First of all, it is clear that only cars with knock sensors can achieve more power through more octane.
But...an expert had told me three years ago that with many very new engines the ECU notices that the fuel has more octane, but nevertheless does not set the ignition to more early because the insurances complained.
This is an indirect proof that more power and smoother running is possible with more octane.
You have to try it out in each individual case.
The Sigma 1.6 definitely converts higher octane into more power. In reach really more top speed at a well known steep hill on the Autobahn.
I can't say it for other Morgan engines except the 3.0 Roadster, it was definitely the case.
It also fits with the insurance statement that Peter's AMG is stated with power at 98 octane and that less octane leads to less power.
The reverse official performance claimed at 95 octane would lead to a different performance at 98 octane, but the car would no longer be insured.
