For last month’s fourth round of the season at Fuji Speedway, JLOC brought one of its two GT300 contenders, the #88 entry, in Evo2 spec for the first time, having made the upgrade during the two-month break that followed the previous race at Suzuka.
However, the team elected to keep the #87 car in its original specification for both that race and the following one at Suzuka amid concerns about Balance of Performance.
That proved to be a deft decision as it was the #87 machine shared by Natsu Sakaguchi and Kosuke Matsuura that was the more competitive of the two JLOC entries, finishing a close second behind the UpGarage Honda of Takashi Kobayashi and Shun Koide.
Yuya Motojima and Takashi Kogure meanwhile brought home the Evo2-spec #88 Lamborghini for a fourth-place finish.
JLOC team boss Isao Noritake told Motorsport.com: “The #87 car will stay in Evo1 spec until the end of the season. The reason is, as predicted, the BoP is tough for the Evo2, and we feel the Evo1 is still able to fight.
“Next year, we will work with Lamborghini to field two cars in Evo2 spec.”
While the #87 machine was helped to a second-place finish at Suzuka by the favourable timing of a late full-course caution, Matsuura said that differences in the BoP help to explain why the older car was able to outpace its newer sibling.
“We are running with two air restrictors [at 39mm] on the #87 car, but on the #88 car they only have one [at 51mm], so they are a little slower on the straights than us,” Matsuura said.
“I think it will be tough for the Evo2 if they don’t revise the BoP.”
JLOC swapped round its chassis after the huge crash Matsuura suffered at the third round at Suzuka in June, which led to the #87 car being written off.
The old #88 car was rechristened as the #87 from the following race at Fuji onwards, with an entirely new car being delivered in Evo2 spec to replace it.
Matsuura reported that “the feeling is a bit different” with the old #88 machine he and Sakaguchi are piloting now, compared with the car that was used for the first three races before being written off at Suzuka.
“The [old] #87 was a bit of an understeer car, but this one is more of an oversteer car,” said the ex-IndyCar driver.
“It’s hard to compare because the BoP and handicap weight change every race, but after we changed the car, the results have been slightly better, so maybe the [old] #88 was faster.”