Team Sirromet struggles in practice.

Team Sirromet Wines will head into tomorrows final qualifying session for the 2007 V8 Supercar Championship Series playing catch-up after both cars battled problems throughout today's practice session.

Team Owner, Paul Morris, completed only ten laps during today's session after a flawed engine wiring loom in his #67 Sirromet Wines VE Commodore forced his engineers to spend most of the session repairing the car.

"The car wouldn't start when practice began, and the crew traced the problem to the (engine) wiring loom," said Morris.

"We missed a lot of track-time while the problem was fixed, which has put us behind the 'eight-ball' compared to everyone else in finding a good car set-up.

"I finally got out onto the track near the end of the session, but there was only time for a couple of short stints - the car had lots of understeer in the few laps I did.

"We will make some changes for qualifying tomorrow and hopefully it will be better.

"There's going to be some 'guesswork' involved, as there always is when you haven't done enough laps."

Team mate Owen Kelly battled for grip at Phillip Island today, resulting in him managing the twenty-seventh fastest time from forty-one laps.

"My car felt pretty ordinary on practice tyres, there was no grip in the front or the rear," said Kelly.

"It was hard getting the front to 'stick' in the high-speed stuff here - I tried a set of 'green' tyres near the end of the session and that's when I did my best (lap) time.

"It was more than 1-second faster than what I had been doing, but in reality the improvement was more about the tyres rather than the car.

"We tried lots of different settings in three-to-four lap runs on the 'old' tyres. Now we will pour over the data to try and find something to make the car quicker tomorrow."

Both Team Sirromet Wines Commodores will compete in tomorrow's opening race for the Dunlop Grand Finale after a knockout qualifying session.