Walbro fuel pump upgrade - is 12V mod required?
- Thread starter scotty
- Start date
I ran 12v mod on my stock 7m with walbro 255lph for about 12 months.. I built the car now.. and plan on Rewireing the fuel system for safety precautions.. plus Comfort in mind 
12v mod on the ops car should be ok.. Unless you start trying to tune for anything higher..
12v mod on the ops car should be ok.. Unless you start trying to tune for anything higher..Ohm out the wiring...If its good then dont worry about anything. You can simply put a jumper in the connector for the fuel pump resistor. If your not going to tune....leave it alone. Going with a larger gauge wire really only help insure that you dont have a excessive voltage drop across the wiring and only getting 10v's at the pump instead of 12v. Like i said if your not going to tune then who cares if you dont get 12V at the walbro. A 16g wire can safely handle 22amps.
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If you know the amp draw of the pump, you will know what you need for resistors. For example, 3P using basic math came up with 2 stockers parallel to run the JZA80 pump.
Nick M;1784096 said:
Not really a good idea. It defeats the the whole point. The resistor is only .7 ohms buy adding them in parallel its like having a .3 ohm resistor. So now the pumps have 11.28v applied instead of the 9v it is desighned to have. So might as well not have the resistors there to complicate things. I dont think the walbro will draw much more current then stock when not in boost and for this to work out the walbo would need to draw twice as much current.
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MRSUPRA;1783096 said:
Maybe you've just never realized what you were looking for. Its a jump in the AFR's at one random interval. It's inevitable and unpredictable. You DO have it unless your system isn't switching from 9 to 12 volt. Here is an old example of mine. Don't mind the odd power curves, I had several leaks in the IC system at the time. You can clearly see where the 9->12V jump occurs. It is fairly consistent because the runs were done in a similar fashion.
MRSUPRA;1784453 said:
You CANNOT tune it out. It looked the same because it switched at the same time. It can switch at any point in the RPM range. It is variable. It was consistent because you ran somewhat consistently. If you did a run starting at 4K vs. 2.5K the switch will occur at different points. This is why the 12v mod is done. It only takes a split second to kill the engine. You can see how much my AFR was affected during the switch.
dont mean to grave dig here but i feel this is kind of important. I ran walbro on my stock 7m setup with the resistor and my fp just stopped working. After alot of diag time i think one of the wires fried between the circuit opening relay and the fp because my car run with the fp and b+ pins bridged at the check connector. Defiantly interested in doing the 12 volt mod cause i can barely start my car with that damn thing running.