Racetronix Corvette Fuel Pump Harness Upgrade 1984-1988
Part Number: RXC43-FPWHG-2
Quantity in stock: 1
Estimated shipping date: Today
Free Shipping: W/$250.00+ Order
Shipping Weight: 2.00 pounds
* Plug & Play (no soldering or crimping required)
* Factory waterproof connectors
* Thick 10 gauge ultra-flexible copper power wire
* Siemens/Tyco 40A waterproof relay
* Waterproof fuse holder w/SS mounting hardware
* Direct alternator hookup for maximum voltage
* All connections are crimped AND soldered
* Silicon grease, spare fuse, wire ties, mounting screws included
* Body to battery ground upgrade with brass battery nuts (with accessory taps)
* Pump booster interface with connector set (increase pump output 35-40% as PnP option*)
As experienced drivers we all know from observation that there are certain electrical items on our car that when turned on cause the lights to dim, blower motors to slow down and the voltage meter reading on the dash to drop. There are various things that cause this such as battery condition and alternator output but for the most part it is factory wire resistance. In an ideal world car manufacturers would use heavier gauges of wire to reduce resistance in order to prevent voltage drop but that would add much cost, weight and bulk to the harnesses. As a tradeoff car manufacturers try to find a happy medium to satisfy the load requirements for a given circuit in the car without negatively impacting the operation of the device requiring the power at the end of the circuit. The C4's factory fuel pump power circuit was designed to provide power for the light current demands of a factory pump. Typically this circuit is comprised of 16 gauge wiring. Current demands can more than double when a high-performance fuel pump is installed. If we take a step back to high school physics, Ohm's law tells us that when we double the current flowing through a circuit with a fixed resistance the voltage loss across that circuit doubles. The power loss is quadrupled across this circuit which is given off as heat (wasted energy) which can cause electrical contacts (connectors / relays) to heat up and eventually fail. Starving a pump for voltage will cause it to slow down which escalates current demands even more thereby compounding the problem. For those who did not take physics we can consider this scenario... We all know someone who has a high-power car stereo system with heavy power cables running to the amplifier or someone with off-road driving lights using a dedicated circuit with relays. We know what would happen if these amplifiers and lights were hooked up to the same factory circuits which supply the the factory stereo or headlamps! So we pose the question 'how is a high-performance fuel pump any different?' Installing an external fuel pump requires a dedicated power circuit. Just because the factory wiring to your pump is convenient think twice about cramming a 20 amp fuse in panel and consider what you are doing!
Real world tests:
All fuel pumps are voltage sensitive. The lower the pump's supply voltage the slower the pump will spin and the lower the fuel volume will be. Walbro gerotor pumps exhibit a significant increase in fuel volume with increased supply voltage. A Walbro pump's average fuel volume increases by approximately 18% when its supply increases from 12 to 13.5 volts. That equates to apx. 216L/Hr vs. 255L/Hr. The voltage drop in the factory harness increases proportionally to the current demands of the pump. Racetronix has documented tests where the voltage drop in a factory harness has caused as much as a 25% drop in fuel pump volume. Many people feel that their fuel pump can take a performance hit and still come up with the required fuel volume plus a safety margin. What they do not factory into the equation is that the 255L/Hr spec is an average at the pump's outlet on a test bench under ideal conditions. Factor in wear, metal lines with bends & kinks, fittings, heated fuel, plugged fuel filters, lower voltage etc. and one would be surprised how much of a hit the flow rating will take if measured at the fuel rail. This is why it is important to give the fuel pump every bit of power it demands in order to help overcome all the factors working against it. This is the only way you are going to have a safety margin factored into your HP fuel requirements.
The factory circuit which supplies the pump is much longer and more complex than many people realize. The circuit looks something like this. Pump connector > in-tank bulkhead connector > external tank connector > relay > fuse box > steering column ignition switch > fusible link > starter solenoid > battery > alternator. Some of these circuits which the fuel pump sources its power from are shared which can compound the voltage drop problems.
The Racetronix harness bypasses the entire factory circuit path to provide maximum voltage at all times to your pump. The Racetronix harness uses heavy 10 gauge copper wire to reduce voltage-drop to very low levels so as not to impact pump performance. Our power feed comes off the back of the alternator where voltage is highest. The voltage at the alternator's output is typically 0.5-1.5 volts higher than at the battery voltage depending on the charge current. It then runs through a weatherproof fuse holder and then to the back of the car. The Racetronix harness has connectors which plug inline with the factory harness at the back of the tank. No cutting or splicing is required. A Siemens/Tyco weatherproof 40 amp rated mil-spec. relay is used. These relays have silver plated contacts and are the best money can buy so that you can be guaranteed to have many years of trouble-free operation. The Racetronix harness has a redundant ground upgrade as it is necessary to improve the harness on the negative side of the pump's supply as well. The only function the factory harness serves is to trigger the relay in the Racetronix harness (0.1 amps) and to supply the level sender signal to your dashboard fuel gauge. If the need should arise the Racetronix harness can be unplugged in a matter of minutes. Some people even use this feature to disable the vehicle and prevent theft by C4 savvy joy riders. All current series II Racetronix harnesses are equipped with a 30 amp intermediate power connector just after the relay. This connector allows any aftermarket pump booster (MSD / KB / BW) to simply plug into the Racetronix harness. Adding a pump booster (voltage amplifier) can increase pump output volume by as much as 35-40% when run at apx. 16.5 volts (pressure dependent). An extra connector set is included to be installed on the pump booster's power leads making it a plug & play interface. All the harness connections are crimped and soldered. Racetronix supplies a spare ATO fuse, black vinyl wire ties, silicon grease and mounting hardware with each system.
We are including as a bonus our optional battery to body ground upgrade kit. This kit upgrades the under-rated factory 10 gauge ground wire. It includes a crimped and soldered piece of high strand count 8 gauge copper wire and a brass battery nut with an accessory tap. Many people assume the thick wire coming off the battery's negative terminal is body ground. In fact this is the motor's ground for the starter. The motor is on rubber mounts with metal pivot points so the ground integrity is always changing. Our upgrade provides a much improved dedicated battery to body ground. Many customers installing this ground system notice that their average vehicle voltage is higher, fans, power windows, power seats and blower motors run faster, headlamps are brighter etc.
All Racetronix harnesses carry a limited lifetime warranty.
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