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Twin-MGU Powertrains Set for Regulation Clarity

Manufacturers want key details of twin-MGU packages included in future tech regs…

Photo: Nissan NISMO

Formula E manufacturers set out suggestions that the FIA consider adding extra detail into future regulations regarding the use of dual-motor powertrains.

The move comes after manufacturers questioned how Nissan was using its unique twin-MGU system in races so far this season.

A number of drivers have also questioned the deployment of Nissan’s power so far this season.

While following Sebastien Buemi’s Nissan at the Sanya E-Prix last month, Mahindra Racing’s Pascal Wehrlein exclaimed on his car-to-pit radio that “the Nissan on the straight is on a different planet. I don’t know what it is but it’s really strange.”

E-racing365 reported last month that some manufacturers had lobbied the FIA for further clarity on what is exactly permissible for a powertrain package using two MGUs.

A hastily arranged meeting of manufacturer technical heads and the FIA took place in Sanya but little in the way of information about the Nissan situation was offered.

Instead, manufacturers were asked to suggest key points to ensure that extra detail in how twin-MGU setups can be used without being in breach of what several technical directors have described to e-racing365 as ‘the spirit of the regulations.’

E-racing365 can reveal some of the proposals that manufacturers would like to see for future technical regulations.

In the short term, which is believed to be for the second half of the current season and with immediate effect, clarity is needed around the RPM gradient signs.

This is understood to mean that both MGUs should rotate and not emit different speed signals. The FIA technical delegates measure and receive the MGU signals as part of their standard technical policing.

This element of the request is believed to center around some unsubstantiated suspicions that a dual-motor setup could in part see one of the MGUs potentially create the storage of energy outside of the RESS.

By regulation, MGUs in Formula E are used for power conversion rather than energy storage.

Crucial Season Six Clarifications Needed

In addition, manufacturers also set out requests for Season Six clarifications to be taken into account for the homologation process which begins this summer.

Nissan is believed to be the only entry using such a dual-motor system this season and was homologated as such last August.

It is believed that the Japanese manufacturer will use an evolution of the concept for Season Six and is well underway with bench testing the refined package.

This means that it would be unfeasible for Nissan to revert to any other design for next season at this stage, meaning rival manufacturers now want to see a compromize made on how such a design is utilized.

The key requirement for Season Six is said to be a precise declaration on the homologation form that the MGU1 speeds should be related to the second MGU’s speed by a single value ratio.

This would stop the possibility to change the speed of MGU2 relative to MGU1 for the possibility of using it as a flywheel storage system outside of the RESS.

One key technical leader in Formula E, who wished not to be named, described the request made to the FIA as “complex on one level but also straightforward in another.”

“We are talking about a mathematical formula here which details the numerical values and ratios between the MGU’s,” said the source.

“One thing which is absolutely clear in the present regulations is that the two MGU’s have to be connected, that is crucial.

“The manufacturers have asked for a tolerance to be taken into account.

“Either way, it should be possible to do this to ensure that the MGU’s do not have any trick ‘spin ups’ and are storing any energy.”

The FIA declined to comment on the matter when contacted by e-racing365.

Sam Smith is e-racing365's Formula E Editor. A 20-year veteran in motorsports media, including press officer roles in both the FIA Sportscar Championship and at Lola Group, Smith is a well-known face in the Formula E paddock, where he served as series editor for from 2014-17. Contact Sam



  1. Avatar

    Kris G.

    April 5, 2019 at 8:49 am

    Why is this becoming an issue now when in the past both NIO (NextEV) and DS did use a twin-motor setup?

    • Avatar

      Chris Llana

      April 5, 2019 at 10:57 am

      I think those motors shared a common shaft, and were therefore always spinning at the same speed.

    • Avatar

      Sam Smith

      April 8, 2019 at 4:52 am

      It is because the second MGU is rumoured to have become an energy storage device and aiding drive and traction off corners.

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