Seven cars to practice with KERS in Bahrain
A dwindling three drivers took to the Shanghai grid a week ago with the controversial energy re-use technology, as the benefits of the 82 hp power bursts comes under scrutiny.
McLaren's duo Lewis Hamilton and Heikki Kovalainen have used Mercedes' KERS consistently in 2009.
"This is one of the circuits where KERS can give you the most time, because there are three very long straights," Spanish test driver Pedro de la Rosa said.
Ferrari took KERS off both cars in China for reliability and safety reasons, but will reinstate the system on Felipe Massa's F60 in Shanghai.
Due to Kimi Raikkonen's additional weight, Ferrari's KERS is seemingly of less value to the Finn, and his car will be without the unit at Sakhir.
"It should be a significant advantage here. A great deal of work at the factory has gone into working on the KERS system since Sepang so I am hopeful it can help us," said Massa.
Nick Heidfeld has used KERS all season so far, but his much heavier BMW teammate Robert Kubica – although sometimes testing the system in practices – has not.
The Pole, who qualified an horror 18th in qualifying in China, will again test KERS on Friday in Bahrain.
"The plan is to run it all weekend," he said on Thursday.
It is clear that Renault is also assessing KERS on a circuit-by-circuit basis, with Fernando Alonso and Nelson Piquet's cars likely to test the system on Friday.
"I think it will a decision we will make race by race and at the last moment, maybe on Friday night," Spaniard Alonso told reporters.