Mr. Gasket 8703 Hot Rod Calculator - Manual (Page 49)

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Uide — 47
Volumetric Efficiency — Based on RPM,
engine Displacement and Carburetor Size
In this example, your 1968 Pontiac GTo has a Ram Air II
400-CID engine and you want to calculate the engine’s vE at
7,000 RPM, which is the RPM at your maximum speed. your
measured airflow capacity at 7,000 RPM is said to be 625 cfm.
KeysTroKe disPlay

0.
1. Enter your RPM, Engine Displacement, and actual measured
airflow capacity at 7,000 RPM:

rPM 7000.

enG
siZe
400.
CU in

User
Carb siZe
625.
CfM
2. Calculate your engine’s VE:
 *
eff%
Vol
77.143
%
**
* Repeated presses of  will toggle through the inputs and outputs,
starting with the calculated Theoretical Carburetor Size.
** The calculated VE of your GTO, at 7,000 RPM, is about 77%. This
value is just under 80%, which for many typical street applications is on
track.
toRque
estimating flywheel Horsepower
— Based on Torque and RPM
If you know Torque output at a specific RPM, you can calculate
Horsepower at that same RPM.
In this example, your 400-CID engine produces 445 pounds-feet
of Torque at 3,800 RPM. Calculate flywheel Horsepower for the
same RPM.
(cont'd)
UG8703E-B-inside.indd 47 3/3/2010 3:03:59 PM