The Buick Grand National debuted in the 1980s as a wolf in sheep’s clothing, a midsize coupe that packed a turbocharged V6 capable of humbling many contemporary V8s. Over three decades later, this iconic machine remains a favorite among performance enthusiasts who appreciate both its unique history and its enormous potential for power. However, keeping a Grand National running at its peak—or extracting substantially more horsepower—demands high-quality, carefully selected performance parts. The aftermarket for these cars is mature, with several brands having built their reputations specifically on Grand National components. This guide dives deep into the best brands for Buick Grand National performance parts, focusing on Garrett, APS, and other manufacturers that have proven their worth on the street and the strip.

Garrett Turbochargers

Heritage and Reputation

When it comes to forced induction, few names carry as much weight as Garrett Motion. Founded in the 1930s, Garrett has been a leading supplier of turbochargers to both OEMs and the aftermarket for nearly a century. The company’s involvement with the Buick Grand National goes beyond simple part sales—many of the OEM turbochargers used on the Grand National were manufactured by Garrett. This factory pedigree gives enthusiasts confidence that a modern Garrett upgrade will integrate seamlessly, with the same reliability that made the original car a legend.

Key Models for the Grand National

For owners looking to replace or upgrade their stock turbo, Garrett offers several air- and water-cooled options that fit the 3.8L V6’s unique packaging requirements. The GT3582R (commonly called the GT35R) is a popular choice, delivering excellent spool characteristics with a broad power band. It can support up to 600 hp with the proper supporting modifications. Another option is the GT3788R, which moves more air and suits builds targeting 700+ horsepower. For those seeking extreme power, the GT4508R and even the G Series turbos (like the G30-770) offer frame sizes that can push into four-digit territory, though they require substantial fuel system and bottom-end upgrades.

Why Garrett Stands Out

Garrett turbochargers are engineered with journal-bearing and ball-bearing options, the latter providing faster spool and improved transient response. The use of Mar-M superalloy turbine wheels and compressor wheel technologies ensures durability at high boost levels and elevated exhaust gas temperatures. A Garrett upgrade is not just about peak horsepower; it is about usable power delivered reliably. The brand’s engineering support and wide availability of service parts mean you can rebuild or modify a Garrett turbo years down the road, which is critical for a vintage platform like the Grand National.

Key benefits include:

  • Factory-original fitment heritage ensures bolt-on compatibility.
  • Ball-bearing center sections reduce lag compared to stock journal-bearing turbos.
  • A wide selection of A/R ratios and turbine housings to match street or race needs.
  • Global availability and extensive community knowledge for tuning.

APS Performance Parts

Precision Engineering from Down Under

Advanced Product Solutions (APS) is an Australian company that has carved out a dedicated following among Buick Grand National owners. While many companies offer generic universal parts, APS designs components specifically for the turbo Buick platform. Their focus on fitment, flow, and durability has made them a go-to choice for serious performance builds, especially for those who want to eliminate the bottlenecks of the factory system.

Flagship Products

APS is perhaps best known for its large front-mount intercooler (FMIC) systems. The factory intercooler is notoriously restrictive, limiting power potential. APS intercooler kits come with polished aluminum end tanks, high-flow cores, and mandrel-bent piping that drastically reduces pressure drop while improving heat rejection. They also offer complete fuel system upgrades, including in-tank pumps, hot-wire kits, and billet fuel rails that accommodate modern injectors for builds requiring over 700 hp.

Another standout product line is the APS downpipe and exhaust systems. The factory single-slip downpipe is a major restriction. APS provides stainless steel downpipes with a smooth mandrel-bend design and provisions for stock oxygen sensors, making installation straightforward while significantly reducing backpressure. Combined with an APS cat-back or dual exhaust system, the result is a noticeable improvement in spool and top-end power.

Why Enthusiasts Rely on APS

APS parts are built to withstand the heat and pressure of a high-boost Grand National. Their intercooler cores are bar-and-plate construction rather than tube-and-fin, meaning greater durability under high boost. The company also provides detailed instructions and customer support specifically for the G-body chassis, which saves countless hours of fabrication. Many local Buick Grand National shops recommend APS as a direct replacement for the weak points of the factory setup.

