WIlliams is poised ditch plans to run its new exhaust blown diffuser at the Turkish Grand Prix because it wants to focus on other updates instead.
The team has a major upgrade planned for the Istanbul race, including a new front and rear wing. With another new diffuser already scheduled to be introduced at the following race in Spain, Williams is likely to stick with the old specification until then.
Although the new exhaust and floor package showed positive signs during free practice, the team is likely to focus on making the rest of the new package work throughout practice in Turkey and wait for the next step of the diffuser development plan to come on line in Barcelona.
A final decision is not expected until at least tomorrow, although Michael admitted that it was likely that it would be dropped.
"We have a new diffuser already planned for Barcelona," Michael told AUTOSPORT. "At the moment we are deciding whether we don't run the China diffuser in Turkey and wait for the new one in Spain.
"We got a lot of data this weekend from Rubens. He went straight into qualifying with a different aero setup and I'm not sure we want to do that again because in Istanbul we will have the new front wing, new rear wing, new brake ducts, diffuser mods. So for Istanbul I think our intention will probably be to leave this exhaust as it was in qualifying today and then make the change again in Barcelona. But we haven't decided yet because we've got a pile of data to look through."
Despite opting not to run it, Michael was upbeat about the results gained from trying the diffuser. These showed that the aerodynamic properties of the design worked as hoped, meaning that the Spain diffuser should deliver a good step forward.
"It showed some very positive signs," said Michael. "But it has got some downsides as well, which is why we reverted back to the standard one for qualifying. We had some problems with burning in P1. We made a good structural fix but we think that all of the metallic work that we had to put on it overnight was detrimental to the aero. That's why we backed out of it.
"Even if you solved that, there were still some areas that are worse than the standard floor, which the wind tunnel predicted.
Barrichello, who qualified 15th for the Chinese Grand Prix after his final Q2 run was interrupted by the Vitaly Petrov-induced red flag and had to try again on option tyres that were past their best, reckoned the diffuser was an improvement. However, he did not want to head into tomorrow's race with the car in a relatively unknown configuration.
"It was just about evaluation," Barrichello said. "We thought it was better, but it's still better to have the gold car. It was a positive evaluation."