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Is my compression ratio too high for nitrous injection?

What is the best compression ratio to use with nitrous injection?

We're often asked what is the best compression ratio to use with nitrous oxide. Unfortunately, there is no specific number we can give that would apply to all engines, as the following factors all influence what ratio would be best for a given engine; 

1) A higher ratio will make more power NA but will have a lower limit of how much nitrous it can handle.


2) A lower ratio will make less power NA but will be able to take more nitrous before hitting any problems.

 

3) A lower ratio will at some point MAKE UP the reduction in NA power, as well as allow you to make more power on nitrous.

 

4) The type & octane of fuel you use is a main contributor to what compression to use, so the higher the octane the higher the compression you can use safely but it's still beneficial to run a lower rather than higher compression ratio.


5) The amount of nitrous you want to add (rather than just aiming for the maximum), also affects what compression ratio would be most suitable. The more nitrous you want to add to an engine, the lower the compression ratio would be most suitable. 

 

6) Many other factors about the engine design affect the optimum compression ratio, so it's impossible to 'predict' what ratio will produce the best results, so the only way to determine that, is to select a random ratio and see how it performs. If it prevents you from adding as much nitrous as you want to achieve your goal, you then either have to drop the comp ratio, increase the fuel octane or retard the timing, to avoid detonation and enable you to add more nitrous.