The Porsche 963

If anyone can build a good endurance race car, that is Porsche. With 19 victories at the 24 Hours of Le Mans, no one should doubt their potential. So why has, five races into the 2023 season, their latest top-class offering – the 963 – yet to participate in any battle for victory in the World Endurance Championship (WEC). The car is operated by privateers but Penske, Jota and Proton Racing are vastly experienced teams who certainly know how to be competitive in the WEC. We use the data from the elapsed so far 2023 season to see how close the 963 is to challenging Toyota and Ferrari for victory at any of the upcoming WEC events.

It is worth pointing out right from the beginning that Hypercars are frozen after their homologation and any evolution in performance can only come from improved management of the car and/or the helping hand of “Balance of Performance” (BoP).

DESIGN

The 963 is a hybrid car entered in the WEC under the LMDh regulations. The chassis is build by Multimatic in Canada. The engine, build by Porsche, is a 4.6 litre, twin-turbo V8 capable if producing 500 kW (680 PS) at 10.000 rpm. The electric part of the hybrid system is the same for all LMDh cars- a 50 kW motor-generator unit supplied by Bosch, batteries from Williams Advanced Engineering and a 7-speed gearbox supplied by Xtrac. The car’s weight is close to the minimum allowed of 1030 kg. As per the regulations the maximum power propelling it forward is set by BoP and is send to the rear wheels.

RACING HISTORY

Before delving into the data we should mention that alongside its participation in the 2023 WEC, at the time of writing of this article, the Porsche 963 has also participated in 6 races in the 2023 IMSA SportsCar Championship in the GTP class. In all of those races with two cars ran by team Penske, and in the last three races with one more car run by JDC-Miller MotorSports. Its most notable results are a first place for Team Penske at the 6hrs of the Glen, and a 1,2 finish at Laguna Seca. The latter being a somewhat shorter race of 2 hours and 40 minutes. This article is based on the results from the WEC, for which we have data made available by Al Kamel Systems SL.

In the WEC the 963 has entered into 5 races, by the time of writing. The first two races featured 2 cars run by Team Penske. Starting from the 6 Hours of Spa-Frankorchamps there is one additional entry from Hertz Team Jota. The 24 Hours of Le Mans saw a one-off appearance of a third entry by Team Penske alongside all the previously mentioned ones. The 6 Hours of Monza saw a fourth Porsche 963- #99- operated by Proton Competition.

The most notable result achieved by any Porsche 963 in WEC so far was a third place for the #6 team Penske car at the 6 Hours of Portimao.

It is worth mentioning that the #99 car was seen for the first time by the team just two days before its first running at the Friday practice at Monza. While it failed to finish the race, the #99 ran at very similar pace to the rest of the 963 fleet, no doubt courtesy of the solid pre-delivery program by Porsche.

Figure 1 show the fastest lap that a 963 has shown to be capable of at all separate events so far in 2023. This lap is a sum of the fastest sectors that every car has done. This is expressed as a percentage of similarly calculated fastest lap from any car at the given event. The individual symbols show all the 963 cars that have taken place. The black line shows the average of their performance. After the initial drop from Sebring to Portimao, there is a very nice and consistent upwards trend which could indicate one of two things: either the teams operating the 963 are improving their understanding of the car and are getting closer to extracting the maximum from it or that the BoP is doing what it is meant to do- bring the field together. We try to distinguish between those options in the following sections. For now we should mention that if this upward trend continues, at Bahrain we can expect a 963 to be one of the fastest cars over a single lap.

A caveat associated with the results shown on Figure 1 is that it includes laps that were otherwise deleted for track limits infringement. Sadly this information is not provided in the public data set and at this point there is little we can do about it. The end effect of this is hard to quantify but is generally not large. It will sometimes make the fastest overall lap appear faster than it officially is, and sometimes it will make the individual laps that are compared to it appear faster than they were. In other words it will move the points on Figure 1 randomly up and down by a small amount. This caveat cannot be the reason for the observed upward trend in 963’s ultimate pace.

