Suggestions for temperature ranges on electronic shift light to adjust rpm

[Miker7]

I've been playing around building some shift lights, that has had a bit of scope creep whilst on the test bench.

Currently its got 15 leds in a curve that light up from either side towards the middle from green to amber to red, when all are lit the lot flash red. Beneath that its got 8 'status' leds. Each LED can be any colour within RGB to represent its status. Originally i was hoping to pull all sorts from the ECU and have one status per LED. However the data my 02 K Series supplies via odb2 is more limited than i'd hoped. The status LEDs now display / flash for the indicator on each side of the car (via seperate wiring) and display the water temperature from flashing blue, to blue, green, amber, red and finally flashing red.

So the questions,

What water temperatures would you consider to be very cold, cold, normal, warm, hot and very hot on a K series? How much would you have the temperature affect the rpm to limit damage?

EG

below 50 = Very Cold   RPM lights start at 3000 and flash red at 5200 (hoepfully the fact the lights are coming on and the temperature status is blue would prompt you to change up)

below 75 = Cold RPM lights start at 4000 and flash red at 6200

below 90 = Normal RPM lights start at 5000 and flash red at 7200

below 97 = warm RPM lights start at 4500 and flash red at 6800

below 104 = hot RPM lights start at 4000 and flash red at 6200

above 104 = Very hot RPM lights start at 3000 and flash red at 5200

The lowering of the revs at high temperatures is to try to limit the heat generated and let the cooling have a chance to pull the temperature back whilst coolant is flowing so you don't get localised heat spots. With me lighting up LEDS equally from side to side this means each LED is 300 revs in the setup above, with flash 100rpm after the last LED is lit.

As I said at the start i've got a little carried away on the test bench 😁

[Skipper555]

Nice idea and project.

Would it be better to alter the range on oil temperature instead?

This tends to increase slower than coolant temperature and is generally more critical than water temperature.

That being said, if you don't have an oil temp sensor (as I think most cars don't) water temp would be a good second best.

I'd personally be more cautious below 75'C coolant, especially from warm up as the oil is still coming up to temperature. Maybe 5000 rpm?

[graearea]

how're you housing it all?

if you need something 3d printed I can help (this isn't me trying to get paid, just is an interesting project)

J

[Miker7]

I'd love to have oil temperature & started with the idea that I'd display oil, water, volts and air temp on the status display. As I don't have oil I figured air and volts aren't that important so i'm just using water and seeing that as an acceptable second best.

I did wonder if below 75 i should be more cautious hence the open question. The current approach uses the same curve with just an amended start point. If i do 5k rpm as flashing lights that means the start would be 2.8k rpm which seems a little low. Guess I need to add a "low temp" curve.

[Miker7]

Just now, graearea said:

how're you housing it all?

if you need something 3d printed I can help (this isn't me trying to get paid, just is an interesting project)

J

I'll be 3d printing something myself. Currently looking at a 3 piece print for a front face with cut outs for the LEDs with overhang to shade it. Middle "body" with an overhang that mirrors the front to give a degree of water resistance & greater area to glue and finally a rear section that fits into the middle body. The base is angled at about 3 degrees which i think matches the scuttle directly over the steering column. Have an initial quick drawing in fusion but haven't done a test print yet. Have LED's stuck to a bit of card with bluetac currently whilst coding.