We did dyno testing on our known 512 /10.75 /trick flow heads engine to find out what fuel it liked and, yes, race fuel is certainly most consistent, but the engine made best power at 93-95 octane.
100 octane lost 15 hp, no timing adjustments or carb adjustments would bring that back.
110 race fuel lost almost 25 hp.
I’m not going to say you didn’t see the results you’re claiming........ but I will say this.......
In 30 years of dyno testing, I have never seen a loss like that by running race gas, no matter how low the CR of the engine was.
Unless........ the race fuel was stale.
If you had fresh 93 summer blend, and a sealed 5 gal can of VP c12....... and dynoed the two back to back on a 600-700hp TF headed 10.75:1 BB stroker with a known good carb on top...... fuel curve and timing all sorted out for the 93, then drained the fuel cell and carb........and dumped in the fresh c12.........it’s not going to lose 25hp.
Not here anyway.
The only time I’ve ever seen any kind of significant difference in power from swapping fuels(assuming they have adequate octane for the combo)....... is going from a non-oxygenated fuel to a heavily oxygenated fuel.
Like, from c16 to q16.
My experience has been that losing 25hp going from pump gas to race gas on a build like that would not be a typical result....... at all.
