Quote Originally Posted by KaiserBill View Post
I'll admit this-- Procharger makes many superchargers all operating at 38psi maximum boost. However, depending on the size of the unit and design application the maximum CFM at 38 PSI ranges from 1525CFM to 2700CFM. ... So, like I first told you there isn't a linear relationship between boost and CFM or Lbs/Min in a turbo or a Supercharger always when you compare different models of units. You really need to know more about the specific unit and what application it used for.
Again, hilariously irrelevant.

Did I ever claim that, in general (among all possible engine/supercharger combinations), there is a linear relationship between boost and CFM? No!

Did I ever claim that, in general (among all possible engine/supercharger combinations), different supercharger/turbo units cannot be capable of producing different CFM at the same boost level? No!

Does ANYTHING about my claim and explanation in my first reply to this thread depend on these ideas that you have falsely attributed to me? No!

The only thing you are showing me here is that there are different size superchargers that are capable (when tested by themselves) of flowing different amounts of air at the same boost pressure. And different engines are capable of consuming air at different CFM, and therefore need properly matched superchargers. And that more CFM generally yields more power, regardless of boost pressure. This is no surprise! I have never said anything opposite of this!

I only say that it's impossible for two different superchargers to produce DIFFERENT CFM on the SAME engine, at the SAME boost levels, and the SAME intake temps. I further demonstrated that a reasonable difference in intake temp would not significantly alter the CFM. You have offered zero evidence against this.

Stay focused on the context of the situation you proposed in the first post. Different sized engines using different sized superchargers with the same boost, producing different CFM and different HP.... this is all completely irrelevant to your proposed situation.


Quote Originally Posted by KaiserBill View Post
So, there you go... You can choose to believe Procharger's chart or not. I'll trust in my extensive library of engine theory and design books...
The funny thing is... many of the things you say are individually correct. Your engine theory and design books are not wrong. The problem is, as usual, context and relevance. You fail to recognize the context in which your statements are true, and in what contexts your statements are irrelevant.

The individual facts you know are correct in some context. You just don't fully understand the contexts/reasons behind the facts you know. Memorizing/regurgitating facts is not enough. You need to understand the theory/relationships/context behind the facts, and how to properly interpret/apply them.


Quote Originally Posted by KaiserBill View Post
On a side note about your math-- 3.6L of air might be what engine's total capacity is-- but that is only theoretical you're VVT engines usually never get more than 92-95% Volumetric Efficiency in naturally aspirated form and that usually at higher rpm-- at low rpms it drops a bit so you might be down to 89-90% maximum efficiency from idle to 3000rpm... Which means that it is a lot easier to push more air into cylinder with less pressure than at 95% efficiency where you need more pressure to see higher hp gains.
Again, context and relevance.

We're not discussing whether or not the relationship between boost and power gains is the same throughout the RPM range. We're not discussing whether there's a linear relationship between boost and power gains, or CFM.

The context was whether or not two different superchargers on the SAME engine, at the SAME engine speed, at the SAME boost levels, and SAME intake temperature could possibly flow DIFFERENT amounts of air. Since the engine is the same, and it is the engine itself that determines its VE, the VE becomes irrelevant in the comparison.

The only way to change the amount of air flowing through an engine is to modify the engine to change its efficiency, or boost the pressure of the air going into the engine. We are talking about two of the same STOCK engines, so they will have the same VE as each other.

Show me how how two of the same engine, with the same displacement and VE, at the same speed, with the same manifold pressure/temperature, could possibly consume air at DIFFERENT rates.