CobyRupert
Super Member
This is one of those dumb questions. My car is getting loud because it needs a new muffler. While driving it, I started to wonder “When (and why) is my car loud without one? “
Should be a simple question, right?
When I press on the gas, I assume it gets louder because more gas is being poured in, bigger explosions in the engine, more energy, a louder rumble. Yes?
When I’m up to speed and the engine doesn’t have to work (apply any torque), momentarily coasting, engine is a quiet as having a muffler, even if throttle is being applied for the engine rpms to match the coast speed (i.e. foot is on the pedal, gas is still pouring in).
Why is it quieter?
When letting foot completely off the throttle, and near zero gas is going in, why does the engine breaking sound almost as loud as accelerating ? And louder than coasting at 1/2 throttle?
What are we really hearing when we hear an engine? And engine braking? Why is noise more a function of the engine torque (accelerating and engine braking), than throttle position or rpm? Are we hearing more detonation as timing differences change (relative to valve positions) as torque (or rpm, vacuum in the old days, etc.,) changes?
I can’t believe I’ve reached this age and understand nothing about what I’m hearing.
Should be a simple question, right?
When I press on the gas, I assume it gets louder because more gas is being poured in, bigger explosions in the engine, more energy, a louder rumble. Yes?
When I’m up to speed and the engine doesn’t have to work (apply any torque), momentarily coasting, engine is a quiet as having a muffler, even if throttle is being applied for the engine rpms to match the coast speed (i.e. foot is on the pedal, gas is still pouring in).
Why is it quieter?
When letting foot completely off the throttle, and near zero gas is going in, why does the engine breaking sound almost as loud as accelerating ? And louder than coasting at 1/2 throttle?
What are we really hearing when we hear an engine? And engine braking? Why is noise more a function of the engine torque (accelerating and engine braking), than throttle position or rpm? Are we hearing more detonation as timing differences change (relative to valve positions) as torque (or rpm, vacuum in the old days, etc.,) changes?
I can’t believe I’ve reached this age and understand nothing about what I’m hearing.