How bad is it to fill up 87
11-21-2004, 05:06 AM
#11
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True, but, the ECU should detect this via the knock circuit and retard timing until it stops..m..
But with retarded timing, you lose performance, perhaps 5-10% in horsepower across the range.
11-21-2004, 06:20 AM
#12
AudiWorld Super User
Geeze, everybody is so reactionary...
Higher octane does NOT equal higher quality.
Folks are correct in that the car is designed for at least 91, but it will pull back the ignition timing as needed so it won't knock.
I have done some experiments though, and here's what I find:
I get much better gas mileage with at least 91, so its false economy to get the cheaper gas.
I used to think like so many here, and put 104 in my race car, only to discover later (and after talking with Total Petroleum engineers) that you want to go as LOW an octane as you can without pinging, as this allows for optimal ignition timing.. As a result, I only run 87 in the race car (thats what it was designed for), and it runs WAY better than with 104 (remember that the Audi is designed for 91 though, or if chipped 93 is probably better yet)....
I typically just run 93 in the Audi. Seems to get the best mileage that way..
Folks are correct in that the car is designed for at least 91, but it will pull back the ignition timing as needed so it won't knock.
I have done some experiments though, and here's what I find:
I get much better gas mileage with at least 91, so its false economy to get the cheaper gas.
I used to think like so many here, and put 104 in my race car, only to discover later (and after talking with Total Petroleum engineers) that you want to go as LOW an octane as you can without pinging, as this allows for optimal ignition timing.. As a result, I only run 87 in the race car (thats what it was designed for), and it runs WAY better than with 104 (remember that the Audi is designed for 91 though, or if chipped 93 is probably better yet)....
I typically just run 93 in the Audi. Seems to get the best mileage that way..
11-21-2004, 06:46 AM
#15
Fine, if it's your Grandma's car. It depends on the driver. I only use it on hwy trips.
Trips that take over 1 full tank, 87 is fine. You only use like 15hp to cruise at 60, pinging in no problem. Far away at home if you cannot find a fair deal on super, I'll just put enough 87 in to get home or to my discount station.
