6H Shanghai - Post Race GTE Engineering Notebook - How 'Balanced' is the Class?

Just like I did for LMP1 EoT previously, I will also compare how the BoP (Balance of Performance) in GTE Pro has played out for each car over the last three races. How close is the class, and how ‘equal’ is it for each competitor? 

For this comparison, we’ll consider the top 50 lap times of each car for each race – Silverstone, Fuji and Shanghai respectively to show what pace the cars can produce and the consistency at which it can produce that pace. As this is a Pro Class, I have not plotted by driver, the standard is high throughout each driver line-up. 

Silverstone

The BoP process is applied automatically, but then extra tweaks can be made outside of this automated system (once a season). For Silverstone, Aston Martin were given a big boost (turbo pressure, lower weight) after being un-competitive up to that point. They earned pole position but fell away almost instantly. Ferrari got a small power boost also. It should be noted that this race was dry, unlike the two that followed

The fastest car was the Ford GT. Not only could it produce the fastest outright lap, the #67 consistently produced the fastest lap times over this plot – not once did a car dip under their line of results. The #66 sister car had consistency (It had a shallower line on the graph) but just couldn’t match the fastest set of laps. It was closely matched by the #91 Porsche 911 RSR but couldn’t compete with its set of four fastest laps. The fastest Ferrari 488 (#51) and the other Porsche (#92) were well matched. Both Fords and Porsches had similar gaps between each car. The Ferraris however had a significant gap between cars despite similar fastest times.

 

Next up are the Astons, which clearly didn’t make much out of their BoP boost and pole position… They are closely matched which could indicate both driver line-ups are getting the most out of their pair of V8 Vantages. Their fastest laps however were more closely matched to the 40th fastest laps of the Ford GTs… The two BMWs were way off the pace, much in need of a BoP break!

This race gave a clear indication of the pace of each car thanks to the relatively stable conditions. These gaps can then be compared against subsequent races to see how BoP changes affect pace.

Fuji

As expected, Fuji had a much-needed BoP change for the BMWs. Their cars were given 20kg reduction in weight alongside a turbo boost pressure increase. To account for the higher boost, they were given 2 extra litres of fuel capacity.

 

After being the fastest in Silverstone, the Fords were given an 18kg weight increase and less boost. The Porsches also had an increase of 2kg and a 0.3mm smaller air restrictor for the intake of the engine (replicating the power change relative to turbo pressure in this case for a naturally aspirated engine). Both teams had 1 Litre less fuel capacity also.

There were no changes to Aston Martin and Ferrari. This aimed to bring the class together to a central more central performance rather than bringing cars up to the fastest (and thus away from GTE Am)

Ferrari had the best package in Fuji. Both the #71 and #51 had very good consistency and outright fastest laps but failed to get the win. These were critical points dropped as teams must make the most of when they have the best car. Both the Porsches and Fords were translated upwards on the plot thanks to the BoP changes – BoP worked as intended in that case. 

In the mix here however was the #82 BMW benefitting from their BoP change. There was a big gap to the sister car though. Aston Martin fared similarly with a large gap – the #95 ‘Dane Train’ the better of their two entrants. The BMW and Aston could both do with some more BoP to compete at this point in the season.

 

This shows how significant a BoP change can be between races. When the fastest cars are brought back it can compress the field to give a tighter race. This race had ‘better’ BoP when comparing the front to the back of the class – consistently around half a second per lap.

Shanghai

Reacting from Sebring results, there were some BoP changes.  Aston Martin were granted a BoP boost (1kg weight reduction and a bit more turbo boost again). 

Thanks to the BoP Vs Fuji, the Aston Martins overhauled the entire class on pace. The winning car (#95) also finished ahead of the winning LMP2 car! This was due to being able to go longer on fuel under the Safety Car than the prototypes. They could also have more mechanical grip in some cases. There were times where GTEs had to lift off throttle mid corner to avoid contact with LMP1s who couldn’t get up to speed to get the aero working.

The next best chassis taking the fight to the Astons were the Porsches, enjoying the conditions – 911s traditionally fare well in damp conditions even though this one has different engine placement to the norm.

 

The #71 Ferrari performed well here, and much better than the sister #51 car. With the platform working so well for the #71, maybe they should have got more out of this race. 

After a small gap, the Fords were the best of the rest, followed by the #51, the BMW pair and the Corvette bringing up the rear in its only WEC race (apart from Le Mans). This shows how a car can go from the fastest to the midfield in the span of two races.

 

The conditions here promoted the larger difference in pace. Hopefully some dry racing in future will give us a more representative set of results.

Looking Forward to Sebring

With the BoP expected to be the same for Sebring, I’d expect the Porsches to do well thanks to the similar package in IMSA. I’d also expect the Aston Martins to do well thanks to their BoP level.

 

If both Ferraris perform as well as the #71 did in China they could be a dark horse; they have historically good downforce with this car, and should do well on the higher speed corners – especially in qualifying. Ford haven’t got as good a BoP as the first half of the season, but have experience of Sebring. Only time will tell for how well the teams react to the bumpy surface!

 

Using this data for Fantasy picks, if the Aston Martins are cheap (as they have been in the past) then they are a valuable choice. If BoP changes however, expect the BMW to do well as they already have superior power looking back to  Shanghai and may get less weight.