 HP at 60 MPH cruising. The bypass is operated by a vacuum actuator control unit that is normally closed. When vacuum is high (idle-cruising) the actuator opens the bypass valve, equalizing the vacuum pressure throughout the system. When boost is required (accelerating) the vacuum is decreased and the bypass valve instantly closes, causing pressure to increase into the cylinders. This equalized vacuum condition virtually eliminates the normal parasitic power loss of a forced induction system.
Why do you need a bypass valve? The best kept secret in forced induction is the little known bypass valve. This small valve, when properly installed between the supercharger and the air throttle body, allows the supercharger to become extremely efficient in terms of economy and parasitic power loss. Our M90 supercharger uses less than 1/3 of 1 HP at 60 MPH cruising. The bypass is operated by a vacuum actuator control unit that is normally closed. When vacuum is high (idle-cruising) the actuator opens the bypass valve, equalizing the vacuum pressure throughout the system. When boost is required (accelerating) the vacuum is decreased and the bypass valve instantly closes, causing pressure to increase into the cylinders. This equalized vacuum condition virtually eliminates the normal parasitic power loss of a forced induction system.
Why do you need a bypass valve? The best kept secret in forced induction is the little known bypass valve. This small valve, when properly installed between the supercharger and the air throttle body, allows the supercharger to become extremely efficient in terms of economy and parasitic power loss. Our M90 supercharger uses less than 1/3 of 1 HP at 60 MPH cruising. The bypass is operated by a vacuum actuator control unit that is normally closed. When vacuum is high (idle-cruising) the actuator opens the bypass valve, equalizing the vacuum pressure throughout the system. When boost is required (accelerating) the vacuum is decreased and the bypass valve instantly closes, causing pressure to increase into the cylinders. This equalized vacuum condition virtually eliminates the normal parasitic power loss of a forced induction system.
well that is at cruising levels....when the blower actually starts boosting it will use alot more power, but still not even close to 100hp.
8cd03go did you miss this part see below quote? They are talking under boost but I know hard to believe.
quote:
When boost is required (accelerating) the vacuum is decreased and the bypass valve instantly closes, causing pressure to increase into the cylinders. This equalized vacuum condition virtually eliminates the normal parasitic power loss of a forced induction system.[/qoute]
ya i know its hard to believe, because i have an 03 terminator too, and trust me it robs incredible power with the blower, why else would a turbo setup make over 100 more rwhp with the same boost level?
hey bro does the turbo 6 feel as strong or stronger than ur cobra? cuz i'm going to get a 03 cobra too from this guy up in scottsdale. it has 25k on the tach, and garage kept and all tht other happy horse crap. but i'm going to get a good mechanis to look over it really well for me ya know b4 i make my final choice.
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RE: turbo #'s in - 
