What octane is the best for that engine, for economy and performance? Why?

D.

 

The white 6 is "high compression." That's what makes using premium fuel in this car not wasteful as it would be with the plain cars that most people drive.

I think the manual says that 91 is the minimum. But the engine has knock sensors, and if there are no fault codes then the knock sensors are working. So if you fill it with cheap fuel or drinking liquor it will try and manage by adjusting the ignition timing.

There has been some talk here about regular grade fuel possibly causing engine problems, and you should know that the fuel remarketers do more than just adjust the anti knocking properties of premium fuel - most of the 'top tier' brands premium fuels have better additives for fuel system cleaning.

In my area the only fuel that is "91 or higher" is 93 and this usually costs 20% more. I have not fixed up my V enough to start driving it around every day yet, but I think it's likely that fuel consumption will be lower with the 93 fuel. But probably not 20% lower.

 

When I drove a 960, I only used 91+, in my area it was 93 as well. It cost 10% MORE but I was getting 15% better mileage. So, the mpg offset the cost.

As explained, the owners manual RECOMMENDS 91+, 87 is MINIMUM. That is the legal minimum is the USA. So the knock sensor system will do it's best to compensate for the lower octane.

Some believe that running low octane gas in a car that has high compression contributes to burnt valves. Also, if the knock senor system fails, knocking is really bad for a motor.