Octane vs Octane/ethanol

The 93 with ethanol is probably just the 91 without ethanol with some ethanol added (Really - using ethanol to boost the octane rating is about it's only legitimate use.)

What is the minimum octane spec given for your 599? (The F spec is usually RON while what's shown on US gas pumps is AKI so they can't be compared directly.)

 

The big advantage of ethanol free fuel is that it is easier on older rubber components. Ethanol raises octane, but reduces the efficiency of the fuel because it only has about 2/3 the energy per volume compared to gasoline. Late model cars are designed to have alcohol resistant componentry.

 

Mike,

What is the percentage of additive ethanol, E10 or E15? Is that 93 from Amoco?

Reason why I inquire is due to a recent article I read warning about fueling up with E15 or higher content of ethanol.

Likewise as a supplier to World Rally, Formula 1 and Indycar teams years ago, we had to change the type of elastomer seals in our products to ensure that the rubber wouldn't excessively swell which negatively affected the dynamic performance and ability of valves to fully shut off and caused dangerous leakage of fuel.

I'm not certain when Ferrari upgraded the rubber type in their cars. In a Forza article written by Ferrari expert Michael Sheehan regarding long term reliability of the 550/575, he mentioned that its fuel pump can be susceptible to leaking. Interesting that when the 550/575 models were being developed circa early 90's, a lot of the more modern elastomers available today had not yet been formulated or were still undergoing extensive lab tests.

 

Jose- Leaking fuel on the 550/575M is usually the result of a cracked fuel pump cover, and occasionally a bad gasket. One of my fuel pump covers cracked.