HONDA 2015 Civic Si Sedan - Owner's Manual - Manual (Page 26)

25
Quick
Referenc
e Guide
Is it possible to use
unleaded gasoline with a
Pump Octane Number
(PON) of 87 or higher on
this vehicle?
Unleaded gasoline with a pump octane number of 91 or higher
is recommended.
If premium unleaded gasoline with a PON of 91 or higher is not
available, you can temporarily use the gasoline with a PON of
87 or higher.
This will result in decreased engine performance, and can cause
occasional metallic knocking noise in the engine. 2.4 ℓ engine models
* Not available on all models