The B-29 didn't use the turbo compound, but was turbo supercharged.
War time required the -29 and it's engine to be rushed into service before proper development could take place. The early engine had the exhaust on the front of the engine on the front bank of cylinders, so overheating from escaping exhaust gases impinged on the front cylinders resulting in overheating. It was found too, that particular attention had to be paid to maintenance of the cylinder cooling baffles. 100 hours was all they were getting out of an engine initially, but reached 400 hours at the end of the war, which was comparable with other combat engines, in airline service the TBO stretched into the thousands as the lessons were learnt. The -29 was closely cowled and take off was not to be attempted if the CHT was beyond a certain temp. The take off was begun with the cowl flaps fully open and it was the flight engineers job to progressively close the flaps as they accelerated down the runway. Such were the cooling demands.
Aircraft to use the turbo compound were the Neptune, Constellation, DC-7, Canadair Argus, Fairchild C-119, Martin Marlin.
A bit of bedtime reading
Avgas.
http://aviatechno.net/files/wright_r...ASH/index.html