[Miata] Regular vs Premium after 2001

[John Freas]

Previously on Premium vs Regular, Robert McElwee <miatamail at gmail.com>
said...

So, who has a car that reads instantaneous fuel consumption or one of those
> nifty $200 boxes that you hook to your OBDII ports that can run some tests
> for us? If we had this conversation last week I could have run some tests on
> the level and straight as an arrow 360 miles I drove on I-10 in Florida.


Our Audi has the computer that can display instantaneous MPG, average MPG,
miles to bingo fuel, engine hours since last reset, average speed, OAT,
velocity of an unladen swallow, etc...

Name your test and I'll try it out (it may take awhile since I am not the
regular driver of the car).

To those who pointed out that rolling back the timing by the ECU can cause a
loss of economy with lower grade fuel, you make a good point.  I was looking
at it from the perspective of the NA, which will not knock unless you really
push the timing, and cannot retard on its own.  Yes, in a NB or NC you can
probably get better mileage under hot, high load conditions with Premium
than Regular.  Whether that works in cooler temperatures or less aggressive
driving conditions, or whether it is enough to offset the increased price of
the fuel is another question.

I'm tempted to try a tank of Premium in the Audi on a long enough trip to
make an apples:apples comparison, however we really don't travel more than
about once per month.  It would take at least two trips to the in-laws, one
a baseline and another with Premium to actually make the test work, plus I'd
have to make sure it was running on an undiluted tank of premium before the
trip, plus I don't know if the ECU has learned that we always run Regular
and will be reluctant to advance the timing, plus it's winter...

    -John
------------------------------
John Freas <%20john7690 at comcast.net>
1992 *YELLOW* "Sting<http://john.freas.home.comcast.net/pix/sting/sting.html>
"
1995 Black R Package
"Spike<http://www.geocities.com/clash_girl/Spike_Scrapbook.html>
"
Elizabethtown, Indiana
- Standard Disclaimer
<http://john.freas.home.comcast.net/disclaimer.html>Applies -
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girl<http://www.geocities.com/clash_girl/Spike_Scrapbook.html>and my
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