Update: Air/Fuel ratio, Coolant & Oil temp PLUS Oil Pressure DIY Display

[MotorvateDIY]

I have a small update....
I now have a working prototype of a small multi-gauge display that*displays engine coolant temp, engine oil temp, current air/fuel ratio and engine oil pressure.

I know the 370z has an oil temp gauge, but I have a G37 and I wanted to know how hot it gets. I can replace this item with fuel pressure, ethanol content, differential oil temp or data from any other sensor. (digital or analog)

Only an engine oil pressure sensor is needed. All the other data is from the car's CAN bus or OBD requests.

PLUS with the engine oil pressure sensor being connected to the "Bluetooth sensor server" there is now no need to route a few wires through the dash. For those that have done this, you know it is not a quick or easy task. The magic of Bluetooth solves this problem.

Here is a short video showing it in action:


The next step is to design the circuit board, get a few made and do more testing.

[ZontheRocks]

Very nice!

[MotorvateDIY]

Originally Posted by ZontheRocks

Very nice!

Thanks! It has been a fun project to work on.

Two things that have surprised me about our cars:
• Our engine oil pressure is VERY high!
More than 120 psi on a cold start (well, In Toronto during December)
With engine oil at or above 80C/176F we still have 90+ psi at high engine RPM

• The differential oil can heat up 3C/5F during a single 0-60 mph run. (and that was during a 0C / 32F day)

With the G37 Sport Sedan being about 500 lbs heavier, I suspect the diff oil heats up quick than the ~3200 lbs 370z.

[Rusty]

Nice work.

I've seen rear diff temps high as 275F with my SpeedHut temp gauge.

Cold start oil pressure will be over 110 psi from what I've seen. Oil pressure at 3000 rpm will be around 90 psi.

Oil pressure sensor should read 150 psi.

[MotorvateDIY]

Originally Posted by Rusty

Nice work.
I've seen rear diff temps high as 275F with my SpeedHut temp gauge.

Cold start oil pressure will be over 110 psi from what I've seen. Oil pressure at 3000 rpm will be around 90 psi.

Oil pressure sensor should read 150 psi.

Thanks Rusty! I assume your oil pressure readings are with 40 weight oil. (was it 5W40 or 10W40?)

Was your 275F / 135C diff temps during a track day?

As for the oil pressure scale maximum number, it won't ever get above about 120-125 PSI as that is when the oil pump pressure relief valve opens (bypass mode). The display is optimized for the expected min/max ranges.

Funny thing is, I do have a 150 PSI sensor on the engine.

[JARblue]

My understanding is the afr reading from the ECU isn't precise enough to really be useful. I ended up getting a wideband sensor.

Look forward to the finished product tho. Nice work

[MotorvateDIY]

Originally Posted by JARblue

My understanding is the afr reading from the ECU isn't precise enough to really be useful. I ended up getting a wideband sensor.

Look forward to the finished product tho. Nice work

That's interesting...
On my G37, during low to mid engine load the AFR is typically around 14.7 - 15.0, full throttle is low 12s and off throttle is 20+. As I understand it, those are expected values.

But I don't have anything to compare it to.

Anyways, I will keep that in mind and try to find someone local that has a standalone wideband.

[redondoaveb]

Originally Posted by MotorvateDIY

That's interesting...
On my G37, during low to mid engine load the AFR is typically around 14.7 - 15.0, full throttle is low 12s and off throttle is 20+. As I understand it, those are expected values.

But I don't have anything to compare it to.

Anyways, I will keep that in mind and try to find someone local that has a standalone wideband.

Check out this video from Seb at Specialty Z

[JARblue]

Originally Posted by MotorvateDIY

That's interesting...
On my G37, during low to mid engine load the AFR is typically around 14.7 - 15.0, full throttle is low 12s and off throttle is 20+. As I understand it, those are expected values.

But I don't have anything to compare it to.

Anyways, I will keep that in mind and try to find someone local that has a standalone wideband.

I was also unaware until redondo shared that video with me. It was enough for me to grab a wideband sensor for NA tuning. I'll probably just hide the gauge in the glove box or somewhere after the tuning process is done.

[Rusty]

Originally Posted by MotorvateDIY

Thanks Rusty! I assume your oil pressure readings are with 40 weight oil. (was it 5W40 or 10W40?)

Was your 275F / 135C diff temps during a track day?

As for the oil pressure scale maximum number, it won't ever get above about 120-125 PSI as that is when the oil pump pressure relief valve opens (bypass mode). The display is optimized for the expected min/max ranges.

Funny thing is, I do have a 150 PSI sensor on the engine.

I run Mobile 1 0w40.

The 275F reading was from both a track day and 2 hours of driving at 75 mph on the highway. It only takes about 12 miles of driving at 55 mph to see the temp raise to 120F on a 75F day.