The
wide front tires imparts a much bulkier look to the front end of the
ARX-02a. And they come with some
draw backs; they are slower to reach operating
temperature (such as on a restart), there is an increased possibility
of hydroplaning in the wet, and there are negative interactions with
the front diffuser. Though Wirth Research ultimately felt these draw
backs were more than made up for by the gains, and indeed WR claims
to have overcome any and all deficits.The Acura ARX-02 was designed to be several hundred pounds under the minimum weight in order to be ballasted to the minimum of 900 kgs. This was done primarily through a monsterous 270 lb piece of steel ballast (24" x 36" x 1") located on or near the front wheel centerline. Along with the light weight engine, the ballast plate helped move weight distribution forward, as much as 53%, though slightly less was found to work best, allowing the wide fronts to work to their optimum.
The
37/71-R18 Michelins. The ARX-02a never benefited from properly
developed tire compounds for the wide fronts. We note with irony that in the intervening years Michelin was finally motivated to develop bespoke wide
front compounds with the subsequent
adaptation of the concept by both
Audi and Peugeot.
Front
dive planes were always a feature on the LMP2 Acura; never were they
raced without some configuration of dive planes. The
ARX-02a's
are similar in concept, but they are much more hard wired into the
the design and less a way of balancing the car. I'll suggest
there are potentially other methods of altering the car's front
aero balance? What leads me to that conclusion is that they
are much
thicker (and thus durable) than the previous diveplanes as seen on the LMP2 cars which
suggests a need to stay on the car. Indeed,
it's my understanding that the -02a's diveplanes acted as drag
reducers, creating a vortici that beneficially interacted with the
airflow moving down the side of the car. That is, it would be
detrimental to the car's performance if they were "pinged" off mid-race
because of car to car contact. The diveplanes are
tapered on the
outboard edge to improve aero performance.
The
Acura's bare nose with diveplanes missing reveals further proof of the
permanence of the diveplanes. The diveplane
unit is bonded onto the front of the fender, thus making them effectively permanent
The
entire louver section on the ARX-02a is somewhat different than on
other LMPs seen previously. Instead of a louver panel that fits
into a recess in the fender, the entire top portion of the fender is
integrated into a "cap" and can be unbolted and replaced as needed.
At Sebring 2009 a partial blanked/louvered panel was used.