Dig-S modifications and dumpvalve

Has anyone got a definitive answer on if a dumpvalve can be fitted to a dig-s?
I know the charger has a bypass valve rather than recirc so in my mind it sounds doable but I really don't know enough about it.

Also just wondering if anyone has gotten round to modding them in general yet?


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There is a bypass valve just before the throttle intake after the intercooler which deals with boost level tweaking and routes excess boost situations (such as throttle closed) back through the intake.

You would need to remove this bypass valve, block the 2nd feed into the supercharger (or use it as an extra intake...), and add a dump valve. Not sure if there needs to be an understanding on how the bypass operates and when as I suspect it could cause a reduction in boost pressure as and when desired.

Unless you are going to start tuning it, such as changing the pulleys (I do believe I worked out there is some headroom on the rpm of the supercharger so it could be done), I don't see any other benefit other than having the car "sneeze" every time you change gear! But then you have the ECU to contend with, its quite a complex engine in terms of how it operates.. such as miller cycle running.


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eh? an 'induction kit' - AKA replacement air filter and different pipe work - wont max out the MAF!! At best, it will just make it a bit more free flowing and increase noise (although at a cost of possibly drawing in more hot air. The Micra happily runs without an air filter - cant get much more free flowing than that (although not really recommended!)

Only way to max out the MAF would be to increase airflow significantly - IE change of supercharger pully to increase forced airflow.

However, the MAF is integrated into the standard airbox so you would need to work out a way to re-mount it. It is important that this should be mounted properly to ensure correct airflow monitoring otherwise you can really screw with the mapping and end up reducing power!