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This 1987 Buick Grand National is a survivor. Unrestored and driven hard.
The owner came across this vehicle in January of 2000. A friend of a friend owned it, and when he decided he was done with the vehicle, his children started fighting over it. Not wanting to deal with the drama, he sold it to a local dealership and told his kids, "If you want it so much, go buy it." Except the owner got there first. As the proud third owner, he drove the vehicle home on cold January day with just 16,271 miles on the odometer. It was bone stock save for a CB antenna. Today, with over 80,000 miles, this car has been completely transformed.
The first twelve years of ownership were largely uneventful. A few simple bolt-ons, custom chips, and 16" wheels went on. These years were mostly spent taking the vehicle to car shows, with an occasional outing to the drag strip or an autocross just for giggles. It was wallowy and difficult to control in autocross situations. On the drag strip, the bone stock motor made it to a 13.07 @ 104mph with a chip.
After the owner sold his primary autocross car in 2012, he turned his attention to his remaining toy. Uprated springs and Bilstein shocks improved the handling, but it still chewed up tires, and the strict SCCA rulebase made running it in autocrosses problematic. Altering the boost at the time bumped the car all the way into Street Modified, a class dominated by lightweight imports with exotic powertrains and no street manners.
Then in 2014, the world opened up. The SCCA Introduced the Classic American Muscle class. Finally, a place to play that suited the vehicle! A larger turbocharger and conversion to E-85 resulted in a lot more power. In August of that year, the car blew a head gasket at Lucas Oil Raceway during a run in which it coasted across the finish line at 111mph, a new personal best. That failure prompted an engine-out service and the beginning of serious work transforming the car. This build has been a steady process of identifying and fixing problems in a methodical way, not shotgun blasting parts at the vehicle and wondering why it was being beaten despite the expense.
The engine was rebuilt by the owner over the winter of 2014/2015. Since the Buick V6 has been tuned on for thirty years, straightforward build recipes exist. The strategy was to build the engine for 550-600hp, but run it at 400-450 to keep it reliable. The heads were professionally ported and polished, the block was bored .030" over standard, torque plate honed, and line bored. New forged pistons were fitted to the already stout stock steel crank and reconditioned rods. The entire assembly was properly balanced at Bell Motor Works in Louisville, Kentucky. The final assembly was completed by the owner. A Comp Cams 260H grind bumpstick combined with the better flowing heads would dramatically increase power. A slight compression bump would help the car get off the line and spool the turbocharger. Engine management is handled by a modified OEM ECU with a custom TurboTweak chip, a Powerlogger data logging module, and a ScanMasterG digital gauge that provides realtime viewing of most engine parameters as well as a Bluetooth link to a cell phone app that logs everything.
The datalogging capability has proven invaluable. It identified a compressor stall/surge problem, described later, and later verified the fix actually worked. By logging oil pressure during autocross runs, the owner debunked a longstanding myth that the stock oil pan and pickup setup wasn't suited for high-performance duty.
The ignition is a Bob Bailey TR6 module with uprated coils. It provides much tighter timing control and a spark-cut rev limiter, with two-step option.
The vehicle's fuel system was switched back to gasoline, and boost was reduced from the 25psi run using E85 to a pump gas friendly 17psi. At its first dyno session after the rebuild using the original 12" torque convertor, the engine put down 310rwhp and 350lb-ft of torque. It was now making just as much power on pump gas as it had on E85, with much less stress on the engine thanks to the lower boost levels. This was declared wonderful.
A Tial blow off valve was fitted after data acquisition at the 2016 Wilmington Champ tour showed the car was taking upwards of 1.7 seconds to build boost after a throttle lift. Air reversion was stalling the compressor. After the valve was fitted, re-spool was reduced to less than half a second after a throttle lift. Driveability dramatically improved.
The OE rubber hose vacuum lines were replaced with a push-loc fitting kit from Cruz Performance to eliminate problems with vacuum lines blowing off their fittings under boost.
The cooling system was upgraded with a huge 3" core aluminum radiator from GN1 Performance, along with dual 1300 cfm fans. A custom PCV system using two catch cans and industrial strength check valves had to be engineered to properly evacuate crankcase gasses without allowing manifold pressure to pressurize the crankcase under boost. The system works so well, the car is likely one of few Buick V6 engines in the nation that does not leak. A Deral power steering cooler helps keep the reservoir from overflowing during heavy use.
Moving further back, a 10" 3100 stall PTC torque convertor took 35 pounds off the crankshaft and allowed the engine to spin up the Precision Turbo and Engine billet turbine 5857 turbocharger. The transmission has been augmented with a CK Performance shift kit, a cast aluminum pan that allows for an extra four quarts of fluid, and a B&M external cooler. An overflow bottle was also rigged to the transmission vent to prevent spoiling the surface if the unit overheated during competition.
After discovering a broken tooth on the ring gear during an inspection in 2016, the ring and pinion were replaced with 3.73 units, and the rear axle assembly was rebuilt with new bearings.
The front brakes are a Wilwood HD disc setup with four piston Dynalite calipers. The rear brakes were converted from drum to disc a using a kit created with off-the-shelf GM calipers and rotors with a mounting plate from ScaredBird. The troublesome Powermaster electric brake booster was replaced with a Wilwood 15/16" manual master cylinder and Wilwood adjustable proportioning valve.
Suspension wise, the vehicle uses Speedtech control arms up front. The owner chose Speedtech because they offered an arm providing additional caster, but still used the conventional spring and shock setup. Bilstein shocks control Moog 5660 springs in the front, and Moog CC651 cargo coils in the back. A custom sway bar created using a NASCAR style 37.5" splined end hollow bar from Speedway Engineering was fabricated by the owner after he was unable to source an off-the-shelf bar with enough bar rate.
At the back, a Fayes2 Watts Link has been installed to override the factory rear roll center, which normally lies somewhere in the trunk. This greatly improved the predictability of the car. The previously ever-present prospect of snap oversteer and spins has been completely vanquished. The stock rear control arms and new OEM bushings remain because the Watts Link requires the stock four link suspension to deform slightly, or else it will bind. The rear anti-sway bar also remains original. The owner has observed other vehicles of this architecture with stiffer rear bars picking up the inside rear tire in turns. This car doesn't.
The wheels are Weld RTS-71B forged in 18x9.5 shod in BFGoodrigh Rival S tires in 275/35R18, the largest fitment the owner can get under the car without cutting sheet metal.
Inside the vehicle, the stock seats were removed after the owner experienced a tilt-column failure during an event. The stock seats were not supportive enough, and the driver had to hold himself in the seat by way of the steering wheel. Not a safe situation. The stock seats were removed and replaced with NRG Sport bucket seats with much better bolstering. A Corbeau four point harness was added for autocross use. The mint condition original steering wheel was removed for safekeeping and another Grand National wheel was sourced used and sent to Dallas Custom Steering Wheels to be recovered in alcantara. The air conditioning and heat remain fully functional, as does the JVC stereo with a mix of Alpine, JL Audio, and Kicker speakers in the stock locations.
The end result has been a car with great street manners and the ability to pull 1.2g laterally on asphalt and concrete. It is competitive in regional SCCA Solo competition, routinely winning its class in its home region, and regularly earning trophies in surrounding regions.
The car has been features in Grassroots Motorsports Magazine (February, 2014, before most of the transformation took place), as well as on the GRM Facebook page during the 2016 CAM Challenge in Peru, Indiana.