Colortune

[Deni]

Hi. I just got a colortune to accurately adjust my idle mixture and mixture up to 4,000 RPM as described in the maintenance tips section. I recently added a small bottle of Lucas fuel treatment to the gas, which means it's pretty concentrated. One effect that it says it has is that it stops pinging (i.e. raises octane?). I don't have pinging, I just wanted to make sure the carbs are squeaky clean after rebuilding them. I would like to know if it will make any difference using the colortune. In other words, is "colortuning" sensitive to octane ratings? Should I wait until I run this tank completely through and fill up with the "regular" 93 octane that I will routinely run in it? Any help appreciated. Thanks.
-Deni

[Pat Kelly]

I have a colortune and I would wait till using normal fuel.
I run 87 octane gas and have no ping on my stock(ish) engines. I've run 93 octane and noticed no difference other than cost.
Lower octane gas burns quicker so you're burning all the fuel in the combustion chamber. Pinging (hot spots) are cooled by the unburned fuel reducing the ping.
Most vehicles that require higher octane have higher compression ratios. The stock XS is 9.5(?) and should get by fine on regular. Big-bore kit raises compression to 10.5(?) and may benefit from the higher priced stuff.
YMMV