t I just am curious if anybody else has converted a e bike to make it quicker,
There are about a billion threads over the years for that type of thing, if you poke around.
There are also many threads about how many volts various motors will take, with more info on the topic, but essentially any motor could electrically take a couple hundred volts, at least.
If all you need is a couple extra MPH, first try this:
Get the powered wheel offground, and run the system to max speed. If it runs the exact same speed offground as it does onground, then the system is speed-limited by the controller's firmware, not the battery voltage or motor, etc.
In that case, there may be a setting in the display that limits the speed that is user-alterable. If it isn't, then you'd need to replace the controller/display with an unlimited one. Once the limit is removed you can find out how fast it will actually go on your specific terrain and riding conditions, but it's pretty likely it would give at least a couple more MPH.
If it runs faster offground than onground, then it's power-limited and/or voltage-limited, and fixing that would mean upgrading to a higher voltage battery and higher voltage controller that can supply the higher power the faster speed will need.
It's likely that the brakes, tires, suspension, etc are capable of the extra couple mph, but if you need a lot more speed you may want to verify they can do this safely, and replace anything not designed for it.