I suspect they recommend premium (91 octane), that's what the recommend
for the 2.0T's predecessor, the 1.8T. However, I usually alternate
between 91 and 89 in my car with no ill effects - mileage and power
seem to be the same....
As far as the chip, for the 1.8T again, a mild chip will get you to
200hp so I would assume the same type of gain (20 - 30hp) would be easy
for the 2.0T with nothing radical.....
'04 A4 1.8Tq MT-6
Central NJ USA
'04 A4 1.8Tq MT-6
Central NJ USA
Where are you? I'd expect Audi to optimise the tuning for whatever's
available in the local market. Here in the UK, the choice I have is 95
or 98 RON. (I can't get fuel as weak as another poster says he uses in
New Jersey.) There's a label inside the filler cap door that says that
either of my possible choices is acceptable. I use 95 in my '02 A4
Thanks - that one hadn't appeared on my server when I wrote my posting
Mike refers to an interesting Wikipedia article, from which I quote:
'87 octane fuel, the "normal" gasoline in the US and Canada, would be
91 in Europe'.
So, in spite of the difference in measurement methods, the fuel
available in the US does typically have a lower octane rating than
that here - I can't buy anything as low as 91. The norm here is 95.
Ergo, I still think that motor manufacturers will have to tune their
engines differently for different markets if they're to function
satisfactorily with locally-available fuel.
Does the higher octane rating of British fuel imply that identical
cars would perform better on British fuel than American?
No. The effective, in-motor octane number of the fuel is the same,
it's just the measurement method is different.
If I give you 3.785 liters of something, or one U.S. gallon, you still
have the very same volume.
RON numbers are always higher that MON numbers on motor fuels. I know
for a fact that some premium gasolines run 98 RON and 88 MON. I've
seen some regular gasolines at 94 RON and 82 MON. They really can
diverge quite a bit.
The wiki article is interesting, but the 87 in the U.S. = 91 in Europe
is just plain wrong IME.
If the engine is tuned to run on a certain octane rating fuel, then it
will perform less well on a lower octane rating. A higher octane fuel
won't, necessarily, improve the performance.
My RS6 is specified for 98 octane, but with the ability to run on 95
octane with lower performance (as are many recent UK-supplied Audis).
Initially I ran with Super unleaded (97 octane). I started using Shell
Optimax (~98.6 octane) and the fuel consumption showed an immediate 10%
improvement. I have made no measurements of performance, but the car
certainly feels better on Optimax.
Peter Bell (Note Spamtrap - To reply, replace 'invalid' with 'bellfamily')
Never heard of a Lond Island here in New York. I do live on Long
Island, though ;-P , and there are even more grades available than that.
I've seen 87, 89, 90, 91, 92, 93, and Sunoco used to sell 94, don't
know if they still do. However, these are AKI, not RON. AKI is
(RON+MON)/2, where MON is the Motor Octane Number. MON is obtained in a
similar manner to RON (using a calibrated test engine), but under
different test conditions. This number is generally several points
lower than the RON, which is why US "octane numbers" tend to be three or
four points lower than corresponding Euro "octane numbers".
Depends on where you live.
In Nevada for instance one
can buy racing gasoline at
the pump. Seriously.
I once filled up a 2000 A4
1.8T with racing gasoline
in Las Vegas, then drove
it straight to San Diego.
Much to my surprise the
mileage improved by 10%
and the engine ran quite
a bit cooler judging by
the coolant temperature
YMMV of course.
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