Before the mods, I got some pinging on hot day's, bumped up to 89 and it cleared it. Now I run 93 due to mods such as timing adjuster at 14 deg, and C&L maf. I was able to sucessfully run 89 octane last week on a road trip to Missouri, turned the timing down to factory spects and only had slight pinging under hard acceleration. i found if I did not rev it past 3500, no ping.