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?