Using nitrous with a jet properly is tricky. If the engine peak HP matches the impeller now, and you add nitrous, the pump will now spin to a higher RPM, but if the peak RPM is now over the engines peak HP, the engine is losing power over the peak and the extra nitrous is wasted.
Jets typically gain one MPH per added 20 HP.
We add more nitrous until the added nitrous doesn't add the desired MPH. Then we either back off the nitrous or go to a larger diameter impeller to absorb all of the extra power to keep the max RPM at or just below the engines HP peak.
TIMINATOR