Key benefits:

  • Purpose-built for the 1984–1987 Buick Grand National chassis.
  • High-flow intercoolers reduce intake air temperatures by up to 100°F on the street.
  • Complete kits reduce installation time and guesswork.
  • Proven on drag strips with 9-second quarter-mile passes.

Other Top Brands for Grand National Performance

Holley – Fuel and Induction Experts

Holley has been a benchmark in the performance industry since 1903, and while they are famous for carburetors, their fuel injection systems and EFI components are equally relevant to the turbo Buick crowd. For Grand National owners converting to sequential fuel injection or upgrading from the stock throttle body, Holley’s HP and Dominator ECUs are popular choices. Additionally, Holley offers high-flow fuel pumps, regulators, and billet fuel rails that integrate seamlessly with aftermarket turbochargers. Their Quick Fuel Technology line includes billet throttle bodies sized for the Grand National, providing improved airflow over the stock unit.

Kirban Performance – The Buick Specialist

No list of Grand National parts brands would be complete without Kirban Performance. Founded by Dennis Kirban, a longtime Buick enthusiast and writer, Kirban Performance is a dedicated source for Buick-specific upgrades. From simple restoration grommets to high-performance camshafts, oil pump kits, and even billet transmission adapters, Kirban has been supporting the community for decades. They are also the go-to provider for many hard-to-find OEM-remake parts, such as dash bezels, interior pieces, and weatherstripping. For a comprehensive build, most owners will place at least one order from Kirban.

TA Performance – Engine Components

TA Performance specializes in performance Buick V6 engine hardware. Their aluminum cylinder heads are a cornerstone of high-horsepower builds, offering a significant reduction in weight and much improved airflow compared to the cast-iron factory heads. They also manufacture aluminum intake manifolds, valve covers, and even roller camshaft kits specifically for the 3.8L. TA’s heads come with larger valves and ready-to-run valve train packages that can support over 1,000 hp with proper preparation. For anyone building a serious stroker or high-boost engine, TA Performance is the most reliable source for cylinder head and intake upgrades.

Precision Turbo & Engine

Precision Turbo is another heavy hitter in the forced induction world, and their turbos are common on high-horsepower Buicks. The PT6266 and PT6466 are excellent choices for the Grand National, offering ball-bearing durability and efficient compressor maps. Many builders pair a Precision turbo with a TA Performance intake and APS intercooler to create a well-coordinated system. Precision also manufactures its own line of wastegates, blow-off valves, and intercoolers, though their turbos remain the main attraction.

Choosing the Right Parts for Your Buick Grand National

Define Your Performance Goals

Before spending a single dollar, it is vital to outline what you want the car to do. A street-driven Grand National that sees occasional weekend cruising and the odd highway pull has very different requirements from a dedicated drag car that lives at the track. Horsepower targets, boost levels, and intended usage dictate everything from turbo size to intercooler capacity to fuel system requirements. A 400–500 hp street build can often get by with a Garrett GT3582R, an APS intercooler, a decent fuel pump, and a reflashed factory ECU with upgraded chip. If you are aiming for 700+ hp, you need a larger turbo, aluminum heads, forged pistons, a race intercooler, and a stand-alone engine management system.

Budget Realistically

Performance parts for the Grand National range from relatively affordable (a used intercooler or bolt-on downpipe) to extremely expensive (fully built short block, billet turbo, etc.). Setting a realistic budget upfront helps you prioritize. Many owners start with the supporting mods—intercooler, downpipe, fuel system—because they unlock the potential of the stock engine without breaking the bank. Then, when the budget allows, they upgrade the turbo and install a larger set of injectors. The community is also filled with used parts in good condition, so keep an eye on forums like TurboBuick.com or Facebook groups.

