Xzazz

I just purchased a 2002 Audi A4 Quattro, its got 72k on it. Near mint condition and no history of any trouble at all. Seems to run beautifully. Love the car, always loved the styling of Audi, but never owned one. I'm a total greenie with cars however and after reading the manual, I of course noticed the need for 91 octane gas, which I'm happy to oblige, however, as I bought the car used, I wondered if the previous 2 owners had done the same.

Is there any risk at all with supplying the car with 91+ octane gas if it hadn't previously been running on it?

Thanks,
James

1move

iTrader: (1)

You will basically prolong the life of it if it hasnt had any. It will run a lot smoother and there should be no issues

IcemanGER

If you use lower octane gasoline because the engine exhibits no sign of knock, you're outsmarting yourself. By retarding the ignition timing, the ECU prevents abnormal combustion and knock, which allows vehicles designed for premium fuel to run reasonably well on lower-octane fuel. Thus, drivers need not worry about the damage associated with abnormal combustion if high-octane fuel isn't available or if they get the occasional "bad" tank of gas. While this removes the immediate hazard, it's a bad idea to make a habit of running a vehicle on gasoline of lower than recommended octane. Retarding the ignition timing makes the fuel/air mixture richer; combustion is less complete, which lowers fuel economy, allows unburned hydrocarbons to pollute the air, fouls the catalytic converter allowing further pollution and causes the engine to run hotter, reducing its longevity. The knock-sensor provision is a mixed blessing. It does protect the engine from knock-induced damage, but without it, drivers would know something is wrong. The money saved by pumping low-grade fuel into a car that demands higher octane is lost anyway in decreased fuel economy and possibly gradual damage.

hope this discussion will come to an end some time.

cheers

PwrDriftr

Most premium car owners use the proper gas. If the car runs well, I think it's safe to assume that it's been well cared for by previous owners and that they used the correct gas. But now that it's your car... use the right gas.