The smell can be only felt inside. If you stop the car immediately and open the bonnet, there is no smell at all. Shouldn't the smell be noticeable outside if it was related to clutch or turbo or exhaust? Some background: When I initially noticed the smell, the car was already making a worn bearing type noise from the AC blower. I replaced the blower and I couldn't notice the smell on a few subsequent hard accelerations. As the smell was noticeable only when the AC is on, I thought the issue was blower related and it was solved. But then it came back after a month. Then I took it to a shop nearby, they disconnected the blower and connected it back up, and....the smell was gone. Now I don't notice it anymore, it's been a week. I don't know whether it'll be back.