The Best of 2010: The Sierra Sierra TIme Attack EVO


sierra sierra evo
This shield protects the dry sump pump pulley and belt from thrown up debris.  It also blocks most of the view of it so we could not get a good picture of the pump.
sierra sierra evo
We were told that this box is the speaker box for the sound system but we are pretty sure that the dry sump tank lives here.

The engine is dry sumped with a system that is engineered by Sierra Sierra using a custom Cosworth billet dry sump pump and pan with a big Setrab oil heat exchanger with plumbing layout built by Sierra Sierra.  As Time Attack cars become more sophisticated with aero assisted traction, dry sumps will become more and more critical for engine life.  The dry sump also allows the engine to be positioned lower in the chassis to drop the Center of Gravity.  To keep the coolant temperature under control, a C&R custom radiator with a Visteon core is used.

sierra sierra evo
A surge pot is used to deaerate the coolant and serve as an extra high system bleed point.  This really helps cooling.

A sophisticated Cosworth Electronics Pectel SQ6 ECU is massaged by Eric Hsu.  While the Pectel SQ6 handles the engine management, the Pectel EDC handles the mapping of the center diff’s torque split.  Both have full data logging and advanced math capability and the team makes maximum use of those capabilities for powertrain and chassis set up.  Ignition is handled by a CDI (built in to the SQ6) direct fire system which helps reliably fire NGK Racing 10.5 heat range spark plugs in the highly compressed difficult to ignite mixture.  The Pectel system also has full wastegate control. Eric uses the Pectel’s advanced Wastegate control by setting different boost levels by gear and rpm. The SQ6 can use rpm, gear position, speed, throttle position and other factors to determine how much boost the engine can have in any given situation.  The ECU is integrated with a Pectel Omega D2 electronic dashboard/driver display.

sierra sierra evo
The heart of the car's electronics live here.  The engine management is handled by a Pectel SQ6 while the center differential is controlled by a Pectel EDC.  The ignition is handled by a CDI controlled by the SD6.  The car's video data logging system is housed here as well.
eric hsu
The cars electronic systems are Eric's primary responsibility.  Eric does all of the cars tuning as well. The team has given the nickname of “HP” to Eric. Depending on which member of the Sierra Sierra team you ask, it could mean “horsepower” or “high profit”.

The drivetrain consists of a Tilton 7.5″ triple plate amorphous carbon carbon clutch on a lightweight flywheel.  This gives a low moment of inertia, fast shifts, long life under tough conditions and smooth drivetrain cushioning action.  The transmission consists of a 5-speed case with Quaife internals consisting of straight cut constant mesh dog engagement gears. Group N rally spec final drive gears are also used. The transmission is prepared and blueprinted by Taylor Race Engineering.  A stock EVO IX transfer case is used controlled by a Pectel EDC for torque split.  A Quaife mechanical front differential and a 1.5 way OS Giken clutch type rear differential are used.  After the transmission the power is fed to the wheels via modified Drive Shaft Shop heavy duty axles.

sierra sierra evo front brakes
Brembo Group N brakes use Brembo's stiff monoblock calipers.  The hats use lug drive for freer float and to take shear stress off of the mounting hardware.
sierra sierra evo
The rear Group N brakes.

Stopping duties are handled by a set of true motorsport grade Brembo Group N rally spec brakes using monoblock one piece construction with full floating rotors using lug drive.  The lug drive allows for freer float and takes shear stress off of the hat bolts.  Cobalt brake pads are used. A lightweight billet Tilton 900 series brake/clutch pedal assembly is used with dual master cylinders and a balance bar providing easy to adjust mechanical brake proportioning.  The rear brake line pressure curve roll off is controlled by a Tilton hydraulic proportioning valve.  XRP braided steel brake lines finalize the brake system.

The brakes use an ultra trick Tilton top hung 900 series pedal and master cylinder system with dual master cylinders and balance bar for brake bias control.  Hydraulic proportioning is adjustable as well with a Tilton valve.

sierra sierra evo
Mike and Jethro are the mechanics that keep the EVO running as well as it does.

A very interesting feature of the Sierra Sierra car is its electrically assisted steering system.  It uses a DC electronics Corsa power steering system.  This eliminates the parasitic losses of a power steering pump and frees up space on the front of the engine for the dry sump pump.  The power steering system has mappable power assist that is laptop programmable.

sierra sierra evo
The car uses an ultra trick DC electronics electrical power steering system.  The hose ducts outside air to help keep the system cool.


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