The main evaluation of the three cars was conducted simultaneously at Thunderhill Raceway Park in Willows, California, with the majority of the analysis performed on the Thunderhill West circuit. In addition to the two new FA24D-equipped vehicles, an older FA20-powered Subaru BRZ was also tested alongside a control reference. Further testing was executed on Thunderhill’s five-mile circuit on a separate occasion.
During Armstrong’s testing of the new FA24D-equipped cars, consistent drops in oil pressure were observed during vigorous right-hand turns, particularly when experiencing rapid turn-ins or changes in elevation. However, slower and less intense right-hand corners did not result in pressure fluctuations. For instance, at Turn 5 on Thunderhill East, a drop in pressure from 62 psi to 28 psi was recorded, representing a substantial 34 psi reduction at high RPM. The combination of elevation changes and right-hand corners appeared to pose challenges for the vehicles’ lubrication systems, as the decline in pressure persisted for a period in such scenarios.
“Our study revealed that the FA24 engine maintains strong oil pressure on straightaways and left-hand turns, yet we consistently observed pressure drops during right-hand turns,” he shared. “We believe these pressure declines could potentially lead to bearing damage, albeit not an immediate catastrophic failure.”
The older FA20-equipped BRZ apparently demonstrates a similar issue during right turns, although not to the same degree as its larger 2.4-liter counterpart. The 2017 model experiences occasional brief drops in pressure, but they are not as consistent or significant as those observed in the newer cars.
Armstrong’s vehicle has not undergone pan removal to inspect for RTV, a sealant that has been mentioned as a potential weak point, unlike the other Toyota tested in the video. Both cars feature slightly modified suspension setups and new tires, with Armstrong noting that the new tires are not as adhesive as the factory-fitted set. The primary modification to their lubrication systems is the addition of oil coolers. Armstrong meticulously outlines the specifications of each vehicle in the video.
Testing for new vehicles only involves one BRZ and one fresh GR86. Further exploration in varying scenarios needs to be conducted before making conclusive judgments. Nevertheless, the ease with which an amateur driver replicated the results is remarkable. Both cars share similar specifications, and the tests were carried out on the same day at the same track with matching instrumentation. While Armstrong’s display might not be definitive, it strongly implies potential deficiencies in the FA24D’s lubrication system during high-performance driving, where RTV-induced blockages or limitations could worsen an already oil-deprived engine.