Chester confirms Lotus' brake-by-wire struggles
Lotus technical director Nick Chester pinpoints the brake-by-wire system as the major culprit for performance but confirms the car's improved reliability now allows the team to start looking for speed improvements.
What did the team learn in Sepang? "We’ve learnt more about our mapping and we’ve made some improvements with the braking of the car, but there is still a lot more to come. We have more work to do at Enstone including improving the set-up and operation of our brake-by-wire system, which is one of the areas where the drivers have the biggest complaints. It’s spoiling their entry into the corner and costing them quite a lot of time."
How does brake by wire work and why is it causing issues? The system looks at what the driver is requesting from the brake pedal and then the demand is split between a braking force generated by the power unit and a normal hydraulic braking force from the callipers. The difficult part is fine tuning those two different types of braking demands so that they work together in a natural, predictable way for the driver. It’s very important to have a brake-by-wire system that responds the way you want and to get the mapping correct so that you have the right braking behaviour to make it easier for the driver to control wheel locking. When you initially apply the brakes you want to get the pressures up high as quickly as you can, for good retardation. But for corner entry, how you come off the brakes is really important. Being able to carry good speed into the corner apex makes a massive difference to the lap time."
If we add up all of the laps done with the E22 so far this year, it’s probably the same as the first three days of testing last year… "That’s right. We are at a very early stage in terms of understanding of the car so there is a lot of latent potential to be unearthed. We are still exposing reliability weaknesses, but we’re working through these well. The unfortunate aspect is that this has occurred at the races, where we want to be scoring points and building a championship campaign. At the races we’re still doing some work that you would normally do in winter testing. Some of that is obviously due to an enormous regulation change - everybody is still learning - but due to our lack of running we are on a much steeper learning gradient. There is a positive that there are much bigger steps that we can make. An example of that is the improvement in wet qualifying performance this weekend relative to Melbourne. How frustrating is it to lose track time due to different reliability issues? It is frustrating. Particularly in Malaysia because the build of the cars was very good, but then a software issue let us down and prevented us running in FP1."
Both drivers have been vocal in praising the long hours done by the team at the racetrack. How much longer do the cars take to work on now? "The cars are much more complicated this year. There is a lot more involved in the build of the car. Obviously it’s only the second race and things will get easier. We will re-design things to make them easier to fit, the procedures will improve and the mechanics will get more familiar with the components. But even by mid-season, I would say it will still be a harder car to work on than last year. I’m sure that’s the same for all teams."
How happy are you with the upgrades brought to Malaysia? "It’s a tricky one to tell because we lost a lot of Friday running, so we didn’t get all the comparisons done that we normally do. We’ll have to do a further comparison in Bahrain to get a proper feeling for how they perform."
What are the main challenges for Bahrain? We go there without a lot of mileage in winter testing so we have more set-up work to do on the track. Obviously temperatures can be quite high, so that is one thing we will have to watch out for. Then it’s about getting more of our development parts on the car and doing more work with the power unit."
