Introduction: A Real Owner's Supercharged Integra Journey

For decades the Acura Integra has served as a blank canvas for enthusiasts who crave affordable performance. While the naturally aspirated B-series and later K-series engines respond well to bolt-ons, some owners want more without sacrificing daily drivability. One owner, Chris M., recently completed an aftermarket supercharger installation on his 2001 Acura Integra GS-R, achieving a verified 240 horsepower at the wheels. This article walks through his experience, from kit selection to tuning, and offers practical insights for anyone considering forced induction on an Integra.

A Brief History of the Acura Integra as a Performance Platform

Produced from 1986 through 2006, the Honda/Acura Integra earned respect for its lightweight chassis, double-wishbone suspension, and high-revving VTEC engines. The third-generation (1994–2001) GS-R came with a 1.8-liter B18C1 making 170 horsepower from the factory. After Acura discontinued the nameplate in 2006, the Integra remained a staple in the tuner community. In 2023 Honda revived the Integra name on a new platform, but the old chassis remains a favorite for budget-minded builds. Chris’s car is a 2001 GS-R coupe with 98,000 miles on the odometer when the supercharger project began.

According to Torque News’ retrospective on the Integra, the GS-R’s combination of weight (~2,600 lbs) and near-170 hp made it a natural candidate for forced induction. Chris’s goal was to nearly double the stock output while keeping maintenance intervals reasonable.

Supercharger vs. Turbocharger: Why One Owner Went Forced Induction

Before committing to a supercharger, Chris evaluated turbocharging. A turbo kit offers higher peak power potential but introduces exhaust plumbing, heat management, and often more complicated tuning. For Chris, the deciding factors were instant throttle response and a linear power curve. “I wanted the car to feel like a larger-displacement naturally aspirated engine, not a laggy turbo,” he explained. Centrifugal superchargers mount easily to the K20 or B18 intake side and provide boost proportional to engine speed, making them forgiving for daily street use.

The trade-off: superchargers typically cost more for the same peak power, and parasitic loss from the drive belt slightly reduces efficiency. However, for a street car that rarely sees a drag strip, the drivability win was clear. A discussion on AcuraZine forums further validates that many GS-R owners prefer superchargers for daily driving over turbos due to reliability of the drivetrain.

Selecting the Aftermarket Supercharger Kit

After weeks of research, Chris chose a Rotrex C30-94 centrifugal supercharger kit from a company specializing in Honda applications. The kit came as a complete bolt-on package, including cast aluminum mounting bracket, intercooler (air-to-water), blow‑off valve, injectors, fuel pump, and a basemap for a Hondata ECU.

Compatibility and Fitment

The kit was designed specifically for the B18C1. No cutting or welding was required, which appealed to Chris because he wanted to revert the car to stock if needed. “Everything lined up with the existing accessory mounting points,” he said. “I only had to drill two small holes in the frame rail for the intercooler pump bracket.” However, he noted that the stock radiator fan had to be replaced with a slim electric fan to clear the supercharger pulley. This is a common requirement with most forced induction kits.

Expected Gains and Realistic Expectations

The manufacturer claimed 240–260 wheel horsepower on 91-octane pump gas at around 8–9 psi of boost. Chris’s build also included a 3-inch cat-back exhaust and a cold air intake (reused from his previous naturally aspirated setup). He skipped upgrading the camshafts or head work to keep costs under control. His realistic goal: 240 reliable horses on a safe air-fuel ratio.

The Installation Process: A Hands-On Journey

Chris performed the entire installation in his two-car garage over four weekends. The process required basic mechanical skills, a torque wrench, and a set of metric sockets. He documented everything to share with fellow forum members.

Step-by-Step Outline

  • Weekend 1: Removed stock intake, radiator, cooling fan, and drive belt. Installed the Rotrex mounting bracket and supercharger unit. Replaced the charge pipe and intercooler routing.
  • Weekend 2: Ran the intake hose from the air filter to the supercharger inlet. Plumbed the air-to-water intercooler lines and mounted the heat exchanger behind the lower bumper. Replaced the fuel pump with a Walbro 255 LPH unit.
  • Weekend 3: Installed RC 750cc fuel injectors and a Hondata S300 ECU. Wired the boost control solenoid for a manual boost controller. Replaced the serpentine belt with the shorter supercharger belt.
  • Weekend 4: Double-checked all clamps, filled coolant system, and performed a preliminary leak test. Started the engine and ran it at idle to check for oil leaks. Chris discovered a loose O-ring on the supercharger oil feed line—tightened it with a new crush washer and the leak stopped.

