Gasoline

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 news:BWJpe.47535$ snipped-for-privacy@text.news.bluey>> Hello.

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 news:GiDpe.1227892$ snipped-for-privacy@telenews.teleline.es...

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 news:6DXre.17424$ snipped-for-privacy@newsfe3-gui.ntli.net...

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.

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 news:6DXre.17424$ snipped-for-privacy@newsfe3-gui.ntli.net...

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)

As usual you're totally wrong once again.

"Pinging" is only a vulgar form of addressing the technical word "Detonation". I'm not surprised that you only knew the vulgar form, given your poor education.

What really surprises me, and in all probability everyone in this newsgroup, is how on earth you might ever have managed to be a petroleum chemist without this knowledge. Then again you wrote "former". I guess that was just a case history of redundancy? LOL

Pinging is just a poor attempt at simply describing the metallic noise the engine makes when there are instances of detonation. Knocking is yet another way of describing this.

Collins English Dictionary definition for "ping":

1.- a short high-pitched resonant sound, as of a bullet striking metal or a sonar echo.

I suggest you read this, just in case you want to seek a new job in the Petroleum Industry of the Uneducated:

Engine knocking

Knocking (also called pinking or pinging)-technically detonation- in internal combustion engines occurs when fuel in the cylinder is ignited by the firing of the spark plug and smooth burning proceeds but some of the unburned mixture in the combustion chamber explodes before the flame front can reach it, combusting suddenly before the optimum moment of the four-stroke cycle. The resulting shockwave collides with the rising piston, creating a characteristic metallic "pinging" sound.

Anyway, why bother to answer any of your low posting again?

news: snipped-for-privacy@o13g2000cwo.googlegroups.com...

LOL.

Here's where I am mistaken: calling "pinging" pre-ignition. That's it.

Detonation and pre-ignition are different things, no matter what you call them.

So, only in your self-important mind am I "totally wrong." I guess you're still having difficulty extracting "fact" from "opinion." The rest of your whiny rant is just the same ill-bred crap we've come to expect from anti-Audi fools.

E.P. (at least I'm big enough to admit a mistake.)

In this case it's a 2005 engine so the problem with early 1.8T intercoolers probably does not apply.

The ECU may only be calibrated for 95 so putting in 98 would not cause the ignition to be advance any further.

I doubt anyone could tell the difference between 95 and 98 in a blind test in this particular car.

Your own words, where you never mentioned "pre-ignition", you very clearly stated self-ignition instead:

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

You're just a loser, that's what you are. You make me cry at how pathetic you can get.

Nice article on turbos there:

news: snipped-for-privacy@o13g2000cwo.googlegroups.com...

Yep, it's a great website.

"Art M" escribió en el mensaje news:0YBue.36294$rb6.9696@lakeread07...

Oh, now you're desperate to get whatever dig in you can - and you've stooped to a *semantics* argument. I absolutely love it.

LOL. Tell me, doofus - how are self-ignition and pre-ignition different? Think really hard now - make sure you know what the heck you're talking about...

You calling me a loser is so hilarious. After all your attempts at trying to protray yourself as the better person, too.

What a shame - but I knew you were a tool from the first. Now you're just flailing - raging like a child in an endless temper-tantrum fashion. Keep it up. It amuses me to no end, your pretence of adult thought. What are you, 12?

E.P.

The body of evidence is overwhelming enough for anyone who cares to read this thread carefully from the beginning, so I'm afraid I have other matters to attend now.

JP Roberts

And yet you couldn't muster the self-control to avoid replying.

Again.

E.P. (ROTFL)

And how, exactly, are "pre-ignition" and "self-ignition" different? They both refer to spontaneous combustion of the fuel/air charge, prior to the occurrence of the spark.

-- Mike Smith