EV's have to have a noise generator up to 40 MPH, to help pedestrians, and particularly the blind.
From what I saw, driving an EV the blind took notice but sighted pedestrians behaved as usual.
In the 50's -70's the club racing cars that I hung around helping where I could, did not usually have silencers. (some cars were driven to races with silencers, and the extreme racers would take the silencers off once at the track.)
These guys would have put a lot of effort or money into exhaust manifolds to assist gases out of the engine, so giving the gases an easy run to atmosphere was the obvious thing to do.
The exhaust pipe could also be made to resonate at max power giving even less resistance.
In the early 70's silencers became mandatory at the tracks.
Because speed became linked with power, and noise in the publics mind, car manufacturers began to use noise to suggest high power.
But as with Johna and the Whale, "it ain't necessarily so".