MOTORSPORT: Holden Commodore turbo V6 axed

V8 engines will continue to rule Supercars racing following GM's decision to suspend development of its twin-turbo V6 for the new Holden ZB Commodore racer.

Originally intended to debut at the start of 2018 and then pushed back to 2019 when issues arose, the project now appears to be effectively dead.

The decision was announced via a Holden press release that had an extremely narrow distribution list – as bad news often has – and broke this morning just hours before the Supercars hit the track at Symmons Plains in Tasmania for the third championship event of the season.

Different sources contacted by motoring.com.au indicate different reasons for the decision. Cost of the program’s continued development to Holden when the new ZB Commodore is already dominating racing with the existing Chevrolet V8 seems a key one.

Another is that some Holden Supercars teams also wanted to stick with the V8 and not swap to the V6, which was to be leased out to them from a central source, rather than available for purchase and their own development.

But there is no sense in the Supercars paddock that this is the start of a Holden pull-out from Australia’s premier motorsport category.

The V6 engine had been under development since 2016 and was based on the LF4.R unit used by GM Racing in North America for a now-defunct Cadillac ATS-V GT3 program.

The decision to swap the Supercar to a V6 had originally been made by Holden Motorsport to support the similar change for the imported ZB Commodore production car, which would no longer offer a V8 option. Supercars created the Gen2 technical rules to allow the change to happen.

The racing engine had been under development locally by Holden’s factory Supercars partner Triple Eight Race Engineering – which also developed the new ZB Commodore and runs the Red Bull Holden Racing Team – and T8’s engine partner KRE.

“After working closely with all Holden teams we have decided to put a hold on the development of the V6 Supercars engine,” said Mark Harland, Executive Director -- Holden Marketing, in the statement

“We are 100 per cent committed to motorsport and our sponsorship of the Red Bull Holden Racing Team and supporting all Holden teams in both the Supercars and SuperUte paddock.

“This is thanks to the monumental effort Holden and Triple Eight have put into engineering and developing the Holden Supercar and we remain committed to that advancement of motorsport engineering in what is one of the most technically advanced motorsport categories in the world.”

The primary issue with the LF4.R was its built-in exhaust port, which has been replaced by a conventional three-port exhaust manifold here and therefore required an all-new cylinder-head.

This had only recently been completed and has now been tested on the dyno but not the track. The engine was due to make some ‘wildcard’ race entries later this year but, obviously, they now won’t happen.

While Holden has pulled the pin on its new engine, Supercars itself has been testing and developing its own twin-turbo V6 as part of a knowledge-gathering exercise for Gen2. That program continues.

“Our current rules allow manufacturers and teams to implement various configurations of power plants. So, while the ZB won’t have a turbo engine configuration at the moment, it’s important that we, as a category, continue to build our learnings and expertise on forced induction,” said Supercars CEO, Sean Seamer.

GM’s former official Supercars race team, Holden Walkinshaw Andretti United, today endorsed the decision by Holden Motorsport to axe the V6 program.

“The V8 engine is synonymous with this category, there is so much history and passion surrounding it, so it’s fantastic to see Holden and the sport listening to the fans,” said AUD director Ryan Walkinshaw.

“With a strong engine program, it’s great to be able to remove the uncertainty surrounding the future of the V8, now being able to continue to focus on the revival of our team, as Walkinshaw Andretti United.”

This morning's news comes a day after the release of official VFACTS figures that confirm Holden slipped to 10th overall on the new-vehicle sales chart for the first time in 70 years in March -- the first full month of sales for the new ZB Commodore range, the volume-selling engines in which are four-cylinders.