Just bought two new engines, one Supertigre G45 and a Magnum 46 XLS. Both were broken in by running approximately 40 oz. of fuel through each on the bench.
Fuel used in both = Byron's 15%.
Prop = Master Airscrew S2 10X7
Plug used in both = OS #8.
Air temp at test time = 86 deg.
Supertigre with stock muffler = 15,100
Supertigre with Tower muffler = No Change
The Supertigre muffler is noticeably quieter and the Tower muffler is lighter although I didn't weigh it to see how much lighter.
Magnum with stock muffler = 14,000
Magnum with Tower muffler = 15,200
Sometimes the Magnum would make 15,300 but it wasn't consistant so I lissted it at 15,200.
Transition on both was great as they came from the Manufacturer. The Magnum, with the Tower muffler, was too rich at about 3/4 throttle when peaked for max rpm and with the idle set as lean as possible. It ran perfect with the stock mufler so I assume the lower muffler pressure on the Tower muffler causes this effect. Just some observations to share with the group. Have a great day all. [8D]