With a souped up DCell obviously I smell some diesel exhaust backing up out my garage, my mechanic friend even likes it working on gas engines all day, but if you are smelling it every day there is a problem. Exhaust leak is obvious, but check for an intake leak (from turbo to intake manifold). My hose going to the intake manifold split a little bit, and i didn't notice for little bit and it smoked like all hell when taking off from stops. Also pretty stinky. Stock car taking off from stops I always tended to floor it, I can see sitting in soot for a second.