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Nitrous Oxide Systems - Squeeze Play

Making All The Power You Can Handle With N2O

By Mike Petralia

Next, in went the jets for a 125hp increase and the Mouse shot back with 606 hp and 625 lb-ft of grunt. Suddenly, we had a genuine 600hp pump gas small-block with just the push of a button. Of course, we had removed 6 degrees of ignition advance by this setting, just to be safe. This was too easy. We wanted more.

All during testing we kept a close eye on exhaust gas temperatures (EGTs) and Brake Specific Fuel Consumption (BSFC) figures to see how our motor was doing. High EGTs and low BSFCs indicate dangerous ground. But, so far this Mouse could handle its cheese with the big boys. We stepped up to what some might say is the maximum safe limit for nitrous oxide injection on pump gas: 150 hp. Before making a pull at this setting, we carefully rechecked the nitrous fuel system's flowing pressure to be steady at 5.5 psi. We squeezed the button again at 3,500 rpm and got 643 hp and 690 lb-ft in return. If you've ever had the chance to drive behind this much power, than you'll appreciate how excited we were. And in typical car guy fashion, we ignored the rules of better judgment and plunged stubbornly ahead with only 92 octane in our tank.

Cheater In The Mix
Seven hundred pump-gas horsepower was our goal, and we were mere ounces of nitrous away. Having no fear, we replaced the small Super Powershot solenoids with the large Cheater counterparts and went straight to the 210-hp setting, defying the wise advice of the NOS techs to start out small. We also pulled an additional 2 degrees out, (our first mis-calculation) and left the flowing fuel pressure at 5.5 psi (our second mis-calculation).

As Mike Thermos and his techs looked wearily on, we squeezed 700 hp and 755 lb-ft of sinful torque from what we were soon to find was our battle-wounded Mouse. So infected with the horsepower bug were we by then that we dove deeper into the nitrous abyss as the NOS crew amusedly watched us approach total annihilation. It was our show, and there was no stopping us now. In typical car guy fashion, we reached into the NOS kit and pulled the biggest jets out of the Cheater kit. We figured that pulling yet another 2 degrees out (10 total) would suffice, and we were ready for another pull.

Editor's note: We'll stop right here and ask you to put yourself in our shoes at this point. If you were at the track, and the 210-hp jetting just helped you to run something like a 10.13 pass, would you have gone home without testing the big jets? And if you did test the big jets, would you have taken the time to at least pour some 110-octane race gas into your tank to up your octane quotient to a safer level? While you can all sit there now and answer "yes" to both of these questions (remember, we know how your brain works), most likely the excitement of being so close to a 9-second pass would overcome your sense of reason, and those 250hp jets would be in before your tires had a chance to cool.

So we did what we felt every car guy would do, squeezed it one last time (our final miscalculation). An engine on the dyno is typically much louder than in a car because it's running at WOT just a few feet away in a closed room with only a thin wall separating you from it. But, if you can hear the engine detonating on the dyno, it's already too late. Although dyno-operator George Vrbancic's years of experience told him something was amiss as soon as we hit the button, it was over in about two heartbeats. The engine made power from 3,500 to 5,000 rpm and even cranked out its highest peak torque of 770 lb-ft before dying. With the battle won, but the war lost, we hauled our once-proud 700-hp Mouse home to see what did it in.

By Mike Petralia
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