A bit of help and input please..

[gyfer]

You can afford a HB , but use a tiny IC ? I am clueless

[toki]

'89 hatch with 200k miles, brembo drilled slotted rotors, tokiko blues, sprint springs, CD player, 2.5"exhaust with highflow CAT = $2300. Not too expensive really. Oh and the rents paid for it hahah. yeah.

[erich]

I am TOTALLY DISAGREE with your statement.In a static air ( no movement ), yes, 7psi ( ~= 0.5bar) should give you about 50% more air VOLUME in same space.

You're right, and that static space is your cylinders.

Quote »But we are not talking about statir air here. Air in the intake constantly moving. The PSI number is to show more air is "pack" in a same flowing air. You have to put FLOW into consideration. That's why Turbo is category into different CFM and efficeincy ( how much heat generated in the process of compressing air ) at different psi.[/quote]We are talking about static air. As soon as the intake valves close the volume of air in the cylinders is fixed. yes, there is a velocity component of the air column, but that is more a resonant feature used for intake runner tuning.

Quote »If above theory can't make your feel confinced : Is the 1.5" IC pipe make same HP power compare to 2.5" IC pipe , at same psi? Don't sound like it should.. right ? Why ? because it flow different.. yes, is flow that make different [/quote]If the pressure and temperature in the intake plenum are the same, you will get the same power. If your intake plumbing is too small you will have a dynamic pressure drop which makes your turbo work harder to get the same pressure in the intake plenum. That is where you are measuring your boost, isn't it?As a side note, all of my intake plumbing is 2.5" stainless steel, as is my exhaust.

Quote »And also, 50% more air DOES NOT mean 50% more power. It never apply, and never will. ( if it does, hell.. why are we learning physics for ? ) [/quote] Ummm..Yes it will, assuming that your air/fuel ratio and temperature is the same. This is exactly why you put a turbo on your car, to get more air into the cylinders, so you can burn more fuel with the proper A/F ratio, to liberate more potential energy into kinetic energy.There is a bit of feedback with increased boost, more air in the cylinder effectivly raises the static compression ratio which gives you increased torque, but the amount of extra power from the compression ratio is dwarfed by the extra power from more air and fuel.So I say again, 10psi@120 degrees is 10psi@120 degrees, no matter what it went through to get there.