The new part – referred to as a ‘skull cap’ or ‘tortoise shell’ – was installed atop Cam Waters’ engine at the circuit and run for the duration of the weekend.
It followed controversy last month in Darwin, where Supercars handed down a report on the Friday of the event confirming a similar part on the GM engine provides an insulating effect.
Temperature has been a hot topic in the Gen3 engine parity saga this year, as feedback from GM convert Brodie Kostecki triggered a Supercars study into the impact of inlet air temps.
That resulted in adjustments to the Ford ahead of Symmons Plains and Perth, where data on the impact of the GM ‘skull cap’ was gathered.
Tickford produced a makeshift manifold heat shield on the Saturday in Darwin before designing a more efficient, carbon-topped cover that was run on car #6 in Townsville.
“Essentially the aim was to gather as much information as possible across the varying session types,” Ford Performance’s Australian motorsport program manager Brendan McGinniskin told Speedcafe.
“Clearly qualifying has not really been our nemesis, so to see what it would perform like in the races was pretty key, so I’m glad we were allowed to keep running it.
“I get there’s a potential perception that if it does provide a benefit, Cam’s the only one with that benefit, but the race performance wasn’t streets ahead of the rest of the Fords.”
Whether or not the item – which features a thermal blanket sandwiched between a carbon fibre lid and the original manifold cover – provided the desired effect is still under review.
Thermocouples placed above and below the insulator showed a difference as expected, but the real key is what is happening inside the manifold itself.
“We need to do more data review. We’re still going through it to make sure we’re looking at numbers that tell us it’s the right thing to do,” said McGinniskin.
“Then we’ll put out an advisory to DJR and the category to say if we believe it’s of benefit or not. If it is, it’s still probably going to be an optional part for teams to fit.
“It’s clearly an expensive item. I don’t have a final cost on it at the moment, but when Tickford initially quoted for it, it was between one and two thousand dollars, minus the insulation.
“That’s why we were relatively upset about the fact they didn’t just remove it from the GM.”
Supercars argued in Darwin that the ‘skull cap’ is an integral part of the production GM engine and can’t be easily removed.
How much impact a potential manifold temperature difference is having on the claimed performance discrepancy between the GM and the Ford in a straight line is unclear.
McGinniskin says the manifold temperature saga is another example of carefully controlled dyno testing not necessarily replicating real-word conditions.
The double overhead camshaft Ford is a physically bigger engine than the pushrod Chevrolet and, he says, could be suffering without the right manifold insulation.
“You’re typically talking a couple of horsepower per degrees Celsius [on manifold temperature], roughly,” he said.
“It wouldn’t take you much of an offset, if it’s five degrees you’re 10 horsepower out, and we’re talking very small percentages when it comes to the difference we’re seeing on track.
“So, any difference we can mitigate just goes to the point of trying to make these engines perform the same when they are very technically different.
“If for whatever reason one engine is heating that air up more than the other, the engine that is heating that air up more is going to perform worse than the engine that’s not.”
Alongside the air temperature analysis, Ford has pushed for a study into the impact of air pressure on the two engines to be undertaken by Supercars ahead of the Bathurst 1000.
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