Overcoming Common Pitfalls

The most frustrating issue was tuning the idle air control. The larger injectors caused the engine to hunt at idle until Chris adjusted the IACV steps in the Hondata software. He also found that a vacuum leak at the intake manifold gasket was causing a lean condition. Replacing the gasket solved it. “Don’t reuse old gaskets on a boosted engine,” he warns. “Buy a new manifold gasket and torque it to spec.”

Another challenge: the bracket that holds the supercharger tensioner needed slight shimming to align the belt perfectly. Chris used washers as spacers, a trick he learned from a Honda-Tech forced induction thread.

Tuning the ECU: Unlocking Full Potential

Chris had experience tuning naturally aspirated Honda engines but was new to boost. He purchased a basemap from the supercharger vendor, then spent three evenings on a local dyno refining it. “The basemap was conservative, around 220 hp,” he said. “I leaned out the fuel mixture in the midrange and advanced ignition timing slightly to reach 240 safely.”

Key tuning parameters:

  • Air‑Fuel Ratio (AFR): He targeted 12.0–12.5 under full boost to stay rich enough to prevent knock.
  • Ignition Timing: Reduced from stock 26° to 18° at peak boost to avoid detonation.
  • Boost Pressure: The manual boost controller allowed adjusting from 6 psi to 9 psi. Chris settled on 8 psi for a safety margin.

He also datalogged using the Hondata software to monitor knock sensor readings. No significant knock was detected after final tuning.

Performance Results: From Stock to 240 Horsepower

After tuning, the Integra laid down 240.6 hp and 201 lb‑ft of torque at the wheels on a DynoJet dynamometer. Stock GS-R numbers are typically 130–140 whp, so the gain of over 100 whp was a massive improvement.

Dyno Charts and Measured Gains

The horsepower curve rose steadily from 3,500 rpm, with a strong surge after 5,500 rpm as the VTEC crossover engaged. Unlike a turbo, torque did not spike but instead climbed to a plateau from 4,500 to 7,000 rpm—almost 50% more torque than stock. The intercooler kept intake air temperatures within 20°F of ambient during the pulls.

Butt-Dyno Impressions: How It Feels on the Road

Chris described the difference as night and day. “Foot to the floor from a 40 mph roll, the car pinned me to the seat. It pulled hard all the way to the 8,000 rpm redline.” On the highway, passing required only a gentle push on the accelerator. The supercharger whine was audible inside the cabin, especially with the windows down. Chris likened it to a small aircraft turbine spooling alongside the VTEC roar.

Daily Drivability and Reliability After Installation

After a year of daily commuting and weekend canyon drives, Chris reports no major issues. He changes the supercharger oil every 15,000 miles and uses synthetic 5W-30 engine oil changed at 3,000-mile intervals. The Rotrex unit itself has been reliable, with no signs of bearing wear. The increased heat from the supercharger required upgrading to a Mishimoto aluminum radiator and a lower-temperature thermostat to keep coolant temps below 200°F in traffic.

Fuel economy dropped from 27 mpg combined to about 22 mpg, but that’s expected with any forced induction setup. He also added an oil catch can to reduce blow‑by from the PCV system, which is a common recommendation for boosted Honda engines.

Cost Breakdown: What Did This Build Really Cost?

Chris kept track of every dollar. Here’s his approximate total:

  • Rotrex C30-94 supercharger kit: $3,800
  • Walbro 255 fuel pump: $100
  • Injector Dynamics 750cc injectors: $380 used
  • Hondata S300 ECU and harness: $695
  • Mishimoto radiator and slim fan: $350
  • Oil catch can: $60
  • Miscellaneous hoses, clamps, and gaskets: $100
  • Dyno tuning session (3 hours): $450
  • Labor (self): $0

Total: $5,935 (excluding the cat-back exhaust and intake he already owned). For comparison, a quality turbo kit for a B‑series can run $2,500–$4,000 plus tuning. Chris feels the premium for supercharger linearity was worth it.

Conclusion: Is an Integra Supercharger Build Worth It?

Chris’s 240‑hp supercharged Integra proves that a relatively simple forced induction setup can transform an already fun chassis into a genuinely quick street car. The power is usable, the installation is DIY-friendly for someone with intermediate skills, and the reliability has been excellent with proper maintenance. For anyone sitting on a healthy Integra GS‑R or even a non‑VTEC B18, a centrifugal supercharger offers a rewarding upgrade path that doesn’t require building the engine internals. As long as you budget for ECU tuning, supporting mods like a radiator and catch can, and commit to 3,000‑mile oil changes, the result is a car that punches well above its weight.

For more information, check out the official Hondata S300 tuning resource and the Rotrex supercharger product page for Honda-specific kits.