[Miata] Regular vs Premium after 2001

[Dillon]

Preface - I have no insight into how Miata ECUs work.

I think they work by detecting knock and in near real-time and retarding the
timing to avoid knock.  This makes sense when timing is too far advanced for
the fuel, temperatures, and loads currently experienced by the motor.

The question is, at what point will the ECU decide to try and advance the
timing again?  If the ECU is too aggressive in advancing timing (which I
think it probably would be if it did so every 0.5 seconds) then you may be
negating the safety benefits of having a knock sensor and dynamic timing
control.

If the ECU is too conservative, you have situations like the.jack describes
where you have to run multiple tanks of high octane fuel (or gentle driving,
or lower temperatures) before the ECU advances timing again.

On Dec 5, 2007 11:33 AM, Robert McElwee <miatamail at gmail.com> wrote:

> Any ECU that takes 300 miles to adjust to a different grade fuel is surely
> defective. I would think that 0.5 seconds of knock would be more than
> sufficient to change parameters.
>
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