SRT VIPER GTS-R
Every aspect of the SRT Viper GTS-R has been
optimized for battle, except for the behemoth
hidden under the hood. To be clear, everything
allowed in the TUDOR United SportsCar
Championship GT Le Mans rules has been
applied to the de-stroked 8.0-liter V10 engine,
but those guidelines are more about taming
Detroit muscle than unleashing its full potential.
Held to something near the 500hp range –
that’s 140hp shy of the 8.4-liter street
version – the Roush-built GTLM unit relies
heavily on its production configuration.
“It uses the same block and heads found
on the street car,” says Bill Riley. “The SRT
team didn’t go and cast their own special
block and heads for racing. Because we have
to race in extreme conditions for up to
24 hours, naturally there are some things
that get changed; we do a different rotating
assembly to get down to eight liters; we do a
different valve train, but the heart and soul
of the engine is all production.”
In the ALMS, and again in the TUDOR
Championship, E85 fuel is consumed by the
GTS-Rs, but when it’s time to race at the
24 Hours of Le Mans, adjustments are
required to work with the watery E10
gasoline mandated by the ACO.
“To go from an alcohol-based bio fuel to a
gasoline-based fuel, there’s a lot of car issues
to deal with,” says Riley. “But we have such
good guys handling the engines, you can only
expect the tuning and mapping to be right
there when we get to Le Mans.”
Fuel capacity differences are also found
when switching between North America and
France, leading the SRT Viper team to have
specialized systems pressed into service.
“We did have to make a new fuel bladder
and to deal with some different plumbing
issues going from the 110-liter E85 tank
in the ALMS to the 90-liter E10 tank called
for by the ACO,” notes Riley.
DE-FANGED? NOT QUITE...
(MAIN) Although the ACO allows GT Le Mans
cars to be fitted with a fully adjustable rear
wing, the size is strictly limited and it cannot
sit any higher than 25mm (approx.1in.)
below the roof. (TOP) Future street Vipers
will benefit from the GTS-R race program.
full capacity because it helps on everything
they touch in the next wave of production
items, and makes us more competitive in
every area the brand is involved.”
Ruedisueli, like many within the SRT
group, travels to every race, contributing
in every phase of an event. Once he’s
done at the track, debriefs are conducted,
which can lead to improvements that will
filter back to the SRT showroom floor.
“We’ve learned a lot in the wind tunnel
about downforce and drag from the racing
program that will pay dividends down the
road,” he explains. “We’ve picked up some
things on air management into the engine
that could be utilized in the future, which
Viper owners would benefit from.
“With the GTS-R, it’s still early days
for us, but we expect to train a lot more
people and to take more from what we do
on the track to improve our road cars as
we turn more miles and win more races.”