In just noticed this recently.I dont believe its been doing this all the time.I shut the car off and I hear this constant pinging coming from the exhaust system.Im like what the hell is that? is this normal for the exhaust to produce such sounds when cooling down perhaps? Its not your usual crackling at totally random times.This pinging is constant and happens every second.weird indeed.Im also smelling exhaust gases from the turbo area.I hope my exhaust maifold isnt cracked

 

The noises you hear are quite common. As for the exhaust smell, make sure all your studs are tight.

 

what are the odds that the exhaust manifold is cracked? I doubt it but you never know with rx7's.These cars have just the worst luck ive seen in a car.

 

could it be your cat cooling down. they can make a crackling or pinging sound when cooling down.

 

Im used to the the cat making noises.But this noise is also prevalent in the turbo are.So it echoes all the way to the catback opening.It kind of sounds like theres a small fire inside the downpipe.I know it sounds weird but thats the only way I can describe it.Ill try and see if I can take a short vid of it with my digital camera and post it on here for all to see what exactly im talking about.