If it doesn't knock on 87 then you are getting the best bang for the buck and no damage is being done.said chuck.
Chuck also said use what is recommended by the people that built it. Amen.
Maybe yes maybe no.
The origional owner of my Mercedes used Regular gas.
Owners manual read to use premium.
The computer retarded the timing so no knocking.
The retarded timing clogged up all the emmission gizmo's to the point gas vapers went to the oil. oil thinned out and he burned a quart every 800 miles. He Sold it to me, I cleaned it all out, burn premium and it uses no oil.
1100cc American Classic Edition.