Fuel Sender Unit - What Ohm Range

[Dan Carter]

Going to add a separate set of gauges for the LS3, but not sure what RCR supplied fuel tank sender we have. Anyone know what OHM rating the unit is?

Gauges come in differing OHM settings. I think it should be a 0-90 ohm sending unit.

 

[Will Campbell]

This has been covered many times- the sender with the kit matches the unusual ohm range that the Koso needs, and so the sender generally can't be used for other gauges, unless they have the ability to "learn" a custom range.

The manual for the Koso, which is linked in the wiki here, shows the two ranges, and how to set them.

 

[Mike]

I believe Superlite buys Centroid senders - E100/F0 sender.

Going to add a separate set of gauges for the LS3, but not sure what RCR supplied fuel tank sender we have. Anyone know what OHM rating the unit is?

Gauges come in differing OHM settings. I think it should be a 0-90 ohm sending unit.

 

[Dan Carter]

Thanks mike

I found that Classic Instruments sells a programmable "ohminizer" that may allow me to convert that signal range to the range I want to support the quad gauge set up I am planning without having to install a new fuel sender and get the best of both worlds. I have to call them today and find out.

 

[Dan Carter]

I talked to Classic Instruments today and they confirmed that their ohm convertor could align their gauge to the ohm range on the fuel sender we have (100 ohm unit). The ohm convertor is about $140 and requires you to program the sender outside the tank (you basically place sender on the full and empty range while hooked to their reader to program it). Since my sender is already in the tank and it has to come out, I opted to buy a whole new sender built for the gauge I plan to install and it was only $80.

So the KOSO will not be hooked up to the fuel tank, but an old steam gauge will.

I simply like to see gauges, no other reason. Sort of like an instrument cross check in the cockpit I guess.

 

[Will Campbell]

I hope your new sender is adjustable, so it can accurately represent the level based on the shape of the tank- if that is important to you.

The sender that ships with the car is designed to do just that- it understands the tank profile, and has a curve that offers resistance at the correct level, so that, for example, half resistance is really half full.

Using a normal lever/float type of sender, or even a standard capacitance sender will result in inaccurate readings, not just for the Koso gauge, but for any standard gauge. For the tank profile we have, they tend to overstate the fuel level, mostly at the top. It should be more accurate as the level gets low, as the tank becomes square at that point.

The point is that just because you have a gauge and a sender that have a matching resistance profile, you don't necessarily have an accurate level reading- you need to have a sender that can accurately represent the level in your tank- which senders that are not calibrated to the tank profile do not.

Luckily, because the tank approaches a square or rectangle at the bottom of the readout, the most important part of the readout should be fairly accurate, no matter what system you have, assuming the rest of the setup (e.g., lever/float travel, height above the bottom, etc) is correct.