The Ford Mustang will race in this weekend’s Townville 500 with a rear downforce boost after a parity inquest found discrepancies in performance with the Chevrolet Camaro.
The Supercars opened an investigation into the parity between the two cars following the near total domination of the Camaro at the Darwin Triple Crown.
No Mustang qualified higher than sixth after Saturday, and the first race on Sunday featured a top-nine General Motors lockout.
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Chevrolet drivers control the top four places in the drivers championship and GM squads occupy the top three spots on the teams leaderboard.
The only Ford victory this season came at the first race of the year in Newcastle after both Triple Eight drivers were disqualified for a technical infringement after a comfortable one-two finish.
The run of results was severe enough to trigger the parity review system per the regulations, and the sport has undertaken further tests in the weeks since Darwin to find the root of the disparity.
In a statement released ahead of the Townsville 500 the Supercars said analysis had identified rear downforce as a key differentiator.
“Data from the Chevrolet Camaro and Ford Mustang was compared using a multi-lap overlay,” the series said in a statement.
“The overlay reflected a minor difference in rear downforce of the Mustang and its performance in the braking zone.
“To address this, Supercars partnered with D2H for computational fluid dynamics (CFD) analysis, which revealed that adjustments needed to be made to increase the rear downforce of the Mustang.
“The recommended changes involve modifying the position, span and angle of the rear wing and [increasing] the size of the boot spoiler on the Ford Mustang.”
The finding tallies with complaints from Ford teams that the Mustang suffers higher rear tyre degradation that the Camaro, which goes some way to explaining why the manufacturer has been relatively more competitive during qualifying than in races.
The discrepancy wasn’t identified during the standard preseason parity process, which is founded on the vehicle control aerodynamic testing process.
VCAT involves a series of back-to-back straight-line tests with both cars, from which the sport can analyse peak aerodynamic load, drag levels, engine performance and a host of other fundamental performance indicators.
The large list of standard and control parts comprising the Gen3 model then fill in the rest of the performance picture.
An additional straight-line test was run on the eve of the first race at the behest of Ford, after which the Camaro was granted a small increase in front downforce to bring the two cars into a similar balance window.
READ MORE: The numbers at the heart of the latest Supercars parity war
Supercars CEO Shane Howard defended the original parity regime conducted ahead of the introduction of the Gen3 rules, saying the renewed testing process of recent weeks confirmed the preseason data despite also revealing new issues.
“The review determined that parity had been established during vehicle control aerodynamic testing (VCAT) based on agreed-upon ride heights and a performance window,” he said.
“However, it was discovered that the actual performance window slightly varied under braking conditions.
“Therefore, the outlined adjustments aim to bring the aerodynamic performance of the two Supercars closer together.”
Howard praised those involved in the work for making conclusions in the limited time frame before this weekend’s Townsville 500.
“We would like to thank the homologation teams and D2H for their extensive work on this review,” he said.
“It required a considerable amount of man hours, expert analysis, and communication to work together to present these adjustments for approval.
“With these changes in place, Supercars is looking forward to racing at this weekend’s NTI Townsville 500.”
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The Supercars statement makes no mention of possible drive train discrepancies, which are the second front in the parity debate.
Ford has lingering concerns about powertrain performance, in particular acceleration characteristics.
Several tweaks to shift-cut timing having been experimented with over the season to date to equalise performance, with the Mustang said to be benefiting from reduced intervals while the Camaro has been racing with longer ones.
It’s unclear whether this will continue to be a problem with the new rear downforce loading.
Ford enjoyed two double-podium finishes at last year’s two-race Townsville 500, with Dick Johnson Racing’s teammates taking turns in second position and Tickford’s Cameron Waters finishing third on both occasions. Shane van Gisbergen swept the weekend’s victories.
Waters secured one pole, with Van Gisbergen claiming the other.
So far this season the Camaro has had an average qualifying margin of 0.342 seconds over the Mustang, a turnaround of 0.491 seconds year on year.
Excluding the first race of the year, Camaro cars have won every event, with the best Ford driver finishing between fourth and fifth on average.
The Mustang has just seven podium finishes for the year compared to the Camaro’s 38. The tally would read 5-40 were it not for the disqualification of both Triple Eight cars from the first race in Newcastle.
