I recently got my hands on a spare stock aluminium underpanel, and I wanted to explore the potential cooling effects of making ventilation slats, similar to the Beatrush/Carbing aftermarket vented underpanels sold.
The premise of this test is to identify if venting the underpanel will improve coolant/oil temperatures by allowing air past the radiator to exit the engine bay instead of being recirculated/stagnated. With less pressure built up in the bay, there should be better flow/pressure at high speeds going across the condenser/radiator stack. I chose the stock panel to work on as everyone already has one and reversing it is as straightforward as finding another.
The test methodology would be to capture relevant temperatures and sensors in both stock and vented configurations, at idle and 110km/h speeds in 6th gear with the list below:
Coolant temperature
Oil temperature
Intake air temperature (not expecting this to change much given the intake is outside of the engine bay)
Ambient temperature
The laser cuts made on the panel were planned out to vent as much as possible without reducing too much rigidity (I did not account for one issue, see if you can find it). The slats are bent at a 45 degree angle to allow the widest opening on each vent.
Discussions previously on this forum have been polarizing, so I'll touch on the potential downsides as well. Venting hot air from the engine bay to the underneath will reduce its stability as more airflow now travels underneath the car, increasing lift. Not sure if that additional airflow would be marginal or significant to impact stability, however this will be difficult to measure/quantify regardless so I will be going by feel.
Relevant modifications to the car include a 82C thermostat, 30/70 Denso tropical coolant, Forester water to oil cooler and a tune, otherwise stock for the most part. Will take my time with this but will pen down my thoughts and findings as I go along.
