Shooting Nitrous On A 500hp Supra Turbo

Nitrous. Turbo. Blowers. Used to be people aspired to install a power adder and be content with the large power increase netted from such a component. Add a supercharger to your BMW, for example, and increases in power up to 45–50 percent can be realized. Only the greedy would need more. Welcome to the land of the greedy: MAX Power magazine.

We are betting that many of our readers are nearing a point in the modification process of their vehicles wherein most areas of performance have been addressed. Case in point, my Supra Turbo, a previous MAX feature car (March ’99).

Like many of you, I’ve spent a great deal of time and money installing virtually every bolt-on available for his car. A GReddy Intercooler, boost controller, Rod Millen Downpipe, G-Force Race computer, GReddy Airinx Intake, and a host of other go-fast goodies from Powerhouse Racing have all found their way under the hood of my Supra. The car’s power output is now a healthy 424 hp to the wheels, but this is not quite enough.

A big T66 turbo kit is due to be installed soon by Dave Jusco (Stay tuned to the pages of MAX for this feature.—MAX). This setup should make the Supra a beast on the dragstrip. In the interim, I’ve analyzed the projected horsepower and powerband of the Supra after the new turbo will be installed, and the plan of attack is to eliminate that dreaded foe, turbo lag.

Vinny Ten and the folks at Performance Factory have done a good job of setting up the turbo so lag will be minimal. But in light of the fact that Supra Turbos always lack that off-the-line punch, it was decided that something else was needed. That something else was nitrous.

Before you grimace at the thought of adding nitrous boost on top of turbo boost, be advised the stock Toyota 3.0L motor is a very stout piece right from the factory. In fact, with a proper fuel system, 600 hp with stock internals is not out of the question. When all the mods are completed on my Supra, power will be kept at a modest 550.

So how much nitrous would we use? For the answers to this and many other questions, we went to the experts, Nitrous Oxide Systems in Costa Mesa, California. According to Wady Hamam, NOS technical guru, “Turbo cars can benefit greatly from a modest nitrous kit. On the Supra, for example, a 50hp shot will do wonders to spool the turbos up faster and totally eliminate turbo lag.”

We were sold. The car was delivered to NOS’ shop for the installation, as everything would have to be done by the pros to ensure proper and safe function. It was decided that a wet system (part #5348 for Supras) would be utilized with a single-fogger nozzle, located in the air stream directly in front of the throttle body.

No Worries
Fortunately, all the guess work is totally eliminated when buying a kit from NOS. As the pioneers of the industry, its kits are always complete. In fact, NOS sells kits specifically for turbocharged applications.

On this particular application, we had a variety of options as to how to activate the system. A progressive controller, a microthrottle switch, or push-button activation were all possibilities.

Since the kit would be used to simply spool up the turbos, we decided that the best option was to use a manually controlled push button along with a microswitch for safety.

The system works like this: First, the bottle valve must be open. Then an activation switch, cleverly hidden in the vehicle’s ashtray, must be in the “on” position. Next, as rpms reach the 3,500 mark, the driver can hit the activation button at will, and as long as the throttle is wide open, the microswitch will allow nitrous to flow. The microswitch is an important safety mechanism. Without this switch, the nitrous would be able to flow at any rpm, which can be dangerous, as fuel enrichment is only adequate when the car is at full throttle.

Results
Once we installed the NOS, a brief testdrive was quite revealing. Not only was all semblance of turbo lag gone, but the car was positively transformed. On most turbo cars, torque is not exactly stump pulling until further up in the powerband. With the NOS kit installed, power and torque are strong as soon as you hit the gas. Boost spikes up faster than you’d think possible, and the acceleration is neck snapping. On our testdrive, we rolled onto boost in First gear, short shifted into Second, and hit the button. This resulted in a sideways slide, as the Supra’s massive 285s struggled for traction. The run was aborted because the car was doing 65 mph at this point, and it was obvious that the tires were no match for the power. With slicks, however, and in a drag race environment, the car should perform as advertised.

A quick check of the EGT gauge revealed that the fuel mixture was not lean, as temps were well within the safe range.

No dyno or dragstrip testing was done at this juncture, but the point of this installation wasn’t just to satisfy my insatiable appetite for horsepower, but instead to get the car out of the gate a little quicker. The only limit to that now is traction. Sorry, but this conclusion will have to wait, because anything worth doing is worth doing right.