`We have hit our performance targets`
Léon Taillieu talks of the development and progress of the new 2.4 litre B8 RS26.

When did the V8 programme begin?
"We started the initial designs for the RS26 in September 2004."

What will the differences be in how the V8 engine is used on the track?
"Firstly, we need to note that Renault is the only team to change from a 72° v-angle to 90°, as dictated by the regulations. They also prevent us from using variable inlet trumpets, which previously allowed us to adjust the engine acoustics at different revs, and improve the torque curve. As a result, the drivers will have the impression that the V8 lacks torque, particularly at mid-range revs."

So will the engine be used higher in the rev range?
"That’s exactly right. We will be using a 7 speed gearbox to optimise how we use the V8. The average engine speed, over a lap, will be between 400 and 500 rpm higher than with the V10. That is quite a significant difference."

Will there be other changes for the drivers?
"The power levels will be lower than in 2005, meaning the drivers will spend a higher percentage of the lap at full throttle. We will have to take this into account when planning how we use the engine over the race weekend."

More time spent at full throttle, and higher average revs… does that have an impact on reliability?
"It could do, but we implemented all the necessary processes to achieve our objectives in this area. We are not worried on this point. Reliability was one of our strengths in 2005, and we will work in the same way this year."

Fuel consumption will almost certainly be lower. Will that have an impact on strategy?
"In principle, a 2.4l V8 will consume roughly 20% less than a 3.0l V10. However, the two engines will be used in a completely different way."

Is the power loss relative to 2005 of the order of 20%, as initially expected?
"We cannot be too specific, but that is a good approximation. The important thing is that we have hit our performance targets."

We have heard a lot about vibration issues with the V8. Can you explain why?
"With every engine, you must draw the distinction between internal and external vibrations. The first group are primarily torsional vibrations of the engine’s moving parts. They are central to the engine’s reliability development, and their level depends on factors such as the firing order, which itself has an impact on engine performance. From this point of view, it is important to select the firing order which gives the best compromise between reliability and performance. The second order of vibrations are external, and a partly a function of these choices. They can be minimised by how the crankshaft is balanced. In the car, it is the external vibrations that are felt by the driver and the chassis accessories."

How does this apply to the RS26?
"The compromise we have chosen with our V8 does not bring a higher level of vibration than that we encountered with the V10. They act in a different direction, but the efforts involved are comparable. Of course, this means we must redesign certain components as a result. But the poor reputation of the V8 in terms of vibrations, comes from the fact that in the 1980s and 1990s, they were being compared to V12 and V10 engines of the same capacity. This meant that the reciprocating masses in the V8 were higher than in the other architectures, and therefore harder to control. Now, we are comparing a 2.4l V8 with a 3l V10, which means the reciprocating masses are identical."

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