Regulating Boost Pressure Without Sensors or Live Tracking
Hoping you all can help me satisfy my curiosity. I'm curious to learn about how a racing sanctioning body could regulate the amount of boost individual cars are running without the use of some kind of live tracking. I understand IndyCar does this with the use of live sensors that are tracked in real time by a team of tech inspectors. In IMSA/WEC, this regulation happens as a natural result of the fact that torque sensors are tracking overall torque and power outputs in real time (i.e. cranking boost pressure itself is not illegal per the rules, but it would put a team's power curve above what the regulations would allow, and tech inspectors would know it right away due to the sensors).
What I'm curious about is how one would go about regulating this without live tracking, for example if a smaller local track or organization wanted to do it but could not afford the cost of tracking every individual car. My first thought is specifying a spec turbo that all turbocharged engines must run, one that will only allow for a maximum amount of boost, so teams couldn't tune it higher if they tried. I notice, however, that listed specifications for turbos themselves don't usually list boost pressure as one of their data points. I only see this referenced with respect to individual cars/applications. I'm led to believe then that "boost pressure" is a function of something more that just what model of turbo is incorporated into the engine and how it's tuned. What other components would need to be specified to accomplish this? Given the same model and size of turbo, how and why does maximum possible boost pressure change from engine to engine?
Thanks in advance!