VT21r – 2021 Subaru WRX STI Rally Car

From the foot-tall wing to its flat-four rumble, the Subaru WRX STI is a legendary performance car built upon decades of motorsport victories. The VT21R is our latest evolution of the STI that has powered Subaru Motorsports USA to more than 100 rally wins and 14 U.S. national championships over the past 20 years. It competes in the American Rally Association Open 4WD Class. To be more accurate—it doesn’t just compete in the class, the VT21R dominates it. VSC has perfected the racecar’s formula since the VA WRX STI debuted for 2015. It won the ARA // Rally America championships for six of the last seven years (2015-2019, 2021). Travis Pastrana and Brandon Semenuk scored first and third in the 2021 ARA driver’s championship. With seasoned drivers and Subaru’s full support, weight and power are the VT21R’s only limitations.

Most everything else in the Open class rulebook is free game—and it’s up to VSC to fine-tune these cars for hundreds of grueling miles at rallies from Maine to Oregon. While the Subaru BOXER is capable of extreme output—see the 862-hp VT20G we built for Pastrana’s Gymkhana video—we tune the VT21R’s 2.0-liter engine for reliable power and longevity. VSC’s cars use a strengthened engine block and heads, along with a custom crankshaft, connecting rods, and pistons to support the higher cylinder pressures and racing ECU calibration. A Garrett turbo feeds a series-regulated maximum 27 psi through a 34-mm restrictor for a total of 330 hp and 400 lb-ft of torque. All this fury routes through a Sadev six-speed sequential gearbox and two limited-slip differentials with a motorsport center differential to quickly adjust the torque split. An anti-lag system ensures the turbo is always spooled and produces such high exhaust temperatures that VSC needed to develop a custom Inconel exhaust manifold. In addition to the exhaust, VSC fabricates many of the VT21R’s suspension parts including the arms, links, and cross members. Even the handbrake lever gets the VSC touch in aluminum and carbon fiber. Reiger dampers ensure the VT21R can drift and land safely in every turn. High-strength 15-inch KMC gravel rally wheels on Yokohama Advan A053 gravel rally tires ensure the best traction in any terrain, while 12-inch brake rotors grabbed by Alcon calipers and Endless pads keep the VT21R out of the woods.

Starting with a stock Subaru STI body shell, we seam-weld the entire frame so the VT21r is rigid enough to withstand the abuse of a multi-stage rally. With a FIA-approved steel roll cage welded onto the frame and attached to the rear suspension and engine bay, the VT21R is both light and incredibly strong. Underbody skid plates made from steel, carbon fiber, and other composites protect the oil pan, differentials, and the rest of the car’s lifeblood at high speed. VSC uses computational fluid dynamics software and a scale model run in a wind tunnel to develop the car’s aerodynamics and widebody kit. The carbon fiber spoiler has vertical slots and can be adjusted to suit the particular event. The bare interior has at least some amenities: air circulation from a roof-mounted scoop, a carbon fiber footrest for the co-driver, a heated windshield, and when it’s really cold (can you say Sno*Drift?), a cabin heater. Total race weight varies from season to season. In 2021, the VT21R ran at an ARA series minimum regulation of 2900 pounds.

Despite such rigorous and extensive modifications that require thousands of labor hours, the VT21R is registered and street-legal. It has to be, or else the team wouldn’t be able to make it to the next rally stage (reached by traversing public roads at legal speeds). But above all, the VT21R shows how VSC’s world-class engineers and craftspeople keep Subaru winning at the highest levels of motorsport.

For more on the modifications, from gearbox to seats and carbon fiber elements, visit the Subaru Motorsports page: https://www.subaru.com/content/subaru/en/motorsports/cars/rally.html

SRTUSA 2021 Open Class Rally Car   
2021 Subaru WRX STI Open Class Rally Car (VT21r)
Prepared by Vermont SportsCar

Engine
Custom Vermont SportsCar 2.0-liter Horizontally Opposed 4-cylinder SUBARU BOXER engine
Turbocharged and Intercooled
Garrett Motorsport Turbo
Approx. 330 bhp and 400 lb-ft torque
(With an ARA OPEN 4WD Class-mandated 34mm Restrictor and 27psi Boost Limit)
Garrett Motorsport Turbo

Engine Management
Cosworth Pectel SQ6M ECU

Electrical
PRS Lightweight Motorsport Wiring Loom
Programmable Power Control Module and Switch Units
GEMS Data Logger

Weight
Regulated Minimum Limit of 2,900 lbs.

Transmission & Drive System
SADEV 6-speed Sequential Dog-engagement Gearbox
SADEV Custom Driveshafts
SADEV Custom Propshaft
Motorsport Controlled Central Drive Release

Clutch
Tilton Racing Clutch

Differentials
SADEV (Front & Rear)

Suspension
Reiger Competition Suspension
Vermont SportsCar Tubular Front and Rear Cross Members
Vermont SportsCar Suspension Arms and Links
Vermont SportsCar Modified STI Hubs and Spindles

Brakes / Gravel Spec
Alcon Gravel Rally Brake Calipers
Lightweight 12-inch Floating Rotors
Endless Brake Pads
Vermont SportsCar Hydraulic Handbrake

Exhaust System
Vermont SportsCar Custom Exhaust Manifold
Vermont SportsCar Stainless Steel 3-inch Quick-Change System

Wheels
KMC Wheels KMC199 15×7 Gravel Wheels

Tires
Yokohama ADVAN A053 15″ Gravel Rally Tire

Roll Cage / Shell Prep
Seam-welded Shell
Vermont SportsCar ARA / FIA Open Class Specification Roll Cage

Seats
RECARO SPA ProRacer with HANS (Head & Neck Restraint)

Lights
PIAA HID Driving Lights
Vermont SportsCar Carbon Fiber, Hood and Bumper-Mounted Light Pods

Interior
Vermont SportsCar Carbon Fiber Dashboard
Vermont SportsCar Carbon Fiber Door Cards
Vermont SportsCar Carbon Fiber Co-driver Footrest
Schroth Enduro Harnesses
GEMS Digital Driver and Co-driver Displays

Fuel Cell
Under-floor FIA FT3.5 Fuel Cell (75+ Liters)

Body
Vermont SportsCar Wide Body Kit
Vermont SportsCar Composite Under-floor Protection
Vermont SportsCar Carbon Fiber Rear Wing
Vermont SportsCar Carbon Fiber Roof Scoop
Vermont SportsCar Carbon Fiber Sump Guard
Vermont SportsCar Stainless Steel Differential Guard

Communications
weBoost Cell Signal Booster, Drive Reach
Peplink Mobile Router
Stilo DG-30 Intercom
Stilo WRC Road Headset
Motorola Two-way Digital VHF Radio

Misc.
Heated Front Windshield
Vermont SportsCar Polycarbonate Side and Rear Windows
STI Quick Ratio Steering Rack (11:1 Ratio)
Motorsport High-flow Power Steering Pump

2021 Subaru WRX STI Rally Jump
Ken Block 43 Olympus Testing
Subaru Motorsports USA 2021 WRX STI
2020 VT20R Interior Controls
Ken Block 43 WRX STI 2
2020 VT20R Interior Co Driver Display
2020 VT20R Exterior Wing
Ken Block 43 Olympus Rally
VT21R Mud Splash Rally
2021 Subaru Snow Rally Jump