Temperature is a big factor in octane requirement. It is not nearly as hot where I live as Pheonix. If I lived in such a hot weather area I may see the need to increase octane.
However, even in hot weather for here (100 Degrees) I can climb either the grapevine grade on Interstate 5 (either direction, but northbound is steeper) or the Conejo grade on highway 101 with the A/C on holding 80 mph (probably more if I wanted to risk the ticket) with no hint of ping or power loss.
Actually I've climbed the Conejo grade much faster than that many times, but I don't remember if any of those times if it was over 100 degrees. It will climb the Conejo at 80 in 5th gear with the cruise control set with the feeling that it could do much more.
I guess that I can't quite get it across to you that I do understand octane. The last car that I owned that could be fully tweeked manually was a 1972 Ranchero. It came with a 429. When I threw a rod, I replaced the bottom end with a Lincoln 460 and added a Cobra Jet cam as well as a Super Cobra Jet intake manifold and liberally ported the heads to match. Carburation was from a Motrocraft 4300D that came off from a Pantera (850 cfm). I could play with the mechanical advance curve, the vacuum advance curve, the carb jetting, the trans shift points, and even the carb secondary openings to my hearts content. Others that drove it at the time referred to it as a bomb because of the explosive acceleration. I could come to a full stop at the foot of the Conejo grade and go over the top at over 120 with a full load of bricks in the bed. It was tuned so tightly to premium fuel that I would get a trace ping just from going from my house at about 1000 feet to a trip to the beach at near 0 feet.
My SVT just isn't near as sensitive, and I'm disappointed.
