Re: Volvo Gxi / Fuel Octane ?
It's an MPI engine, and there is no way to reset the timing. The ECM does all that.
No harm will come to your engine using 87 octane, you will just loose a little bit of power.
Here is some more info from the owners manual of a GXI.
Gasoline recommendations
USE ONLY UNLEADED FUEL. Maximum engine performance
requires the use of lead-free gasoline with the following
minimum or higher octane specification:
Inside the U.S.: (R+M)/2 (AKI) 89
Outside the U.S.: (RON) 93
If fuels with 89 AKI pump posted (93 RON) octane number or
higher are not available, lower octane fuels (minimum 87 AKI
[90 RON] octane) can be used. With the use of lower octane fuel, a slight decrease in power can be expected.
Premium fuel contains injector cleaners and other additives that protect the fuel system and provide optimum performance.
Volvo Penta strongly recommends the use of premium grade
fuels.