Alan Permane, Race Engineer, Car No. 6
Sepang is a circuit that includes a little bit of everything: there are high-speed corners, with high speed changes of direction (Turns 5 and 6 for example) as well as low speed hairpins with major traction events on the exit. Consequently, the car must be well balanced and stable, both under heavy braking and in the slower corners. Like in Melbourne, we spring the car stiffly for this circuit, although unlike the last race, the track is neither bumpy nor are the kerbs particularly high: this means we have to compromise less in terms of the car’s overall stiffness.
Downforce levels are also similar to those seen in Australia – medium to high, in order to optimise performance through the long, quick corners and under braking. However, the ideal set-up and a suitable set-up for the race can sometimes be quite different, and we may have to reduce downforce levels for qualifying, and therefore the race, to protect against being overtaken. However, the top speeds of the R25 were extremely competitive in Melbourne, which should minimise the need for any compromise.
Tyre performance will be critical in Malaysia, and is one of the primary unknown factors we face during the race weekend. The fast corners, combined with high track temperatures, put more energy through the tyres than at Melbourne, and this in turn means tyre wear is higher. So far, the R25 seems to look after its tyres well, and wear rates are even with Giancarlo’s smooth driving style. However, it is still early days, and we have not yet run the long-distance tyres with significant track temperatures.
In terms of set-up, we will concentrate on minimising levels of tyre wear, and I am sure we will make adjustments relative to 2004 in order to specifically control this. One thing that emerged in the race in Australia was that if we have to compromise on balance in the race, we prefer to run the car with slight understeer rather than increasing the levels of front wing and risking an oversteering car later in the race. Throughout race conditions, we try to protect the heavily worked rear tyres as much as possible, and the lap-time penalty for any unpredictable oversteer in Sepang will be higher than it was in Melbourne.
Finally, we will have to adjust the cooling levels to suit the ambient temperatures. Our simulations provide us with accurate data for making the necessary adjustments to the car, and as is normal, the cooling efficiency of the R25 has improved relative to its predecessor.
Fabrice Lom, Engine Engineer, Car No. 6
The demands placed on the engine by the circuit configuration at Sepang are not particularly severe: with only 57% of the lap spent at full throttle, the circuit is situated in the bottom half of the season in terms of its severity. Equally, there are no very slow corners which see the engine operating at very low revs, meaning the rev range required is also within our normal limits.
The primary danger for the engine is that it has to run at partial throttle openings at very high revs, particularly through turns 5 and 6. If not properly managed, this can endanger pistons and piston rings through the phenomenon of blow by.
The most abnormal characteristics of Sepang for the engine are the temperature and humidity. The high temperatures and humidity decrease the available engine power and alter the air intake acoustics such that this peak power is produced at higher revs. The engineers must therefore cope with the contradictory demands of excellent cooling in the high temperatures, and running higher engine speeds in order to maximise output, which in turns increases the engine’s heat rejection. As a result, compromise is always the name of the game at Sepang when it comes to optimising the performance of the V10.
