BajaRon
Well-known member
I've got an 08 RS. 10.8:1 compression ratio is pretty high to be running on 87 octane. (Though not as high as the 2013 998).
I tested 87, 89 and 91/93 for about 6,000 miles. One trip from east Tennessee to San Diego and back. I consistently got 2-3 mpg better with 91/93 octane. Saw no discernible difference in mileage between 87 and 89 octane. So I run premium fuel.
I am sure it would be more expensive to use an octane booster to go from 87 to a higher octane than just getting it out of the pump. Octane booster is for those who need more than pump available octane.
Octane prevents knock or pre-ignition. Used to be that Octane was the only way to control this. But these days they just put knock sensors in the system and retard the ignition timing to prevent knock.
This allows them to recommend a lower octane than what you really should be using. Since you don't always need the higher octane, you can run 87 and when you get to the point where you do need higher octane, you get retarded ignition instead.
Retarding the ignition reduces engine efficiency and lowers horsepower, which translates into lower fuel mileage. The hotter it is or the harder you run your Spyder, the more you'll need a higher octane fuel. The colder it is the less octane is needed.
And there are other factors as well like humidity, etc. So if you're in climates where your ambient temps are 80 or below, you're probably not going to see as much (or any) improvement with higher octane than someone that is consistently running in the 90's or higher. My trip to California was in 90-100+ degree weather most of the time.
I tested 87, 89 and 91/93 for about 6,000 miles. One trip from east Tennessee to San Diego and back. I consistently got 2-3 mpg better with 91/93 octane. Saw no discernible difference in mileage between 87 and 89 octane. So I run premium fuel.
I am sure it would be more expensive to use an octane booster to go from 87 to a higher octane than just getting it out of the pump. Octane booster is for those who need more than pump available octane.
Octane prevents knock or pre-ignition. Used to be that Octane was the only way to control this. But these days they just put knock sensors in the system and retard the ignition timing to prevent knock.
This allows them to recommend a lower octane than what you really should be using. Since you don't always need the higher octane, you can run 87 and when you get to the point where you do need higher octane, you get retarded ignition instead.
Retarding the ignition reduces engine efficiency and lowers horsepower, which translates into lower fuel mileage. The hotter it is or the harder you run your Spyder, the more you'll need a higher octane fuel. The colder it is the less octane is needed.
And there are other factors as well like humidity, etc. So if you're in climates where your ambient temps are 80 or below, you're probably not going to see as much (or any) improvement with higher octane than someone that is consistently running in the 90's or higher. My trip to California was in 90-100+ degree weather most of the time.
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opcorn: The Spyder is happy, I'm happy. I also use blue Stabil starting in November. Never know when that last ride of the season will come. :thumbup:
