Stock BRZ Engine Knock Video

[humblebrz]

Originally Posted by ToySub1946

Throw out bearing is actually in use (spinning, using it's bearings) when the clutch pedal is pressed. If the throw out bearing were bad, this is when you'd hear it.

And with the pedal depressed, clutch is released, and transmission input shaft should stop moving....so there would be less vibration going through the rear of the transmission, less vibration on transmission rear mounts and driveshaft, etc.

So answer: something else.

Are we looking at a bad clutch or flywheel?

[Ultramaroon]

That doesn't sound like clutch/TOB. Too regular and too high of a frequency at idle.

I know it sounds lame but I keep going back to something driven by the accessory belt.

edit: I just went back and reread your OP. Heaviest electrical load is immediately after startup. Alternator is already working hard to recharge the battery from starting and then with extra drain from heating elements... blah blah blah.... you already know that.

I'm convinced it's an accessory if not actually the alternator.

If you hold the gas pedal all the way to the floor before/while you're cranking it, the injectors will never fire. Flood-clearing mode. I bet if you crank it for 10 seconds (limit per the manual) even when it's warm you'll be able to replicate the sound.