McLaren has overcome Renault packaging headaches

After three years of disappointment with Honda, McLaren elected to end its deal with the Japanese manufacturer at the end of 2017 and sign a customer partnership with Renault for this year.

Although the move is set to deliver a much-needed power boost, Goss has revealed that the switch did require some major work at the back of the car due to way that Renault packages its turbo and energy recovery systems in a different way to Honda.

"The Renault architecture is very different," Goss told Motorsport.com. "You have two fundamental engine architectures out there.

"You have the Mercedes/Honda approach, and you have got the Ferrari/Renault approach. Essentially the difference comes down to where the turbocharger sits.

"The Mercedes/Honda approach is you have the compressor on the front of the engine, the turbine on the back of the engine and the MGU-H sat in the middle of the V.

"The Ferrari/Renault approach is that you have got the compressor sat at the back of the engine, the MGU-H behind it and the turbine behind that.

"They require a very different approach to your chassis and your gearbox, and now we have had recent experience of both we can see there are pros and cons of both.

"There are things I love about the Renault approach and there are things that frustrate me a little bit, but in the end we were fortunate that the decision to move from one engine to another was made just in time. It couldn't have been made any later."

Goss has explained that the differing requirements of the Renault packaging had an impact on several areas of the car - including the fuel tank, gearbox and rear suspension.

"We had to reconfigure the chassis, change the cooling system and reconfigure the gearbox to make it fit," he said.

"But we've managed that in time without any significant compromise to the chassis. It was quite a big change.

"The Renault engine will sit further forward in the chassis. With the Honda you had the air intake that had to come down into the front of the engine, and that volume came out of your fuel cell. So as a result, the chassis was longer.

"But then what you hadn't got was a turbocharger sat off the back of the engine, which then gets in the way of your inboard suspension.. So you ended up with a much easier task at the back of the engine.

"When you move to a Renault, suddenly the front of the engine becomes a lot simpler and as the result we win back a substantial amount of fuel volume.

"You can push the engine forwards and the aerodynamic blockage of the engine and exhaust is considerably better, because that has moved forwards behind the chassis.

"But then you have a turbocharger that is sat in the bell housing and, as a result, to accommodate that you have to redesign your rear suspension internals and lengthen the gearbox.

"But we've done a fantastic job. A really fantastic job. It was very, very intense. We had pretty much two weeks of very intense effort to get it sorted, but we knew pretty much what we needed to do."

Performance step

McLaren's chassis was regarded as one of the best in the field last year, although a lack of power made it difficult to judge exactly where it compared to Mercedes, Ferrari and Red Bull.

But although the team is upbeat about carrying forward its promise in to 2018, Goss is well aware of the opportunities all teams will have to revamp their designs and make a big jump forward.

"Obviously you choose the architecture of the car at the beginning of the season, and there are some things that are built in that you cannot really change during the season," he said.

"So when you redesign the car, that is your opportunity to make those changes. I think people will, through looking around at other cars, be able to make those changes.

"You would expect there to be a step and, given the cars are relatively immature, you would expect it to be a bigger step than in previous seasons."