Ensure Compatibility

The Buick Grand National was produced from 1984 through 1987, and while the powertrain is largely common across those years, there are subtle differences in injection systems, wiring, and accessories. For example, 1984–1985 models used a different computer setup than the 1986–1987 cars. When ordering parts, always specify the year and model. Brand-specific compatibility charts (like those from Kirban or APS) are worth consulting before purchase. Additionally, if your car has been previously modified, you may need adapters or custom brackets to fit new components.

Supporting Modifications Are Non-Negotiable

It is a common mistake to install a massive turbo without upgrading the fuel system, intercooler, or exhaust. Even the best Garrett turbo cannot deliver its full potential if the car is still running a restrictive stock downpipe, a clogged fuel pump, and the tiny factory intercooler. When planning upgrades, think in terms of systems rather than isolated parts. A complete package generally includes:

  • Fuel system: High-flow pump, hot-wire kit, larger injectors (at least 60 lb/hr for 500 hp; 80 lb/hr for 600+), and an adjustable fuel pressure regulator.
  • Intercooler: A large front-mount core (APS or similar) capable of handling heat soak during repeated boost runs.
  • Exhaust: Free-flowing downpipe (3-inch recommended) and a cat-back system with no restrictions.
  • Tuning: A properly burned chip or stand-alone ECU tuned by someone experienced with the Buick V6.
  • Transmission upgrades: The stock 200-4R can handle moderate power, but 500+ hp usually requires a billet servo, shift kit, and possibly a rebuilt unit with stronger clutches.

Installation and Tuning Considerations

Professional vs. DYI Installation

Many Grand National owners are hands-on and enjoy the process of upgrading their cars. Basic bolt-on parts like intercooler kits, downpipes, and even turbo swaps can be done in a driveway with standard tools. However, certain tasks—such as installing a camshaft, porting cylinder heads, or wiring a stand-alone ECU—require more expertise. If you are not comfortable tuning or setting base timing, it is wise to have a professional Buick specialist or a reputable performance shop handle the final stages. Bad tuning can quickly destroy an engine, especially with a large turbo and high boost.

The Importance of Tuning

The factory ECU on the 1986–1987 Grand National (called the ITC or ECM) can be reflashed with a custom chip, which is the simplest route for modest upgrades. Companies like Turbo Tweak and Cal Hartline offer mail-order chips burned for your specific combination of parts. For larger builds, a stand-alone ECU like the Holley HP or the MoTec M130 unlocks full control over fuel and spark maps, boost control, and data logging. Tuning should be done on a dynamometer (dyno) to maximize safety and performance.

Maintenance Before Upgrades

Before bolting on high-performance parts, ensure your Grand National is mechanically sound. Compression test, leak-down test, and a thorough inspection of the cooling system, ignition system, and fuel delivery are essential. Old vacuum lines, decaying rubber hoses, and weak spark plugs can limit the gains from even the best aftermarket parts. Replace any worn components—especially the camshaft and timing chain—if your engine is high-mileage. Many owners choose to rebuild the entire short block with forged internals before adding significant power.

Where to Buy and Community Resources

Purchasing performance parts for the Buick Grand National is best done through established dealers and specialist vendors. Kirban Performance, GNX–Style, and RJC Racing are trusted sources. Online forums like TurboBuick.com and the Buick Grand National Facebook Group offer peer reviews, installation tips, and a marketplace for used parts. Reading build threads on these forums can give you a real-world sense of what works and what doesn’t. Additionally, many of the brands mentioned (Garrett, APS, Holley, TA Performance) can be purchased directly from their official websites or through performance retailers like Summit Racing or Jegs.

Conclusion

Upgrading your Buick Grand National with quality performance parts can transform an already legendary car into a genuine modern-day powerhouse. Whether you choose a Garrett turbo for its proven reliability, an APS intercooler for its fit and finish, or a combination of Holley fuel management, TA Performance heads, and Kirban’s specialty items, the key is to select components that work together harmoniously. By defining your performance goals, setting a realistic budget, and investing in supporting modifications, you will unlock the full potential of that turbocharged 3.8L V6. The aftermarket ecosystem for the Buick Grand National is rich and well-developed—taking advantage of it will reward you with an exhilarating driving experience that honors the car’s heritage while pushing its boundaries far beyond the factory specifications.