Porsche DTM team finds possible cause behind dismal start to 2024 season

The squad had already played down expectations heading into its sophomore season in the DTM, claiming that the organisers ‘won’t allow’ Porsche to win back-to-back titles in the series after its 2023 success.

But so uncompetitive were the two 911 GT3 Rs at Motorsport Arena Oschersleben that Manthey EMA drivers Thomas Preining and Ayhancan Guven could muster only one top 10 finish between them in the two races - and that too after BMW driver Marco Wittmann retired with just three laps to go while leading Saturday’s opener.

After careful evaluation, the squad has one answer as to why the Porsche lacked the pace to mix with the top cars in round one of eight: the ride height stipulated under Balance of Performance.

For the first time in the DTM, the Porsche 911 GT3 R had to run a minimum ground clearance of 101mm on the front axle, as per the BoP formulated by SRO.

"The fact is that there was a major change before the race weekend compared to the test, namely the front ride height, which changed by five millimetres," explained Technical Director Patrick Arkenau in an interview with Autosport sister title Motorsport-Total.com.

"This was the first time that there had been such a significant parameter change in the BoP. Due to the known test ban, we were unable to test this and did not know the effect. And we still can't clearly quantify it today.

"This has an effect on the entire vehicle."

Each driver is limited to just five test days until the season finale in Hockenheim this year, according to the new testing restrictions introduced by the ADAC to rein in costs.

Manthey EMA did conduct a test at Oschersleben on 16 April with race drivers Preining and Guven, but that was three days before the BoP for the season opener was revealed.

Hence, all running took place with the usual ride height of 96mm on the front axle, which meant it had no data about how the car would behave with the increase in ground clearance.

While a change of 5mm may sound little, it could have a big impact on the dynamics of the car.

"It has an effect on the entire vehicle," emphasised Arkenau.

"You have to compensate for that and also go two millimetres higher at the rear.

"This means that the ride height effect is doubled at the rear axle. This also doubles the kinematic effect."

In addition to higher drag and reduced braking performance, the car also has a higher centre of gravity, which negatively impacts cornering.

Preining slower in qualifying than in testing

It was interesting to note that Preining’s best time with the familiar ride height was a 1m22.247s, which was enough to place him fourth in the classification in testing.

But in the two qualifying sessions over the race weekend, after the ride height had to be adjusted under BoP, the fastest Porsche lap was fractionally slower at 1m22.291, which put Preining 16th on the grid on Saturday - out of 20 cars. 

The drop in pace is even more striking considering the pole time was almost seven tenths quicker than what anyone had managed during the pre-season test.

"Tommy was very surprised when he was told where he would start after qualifying," said Arkenau. "That was a very clear top five position for him. It certainly wouldn't have been enough for pole, and he was aware of that. But there was no mistake that cost him a lot of time.”

Intriguingly, two separate weight reductions for Porsche between Saturday and Sunday races, totalling 25kg, had no significant effect on the performance of the car.

"The picture didn't turn properly, the step wasn't there," admitted Arkenau. "That means there's something in there somewhere that's massively distorting the picture. An effect that none of us understood. For us, the only indication we currently have is the front ride height."

The team can’t say for certain that this was the root cause of its troubles, with the problem also difficult to reproduce using simulation tools. 

"We have started to analyse the whole thing and are still in the process of doing so," he said. "We are also not ruling out the possibility that there is a fault on our side. However, we currently have no indications of this.”

Arkenau explained that a comparative test would have to be carried out so the team is sure of the real impact of the change in ride height. However, this would mean sacrificing valuable test time as part of the test restrictions. 

"If I lose half a day of testing as a result, then I'll be at a disadvantage against the others in the next race," he said.