PRECISION RCEWORKS 201-0049 BMW Boost Reference Harness Owner’s Manual
- June 16, 2024
- PRECISION RCEWORKS
Table of Contents
Installation Instructions for: 201-0049
PUMP ACTIVACTION GENERAL INSTALLATION DIAGRAM /
CONFIGURATION OPTIONS
201-0049 BMW Boost Reference Harness
WIRE ROUTING AND EQUIPMENT LOCATIONS ARE FOR ILLUSTRATION PURPOSE ONLY
EACH VEHICLE IS DIFFERENT AND WIRES MAY NEED TO BE ROUTED DIFFERENTLY
Test Wire: A test wire is included with harness can be used for setting fuel pressure or troubleshooting but is not intended as long term control method of pump
Pump Activation Methods
The Precision Raceworks pump activation harness is configurable to be used
with your choice of either positive trigger or negative trigger control
method.
Note: The standard relay included can not be ran PWM it must be used as
on or off.
Our solid state relay upgrade for this harness can be used for PWM speed
control.
Negative Trigger Harness
Negative trigger activation is the most common method used. This option allows
for us of any negative trigger source to activate the fuel pump. A pressure
switch (AKA hobb switch) is the most common negative trigger method for pump
activation. Additionally this trigger can be an electronic controller.
Kit includes 13psi Pressure Switch
Positive Trigger Harness
While negative trigger is more common, a positive trigger may be desired. The
above example illustration shows the positive trigger hooked to a switched 12v
source so that the pump runs anytime the vehicle is in the ON position. Other
positive triggers can be used.
Positive trigger is not compatible with solid state relay.
Main Harness
The main harness provides power to the fuel pump based on the positive or
negative trigger configuration. This harness comes standard with a mechanical
relay and fuse. The fused wire is connected directly to the battery positive
and the ground wire is connected to battery or good chassis ground connection.
Fuel Pump Harness
The fuel pump harness provided has an easy quick connect to the main harness
capable of high current (30A). This section of harness comes with 2 ring
terminal that will fit M6 bolts. Additionally this wire is fuel compatible and
can be used with wire bulkhead to route directly into the fuel tank.
Recommended Wiring Procedure & Modification for use with Electronic
Controller activation
- Cut the harness about 2 inches back from the 2 wire electrical connector
- Discard the pressure switch (or keep if you ever decide to use pressure switch)
- Remove loom and heat shrink from wire (Razor maybe needed do not cut wire)
- Cut the brown wire flush with the rubber seal (or tape up if planned to use in future)
- The green wire is the Negative trigger wire for the Pump Activation harness This will be the wire connected to your electronic controller of choice that outputs negative trigger.
PWM Variable Speed Control Functionality
The standard relay included with the harness will fail if controlled PWM, only
use values of 0 and 100% for duty cycle of controller when used with standard
relay. Recommended PWM frequency is 20-40hz.
This harness is compatible with our solid state relay (sold separately) when
this relay is installed in place of the mechanical relay PWM control through
use of the negative trigger input can be achieved to allow full control of
pump speed. A value of 0% duty will equal zero for pump speed, and a value of
100% duty will equal 100% pump speed. The pump speed is linear with duty cycle
so as an example 50% duty cycle would be 50% pump speed. Recommended Frequency
is 200-400hz.
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