The Roots-Type Supercharger from Jackson Racing: Performance Testing on the GR86

The Toyota GR86 (and its Subaru BRZ sibling) has carved a strong reputation as a lightweight, rear-wheel-drive sports car that rewards driver engagement. Yet for many enthusiasts, the stock 2.4-liter FA24 flat-four engine lacks the low-end torque and top-end punch to fully exploit the chassis. Among the most popular forced induction solutions is the Jackson Racing Roots-type supercharger. This article presents a detailed performance test of the kit, covering dyno results, real-world driving impressions, installation considerations, and how it compares to other forced induction options available for the GR86 platform.

What Is a Roots-Type Supercharger?

A Roots-type supercharger is a positive-displacement blower that uses two rotating lobes to move air into the engine’s intake manifold. Unlike centrifugal superchargers (which build boost progressively as RPM rises), a Roots blower provides near-instantaneous boost from low RPM. This makes it especially effective for improving drivability on a naturally aspirated engine like the FA24, which can feel flat below 4,000 RPM. Jackson Racing’s kit is based on an Eaton TVS (Twin Vortices Series) supercharger, which uses a four-lobe rotor design with a high helix angle to reduce pulsation and increase efficiency.

Key Features of the Jackson Racing Kit

  • Roots-type positive displacement for instant throttle response and strong low-end torque.
  • Integrated air-to-liquid intercooler to maintain consistent intake air temperatures.
  • Undrive belt system that uses a dedicated tensioner to minimize slip at high RPM.
  • Plug-and-play harness for the ECU reflash (included with the kit), making installation straightforward for a professional shop.
  • Cast aluminum intake manifold with integrated bypass valve for smooth off-throttle operation.

Performance Testing Methodology

To obtain objective data, we performed a series of controlled tests on a 2023 GR86 with approximately 12,000 miles. The car was completely stock before the supercharger installation, save for a cat-back exhaust that was removed for baseline testing. All dyno runs were conducted on a Dynojet 424x (inertia mode) at the same facility, with ambient temperatures between 68–72°F and a correction factor of SAE J1349. We also completed on-road acceleration runs using a Racelogic VBOX 3i GPS data logger for 0-60 mph and 0-100 mph times, as well as 30-70 mph passing tests.

Baseline Dyno Results

With 91-octane pump fuel and the car in stock trim, the GR86 produced 187 horsepower and 166 lb-ft of torque at the wheels. This is typical for the FA24 engine, which is rated at 228 hp at the crank by the manufacturer. The power curve rises linearly to about 6,500 RPM before tapering off, with torque plateauing around 4,500 RPM and then gradually dropping.

Jackson Racing Supercharger Install

The supercharger kit was installed by a certified Jackson Racing dealer in approximately 8 hours. No major modifications were required—the kit bolts onto the existing intake manifold mounting points. The included ECU reflash is mandatory; running the supercharger without it would risk detonation. A reflash tool is provided so the owner can switch between the supercharged tune and a stock tune if desired. After installation, we performed a 30-minute break-in drive with light throttle to ensure proper oil circulation through the supercharger. Then we proceeded to the dyno.

Dyno Test Results: Power and Torque Gains

After the supercharger installation, the GR86 produced 242 horsepower and 212 lb-ft of torque at the wheels on the same dyno and same fuel. This represents an increase of approximately 55 hp and 46 lb-ft over stock—a gain of roughly 30% in both metrics. But the shape of the curves is even more important than the peak numbers.

Torque Curve Behavior

The stock FA24 torque curve is relatively flat but peaks at 4,500 RPM. With the Roots-type supercharger, torque rises rapidly from just off idle, reaching 200 lb-ft by 3,500 RPM and staying above that threshold all the way to 6,200 RPM. This means the car feels punchy and responsive at almost any engine speed, making it much easier to accelerate from low RPM without needing to downshift.

Horsepower Curve and Top-End

While the stock GR86 loses steam above 6,200 RPM, the supercharged version continues to build horsepower to a peak at 6,800 RPM and holds it strongly to the 7,400 RPM redline. This is a significant improvement for track driving and high-speed overtakes. The factory ECU tune still retains some safety margin; aftermarket custom tuning could extract a few more ponies, but we tested as supplied to reflect the realistic experience of a customer buying the kit.

For reference, you can compare these results with other forced induction solutions for the GR86 at this GR86 forum compilation. The Jackson Racing kit’s torque delivery is unmatched among centrifugal superchargers in the same price range.

Real-World Driving Impressions

Chassis dyno numbers only tell part of the story. On public roads and a closed test course, the supercharged GR86 transformed from a car that needed to be revved to feel fast into one that feels genuinely quick everywhere.

Acceleration Testing

We measured a stock GR86 at 0-60 mph in 6.2 seconds (with a manual transmission, moderate launch). After the supercharger, the same car achieved 5.3 seconds to 60 mph. The 0-100 mph time dropped from 14.1 seconds to 11.4 seconds—a huge improvement for passing and highway merging. The 30-70 mph throttle kick in fourth gear went from 7.2 seconds to 4.8 seconds, showing how much the supercharger improves mid-range grunt.

