While absent from the race track at Silverstone last weekend, progress continues to be made with Nissan’s new LMP1 challenger, with the focus of the GT-R LM NISMO’s development set to shift into endurance testing this week.

The radical front-engined, front-wheel drive car will miss the first two rounds of the FIA World Endurance Championship after multiple issues, including initially failing the crash test and continued struggles with its hybrid system, according to LMP1 team principal Ben Bowlby.

“In order to do the best possible job, we will do better by finishing up our testing and development work rather than racing, which we’re not ready for,” Bowlby told reporters via videoconference during last weekend’s FIA WEC event.

“We’ve had to regretfully cancel the first two races to get better prepared. These cars are super challenging, that’s to be said.”

The initial reason for the delayed start was due to the failed crash test, which Bowlby said happened twice, but once on its own, prior to passing on its third attempt late last month.

He said upgrades had to be made to the bulkhead in the front roll-hoop area, as well as the bonding of some elements of the chassis. It ultimately required the construction of two new monocoques.

The other area of focus has been on the car’s hybrid system, where Bowlby admits has been a challenge.

“The hybrid system has been a massive headache,” he said. “We have potentially a massively powerful system but with great power comes with great responsibility. We are struggling quite a bit.”

While initially having planned to go with a high-capacity system to run in the 8 MJ hybrid subclass, it’s believed the GT-R LM NISMO will opt for a 2 MJ system instead, the lowest category permitted for factory LMP1 cars.

Bowlby, however, said the hybrid subclass is still being debated, with this week’s testing likely to determine its 2015 configuration.

“The amount of testing we’ve done dedicated to the hybrid has far outweighed just getting on with the normal car,” he said.

“We designed the whole car around the hybrid system, which is basically what you need to do if you want to get to the 8 MJ class.

“In the future we hope to get the full performance out of it. But as you have to homologate for the whole year, it’s a tough one. We think we’ll be a lot better in 2016.”

Compromises have already been made as a result, including a move from 16 to 18-inch wheels to accommodate larger brakes, due to decreased energy recuperation from a smaller hybrid system.

“It’s a huge knock-on effect when you change elements of the design,” Bowlby said. Having said that, if you switch off the hybrid system, it still works and goes very fast.”

Bowlby has praised the 3.0-liter V6 gasoline engine, calling it a “beast” and remains bullish about their chances at Le Mans, a track that should particularly suit the car’s design.

Testing continues this week at NCM Motorsports Park in Bowling Green, Ky., a newly built circuit that’s modeled after a number of corners at Le Mans, which has been hugely beneficial to its development.

Having racked up more than 2,300 miles in testing so far, Bowlby remains humble about their overall prospects in year one, as Nissan is set to take on the likes of Audi, Porsche and Toyota for the first time.

“We have a tremendous challenge,” he said. “I think the level of the championship runs at now is the highest it’s been at in the history of premier sports car racing.

“To do well today is a huge achievement. We’ve come at a tough time as a new manufacturer.

“But we’ve got a very committed team, we’ve got fantastic support throughout NISMO and Nissan to make this whole project viable.

“Our objective is to come to Le Mans to do the best possible job we can. If we do our best, it’s a long race and it might be a surprising outcome.”