It hits it pretty quick if you punch it from 75 or 80 mph; you really don’t need that much distance. I hit it regularly on the PA and NJ turnpikes, partially as a matter of so-called “Italian tuneup”. As an EGR equipped direct injection engine, the M274 is prone to carbon build-up, so running it up to speed while keeping the engine in the 5k + range once in a while helps blow some of that sludge out of there.
Fuel additives don’t do anything about carbon build up on DI engines; anything that tells you otherwise is nonsense. The problem with DI engines is carbon builds up in the intake and valves, but because the fuel is injected directly into the cylinder, nothing washes it off... so increasing the detergency of the fuel that never touches it does nothing at all.
The only non-disassembly solution is to increase temperature and air pressure at the same time for a somewhat extended period of time- a minute or two is my thought, -which will cause some of the carbon buildup to fall into the cylinder and get vaporized. It is important to keep in mind that this kind of operation invariably ALSO leads to increased wear and stress on the engine components, so it is something you should do only occasionally, particularly if your fuel economy starts dropping substantially for no apparent reason.
Addendum: There is nothing wrong with running it at 101mph all day long if conditions warrant. The thing I’m warning moderation about is high-load, high-RPM, accelerating driving. 101 in 7th isn’t going to stress it, especially on a flat road.
