Originally Posted by Radar Chief
Sorry but this is just incorrect.
Parasitic Horse Power Loss, everything run by the engine is taking horsepower to make it work.
Plainly put, it takes more horsepower to run an automatic transmission than a manual one.
Take two cars with equal weight, engine, gearing and aerodynamics, the only difference being that one has an automatic and the other has a manual and the manual transmission with get better gas mileage because it’s not spending horsepower to spin fluid pumps or to power shift servos.
This is why “shitty little econo boxes” are still running manuals.
I think DJ is right here. The difference in parasitic loss is what 18% for an auto and 15% for manual, that measly 3% is easily made up by a computer controlled trans. This argument was true 25 years ago when the auto's were power glides and TH400's. Today's autos are VERY efficient, If manuals truly were more efficient you would see them in cars like the Prius that ONLY come in an auto.