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Mixing parts for fuel gauge


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One of the challenges of mixing parts is making them talk together correctly.
One of my challenges here is making the WRX sending unit (in the tank) or any other unit work correctly with the gauge. I cant change the gauges range so I need to focus on modifying a sending unit to work with the gauge.

The stock CBR gauge has a range of 10-130 ohms. While the 2003 WRX has two senders stacked in series of 0-50 ohms each that creates a range of 5 to 100 ohms.

Here is the range of what will display if I changed nothing, and used the WRX senders. I would run out of fuel before my gauge read 1/4 tank. Now I could just "deal with it" but I don't want the car built that way. I want everything to work, and work correctly as it would in an OEM car.
sending unit map.jpg
Now if my ranges were to large, I could just install a resistor in line to the gauge and problem solved. However this is a range that is less than the gauges range. So some sort of an signal adapter, or a completely different sending unit is needed.

One possibility is to use the CBR600RR fuel sender. However its size may not display the accurate amount of fuel in the tank as it may not reach down far enough, or even fit in the tank. Plus the Honda unit is a pump/sending unit combo.
07-11 cbr600rr fuel tank sending unit.jpg
Here is the 07-11 CBR600RR fuel gauge sending unit. As you can see the arm is much smaller in length than a car unit is. Perhaps if there is a way to put a new arm on it, it could be all I need. I wouldn't be able to use the pump built in it as it wouldn't be able to keep up with the EJ20 turbo engines thirst.
03 WRX gas tank sending unit.jpg
And here is the WRX unit. you can see how much bigger it is. Hmmm

Any thoughts or suggestions?
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