[DeTomaso] air supply question SPA[1]

[Ken Green]

I suspect more HP than displacement because the HP is proportional to the amount of air passing through the engine, although a NOS system may alter that some.  There are standard equations for the HP, this is from the SDFI web site:
 
Engine airflow can be directly related to hp developed. The volumetric efficiency of an engine is always the highest at its torque peak. Above this rpm, pumping efficiency drops off. A round average for airflow vs. hp is 1.5 to 1.6 cubic feet per minute for each hp developed. If you want to work this out in mass flow, a standard cubic foot of air weighs about 0.0765 pounds on a standard 15C day. For example if we have a 4 cylinder engine developing 200hp it would be flowing around 300 SCFM or 23 lbs./min. using the 1.5 figure. In CFH and lbs./hr. we would have 18,000 and 1380 respectively.  . . .
 
So if you compute the CFM for the target HP, then use a standard forumla to compute pressure drop for the flow rate through the intake tract you're considering.  I think the percent HP loss would be the pressure drop divided by one atmosphere 14.7 PSI).
 
Ken
 


--- On Mon, 5/25/09, David in Durango <adin at frontier.net> wrote:


From: David in Durango <adin at frontier.net>
Subject: [DeTomaso] air supply question SPA[1]
To: "panteras" <detomaso at realbig.com>
Date: Monday, May 25, 2009, 11:32 AM


Whizzbang motorheads, rocket scientists, geeks and friends,

We want to supply cold air to a motor.  Is HP or displacement the determining factor in "how big a pipe do we need so the motor doesn't starve for air?"

A carb is what? 4" or less of flow at wot?

I am supposing the length of pipe would matter at some point . . . at what lenth?

Thanks for playing . . .







[1] some Pantera application



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