What HP Can Your Fuel System Support?
|
BSFC:
(input) |
HP*lb/hr |
This is your Brake Specific Fuel
Consumption. 0.62 is an empirically supported estimate for modified,
stock-turbo
13B-REW engines. See this
page for some additional information. |
Fuel
Pressure:
(input) |
psi |
This is the effective fuel pressure,
which is your fuel rail/gauge pressure minus the manifold (boost) pressure. |
Fuel
Injectors:
(input) |
|
How many injectors do you have, and how
much fuel do they flow at the standard 43.5 psi pressure? Enter values
in cc/min or lbs/hr. |
Max
Duty Cycle:
(input) |
% |
This is the maximum duty cycle that the
injectors will experience. The stock 93-95 RX-7 ECU tops out around 63%.
The recommended maximum value for programmable engine management systems
is 80%-85%. Above that, the injectors might stay open, which gives up
tuning control. |
Drivetrain
Losses:
(input) |
% |
This is an approximation of the power lost
in the transmission, differential, etc. I am not sure
what values are appropriate for FWD or AWD cars. |
Flywheel
HP:
(output) |
HP |
With the above components, your fuel
system should be capable of providing enough fuel for this amount of
flywheel HP. This is comparable to manufacturers' HP ratings. |
Wheel
HP:
(output) |
WHP |
With the above components, your fuel
system should be able to supply enough fuel for this amount of HP at the
wheels. This is the power that is measured on a chassis dynamometer. |
Specify These Additional Parameters to
Calculate Fuel Pump Requirements:
|
Boost
Pressure:
(input) |
psi |
If your car is a turbo, how much boost
are you running? For normally-aspirated cars, enter zero. |
Fuel
System Pressure Drop:
(input) |
psi |
A lot of the fuel pressure generated by
the pump can be lost in the restrictive plumbing of the fuel system. This
value affects the pressure your fuel pump will be required to supply.
See this
page for some interesting test data. |
Fuel
Pump Requirements:
(output) |
You need a pump that will flow:
|
Based on the parameters given above,
you will need a fuel pump that meets these requirements. It is a good
idea to give yourself a little safety margin over and above this
requirement. |
