C7 Z06 Cooling development Part II
So for our next testing configuration, we decided to reverse the routing of the main coolant circuit. We would be reducing the heat transfer across the auxiliary radiator, but increasing it across the larger main radiator. In theory, that would net us more total cooling. Here's a diagram of how it was routed:

We went out and ran another session, and here's what we found:

There's already a much more visible gap between the three coolant temperatures. That's a good sign that the main radiator is working harder now.

We found this odd anomaly in the blower temps, though. For some reason, blower inlet temperature measurements are spiking for around 4 minutes. We're not sure exactly what's happening since we're not logging mass flow rate or pump amperage, but we've got some things we're going to investigate. Blower temperatures overall seem fine, though.

Airflow temperatures are spread much more evenly, and interestingly enough, the temperature leaving the main radiator is significantly higher than yesterday. We're now seeing temps well over 200° on the backside, when we were barely crossing 180°.


Temperature deltas now look much more like what we'd expect to see. Simple temperature gradients aren't enough to totally characterize a heat exchanger, but in the absence of mass flow rate, etc. we're definitely more confident that the main radiator is working more efficiently than in the previous layout.
We ran the PDR this time, and here's what we got:
Max Water Temp- 250°F
Max Oil Temp- 302°F
Max Trans Oil Temp- 210°F
We attempted to log some ECU parameters with HP Tuners' VCM Scanner since the onboard PDR won't share anything more than a few specs, but the laptop came unplugged from the scanner during the session, so we didn't get anything.
Next, we'll try to re-arrange the heat exchangers to get a little more airflow across the important bits. We're making strides towards a solution, but there's several steps here. Step 1 is getting blower temps down. LG Motorsports already solved that with the big cheek coolers. Step 2 is now getting engine coolant temps down to keep it out of limp mode. Steps 3 & 4 will be doing the same with engine oil temps and transmission fluid temps.

We went out and ran another session, and here's what we found:

There's already a much more visible gap between the three coolant temperatures. That's a good sign that the main radiator is working harder now.

We found this odd anomaly in the blower temps, though. For some reason, blower inlet temperature measurements are spiking for around 4 minutes. We're not sure exactly what's happening since we're not logging mass flow rate or pump amperage, but we've got some things we're going to investigate. Blower temperatures overall seem fine, though.

Airflow temperatures are spread much more evenly, and interestingly enough, the temperature leaving the main radiator is significantly higher than yesterday. We're now seeing temps well over 200° on the backside, when we were barely crossing 180°.


Temperature deltas now look much more like what we'd expect to see. Simple temperature gradients aren't enough to totally characterize a heat exchanger, but in the absence of mass flow rate, etc. we're definitely more confident that the main radiator is working more efficiently than in the previous layout.
We ran the PDR this time, and here's what we got:
Max Water Temp- 250°F
Max Oil Temp- 302°F
Max Trans Oil Temp- 210°F
We attempted to log some ECU parameters with HP Tuners' VCM Scanner since the onboard PDR won't share anything more than a few specs, but the laptop came unplugged from the scanner during the session, so we didn't get anything.
Next, we'll try to re-arrange the heat exchangers to get a little more airflow across the important bits. We're making strides towards a solution, but there's several steps here. Step 1 is getting blower temps down. LG Motorsports already solved that with the big cheek coolers. Step 2 is now getting engine coolant temps down to keep it out of limp mode. Steps 3 & 4 will be doing the same with engine oil temps and transmission fluid temps.