I had an idea for a super setting for an RPG or maybe a novella or three. Being prone to overthink I wanted to start by setting power levels. Sadly I can't just assume the hero can lift a building in his hands (unless he was using TK to mimic super strength you'd end up with a demolished building and that'd make a difference to me.)
So I came up with the 'Rule of 15.' The Golden Age Superman in his earliest appearance could lift a car that weighed around 3000 pounds. A very fit human male could lift 200 lbs. So 3000/200= 15. Super powers magnify human capabilities by 15 where applicable.
In DC Heroes terms this is a puny +4APs for a stat around 7-8 APs which is still pretty good. You could rip apart a normal car or flip an armored truck. In Open d6 I'm not as sure. I'm still trying to work out benchmarks for it but it seems to equate to +5d which is also pretty good.
So supers wouldn't be able to flip tanks. A brick still could probably run up to one ignoring the machine gun fire, rip open a hatch and jump in to beat the hell out of the crew.
Let's look at running. The human peak is around 15 mph. Multiply that times 15 and you get 225 mph. You aren't moving at multiple mach speed but you could still run fast enough to run on water or climb a 20' wall. Not too bad.
It breaks down if you try to model some powers like the GA Superman's leaping. Superman was said to leap 200 meters in a single bound. The world record is about 8.9m so if your super was a world record holder he could pull about 133.5 meters. Usain Bolt might get a distance of 9.46m so if he was bitten by a radioactive grasshopper (or whatever) he could reach a distance of 142m. But that's still pretty super.
For powers that don't have a physical basis like invisibility you could model it as an increase to skills such as invisibility increasing Stealth skill +5d in Open d6. Flying is a hard one. It gives a lot of freedom of motion as well as negating some threats (you don't worry about someone throwing you from a building for example.) You might just multiply a character's dice code by 15 meters so an average character could make 45m per second. Energy blasts could be based on the character's strength or mental score with the stock +5d add.