Le Mans Daytona hybrid: IMSA and Le Mans Agree to Specs for Prototype Class

Steven Cole
By Steven Cole Smith
Sep 18, 2020 | Le Mans, Hybrid, Prototype

At the long-delayed (June to September) 24 Hours of Le Mans, we received the similarly long-delayed, semi-final plans for the new prototype car that will replace the top class, DPi, in the IMSA WeatherTech SportsCar Championship series, and will also be legal to run in the World Endurance Championship and, more importantly, Le Mans.

Called LMDh, short for Le Mans Daytona hybrid, will replace the Daytona Prototype international in IMSA, and the current LMP1 cars in the WEC. And since Le Mans is (usually) the last race in the WEC season, the cars will be able to run in the 24 Hours with no changes. This means that IMSA Prototype manufacturers like Mazda, Cadillac and Acura will finally be able to race at the largest sports car endurance event in the world.

This was not possible before, because the WEC’s LMP2 class, which is quite similar to the IMSA DPi and LMP2 configurations, was only able to use the British-built Gibson V8. Certainly Cadillac, say, would have been welcome to come to Le Mans, but it would have had to run an engine that had no affiliation with a manufacturer.

As expected, the new car’s specifications, confirmed at a press conference hosted by IMSA President John Doonan and his counterpart, ACO President Pierre Fillon, will be 670-horsepower engine, combined with a modest hybrid system that is essentially bolt-on.

The engines will be supplied by the manufacturer and limited to about 630 horsepower. They will be coupled to a 50 kW electric motor supplied by Bosch that can achieve up to 200 kW of regeneration capability. The hybrid powertrain, including a battery system produced by Williams, will cost $355,000.

Minimum weight for the car is 2271 pounds. Wheelbase will be 124 inches. Maximum length is 201 inches, maximum width is 79 inches. (This is all translated from metric, where they are even numbers, like a width of 2000mm.) As you can see from the above rendering, they don’t look remarkably different from current Prototypes.

The chassis, to be offered from Ligier, Multimatic, Oreca and Dallara, will be cost-capped at $409,000, not including the transmission. Xtrac will make the gearbox.

ACO and IMSA have led a collaborative effort along with the four chassis constructors and the three hybrid powertrain suppliers to come up with a common LMDh solution,” said Matt Kurdock, IMSA's new technical director. “The Bosch motor is integrated with the Xtrac gearbox, while the Williams Advanced Engineering battery will be integrated with the Bosch motor controller. This is all in a compact assembly, which installs from underneath the survival cell in an isolated compartment from the driver.”

The goal was to be able to build a car, minus the combustion engine, for 1 million euros. That’s $1,185,000 in real money.

Fillon also confirmed that the top class of the FIA WEC will be called the Hypercar. Peugeot also confirmed that it plans to build a pair.

There was no firm timeline presented, but it is unlikely the car will debut in 2021, due to the pandemic. The 2022 Rolex 24 at Daytona remains a possibility, but a long shot.

Stay tuned. We’ll know more soon.

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View comments on the GRM forums
Jerry From LA
Jerry From LA SuperDork
9/21/20 12:51 p.m.

About friggin' time.

trigun7469 SuperDork
9/21/20 1:04 p.m.

Is having no factory teams a good thing?

9/25/20 10:58 a.m.

Bosch-Williams components add nothing but expense, since they are spec items. Engine configuration should be free since there is a horsepower cap. Entries in this class should be limited to manufacturers only. 

Privateers (pro-am), on the other hand should use the same chassis brands, but with four cylinder two litre turbo motors capped at around 600 hp. Since virtually every manufacturer/parent produces an engine of this type, it would provide an alternate way for multiple manufactures to cost effectively participate. Production blocks and heads of which 3,000 have been retailed; other aftermarket components and machine work permitted. No hybrid. No direct manufacturer teams. No DRS. Three-pedal, H-pattern manual transmissions only; no electrical, hydraulic, computer, or other shifting assists; mechanical synchromesh okay. Unassisted hydraulic clutch actuation. No electro/computer controlled suspensions. This is sport/entertainment; not technology development. Same rule book for everybody; no Balance of Performance. Pro drivers (i.e., competitive driving-related is primary income source) limited to one per car per event.

A universal safety cell should be an integral component common to all chassis brands.

Bodywork above the tub optionally configured by the entrants in both classes to represent/reinforce styling elements consistent with a respective engine manufacturer's brand. 

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