OK, we all know old Prius' burn a lotta oil but...

Actually the Prius seems to not smell too too bad actually It's not as bad as other cars I've had before with the hatch open like a Chevy V8 older carbureted business and all that but yeah that's what you get I don't think the oil adds a whole lot it would it make the smell a little heavier and oily smelling burn some oil with your plumbers torch on a piece of metal and there you go mix that with your exhaust a little bit there you have it. But the Prius has a tendency to let exhaust slip up through anywhere in the rear it can get up there I don't know if there's a way to pry the muffler down a little bit or put longer rubbers on it maybe Not sure haven't really looked into it but I do know in my '09 this can happen pretty quickly without the hatch open of course I have the back end of the car pretty open and a lot of the plugs are pushed through for water pass through so that means air can pass through also

 

Yes oil burning will cause the exhaust to be a little stronger. Especially when the expensive catalytic converter is getting overwhelmed.

Obviously the car is not designed to be driven with the hatch open.

 

My generation 2s seem to burn oil at given mileages very similar to all of the Corollas I've owned since like 73 seriously so that's four or five different engine iterations over those years and everything All of them seem to consume about similar amounts of oil at similar mileages I don't really find the Prius to be excessive in any shape or form

 

Don't do that unless all the windows are open. The car creates a vacuum behind it when moving and if the hatch is open that vacuum will extend into the cabin and pull a lot of exhaust in. Opening all the windows reduces or eliminates that vacuum (depending on the shape of the car). If the car is really fouling the cat badly there will be elevated CO and NOx, and possibly some oil mist, none of which are things you want to breathe.