Grand national

The Buick Grand National enjoyed it’s performance success in the middle of the 80’s. The turbocharged V-6 3.8L shined like a diamond in the roughness of emission choked vehicles of the day. Slight modifications to grand nationals would provide great power gains. Emissions choked all but a few other cars. The four most popular grand national years, were all fuel injected cars from 1984-1987. The final two years of the grand national, 86-87 were also intercooled and had a much better flowing exhaust header and crossover setup.

 

The intake manifold was also a little better. Slight modifications make huge power improvements. The 86-87’s can run 12 second quarter mile times for approxamately $1000.00 worth of aftermarket parts. That’s fast for not alot of money. Simple add ons such as cold air systems and computer chips with higher boost can make 40+ horsepower. The 84 and 85 model can be converted by changing the intake setup and exhaust to the newer style. Most people will not do this as it can be quite a bit of work. Most people changing intercoolers will have their stock intercooler modified to add more fin cross area. Others will purchase a front mount air to air intercooler similar to the stock intercooler. Many drag racers will purchase an air to water intercooler. It has a smaller amount of internal volume meaning less lag time, yet cools more than an air to air intercooler. Water can exchange heat faster than air and is more efficient. The downfall is the price which is usually much higher than an air to air. The exhaust is also one of the first things to change on all of these cars and can yield great benefits. The 1986 and 1987 headers were fairly efficient and are not usually changed until after the car is already running very fast. For the 1984 and 1985 grand national, aftermarket headers could benefit the car. Both cars will greatly benefit from a 3″ downpipe. Many of the down pipes handle the wastegate layout much better than stock. Some people go with single 3″ exhaust to the rear, for less weight than the 2.5″. While some people complain it’s a little bit louder, that is only relative to the very quiet 2.5 inch dual exhaust. By nature of the layout both systems flow about the same, and make similar horsepower. The fuel system should soon be upgraded to keep up with the performance gain. An adjustable fuel regulator is usually one of the first fuel system upgrades. The fuel pressure should be checked as is stock and usually turned up a few psi at idle. Going to0 high with fuel pressure will blow out black clouds of smoke, (too rich) and will actually lose power.