What is side drafting? How air was the winner for Waters

Broc Feeney didn't really say it, but he knows what lost him one of the greatest Supercars races of all time.

It wasn’t the lap 49 collision with Cam Waters, pit stops, race pace or a the multiple redress attempts.

It was air.

It was how the air surrounding Feeney's #88 Red Bull Ampol Chevrolet reacted when it was side-by-side with Waters' #6 Monster Energy Ford coming to the finish line.

Side drafting, as it known, serves two purposes — speeding you up, or slowing someone else down.

Side drafting is wholly a game of momentum, yet Feeney and Waters, with Feeney's teammate Will Brown behind, were set to engage in a proper drag race.

While Waters got a tap at the final corner, which was looked at by officials after a Triple Eight request, he was still behind heading down the straight.

So, how did Waters come from behind in the final metres to win by just 0.03s?

A draft occurs when there is less air on one's vehicle, so when a vehicle is beside another, you are getting more air.

To pull it off, one driver behind aims to get close enough to a rear-quarter panel of the other. That then disrupts the air flowing over the leader’s car and sends it on to the rear wing or onto the wheels, slowing the leader.

It then allows the car undertaking the side drafting to pull even, or in Waters’ case, ahead.

All told, with side drafting, whoever is in front is at somewhat of a disadvantage.

Looking at the data, Waters’ side draft advantage on Feeney down the main straight at the finish peaked at 7km/h quicker. It was then dropping as he moved in front of Feeney, reducing to a 5km/h advantage as they crossed the line.

In Supercars, side drafting is arguably most prominent at Bathurst's Conrod Straight on Tasmania's Symmons Plains back straight.

After the race, Feeney said: "It was pretty hard racing out there, obviously I got turned with about five or so laps to go.

"Will got caught up in the middle of it, and sort of all three of us were racing. I was obviously struggling there at the end, and got the rear bar in the last corner.

"I think Cam tried to redress a little bit, but he was able to slipstream past me there at the end, nothing I could obviously do down the straight there."

All told, Waters used the side draft to perfection, making the winning move in the final hundred metres of the race to claim victory by a barely believable 0.0308s.

"I just hoped that I could get him across the line," Waters said.

"I ducked my head down under the steering wheel and tried to get whatever I could and get a little bit of a side draft, and all the power in this Ford got me across the line."

Supercars will return to the track on Sunday at 11:10am AEDT for Boost Mobile Qualifying, followed by the Boost Mobile Top Ten Shootout at 1:05pm.

The 200km Race 3 will commence at 4:05pm.