From What I have read, the coolant temp gauge on the series 1 is inactive until its too late. Its been described as a glorified idiot light with only a couple of positions.

Is the gauge in the Series 2 the same way? I tried to search about it but couldn't find much about the series 2. Just a plethora of results about the series 1

 

Yep, the same.

 

The sender itself is decent. I use it exclusively with my digital dash software (Adaptive Tuner)

 

So if the sender is variable, what keeps the gauge from also being variable? Is there a way to modify the stick in-cluster gauge to read real temperature?

 

The circuitry in the dash cluster prevents the gauge from being dynamic. With a combination of a resistor and a diode you can control the analog hysteresis of the gauge. The reason manufacturing does this is because they dont want people calling the shops every other day wondering "why is this gauge moving above middle, is it bad, am i overheating, etc".

The way to "fix" this is to disassemble the cluster and essentially turn the parallel resistor-diode circuit after the input signal from the ECU and add an R2R ladder with a large resistor so that it creates a more linear output curve.

Its a fairly "common" process that is done. A similar setup (albiet slightly altered) for the fuel gauge (which is why you dont see the fuel gauge swing up and down with every bump in the road)

 

Hmm. Sounds beyond my capability. Its apparently more than just rerouting a signal wire from the temp sensor to the gauge directly.

 

Visual representation of the circuitry that I am talking about. With the top being similar to how almost every car with an analog coolant gauge is designed, vs the lower one which is how analog gauges like defi/prosport/aem et al are designed.

And yea, the latter is meant to curve like that in the end as the resistance of the sender reaches Z

 

I really want to be able to see live actual temp. Ill probably just end up running a separate gauge like you did. Just not sure where to put it to keep the interior clean.

 

Yea that was the tough part. I now have my gauges in a homebrew ashtray pod. Looks a hell of a lot cleaner.

If you decide to get a gauge, i recommend using the Racing Beat water adapter as that will show you live temps regardless of thermostat state. I have the upper rad hose adapter and it works just fine, but only once the thermostat opens.