Retarded Ignition

[daveb666]

I've recently got Nistune fitted to my CA18DET (Hi Matt ) and have now got a 'base-map' on the car ready to run in my new engine but have a quick question.

I used to have 'pops and bangs' on my old map - this map being done through a ROM tune using an emulator to a blank chip on a rolling road.

I was hoping to have something similar when my proper map is done on the Nistune but from reading other posts (all be it from 2016) Matt said negative values aren't possible and "... depends on factory coding and if I can achieve this"

Is this a Nistune thing or a Nissan thing? As I said I definitely had serious pops/bangs before so it must have allowed negative values I imagine.

Is this something you're still looking into Matt or is it a no-go?

[Matt]

I would say no go at this time for negative timing. however that is a Nissan thing. So compare your previous ROM tune to what you have now. Usually the bangs are unburnt fuel on decel hitting the cat converter/exhaust

Jap tuners would put big numbers up top that would be read on decel to inject fuel then. More fuel than timing I thought

[madaxgt]

Could you not just offset (retard) the CAS sensor then add the positive spark offset in all necessary maps so you could achieve a actual negative spark timing? Or is there code somewhere that would not be covered by this and cause problems at some point with too much retard??

[Matt]

Yes you could do that, advance all maps (including idle/decel timing) and try that out