Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community - FT86CLUB - View Single Post - High compression engine fuel requirements

Ben_G · 01-15-2013, 09:00 AM

So I know that higher octane helps prevent detonation (knock).

I know that we need 91 minimum.

What I don't know is why we need 91 octane? Is it so that we can run more advanced timing? More RPM?

Just asking because Mazda's Skyactive motor (which is 12:1 compression) can run on regular (87) gas.... but it makes less power and has lower RPM.

Before any tells me not to complain about the fuel requirements, i'm NOT. I just am curious about the factors that contribute to the 91+ requirement.

01-15-2013, 09:00 AM	#1
Ben_G Senior Member Join Date: Jun 2012 Drives: Blue BRZ Location: Canada Posts: 506 Thanks: 108 Thanked 127 Times in 75 Posts Mentioned: 0 Post(s)	High compression engine fuel requirements So I know that higher octane helps prevent detonation (knock). I know that we need 91 minimum. What I don't know is why we need 91 octane? Is it so that we can run more advanced timing? More RPM? Just asking because Mazda's Skyactive motor (which is 12:1 compression) can run on regular (87) gas.... but it makes less power and has lower RPM. Before any tells me not to complain about the fuel requirements, i'm NOT. I just am curious about the factors that contribute to the 91+ requirement.