What changed in 2011? this qoute:
"As little as a couple of seasons ago, engine wear was such that an engine nearing the end of its multi-race cycle would be significantly less powerful than one at the start of its life. That is no longer the case, in large part thanks to advancements in lubricant technology. Drivers no longer fear dramatic performance losses in older engines - and teams don’t fear failures as they used to.
“Over the last few years we’ve been working on the products we have and the oil chemistry,” says Neale. “And that’s given us a phenomenal efficiency improvement, like an 80 percent reduction in wear of metals. That means there’s more power available for the driver for longer. With engines and gearboxes needed to last for multiple races, it means that the power lasts. "
--- from Link - click Here for source
"As little as a couple of seasons ago, engine wear was such that an engine nearing the end of its multi-race cycle would be significantly less powerful than one at the start of its life. That is no longer the case, in large part thanks to advancements in lubricant technology. Drivers no longer fear dramatic performance losses in older engines - and teams don’t fear failures as they used to.
“Over the last few years we’ve been working on the products we have and the oil chemistry,” says Neale. “And that’s given us a phenomenal efficiency improvement, like an 80 percent reduction in wear of metals. That means there’s more power available for the driver for longer. With engines and gearboxes needed to last for multiple races, it means that the power lasts. "
--- from Link - click Here for source