InlinePRO Intake Manifold
02-08-2010, 01:24 PM
#65
Originally Posted by HYPERTUNE,Feb 6 2010, 04:13 AM
I've got a question! 
Why did you copy my intake manifold?
Why did you copy my intake manifold?
If it's impossible to find then gg.
02-08-2010, 06:53 PM
#66
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Originally Posted by Momentum,Feb 8 2010, 11:32 AM
Lets use your example. Car A has "-10psi manifold pressure" so the pressure at the inlet of the velocity stack is actually 4.7psi. The pressure in the cylinder even at idle would likely be just under that (lets say 4psi) so the pressure differential in this case is .7psi resulting in just enough flow for idle.
Now Car B has "+10psi manifold pressure" so the pressure at the inlet of the velocity stack is actually 24.7psi. Lets say were looking at the portion of the intake stroke where the valve has just opened for simplicity, the pressure in the cylinder is likely just above atmospheric (or just below if it's very efficient) so lets assume 14.7psi. Car B has a pressure differential of ~10psi.
"negative pressure" is actually not something that exists, most of the time when referencing pressure we use "gauge pressure" to make things easier to look at. In reality you cannot have below 0psi.
For volume flow rate (and velocity stack design) the difference in pressure is all that matters, you want to create the lowest possible pressure drop in the system. The volume flow rate will be virtually the same if Car A has 10psi over 0psi as Car B with 20psi over 10psi. However Car B will make more power because there is an increase in mass flow rate.
It's true that a velocity stack becomes less important in a forced induction car because the resulting difference in pressure loss has less effect on the total mass flow rate but it doesn't mean they don't work better than bottom mounted stacks.
Now Car B has "+10psi manifold pressure" so the pressure at the inlet of the velocity stack is actually 24.7psi. Lets say were looking at the portion of the intake stroke where the valve has just opened for simplicity, the pressure in the cylinder is likely just above atmospheric (or just below if it's very efficient) so lets assume 14.7psi. Car B has a pressure differential of ~10psi.
"negative pressure" is actually not something that exists, most of the time when referencing pressure we use "gauge pressure" to make things easier to look at. In reality you cannot have below 0psi.
For volume flow rate (and velocity stack design) the difference in pressure is all that matters, you want to create the lowest possible pressure drop in the system. The volume flow rate will be virtually the same if Car A has 10psi over 0psi as Car B with 20psi over 10psi. However Car B will make more power because there is an increase in mass flow rate.
It's true that a velocity stack becomes less important in a forced induction car because the resulting difference in pressure loss has less effect on the total mass flow rate but it doesn't mean they don't work better than bottom mounted stacks.
And secondly for car A you are ignoring atmospheric pressure. I think you are confusing yourself by using the absolute pressure scale. If atmospheric pressure is 14.7 psi and cylinder pressure is 4 psi, you still have a 10psi pressure differential. You may have a .7 psi pressure differential if you take a look at very small control volume, but this is irrelevant to the overall system.
And lastly a velocity stack, depending on geometry can actually hurt a forced induction cars mass flow. There are 2 reasons for this, but they both equate to 1 parameter called K= pressure loss due to entrance effect. As you can see in the diagram the velocity stack config has the highest loss factor of all the entrance effects. This is because pressure loss varies linearly with air density and as the square of velocity. So as a turbo car shoves more air into the manifold, air density increases as well as air velocity, leading to higher pressure drops due to K. For forced induction a well rounded inlet would make more sense.
02-09-2010, 02:27 AM
#69
Originally Posted by BerlinaMOBster,Feb 9 2010, 11:58 AM
Will all these accusations about i find it kind of strange that inline has not addressed hypertune yet...
anyways... has anyone bought the Inline mani yet?
anyways... has anyone bought the Inline mani yet?
