McLaren expected to race new diffuser in Germany

Martin Whitmarsh said he expects McLaren to race their exhaust-blown diffusers in Germany this weekend. It brought to the British Grand Prix but removed them after Friday practice.

Speaking during the Vodafone McLaren Mercedes phone-in Whitmarsh said:

We’re working on the premise that we’ll have blown diffusers on both cars to start with. In Silverstone Lewis wanted to keep the blown diffuser on on Friday night. But we made the decision there to switch them both back to the old diffuser.

We could end up dividing the drivers if there was a preference from one side of the garage to the other. If I can I will avoid that but we’ll do it if we think it’s the right way to perform.

There are advantages to running one car in one configuration and one in the other. But provided that in so doing you don’t end up rightly or wrongly accused of treating the two drivers differently.

Martin Whitmarsh

He pointed out that it was difficult to conduct side-by-side tests of the cars in different configurations because of the time it takes to change the floors:
 

One of the challenges is that whereas flaps, wings and various aerodynamic appendages are fairly quickly changed on a car, and you can do a back-to-back during a session, the blown diffuser is completely different floor, different heat management components and of course a different exhaust. Therefore it’s not possible to perform an in-session back-to-back. It’s quite difficult to do it even between sessions.


So we will have to rely on the data we previously collected. There will be modifications to the blown diffuser which will probably change between the cars or from one car to another. There is a compromise – in the old days we’d go testing and have two cars run alongside each other. We can’t do that, so we’re torn between the priorities of develop the car for long term improvement versus using the very limited track time the drivers get to understand that particular event, that race circuit and prepare for Saturday qualifying.

So it’s not easy, but it’s the same challenge for everyone.

Martin Whitmarsh

He explained that part of the decision not to run the new part at Silverstone was because of other challenges presented by the circuit:
 

Our priority was get as much data as possible and make sure we were treating the drivers as equally as we could. I don’t regret taking it and I don’t regret running it on the Friday.


I think at the time there were a number of things happening at the circuit. The new track had some entertaining bumps in the new section and on the old sections of the circuit, presumably from construction traffic – not a feature that you normally have to deal with at Silverstone.

It was also gusty. And clearly we can’t test before races so I think we got some good information.

There were some views within team by Sunday that we could have left it on the cars but we were conscious of the need to score as many points as possible in the British Grand Prix.

So a decision was taken on Friday to eliminate some of the variables. We couldn’t eliminate the gusts or the bumps but we could eliminate [the new package].

I think it was the right decision. We then had a back-to-back in a sense – on Saturday we ran without the blown diffuser and that was useful to compare with the data we generated from the day before.

I think we did the right thing and I’m comfortable with it.

 
Martin Whitmarsh