Engine test centres on gravity

V8 Supercars has measured each of the engines used in the category to find its centre of gravity and would like any changes that flow from that process to be in-place as soon as the April 24-27 ITM 500 Auckland.

However, it is playing down any expectation that changes – which will be more substantial for AMG, Nissan and Volvo – will trigger any significant performance issues.

“When we change it you probably won’t see any changing of the guard,” predicted V8 Supercars Category Technical Manager Frank Adamson.

The process, conducted over the course of last weekend’s Winton 400, is part of the ongoing objective of establishing and maintaining technical parity in the category.

The need to conduct the testing had become apparent because lighter aluminium quad cam engines have arrived in the V8 Supercars along with the new manufacturers Erebus, Nissan and Volvo.

They are around 30kg lighter than the cast-iron block push-rod V8s used traditionally by Holden and Ford. That means they can add ballast low down, which aids handling.

A preliminary move to address this issue was made at the Tyrepower Tasmania 400 when the Volvo Polestar Racing S60s had to move 20kg of ballast from low on the engine to higher in the engine bay.

At Winton, an example of each engine from all eight suppliers to teams in the Championship was tested, including three Holden, two Ford and the three newcomers.

“There were two incumbent engines, which were a Ford and Holden engine that were basically the same configuration of engine – iron block, aluminium head, pushrod engine,” Adamson told v8supercars.com.au. “The centre of gravity of both those engines is – give or take – the same.

“But the new engines are a different architecture with an aluminium block and aluminium heads – fundamentally a much lighter engine.

“With the arrival of these engines with Car of the Future a minimum total engine weight of 200kg was established, which is around where the Holden and Ford are.”

The new engines weigh in around 170kg, which means they have to be ballasted to provide technical parity for the five cars. But the placement of that ballast has not been regulated until now.

“There was always an intention to put a centre of gravity height in as well,” explained Adamson. “But we couldn’t really do that until all five engines came along. So over the last year we have allowed them to run as they were.

“To ballast up to the weight they could put the ballast on the engine, so they could build a heavy sump for instance and so have the opportunity to get the weight a bit lower than the Holden and Ford.

“We are not sure how much advantage that delivered; we are talking about a 200kg mass fixed within a 1500kg mass. Pure physics law would dictate the lower of centre the better, but out there on the track going over bumps, braking and shifting mass, who knows how big an advantage it is.”

The testing process involves fixing the engine into a rig and then being weighed on scales to calculate the centre of gravity.

Once the results are known each engine builder will be advised where the centre of gravity is required to be. The quad cam engines will require more work to hit this specification than the Holden and Ford engines.

Because all engines sit in the same location in the New Generation chassis, that should neutralise engine centre of gravity as an issue.

“We’d like to see the changes made for New Zealand,” Adamson said. “But practicality will dictate. The sooner the better essentially.”

The move to address centre of gravity equivalence follows on from V8 Supercars establishing a peak power figure for engines, rather than trying to map out a control power curve as had been originally planned. V8 Supercars Commission Chairman Steve Horne addressed that issue in this recent Q&A interview.