Gasoline
 

Hello.

What is the best gasoline for an 2005 A4 1.8T quattro? Eurosuper95 or
SuperPlus98?
[1781cc, 4cyl, Turbo, Intercooler, 163CV, Compress ratio 9.3]

Thanks for your answer

Exceso wrote:
> Hello.
>
> What is the best gasoline for an 2005 A4 1.8T quattro? Eurosuper95 or
> SuperPlus98?
> [1781cc, 4cyl, Turbo, Intercooler, 163CV, Compress ratio 9.3]
>
> Thanks for your answer
>
>
Look inside the fuel filler flap.

I haven't received the car yet, but Audi recommends using Eurosuper95.
Perhaps because this car has a teoric compression ratio of 9.3, as I said,
caused, among other reasons, by the use of 5 valves per cylinder. But
perhaps (I don't know) the fact that it comes with turbo and intercooler
turns the *real* compression bigger, and it makes more suitable the
SuperPlus98... that's my doubt.

Thanks for your answer


"Chris Bartram" > escribió en el mensaje
k...
> Exceso wrote:
>> Hello.
>>
>> What is the best gasoline for an 2005 A4 1.8T quattro? Eurosuper95 or
>> SuperPlus98?
>> [1781cc, 4cyl, Turbo, Intercooler, 163CV, Compress ratio 9.3]
>>
>> Thanks for your answer
>>
>>
> Look inside the fuel filler flap.

When all else fails read the manual....

Obviously the SuperPlus98, but if your car is not chipped, then the 95 will
just do the same job at a cheaper price.

The higher the Octane number, the better the engine will run in the summer
when it's hot.

"Exceso" > escribió en el mensaje
s...
> Hello.
>
> What is the best gasoline for an 2005 A4 1.8T quattro? Eurosuper95 or
> SuperPlus98?
> [1781cc, 4cyl, Turbo, Intercooler, 163CV, Compress ratio 9.3]
>
> Thanks for your answer
>
>

> Obviously the SuperPlus98, but if your car is not chipped, then the 95
> will just do the same job at a cheaper price.
>
> The higher the Octane number, the better the engine will run in the summer
> when it's hot.

Why do you say obviously?

Buying 98 for that engine is probably just going to empty his wallet faster.
163PS isn't a particularly high power output so it should be happy on good
quality 95. AFAIK, the 1.8T from 180PS and up requires 98 for full power and
better fuel consumption.

I've read that the choice of one or another type of gasoline depends of the
compression ratio of your car, not estrictly of the power. The 1.8T has a
compression ratio not much high (9.3), and for that reason the RON 95 gasoline
seems to be the appropriate (in my opinion).

But for a 80 2.0 E with 115PS and a compression ratio of 10.4? Although it has
less power than the 1.8T, after driving it for ten years I think in this case
the 98 is better (it's only an impression, but I think that driving normally
with 95 it consumes about 8.2 - 8.3 l @ 100 km, and with 98 about 7.7 or 7.8 l).
Some suggestions or experiences?

Thanks for your answers



"Dave" > escribió en el mensaje
...
>> Obviously the SuperPlus98, but if your car is not chipped, then the 95 will
>> just do the same job at a cheaper price.
>>
>> The higher the Octane number, the better the engine will run in the summer
>> when it's hot.
>
> Why do you say obviously?
>
> Buying 98 for that engine is probably just going to empty his wallet faster.
> 163PS isn't a particularly high power output so it should be happy on good
> quality 95. AFAIK, the 1.8T from 180PS and up requires 98 for full power and
> better fuel consumption.
>
>
>

In message >
"Exceso" > wrote:

> I've read that the choice of one or another type of gasoline depends of the
> compression ratio of your car, not estrictly of the power.

It's correct that compression ratio may be the major factor in
determining what octane rating best suits an engine, but there will be
other, less significant, factors. Do remember, though, that a
compressor (turbo or super-charger) does, in effect, increase the
compression ratio significantly.

--
Peter Bell (Note Spamtrap - To reply, replace 'invalid' with 'bellfamily')

Obviously, because of less potential detonation problems. These are
exacerbated by hot temperatures as the intercoolers in the early 1.8T are
somewhat underengineered considering the demands of chipped cars. The net
result is hotter air intake, which means the fuel mixture shows a tendency
to self-ignite at the wrong times for the engine - read detonation
translating into less power per time unit.

The chips adjust the fuel-air-boost map to provide maximum efficiency, but
they also advance ignition timing to the maximum bearable by the engine,
given a particular temperature. The engine is possessed with two detonation
sensors, and the moment the ECU detects any instance or this happening, it
will delay ignition, thus providing less energy release per fuel unit - read
power. The problem with this is that even if the ECU and sensors do a fine
job, there always needs to be detonation for the system to delay timing -
read the fewer the instances of detonation before the system acts the less
stress on the engine in the long term.

The Octane number is just a measure of how easily the fuel will self-ignite,
therefore, the higher this number, the better the fuel in terms of lower
detonation, which translates into lower consumption as the fuel is more
efficiently burned because it is not being burned at the wrong times.

JP Roberts



"Dave" > escribió en el mensaje
...
>> Obviously the SuperPlus98, but if your car is not chipped, then the 95
>> will just do the same job at a cheaper price.
>>
>> The higher the Octane number, the better the engine will run in the
>> summer when it's hot.
>
> Why do you say obviously?
>
> Buying 98 for that engine is probably just going to empty his wallet
> faster. 163PS isn't a particularly high power output so it should be happy
> on good quality 95. AFAIK, the 1.8T from 180PS and up requires 98 for full
> power and better fuel consumption.
>
>
>

JP Roberts wrote:
>
> The Octane number is just a measure of how easily the fuel will self-ignite,


Bzzzt.

Octane number is measure of the fuel's resistance to *detonation.*
Self-ignition is called "ping", and that's something different.

Turbomotors should use the highest available octane fuel, due to
effective compression ratio and charge temperature. 98 RON or better.

E.P. (former petroleum chemist)