If you damage your engine with detonation would you know it right away? Or can you still drive around without even knowing?

 

You will know.

1. You find yourself picking up pieces.

2. Uses a quart of oil every 5 miles.

3. Engine shakes violently as it's not running on all cylinders.

4. Various fluids coming out of the engine compartment.

5. Lots of loud noises. and it's not that new exhaust.

6. The tow truck driver is impressed.

 

...All that...to the sound of ricers laughing as they swerve past your wreckage...