Dubbed the Japanese Ferrari when it debuted in 1990 as a 1991 model, the Acura NSX is a "wish car" for many heavy-footed enthusiasts, this writer included. The wind-splitting dream machine is pure performance with a stout VTEC-enhanced 270-hp V6 mounted amidships, a smooth five-speed manual and 11-inch discs front and rear. The high-tech aura of the car can be seen in the sheet metal and beyond. Aluminum is the weapon of choice for the chassis, body panels, sub-frames, suspension a-arms, coil springs and anti-sway bars.
The first gen NSXs (1991 to 1996) are the most abundant and affordable examples but the gene pool is only about 6,800 samples deep, so these seductive sport coupes are rare gems indeed. The prices of used and abused early 1991 and 1992 models have come down to where mere mortals can afford them. The "used" check in from $27,000 to $30,000 while the "abused," higher-mileage models can be had for as little as $20,000; and as usual, the key to finding the bargain is timing.
When it comes to boosting, the NSX turbo freaks have had it hard. The midship engine configuration makes turbo placement a tough cookie to crack. There have been twin variable-vane turbo systems with the hairdryers placed beneath the engine. The challenge here is oiling the center section(s), which end up below the oil pan making regulating the flow of oil difficult. Also intercooler placement can be a nerve-wracking, knuckle-busting process, with some systems putting the chiller in the rear trunk area.
Gerry Johnson is a machinist/enthusiast turned car builder/tuner and his boosting odyssey led to the creation of Performance Autoworx in Modesto, Calif. Johnson was in the market for an NSX and found the one in Dallas, Texas. He drove it home and installed a set of lowering coils and some Work wheels he had waiting in the wings.
"After owning many fast cars in the past (five 300ZXs, an '89 slant-nose Porsche) I was a little, actually a lot, disappointed with the power of the NSX," relates Johnson. "So I began the search for power-turbo power, that is-and found one company that was making a twin setup for the NSX using Aerodyne turbos. I bought one and installed the kit and was pleased with the increase, but after a few months, 75 extra ponies was no longer enough. So I added some larger Aerodynes, pushed the boost from 7 psi to 10 psi and added an Electromotive TEC-II for management. This was too much for the turbos; they were killing bearings almost instantly even through they were rated to 15-17 psi. After burning up seven turbos and $7,000 in the course of a few months, I had enough and that's when this NSX adventure really begins."
"I decided to build my own turbo kit using a Garrett turbo," says Johnson. "To simplify things with the plumbing of the system I decided to go single and I then set off fabbing the piping and so on. I also knew I had to build the engine to make the power I was aiming for."
Bell & Gaines Racing fitted the C30A with cylinder sleeves and Johnson fortified it from the crank on up with a set of 9.5:1 compression JE slugs; stock titanium rods machined and bushed to incorporate floating pins and ARP fasteners on call at every turn: rods, main studs, head studs, etc Johnson also worked his magic on the V6's cylinder heads. He un-shrouded the pockets and worked the short side radius just past the seats to enhance flow around the valves and then matched the intake ports and polished the runners. The heads were assembled with Ferrea valves, Crower titanium retainers, Crower keepers and R&D double spring valve springs.
To address any possible oiling issues, Johnson upgraded the oiling system with a billet oil pump gear designed to increase flow 30 percent, constructed special baffling in the pan and added a Fluidyne oil cooler.
As the accompanying photos reveal, the turbo is placed low on the passenger side in the rear diffuser area and plumbed directly into a polished Magnaflow muffler then piped across the back of the car, exiting on the driver's side. Johnson's turbo is a Garrett Stage 3 Ballistic unit with a 62-1 compressor wheel. The system has a max of 28 psi, but Johnson tabs street boost at 15 psi. The intercooler hurdle was cleared in a clever manner. Johnson went top mount using a Spearco core and a custom carbon fiber scoop to direct cool air into the unit.
"After talking with Fred Schueptler at Electromotive about the then-new TEC-III, I was convinced I had found the perfect ECM for my car," says Johnson. "I bought one, a set of 680cc Bosch injectors, a Denso 320 lph pump and some -6 line and I was soon ready to tune."
The Acura was a handful on the dyno because the trick carbon fiber diffuser makes tying down the car difficult. Even with a volunteer acting as dead weight by sitting in the trunk, the Acura tended to spin the tires at 6400 rpm. Still, the NSX generated a 507 by 507 graph (507 hp and 507 lb-ft of torque) on a Mustang chassis dyno at a scant 16 psi. The power curve is mean and flat. Sampling for the run begins at about 4800 rpm and by 5100 rpm wheel horsepower is already at 450 and the C30A maintains peak power for quite a while.
Johnson says his car will get about 24 mpg under normal driving conditions. He has driven it up to 350 miles to shows and other events and has averaged about 10,000 miles per year, so this baby knows the road. A customer drove his boosted NSX 2,300 miles back to Missouri netting more than 26 mpg during the trouble-free trip. "I would have to say that driving my car compared to a stock NSX would be like having a real healthy big-block chevrolet for a motor," says Johnson, " there is no turbo lag and it has instant throttle response, the sound of the air rushing threw the IC and the blow-off valve are almost intoxicating. It is a rush just driving the car to the store because of its power down low and the turbo's response time. At higher boost levels like at 18 to 20 psi it will tear the CV joints out in just a few hard runs and when I boosted it at 23 psi on a third gear pull on a back country road it tore almost all the teeth off the pinion gear and half the teeth off the ring gear."
Johnson's 1992 NSX is a rolling business card for the Performance Autoworx NSX kit, which can best be described as a limited-production one-off. But the car is not as static as a typical business card. "Since adding the turbo kit, the car has undergone many other changes. I have had eight sets of wheels on the car; three sets of Works, four sets of Volk Racings and the current Ro_Ja offerings. I have had four sets of seats; two sets of Brides and two sets of Sparcos as well as three different rear diffusers. Currently, the car is body tuned with Wings West rockers, a Fiber Images carbon fiber hood, carbon fiber side intakes and custom headlights.
The turbo system is not sold for public installation; all kits are installed and tuned at Performance Autoworx. The cost is currently $8,900-the car arrives naturally aspirated and leaves fully boosted, tuned, and ready to burn rubber. This price includes the TEC-III, intercooler and all labor. The only options are a boost controller and turbo timer. Adding a built C30A to the ledger will cost $9,000 and says Johnson, "you will get all the best of everything."
The bottom-line here is it's time to scorch the earth in search of that $20,000 abuse victim. Then add $17,900 and for $37,900, or what most 1997-and-ups are going for, you can feel the Gold Rush Fever at 500-plus to the wheels. Hello, eBay?