Hello, So, I've been watching more and more races recently, and I've noticed that in many of the categories, the engines seem to have this really high-pitched sound going on that increases in pitch when the vehicle shifts up. I originally thought this was the turbo, but wouldn't a turbo whine's pitch drop when you shift up to go with the engine's RPM? Sorry if you don't understand what I mean. If I'm confusing you, I'll link a YouTube video to try and help.
It's the gearbox. Gearboxes in race cars are extremely loud due to the way they are made. The pitch changes because of the ratios in the box. The lower the ratio, the higher the wine is, the faster you go. So, that explains why 2nd gear is slightly lower pitch than 5th or 6th gear.
In a professional racing scenario, wouldn't a loud gearbox be a bad thing, because that sound translates into lost power being transferred?
It's possible, yes, but it's unavoidable. It's in the same way that it's technically "bad" that electronics generate heat. It's always going to waste energy but nothing can ever be 100% efficient.
Apparently, making it quiet would actually waste more energy. Or do I have the rationale for using straight-cut instead of helical-cut gears wrong?
It is not always true that spur gears are stronger than helical, but Helical gears generate side (thrust) loads due to the angle of the teeth, which means bigger stronger bearings and gearbox housings are required for a given amount of power. Its also easier/cheaper to cut spur gears for low production volumes. The downside is that they are earsplittingly loud.
