Bolt and Go, Part IV

At CHP, we thrive on building engines and raising the horsepower bar--especially when the results produce performance as rewarding as Holley's Pure Street Avenger system. Since our Bolt and Go series began in the Apr. '02 issue, we've been busy bolting on the first three stages of Holley's Pure Street system and watching our Nova's track times fall like dot.com stock prices.

Starting with a stock two-barrel 350 Nova, our baseline e.t. was a sluggish 17.27 pass. From there we added Holley's Pure Street Stage One system consisting of a Holley carburetor, intake, ignition, headers, and exhaust system. Those modifications lowered our e.t. to a healthy 15.44. With Stage Two, our Nova received a high-lift Lunati camshaft and timing chain. To enhance Stage Two's power, we also installed an Art Carr 10-inch high-stall converter. Our track times again improved to 14.81. Stage Three added a pair of Holley SysteMAX aluminum cylinder heads, a set of Reider Racing 3.73 gears, and an Eaton posi unit to maximize the Nova's acceleration curve. When we were done, we had shaved the Nova's track times from a lazy 17.27 at 79.16 mph to a hustling 13.37 at 102.18 mph. But like you, we can't stop pushing the performance envelope, so we dialed in a Nitrous Oxide Systems (NOS) Powershot system that pushed our Nova solidly into the 12s. Here's how it works.

Throttle in a Bottle

The first step to installing the Powershot system involved removing the carburetor and adding the injector plate. Because the plate is 1/2 inch thick, longer carburetor mounting studs are also provided, along with two plate fittings for mounting the nitrous and fuel solenoids. The Powershot kit is activated by a micro-switch that must be mounted on the carburetor linkage to trigger at wide-open throttle >> (WOT). We mounted our switch on the rear carburetor stud, and by bending the mounting bracket, the switch engaged at exactly full-throttle. Power to the micro-switch is supplied by a 12-volt switched source at the Nova's fuse-block.

With the bottle and mounting brackets secured in the trunk, we routed the braided-steel line from the bottle along the existing fuel line into the engine compartment. We were careful to avoid the heat and suspension areas and secured the line in several places with nylon tie wraps. To prevent engine-damaging detonation with the nitrous, we retarded the initial timing by 6 degrees, reducing our total ignition advance from 38 degrees to 32 degrees.

Track Time

We made a few quick test blasts in First and Second gear and immediately felt a drastic performance improvement with the Powershot system. The following day we headed to our local track with our tools and a pair of Mickey Thompson E.T. Street tires in the trunk. For our first pass, we short-shifted the Nova at 4,500-5,000 rpm to evaluate how the car responded to the nitrous. This netted a 12.80 e.t. at 110.08 mph. Now that we felt comfortable with the nitrous system's manners, we lined up the Nova for a full-on test. This time we shifted at 6,000 rpm and stopped the clocks at 12.46. To see if we could back up that time, we rechecked the rear tire pressure, lined up one more time, and staged the car. The Nova blasted down the track again and clocked a 12.45 pass at 110.73 mph. Wow! With the Pure Street package, a mild stall converter, and the proper gearing, we now have a car that can do it all. A mid-12-second street car that drives easily in L.A. traffic. That's a pure blast.