The ACO has approved a series of updates to three of the four LMP2 chassis, in an effort to eliminate the performance gaps currently seen with the new-for-2017 prototypes.

The Ligier JS P217, Dallara P217 and Riley Mk. 30 have all been given additional allowances for 2018, both in its regular-season sprint configuration and Le Mans aero kits, in order to close the gap to the Oreca 07, which has served as the category’s benchmark.

No changes will be permitted to the Oreca as a result.

“The spirit of these adjustments is to guarantee a hotly contested category as well as a level of competitiveness between the constructors and the teams,” a statement from the ACO read.

Details on what adjustments will be permitted by each constructor have not been detailed, although all updates must be provided, free of charge, to existing customers.

It’s unclear if these allowances fall under the one-time “joker” update permitted for each LMP2 constructor in a four-year homologation period, or that a special exception has been made.

Multimatic’s Larry Holt indicated to Sportscar365 last month that the Riley LMP2 car will likely be re-homologated altogether, although not confirmed by the ACO or FIA.

Data from the European Le Mans Series races, as well as 24 Hours of Le Mans, which has seen the most diverse fields of LMP2 machinery this year, were taken into account for the selection of modifications.

The modifications, however, must not give any constructor a “consistent advantage” compared to the benchmark Oreca.

LMP2 Updates Also Required for DPis

It’s understood any updates made to the LMP2 chassis must also be applied to the DPi variants competing in the IMSA WeatherTech SportsCar Championship, per IMSA’s agreement with the ACO.

The permitted changes, therefore, will impact the Dallara-chassied Cadillac DPi-V.R, Mazda RT24-P, which is based on the Riley LMP2, plus the Nissan Onroak DPi.

Per IMSA rules, any changes to DPi machinery will result in a re-certification process that could include wind tunnel and/or dyno testing.

Participation in the December test at Daytona, for new or updated cars, would also be required for Balance of Performance purposes.

It’s understood one of the issues IMSA is currently facing is the lack of available wind tunnel time at Windshear in North Carolina, which would be needed not only to re-certify any new or modified DPi but also complete baseline testing for all updated LMP2 models.