Racecar Engineering – September 2019

(Joyce) #1

14 http://www.racecar-engineering.com SEPTEMBER 2019


hasspacefora moreefficientdiffuser.
Zurlinden.‘Oneis thetorqueanddriveability,
andthesecondis theweightandpackaging.
Theexhaustis asshortaspossible,andit
is moreadequateaerodynamicallythanatthe
rear.It is stillthebestsoundingGTEcar[andwill
remainsoas]it is a normallyaspiratedcar.’

improved.Allthis,coupledwitha development
sequence,thiscouldprovetobea significant
4.194-litreit is nowthelargestenginefittedtoa
andtheteamsaysthatit hasalsoimproved
thereliability.Fuelconsumptionis alsoa little

better than the old car, but with the balance
of performance system that does not make a
big impact on the performance and was not
a primary target. That said, in the sprint races
in the States fuel consumption can make a
difference to the overall race result.
‘This is more than an evolution, I would call
this a brand new engine,’ says Zurlinden. ‘The
torque curve is more flat, which [makes] the
driveability better, this was the target. We see
with the customers this was an important point,
to make it easier to drive, and this was also the
point with the aero, to make it easier to set-up.’
Porsche has also improved the gearbox,
which is now lighter and more rigid than
its predecessor, while offering drivers faster
gearshift times, the company tells us.
The primary focus for the car was to improve
the driveability, with a view to competing on the
various different race circuits around the world.
The US tracks are typically low abrasion, while
the WEC typically operates on Grade 1 circuits
with higher abrasion and more grip. Porsche
struggled on some circuits more than others,
and so the team worked on improving the
operating window. ‘Now it is more predictable,’
says Zurlinden. ‘Before, you had a sweet spot to

find, but this [new car] is really easy to set up.
The suspension has changed. It is an evolution
of the previous concept and some parts are
even the same. We got the feedback from the
customer teams, and from the works teams, and
90 per cent of the points that they requested
are now in the car. We worked together with
customer drivers, teams, mechanics and
engineers as well as the works teams. Since we
have the GTE car running in customer hands^
we have learned a lot, also about reliability and
how to use things, how people see it, and this
is an important step for all of us.’

Racing ahead
While this might be the last of the 991s, it
may also be the last of a generation of GTE
cars, depending on what happens to the top
class in the WEC and what the manufacturers
commit to. There are rumours that Porsche
may compete in the hypercar category itself,
against Aston Martin and Toyota, but with no
final regulations in place no one can plan that
far ahead. For now, Porsche is happy to have
produced its new Le Mans challenger, and to
have places to race it. Now it just hopes it will
be as successful as its predecessor.

‘We had the feedback from customer teams and from the works teams

and 90 per cent of the points that they requested are now in the car’

The car is expected to be easier on its tyres, which could prove to be a significant factor in longer WEC races now that refuelling and tyre pit stop rules for GTE have been changed

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