91 or 96?

Grant · Post by **Grant** » Sat Nov 20, 2004 9:02 am

I decided to conduct a rather basic test on the benefits or otherwise of
switching to 96 octane fuel. As the price difference is only about 4% a
small improvement in fuel economy could mean my fuel costs would be lower.
A bit early to tell yet, but over the last couple of weeks and more than
2400km, the first impression is that the car is smoother and quieter. Maybe
a slight improvement in performance, but that could be wishful thinking!
Fuel econonmy has improved by about 6% as well, so I'm on the winning side
as far as costs are concerned. The engine has not been tuned to benefit from
the change in fuel either. The timing is still at standard. I hope changing
it to 14 degerees will be of some benefit as most people find so will do
that as soon as possible.
My 1992 car has now done more than 180,000km and is automatic, so is well
used. Being automatic, it is slightly lower compression than a normal
(manual) engine to lower the torque curve to better match the torque hungry
automatic gearbox so this could mean different results to the majority of
cars. It's BRG to, so the results will bear no comparison to those less
fortunate red ones out there.
With the roof down, a return trip to Dunedin (1438km) over three days this
week returned 12.35km/l or 34.83 mpg. This with the roof down, two people on
board and a boot full of gear. A trip like this with the roof up returns
about 5% better fuel econonmy.
After a longer test, I'll report back.

Grant.

Mike Jolley · Post by **Mike Jolley** » Sat Nov 20, 2004 2:57 pm

did this exercise with my nissan sereena,little more mpg on 96 so same cost
as running 91.Mx5 better with advanced timing and run GULL there 96 is
tested at 102 by AA. mike

Grant · Post by **Grant** » Sat Nov 20, 2004 3:03 pm

No Gull here though unfortunately.

Grant.

Graeme H · Post by **Graeme H** » Sat Nov 20, 2004 6:45 pm

I get about 500 km out of a tank of 98 before i start to sweat. Don't know what this equates to tho...too lazy to work it out.

Graeme h

[...]

fortunate red ones out there.
With the roof down, a return trip to Dunedin (1438km) over three days this
week returned 12.35km/l or 34.83 mpg. This with the roof down, two people on
board and a boot full of gear. A trip like this with the roof up returns
about 5% better fuel econonmy.
After a longer test, I'll report back.

Grant.

http://miata.cardomain.com/id/britracinggreen

Biff · Post by **Biff** » Sun Nov 21, 2004 1:10 am

Wasn't Challenge the next best?
Do they still exist?
Biff

Biff · Post by **Biff** » Sun Nov 21, 2004 1:12 am

I can only get 400k (+/- 25K), b4 I start to sweat; out of mine on 91?
B

Grant · Post by **Grant** » Sun Nov 21, 2004 8:08 am

Challenge used to be good but some time ago they were bought by Mobil, I
think it was. They are no different to the other major companies now. There
are a few independant retailers out there now, mainly in small towns where
the big companies have pulled out. They trade under the Alliance name and
accept Mobil fuel cards. Possibly they use Mobil for supplies as well, but
only guessing.
As far as I know, the fuel tank capacity is 48 litres so on a long trip it
should be quite easy to get 500km out of a tank full. The fuel guage would
be resting on the 'E' mark for some time though and it's always a worry when
it points to 'E' even if you know there's probably enough there for another
80 to100km. Mine takes about 40 litres to fill when it shows empty.
My worst case consumption on 91 drops to about 10km/l around town, and I
would expect manual transmission cars would fare better than my auto. Of
course red ones, as they go faster, probably aren't quite as fuel efficient!

Grant.

Warwick & Heather · Post by **Warwick & Heather** » Sun Nov 21, 2004 8:29 am

I find that my 1.6 manual blue machine covers 430km before empty (touring)
and then I head in for a fill of 96.
Gull had rated their 'super' at 97 octane as it came from Singapore and the
commerce commission wouldn't let them claim it was '96'.
However... they have now changed all the pump handles in Palmy to '96'
suggesting they have either changed the source or had the mix re-tested.You
can also get '98' at selected BP/Mobil stations but haven't tried it yet.

Warwick

Graeme H · Post by **Graeme H** » Sun Nov 21, 2004 10:41 am

I only use 98...maybe that's why i get good mileage...but my car's on E for a good while.

GH

[...]

GrubbyMX · Post by **GrubbyMX** » Sun Nov 21, 2004 11:28 am

Why do you sweat Biff? Because of the gauge or have you been stranded?
The tank is 45l (I have filled it from MT and it is) and my long term
consumption is 12.2km/l. I worry @ 500k
Ran on 96 for about 5000k, could detect stuff all difference and the
comsumption increased about 0.5%. However I did no other changes, going to
the much talked about 14BTDC may have had an impact. Anyone any ideas about
that?
Ralph

my2cta · Post by **my2cta** » Sun Nov 21, 2004 9:40 pm

When I used 91 in my NB I'd average around 11.7 km/l. Since switching to 96
I average around 13.5 km/l. On long trips, top down, I typically get better
than 14 km/l and several times have gone over 600 km before filling the
tank. Best ever was 14.9 km/l (616 km, 41.2 l to refill). Takes around 41 l
once the needle is at the bottom of the 'E'. Mostly I use Mobil.

Tim
MY2CTA

Biff · Post by **Biff** » Mon Nov 22, 2004 6:13 pm

Hi mate,

I just don't know how far past the "E" it actually is E!

So @12km/lt with 45lt, we should be safe till 540km...I think I'm
getting around 10km per litre, ruff calcs on a fill up.

I might see if I can get it to E say on a Friday, fill a 5lt gas can, stick
it in the boot, and go until it stops.

Know for sure then

Is the general consensus more kl on 96 than 91?

14BTDC, better mileage and more grunt?

Seen this?

http://www.k10k.net/dropbox/newstempstu ... 185030.mpg

and go here, you have to register but its Jason's site in the states:

www.miatapix.net/mileage

Cheers

Biff

R.V.Boxall · Post by **R.V.Boxall** » Tue Nov 23, 2004 10:30 pm

Just to join in with a recent check on the consumption of my 1600cc manual
special green machine, it did 400k's on 31 litres of 91 from New Plymouth to
Masterton, and 400 k's on 35 litres on the return trip. General taiwind one
way, head wind the other. Hood up for 100 k's in each direction.

Recommend the Martinborough Wine Fest for a good day's piss-up with 10,000
others, but don't drive yourself on the day!! The law was out on every exit
road at 6.30 pm, shooting fish in a barrel! Oh, and it's not a wine tasting,
it's a wine sculling!!!

Why has my MX got a V on its bonnet and ignition key, and mot the Mazda M,
please?

Ron

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