Tom Wilson
March 1, 2013

Full results are in the data, but to sum it up, the Snow kit cooled the air charge 22 to 23 degrees on average and delivered an extra degree of ignition timing and thus extra 8 hp with no tuning whatsoever when running naturally aspirated. With the whiff of dry nitrous-meaning no extra fuel was added-the cooling effect was the same, making the super-simple nitrous hit safe and effective, as the medicine adverts like to say. That's tremendous cooling.

The only curious result was the combination of nitrous and water injection didn't result in any greater cooling effect than with the water alone. One explanation is the general trend during these tests was for the intake air temps to continue to drop at the end of the test when the water had already quit flowing, clearly a lag in the data stream. This suggests the water cooling effect could be even greater at the track where the full-throttle applications are longer than a dyno pull, especially with nitrous, where the engine accelerates that much faster.

Given that Snow Performance has worked out the details of water injection, the resulting user-friendly injection kits would seem natural for open-track Mustangs, blown or not. The charge cooling gained certainly delivers peace of mind - not to mention extending the horsepower fun to the entire open-track sessions.

Horse Sense: Water injection was highly developed in World War II as a power enhancer for supercharged airplane piston engines. Today that heritage continues development at the hands of Reno air racers, who have abandoned air-to-air charge cooling in favor of even more water injection in their 4,000hp V-12s.

Road-Course Nitrous
Over the years we've seen a few nitrous systems designed for road course duty. Mainly these were 75-plus-horsepower hits staged to ramp up once full throttle was reached. Great in theory, these systems couldn't offer the fine throttle response a road racer must have, and instead offered something more like "nitrous lag." They gave a useful thrill on big tracks with few corners but were too notchy on tight tracks with numerous on-off throttle applications.

Now Snow Performance reports simple nitrous systems showing up at open-track events. These are nothing more than the nitrous bottle plumbed into the intake tract with a 50hp nozzle. No additional fuel is added; such dry systems rely on a stock engine management computer's tendency to run rich at WOT. That's crafty but dangerous thinking in our book. It's the sort of thing stock-car racers have been known to do when qualifying for a particularly important race (the bottle goes in the leg of the driver's suit).

Naturally, the worry with such a basic system is running lean, but Matt Snow says his water injection system provides a good safety net in these cases. The water and methanol act as both coolant and fuel to match the nitrous' oxygen.

And are we seeing the term dry nitrous system migrate from it's original meaning where it denoted an arrangement that blew nitrous into the intake tract and the additional fuel via the engine's injectors rather than adding an additional fuel nozzle in the intake tract? If so, we'd prefer something like nitrous-only to denote these new helping hand systems.

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