a typical system will supply only one to three minutes of nitrous to the engine. In the process, it adds about 100 horsepower to a typical big block engine. The biggest problem is that the extra gasoline that the nitrous allows in the cylinder increases pressure in the engine so much that it can do some real damage, unless the engine is designed to handle it. That would be the same problem you would have with an engine breathing pure oxygen -- it would have to be quite beefy to handle the load.