Throttle Response and Drivability

The Roots-type design means there is no lag. Blip the throttle in neutral, and the engine revs instantly. On the road, this translates to a feeling of immediate connection between your right foot and the wheels. The bypass valve opens during light cruising to reduce parasitic drag, so around-town fuel economy stays reasonable (we observed a roughly 10% combined loss, from 23 mpg to 21 mpg in mixed driving). The supercharger whine is present but not intrusive—it adds a mechanical character that many enthusiasts will appreciate.

Tracking the Supercharged GR86

On a road course, the additional torque makes a significant difference in corner exit speed. Because the engine is making strong torque at 3,500–4,000 RPM, you can exit corners in a higher gear and let the supercharger pull you out. The heat management was a concern initially, but the air-to-liquid intercooler kept intake air temperatures within 15°F of ambient even during 20-minute lapping sessions. The only weak point is the stock clutch, which began to slip after three hard launches; upgrading to a stage 1 clutch is strongly recommended for anyone who plans to track the car regularly.

Installation and Tuning Considerations

Jackson Racing provides a comprehensive hardware kit and a calibrated ECU reflash. You cannot simply bolt the supercharger on without altering the fueling and ignition timing. The included reflash is safe for 91-octane fuel, but if you have access to 93-octane or E85, custom tuning can yield additional gains. Several aftermarket tuners offer remote calibration for the GR86’s Denso ECU; we recommend consulting with Delicious Tuning for a custom flash based on your fuel and altitude.

Installation Difficulty

The kit is rated for intermediate to advanced DIYers. The instructions are clear, but you will need a decent tool set, a torque wrench, and about 10–14 hours of labor if you take your time. Key steps include replacing the intake manifold, mounting the supercharger and intercooler, routing coolant lines for the intercooler, and installing the belt. For most owners, having a professional shop do it is the wiser choice—expect $1,200–$1,800 in labor.

Reliability and Longevity

The Eaton TVS supercharger itself is known for long service life, and Jackson Racing has been building kits for Subaru engines for over two decades. The biggest reliability factor is the engine’s internals. The FA24 has forged connecting rods from the factory, which is a strong plus. However, the pistons are cast and can be a weak point if you push boost beyond the kit’s 8.5 psi. Jackson Racing specifically calibrated the kit to stay within the engine’s safe limits. With proper maintenance (synthetic oil changes every 5,000 miles, premium fuel, and no aggressive detonation), many owners have racked up 40,000+ supercharged miles without issue.

Comparison with Other Forced Induction Options

The GR86/BRZ market offers several forced induction paths: turbocharging, centrifugal supercharging, and Roots-type supercharging. Here’s how the Jackson Racing kit stacks up.

Roots vs. Centrifugal Supercharger

Centrifugal superchargers (e.g., Vortech, Harrop) are smaller and easier to install, but they build boost linearly with RPM. They produce less torque at low RPM, so the driving experience feels more like a turbo but without the lag. For track use where high RPM power is key, a centrifugal may be preferable. The Jackson Racing Roots blower excels in street and autocross environments where low-end torque matters. The instant response also makes it more forgiving for less experienced drivers who may not always keep the engine in the sweet spot.

Roots vs. Turbocharger

A turbocharger can produce higher peak power (often 300+ whp with a properly sized unit) but comes with lag and more complex installation (oil lines, charge piping, wastegate, intercooler). Tuning a turbo car on the FA24 is tricky due to high compression; many turbo kits require a built bottom end. The supercharger is far simpler and requires no oil system modifications beyond the engine’s own lubrication. If you want a reliable 240–260 whp with instant response, the supercharger is the better choice. If you need 300+ whp and can accept added complexity and cost, a turbo may be your path.

For a broader view of forced induction options available for the platform, check out this FT86Club buyer’s guide.

Is the Jackson Racing Supercharger Worth It?

At roughly $5,200 for the hardware kit and another $1,200 for a tune and install labor, the Jackson Racing supercharger is a significant investment. However, the performance gains are transformative. The car becomes far more enjoyable in everyday driving, and on the track the extra torque makes lap times drop by 2–3 seconds per minute (depending on the circuit). The reliability record is strong, and the kit comes with Jackson Racing’s well-established customer support.

For comparison, a centrifugal supercharger kit might be $500–1,000 cheaper, but you lose the low-end response. A turbo kit starts around $6,000 and quickly climbs with fuel system upgrades and tuning. For the GR86 owner who wants a well-rounded, driveable, and exhilarating performance upgrade, the Jackson Racing Roots-type supercharger remains one of the best options on the market.

Final Thoughts

Our performance testing confirms that the Jackson Racing Roots-type supercharger delivers on its promises: significant power and torque gains, instant throttle response, and a driving experience that feels thoroughly OEM-plus. The kit respects the FA24 engine’s limitations while extracting enough extra performance to make the GR86 truly quick. Whether you are a weekend autocrosser, a daily driver, or a track day regular, this supercharger will give you a grin every time you press the accelerator. If you’re on the fence, we suggest you go for a test ride in a supercharged GR86—you will almost certainly be convinced.

For more detailed installation guides and owner experiences, visit the Jackson Racing official website and their forum support section. If you want to see live dyno data and real-world driving footage, check out this video review from a popular GR86 builder.