To find out just where that critical mass lies, we put a tough motor to the test. Our stroker small-block was built right from the start with forged pistons, a forged crank, H-beam rods, and all the good hardware to take tons of abuse. But, everything good has its limit, and a bit later we'll show you how we went beyond it. The important thing to remember when running nitrous oxide is that too much is not a good thing, and small amounts of the stuff can go a long way. Check out our test results and pay close attention to the details we present. We learned a lot from this dyno bash, which hopefully will keep you from sqeezing your engine to the point of destruction.
The Dyno Squeeze
We wanted to push right through the envelope and see just how much nitrous our strong Mouse could take before it cried Uncle. We hope that by doing so, you'll read what we've done and not make the same mistakes! Basically, we found that even a strong motor will not live with more than 200hp worth of nitrous when 92 octane is its only source of fuel. Racers typically run 110-plus octane and some will even inject alcohol into the mix to keep the engine out of killer detonation. While our engine had more than 10:1 compression, and a more wisely built street nitrous motor would have less, we know that car guys don't always take the wisest path.
So we didn't either, in fact we did exactly what you're NOT supposed to do just to see precisely what it would do. We gathered up several different Nitrous Oxide System kits and ran through some of the recommended fuel and jet settings to see how close our power gains would come to the claims made by NOS. In truth, we don't think anyone could have come closer to perfection. NOS really has their numbers nailed down and when they say you're going to see a 100hp increase, you can bet you're making about 100 hp more.
If, like us, you insist on running strictly pump gas with your doses of nitrous oxide then consider taking LOTS of ignition timing out of the equation. The bare minimum is 2 degrees for every 50 hp of nitrous, but you're safer with 4-degrees-per-50 hp. Keep in mind that most successful racers run as little as "0" degrees advance when their nitrous systems are at the highest power levels. It's the only way to keep the engine alive, and although higher octane helps, too much advance can still be a killer with nitrous.
To begin our tests, we choose the smallest of the small nitrous kits just to see how it would do. We modified our air cleaner base and mounted NOS's Top Shot nitrous kit above the carburetor. The Top Shot is truly the easiest nitrous kit we've ever run, and it would take only about one hour to install on your car. Don't let its diminutive size and easy installation fool you, however. The Top Shot is a legitimate power adder, capable of injecting 100-150 extra horsepower, all the while hidden inside your air cleaner. Check out the dyno test figures for the Top Shot set at 100 hp to see how you can turn your pump-gas Mouse into a pony killer without anyone being the wiser.
While the Powershot kit is truly the next step up from the Top Shot, it is not adjustable, and we only wanted to test adjustable kits. So we removed our Holley four-barrel and placed the Super Powershot plate underneath. This would be the last time we had to remove the carb for our tests since both the Powershot/Super Powershot and Cheater systems we'll run share the same nitrous plate. It was so easy to make tons of power with this kit, we thought we'd found Nirvana. The first pull on our pump gas stroker with the Super Powershot jetted for a 100hp increase netted us 587 hp and 598 lb-ft of torque. That's an instant increase of 92 hp and 115 lb-ft of torque.