British Touring Car racer Rob Austin believes his Audi A4 can make a big step forward at Oulton Park this weekend after a switch of engine supplier.The Rob Austin Racing machine started the season with a Ric Wood-prepared turbo unit, but persistent issues have now resulted in Austin switching to the Lehmann engine.The A4 ran with the engine, which already powers the Special Tuning Racing SEAT Leons and AmD Milltek Racing Volkswagen Golf, in the first Oulton practice session this morning. Austin was quickest of the NGTC cars in 20th and believes there is more to come."It's a reliable, proven lump that we can fit and forget," he said. "We can now focus on the car rather than sorting the engine."It felt really good and we're keeping with people in a straight line now."The team has also reduced the weight of the car and improved the steering issue that has afflicted all the NGTC machines this season."I've always maintained the car is good on paper," added Austin. "I think I can go a couple of seconds faster [than the 1m31.140s he did this morning] and I'm hoping to qualify near the top 10."If the car does show significantly improved pace, there is a chance David Pinkney, who had planned to contest the series with the team, could return."My understanding is that as soon as we've proved the car, he will be back," said Austin. "If it goes really well here he may be back for [the next round at] Croft."