Intermittent Exhaust Tone Change

Possible small exhaust system crack? It closes up as the system gets warm? Will only get louder as the crack deteriorates, if that's the problem.
If you like that deep throaty rumble sound versus the putt-putt Model T sound. A Solo performance side exit exhaust system may be what you should look at if you have to replace your exhaust system.
Good luck and keep us updated.

Where would I find those Solo Exhaust systems?
(I think I can talk the Missus into it: she likes that growl also.

Smartmadness should have the exhaust system.

Bob Denman said:

Where would I find those Solo Exhaust systems?
(I think I can talk the Missus into it: she likes that growl also.

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Unless smartmadness is giving a discount or free shipping you can buy right from solo performance.

Thanks! Time for some internet shopping!

Bob Denman said:

Hi guys! I've noticed that every once in a while: I'll start the Smart up, and the exhaust tone will have this excellent little "growl" in it. As soon as I get it backed out of the garage, and start to hit the road: it disappears!
While I really LIKE the change: it's not predictable or repeatable at will. It has to be something going on that I probably need to address.
Can anybody give me a clue as to where I should start looking? It's tough to diagnose; because it's just not there when you're looking for it/
Thanks!

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I have had the same experience in my 2018 Smart, and have experienced it since new. So, for me, I believe it is likely something other than the aforementioned exhaust crack. But have no other ideas!

Since your car is a 453 with a turbo and the other posters have the non turbo 451, could the sound be turbo related? I ask, because I have absolutely no experience with the newer model.

I noticed a post in another thread that mentioned something about a heater for the catalytic converter making some noise. I'm going to operate under the assumption that this is the case, and let sleeping dogs lie...

Just an FYI
I had this very same condition in my 2015 451. Upon start up at idle it would give a little growl for the first couple of minutes then disappear once it warmed up and I went about driving.
As the months progressed and the growl grew into a slight roar, upon inspection I discovered a leak at the bottom of the flex pipe connecting to the muffler. In time this leak grew into a steady open pipe scenario when the flex pipe let loose from the muffler. That cute little growl turned into the car sounding like a 1975 Ford Pinto without a muffler.
The flex pipe itself actually contains an inner pipe I discovered when I took a sawsall to it when we installed our Solo cat back to replace the OEM muffler.
I apologize as I’m a little late into this conversation and you did say the dogs are laying down now, but just wanted to add my two cents into it because it sounds so familiar to what we encountered.
May you have good luck and fortune with whatever you decide.
Paula