Rick Kelly says he still has more to learn about his newly lightened engine after he battled car balance on new and used tyres at The Bend Motorsport Park.

This week Kelly Racing installed a rebuilt engine into the #15 Castrol Racing Ford Mustang.

Team-mate Andre Heimgartner will receive a lightened engine ahead of this year’s Supercheap Auto Bathurst 1000.

Kelly claimed 23rd in Race 28, which was marred by a spin on Lap 5 courtesy of contact with Brad Jones Racing driver Todd Hazelwood.

The Supercars champion said his first outing with the revised engine package brought with it a new challenge.

“We’ve made some significant changes to the car with the engine and moved a few things around to hopefully unlock a bit more performance,” said Kelly.

“The potential in the car theoretically is better now, we just have to learn a little bit more about it.

“It’s produced a very different car on new versus old tyres and we were battling with that all day which put us on the back foot in qualifying and then you’ve got a tough job in the race.”

Saturday’s running at the OTR SuperSprint saw Kelly end both practice sessions in 12th before failing to make it through to the Top 15 Shootout, qualifying 16th.

Kelly was ultimately unablee to assess the potential of the new engine package in-race due to the contact with Hazelwood, which went unpunished and saw the Mildura driver languish.

That was further compounded when his engine cut out in the pit lane during his compulsory pit stop.

In the end, Kelly only finished 23rd, but was encouraged by his late race pace.

“We got spun around at the hairpin in the first few laps, which was unfortunate, and then the engine cut out in the pit stop which put us a long way back,” said Kelly.

“The positive is we had fantastic pace from there and caught right back up to the back of the pack.

“We just need to use that tomorrow and try to understand a bit more about unlocking the pace on a green tyre because that’s our weakness at the moment.”

The OTR SuperSprint at The Bend Motorsport Park continues tomorrow with back-to-back qualifying sessions beginning at 09:10 local time/09:40 AEST.