For the sun you must multiply it by 1.0827431828*10^9 instead of 1878968. That is the square root of the product of the gravitation constant and the sun's mass. The gravitational constant is about 6.67408*10^-11. If you were to this for Jool, it would be G (gravitational constant) multiplied by Jool's mass. It works the same for every planet/moon/body.
The constant is there because if you are orbiting a heavier body, it will have more gravity, and will require more delta-v to achieve the same result.