The 911 GT3 R proved to be one of the more competitive cars at the beginning of the year, with a 1-2-3-4 result led by Christian Engelhart at Oschersleben prompting rivals to describe the DTM as a ‘Porsche Cup’ series.
However, Porsche’s results took a nosedive at the fifth round of the season earlier this month, with not even a single car from the manufacturer finishing inside the top 10 in the opening race. There was a considerable improvement in the second race with Preining and team-mate Dennis Olsen finishing fourth and fifth respectively, but the next-best Porsche car finished down in 12th, highlighting the marque’s place in the pecking order.
Preining, who saw his 28-point lead in the championship turn into a seven-point deficit, explained that Porsche has been gradually falling behind its rivals, and the pace difference was simply more pronounced at the Lausitzring due to the nature of the track.
"We simply have a disadvantage compared to the competition and that has grown over the course of the season," Preining told Motorsport.com’s sister title Motorsport-Total.com.
"That's the main reason for the lack of lap time and why we can't really overtake in the race. When you start braking, we're so far behind that we can't start any meaningful maneuvers.
"All the competition, no matter which manufacturer, the difference is just very big.
"On this track it comes out especially because you're just accelerating out of the last corner and out of Turn 5 in second gear onto a very long straight.
"That's where it's more noticeable, but we've already had the disadvantage throughout the season, only this time it was glaring."
Porsche started the season with a 39.5mm air restrictor, but its diameter was reduced by 1.5mm from the second round at Zandvoort as part of the Balance of Performance changes.
This meant that while BMW and Ferrari cars were able to reach top speeds in excess of 250km/h, the majority of the Porsche drivers were in the 245km/h range at the bottom of the table.
Manthey EMA founder Olaf Manthey feels Porsche particularly struggled accelerating out of slow corners at the Lausitzring.
"Because we have some corners in there that are more or less stop-and-go, which are practically accelerated out of first or second gear,” he explained.
"They just drive away from us by about 15 meters to the next braking point. You can't brake 20 meters later to be able to attack."
Preining remains pessimistic about an uplift in Porsche’s performance in the final three rounds of the season, but feels qualifying higher up the grid could provide a ray of hope.
"Unless there's a big change, there won't be much change there," said the factory Porsche driver. "Especially at the Red Bull Ring and Hockenheim, the difference will be extreme.
"I hope that we will be better again at the next races. And then there's nothing to stop us from turning the gap into a lead again. But to do that we have to find something from the pace so that we're already further ahead in qualifying."
The decline in Porsche’s fortunes has coincided with Lamborghini becoming the new benchmark in the DTM, with the Italian manufacturer winning three out of the last four races across the Nurburgring and Lausitzring rounds.
Preining conceded that Lamborghini is “winning almost every race” at the moment and Bortolotti is his fiercest rival, but feels the unpredictable nature of the DTM means anything could happen in the final three rounds of the campaign.
"You can see this [Lausitzring] weekend how quickly that can change in the DTM,” he said. “It could be that [Bortolotti] struggles at the Sachsenring and then [Lucas] Auer [of Mercedes] is good.
“Or we have another bad weekend and then we're not even in the conversation. It's different every day."
