Engine parity became a point of contention following a dispute during the season opener at the Bathurst 6 Hour event, which saw reigning champion Kody Garland withdraw.
The category enlisted the help of Riskie Racing pair Andriske and Brandon Madden to methodically test both engines and ensure that any discrepancies found during the remaining rounds can be quickly rectified.
Using Andriske’s Yamaha XJR-powered car and Josh Thomas’ machine fitted with the newer Yamaha MT-09, both drivers were able to test each car and trial different combinations of restrictors while optimising the aerodynamic balance.
Andriske was confident that parity had been achieved throughout the day, with the right combination of restrictors for the XJR found to bring top speeds almost identical.
Entering the second round at Symmons Plains, another track where engine performance is critical fot the track’s long straights, the data gained from the test day can be easily referred to when determining any additional changes to be made.
“I think it’s within a fixable amount,” Andriske told Speedcafe.
Buy tickets
“We also now have speed traces, what difference a restrictor will make, what size restrictors will do what.
“And I think if there is a deficit by any means, by any competitor, then we can look at, you know, is it the driver? Is it the car? Is it engine parity?
“Just trying to find that happy medium between both setups is a mission.
“I think where we are right now, I think we have to slow the XJRs down. We have to.
“They’ve just got too much for the MT-09s, but how much we do that is the big million-dollar question, and I think we’re pretty close to that now.”
The XJR is a 1350cc four-cylinder engine making more power than the newer MT-09 at just three cylinders and 890cc.
The trade-off comes with cheaper cost to buy, lighter weight, and greater availability of rebuild parts for the new engine.
XJR runners locked out the top three in qualifying at Bathurst, with Andriske just 0.195s behind Garland for pole position.
Between qualifying and Race 1, XJR engines were further restricted in a move that some drivers agreed was too far and made them uncompetitive.
From Race 1 to 2, the category implemented a change to rectify the XJR’s performance, but it was still not enough, as MT09 runner Diesel Thomas built a lead of almost eight seconds over Andriske during the race.
Garland was of the thought that this change would not be sufficient, and the subsequent dispute saw him withdraw from the event.
“Coming out of qualifying, it was sort of a benefit to us [XJR runners], we had the upper hand,” said Andriske.
“And then coming out to Race 1, that’s when we made a change and we went too far.
“Coming out of the back end of that race, everyone got out of the cars and agreed that the dial had changed, it was too far the other way, and we agreed to come back.
“I think the discrepancy was how much we were going to come back.
“And through the actual course of the weekend, knowing we didn’t go enough, it only took us one race [Race 2] to work that out and then balance the field again.”
By Races 3 and 4, Andriske felt that the balance was correct, however Garland had already withdrawn from the event by that stage.
XJR and MT09 runners won two races apiece at Bathurst, and the top 10 split in qualifying was six to four in favour of the XJR motor.
Aussie Racing Cars elected to keep the older engine available to use so as not to disadvantage teams with existing stock of complete engines and spares.
Andriske noted that when his stock of the engine runs its course, the team will be switching to the new engine.
“I think the intermittent phases of having an MT09 and an XJR for say 12 months, there’s always going to be a dance of what’s going to be better,” Andriske said.
“I think for us, as in the Riskie Racing side of things, we’ve got the XJRs because they’re proven.
“We’ve run them for a couple of years now and we know what they do.
“We’re down to a limited number, we’ve still got stock on those engines. So once we run out of stock, then we will be changing, but until that happens, that’s where we stand.”
The Aussie Racing Cars championship resumes at the Tasmania Super440 on May 22-24.
Discussion about this post