There comes a point in your power buildup where you may consider adding nitrous oxide injection to your supercharged car. This point typically coincides with reaching a level of performance that means increased investment and diminishing returns from your supercharger. For example, my car comes from the factory with a 5th generation Eaton MP45 supercharger. This supercharger is limited to about 230hp worth of flow rating and so no matter what I do with bolt-on upgrades on my engine, my peak horsepower will not exceed 230hp limit because that is the point at which the supercharger becomes the bottle neck in my system.
As we’ve talked about in previous articles there is still the option of porting the factory supercharger for a 10 to 15% gain in capacity (which in this case would be another 23 to 35 horsepower). There is also the option of retrofitting a larger supercharger such as the Eaton M62 to gain potential up to over 300hp depending on the final choice of a supercharger.
This modification path (porting or replacing the factory supercharger) can prove to be complex and costly, especially if the supercharger is integrated into the intake manifold (and possibly an air to water intercooler) as the case is with many factory supercharged cars.
A possible viable solution for this situation is to use nitrous oxide injection to supplement the power delivery when racing, and being satisfied with a reliable lower powered car when the nitrous is off and we’re not racing.
The reason why nitrous oxide (N2O) becomes a great power adder is twofold:
1- Nitrous is cheap as far as horsepower per dollar goes, and especially in the situations where we’re already supercharged and so will only be using it on the rare occasions when we do hit the track.
2- Nitrous oxide is a great ‘chiller’ as it comes out of the bottle at a temperature of negative 127*F