Figure 2 shows the lap time maintained by the Porsche 963 cars at every event. This is done by taking the median lap time, after removing the laps affected by yellow flags or rain. This is again expressed as a percentage of the median lap time of the winning car at the given event. The median is the middle of the distribution of lap times, i.e. half of the laps are slower than it and half are faster.

Here again, as with the ultimate pace, the 963s tend to get closer to the performance of the winning car over the course of the season. From being consistently around 1.2% slower than the winner in the beginning of the season, to around 0.5% slower during the last two races. This trend is consistent with the one shown on Figure 1 and again can express both adjustment in BoP and improvement in the car management. In the only event it participated in (Monza) car #99 seems to follow the same trend within the scatter shown by the rest of the cars. This would indicate that the trend is due to BoP. On the other hand #99 is lower than the Penske and Jota entries, so some improvement in the management of the car cannot be ruled out.

The drop in sustained pace at Monza is interesting and worthy of further discussion. The race was won by the #7 Toyota so we need to compare with it. BoP was adjusted after Le Mans exactly to the effect of slowing down the 963s with respect to the GR10 Toyotas. While the minimum permitted mass of both cars remained almost the same (the Porsche was 1kg heavier at Monza than at Le Mans), both had their power decreased but by a larger amount for the Porsche- 10 kW versus 5 kW for the Toyota. Monza is power sensitive circuit and this could probably explain the drop in performance. However, if that were the case then this drop would also show on Figure 1, where one lap pace was discussed, and it does not. In other words there is something that Porsche 963 can do over a single lap that it cannot sustain over a race distance. One possible reason is tire wear. It is possible that the Porsche did not cope with the high ambient and track temperatures at Monza as well as the Toyota did. Sadly the publicly released data set does not contain any information relating to tires, so we cannot test this.

Figure 3 shows the top speed that the 963 fleet has achieved during all race weekends in 2023 so far as a percentage of the highest top speed achieved by anybody during that event. This is shown by the red dotted curve and is the average of the entire 963 fleet. The blue dashed line shows the top speed of the winning car expressed in the same way. As the actual top speed values we always take the third fastest because this is more robust against outliers. We take this approach because we have no information which laps were deleted due to track limits infringement nor on which laps the car we analyse has picked up a tow from another car.

The first most notable feature of this plot is that the car with the highest top speed is never the winner and that is more true at Monza than anywhere else (blue dashed curve). Odd, isn’t it. The subject of this article – the Porsche 963 (red dotted line)- while never the fastest is closer to the winning car than it is in terms of lap time and sustained lap time, with the difference never more than 1%.

The top speed of a car is limited by the available power, and in WEC the power of all cars is defined by BoP. We plot, with the thick solid lines, the allowed power output of the winning car (blue), the Porsche 963 (red), and the fastest car (green) again expressed as a percentage of the highest power in the field, which is always 520 kW. Looking at the curve for the winning car first- it is never the car with the highest power. The usual winner this season, Toyota, won at Monza despite taking additional drop in power. Monza was the only track on which the car with the highest power output achieved the highest top speed. Despite its higher power output for most of the season, the Prosche 963 never won nor achieved the highest top speed.

One would expect that the power curve and the top speed curve should have some commonality. The exact values do not need to match but the shape of the curves of the same color should be similar. This is however not the case for the Porsche and the fastest car. The top speed curve of the winning car does resemble their power curve only as a general trend of ever decreasing percentage of the maximum. We did test this with the power/weight curves and they are even more discrepant from the corresponding top speed curves. Perhaps this can be taken as an indication that the teams operating Porsche 963 do change their approach and any evolution seen in the previous sections is not only due to adjustments in BoP.

CONCLUSIONS

The Porsche 963 is getting closer to its competitors and it might be fighting for victory in the last race(s) of the season. This evolution is likely determined by both the balance of performance and improved understanding of the car by the teams that operate it.

Interestingly the BoP for the remaining races will raise the weight of the Porsche further, while also increasing their power. This could result in even higher tire wear and could prevent them from fighting for victories if the temperatures at Fuji and Bahrain are high.

more from kineticum.com

Previous comments