Well... there you go again given an excellent reason!

I just read the Emtron ETC Manual and it would be very easy to get the data off the CAN bus.

I just need to receive and process the data at default CAN ID 0x691 (ETC4) or 0x700 (ETC8M)... or what ever it has been changed to.

Not everybody needs a standalone. I had no choice due to what I was trying to do. For someone with an +800whp car these sensors and logging would be a great middle road. For just the hardware and sensors, it cost me $16,000 for my setup. I had a custom fab mount for a 5in. Emtron display so I could see it all the time and not have to drag out my laptop unless I wanted to log or pull the logs. If your prices are reasonable, you should sell it no problem. People may not want all the sensors. You can just do bundled packages.

Since the Emtron EGTs are on the CAN bus, it shouldn't take too much time to figure out the data encoding and save the actual temperatures to the SD card.

I'll need to do some research to see what is the best option for exhaust pressure and intake air temp sensors.

Thanks for taking the time to provide input on this.

Sometimes you get lucky...
The IAT sensor's electrical characteristics (temperature & resistance) are the same as the engine coolant temp sensor.

This means I have everything needed to calculate intake air temp, and since the temp sensor on MAF bank 2 isn't used, we can use it.

I'm also going to add crankcase pressure. This will indicate the amount of cylinder ring blowby.

Parts have arrived...
Coolant pressure testing starts next week.

I'm very curious to see the how the pressure rises as the coolant temp rises.
Also, is the system pressure different with the thermostat open and closed?
Does engine increasing RPM increase system pressure?

I only have theories, but soon will have data.

There is a big difference with the thermostat open and closed depending on the temperature of the engine. RPM does increase the pressure. The thermostat is a restriction which can increase the pressure over the radiator cap pressure. A lower cap pressure will reduce the overall pressure. A 19psi cap I will see 25-27psi at full tilt at 8000rpms. With a 13psi cap I see 15-17psi at 8000rpms. It also depends on where you measure the pressure. First thing to do would be get a baseline. We did that at 12psi of boost on my car. You are looking for a deviation from the norm.

Great info!

Where did you measure the pressure? Top rad hose?

Yes, top radiator hose. I used the Z1 aluminum coolant temp piece.

I know several guys who have removed their thermostats. The pressure will follow the cap pressure rating. I have one JCHammond made with a restrictor installed. We shall see what happens with coolant pressure and temp.

I'm going to replace the factory plastic heater hose connector, with an aluminium "tee" to get pressure.

This is on the same "coolant path" as the upper rad hose, and measures the pressure at the exit of the cylinder heads.

I've updated the code in the Bluetooth Sensor server for coolant pressure and battery voltage, next is to update the data logging code to receive, format and save the data to SD card.

Over the next week, I hope to have everything done and tested.

The coolant pressure sensor is installed and the data logger code updated.

First garage warmup / coolant leak test in the garage.
Top: Engine RPM
Middle: Coolant Temp C
Bottom: Cooling system pressure PSI:

http://www.the370z.com/attachment.ph...1&d=1742595013

Next up:
Long test drive to get the coolant fully warmed up and do a few high RPM runs.

What year car do you have? Does it have the 2009 to 2011 coolant tank or the 2012 to current pressurized coolant tank. They use different radiator caps. The early cars have 19psi caps and the later cars have 13psi caps.

It is a stock 2011 G37S, 6 speed manual with Stillen cat back exhaust. It has the non-pressurized coolant tank. The rad cap shows pressure rating of 137 KPa or 20 psi.

On the second test drive, the coolant temp was 82C / 180F and I did a WOT pull in second gear to 7500 RPM. Max coolant pressure was 27 PSI at 6662 RPM. It then dropped to 23 PSI at 7575 RPM and the coolant temp dropped to 78C / 172F.

I wonder if the pump started to cavitate?

This 4°C/7°F coolant temp drop also happens in the summer, with the engine fully warmed up.
I have a log from last summer and it did the same WOT / 7500 RPM temp drop (4°C/7°F) after driving for 40 minutes with coolant temp at 88C / 190F and oil temp at 95C / 203F.

By the way, this temp drop will never be noticed with the factory coolant gauge/dots. The gauge cluster is programmed not to show any temp change between 70C / 158F and 115C / 239F. This is a common strategy to prevent people from freaking out if the coolant gauge moves and tying up the dealer's shop floor when everything is OK. (even though the coolant temp does change quite a bit depending on operating conditions)

Now that I've verified there are no leaks, I'll be doing a few longer test drives today.

That is exactly what I see. I am removing my thermostat today and installing a 17mm restrictor in its place. The thermostat is a restriction causing it. I will know more once I log it. I see my coolant temp and coolant pressure on my 5in. Emtron display. Along with other things.

Well.... I like it when the data results match, as it gives me confidence that the math and programming is correct!

I'm going to do a special version of the GTR gauges and will re-purpose the "Trans Oil Pres" gauge to show ECP (engine coolant pressure... new acronym!) for this afternoon's longer test drive.

As for the temp drop at high RPM:
Since the stock thermostat starts to open at 82C / 180F and isn't fully opened until 95C / 203F, the rad will have "cooler" coolant until the entire system is 95C / 203F.

Keep in mind, the thermostat acts like a "blend door" and controls the "mix" of recycled (hot) coolant and cooler (rad) coolant UNTIL all the coolant is at 95C / 203F or more.

With the 17mm restrictor plate, you will heat up all the coolant at the same time, which will take longer but will eliminate the temp drop.

However, from a knock perspective, having the engine coolant 4C/7F cooler at WOT isn't a bad thing.

Anyways, that's my theory!