A little counterpoint here.
Octane is nothing more than resistance to ping due to slowing down the rate of the burn. If you don't need it, there is no reason to pay extra for it. I cannot tell the difference between 87 octane and 91+ octane in my SVT, so I use 87 octane.
I bought my SVT new. The dealer had lost the SVT suppliment, and like you, I did not notice the "premium fuel only" on the fuel gauge until I had already run three or four tanks of 87 octane fuel through it. Since it worked fine with the lower octane fuel, I continued with it. Ocassionally I run premium in it just to make sure. The last time was last week. I still can't tell any difference in either performance or fuel economy.
I now have nearly 200,000 miles on it. During this time, I have only detected a very slight ping on two ocassions. Both times were warm winter days (we have a lot of those here in Southern California) with winter blend fuel. Both times it was only evident on light acceleration between about 25 and 40 mph.
I am also convinced that the knock sensor system on our cars does little or nothing. For one thing I cannot remember ever needing to replace one that has failed. Also I have driven my car with the NGS attached with both regular and premium fuel and I was not able to detect any difference in the timing readings.
I must say though, that I maintain my car very agressively, including the things that could impact the engine octane requirement. I change the plugs every 60,000 miles. I change the air filter every 15,000 miles. I use an injector cleaner somewhere between 5,000 and 10,000 miles and clean the throttle body at the same time. I do a complete engine decarbon about every 15,000 to 20,000 miles. I change oil and filter every 3,000 miles if I have dino oil in it or every 5,000 miles when I use synthetic. I drive it hard at times, taking it nearly to red line at least once a day.
So you must be very aware of just what octane does and how it impacts our engine and maintain it agressively or you should only use premium.
By the way, I spent most of my adult life as a tune up mechanic, most of that when timing adjustments were part of every tune up. I have always been involved with high performance or modified cars. Most of the cars I have owned either required (and I used) premium fuels, either from design or from modifications. I mention this to make you aware that I am very familiar with octane. More than one of those cars ran best when ignition timing was advanced beyond where premium pump fuel could handle it, necessating the addition of up to 50% aviation fuel.
Anyway, 87 octane works fine in my SVT (98 E0). I don't know how well it will work in yours, but it works for me.
, thanks!
