Here is a good blurb on it:

So, you know no that sailfish is not an option, that doesn't mean you cannot calibrate.

What you need to know is even on a Creator, we typically DO NOT modify steps per mm.
EVEN if you extruder is off, that is why there are OTHER calibration settings that affect the same thing.

Basically, the entire system works like this:
The slicer determines the volume required for any given segment of extrusion by the length of the segment, the extrusion width (related to and derived from nozzle diameter) and layer height. This forms a logical smashed oval cylinder in 3D space and that space is a volume. Then to reverse the math, the volume is converted to a commanded length of filament, for which we told the slicer a diameter.
Again, first we get a volume for a segment, and since at the extruder volume in= volume out, we command a length of a known input diameter of filament.
Notice that key- the SLICER must be provided the ACTUAL measured accurate filament diameter of the filament loaded you intend to print with in order to result in correct extrusion volume.

You have a situation(and we all do as Dreamer owners) where that steps per mm for extrusion might not be 100% correct for the stock drive gear on the filament feeder. The truth is, we don't care that it's not perfect.
As long as it is consistent, wrong (within a certain reasonable amount) is perfectly fine. Not ideal, but OK.

Because, in the slicer, we have a fine tuning variable called "EXTRUSION MULTIPLIER". In some way, shape, or form, every slicer has this tuning variable.
This modifies the final gcode output of ALL E (extrusion values) globally. 1.0 is no change, and depending on how the slicer implemented it, greater than 1 either feeds more or is technically a divisor and reduces (again, different slicers use different methods). Again, in some ideal world, if we had steps per mm perfect, and we exactly nailed the diameter of the plastic- then extrusion multiplier should be 1.0 in every software slicer you use. That's just about never the case.

So yes, in an "ideal" world, we want steps per mm to be correct. We don't live in a perfect world and it not going to be. I can tell you right now it's probably not correct on the creator either. Nobody messes with it.
It's simply a result of the drive gear chosen.

So, the Sailfish manual method of tuning extrusion multiplier is STILL VALID for nearly EVERY SINGLE 3D printer around. EVEN THE DREAMER.
http://www.sailfishfirmware.com/doc/...l#x27-670005.1

5.1.4 Calibration Box

To achieve quality prints, start by ensuring that you can print a decent calibration “box” whose top is nice and flat. Producing a respectable box involves calibrating a slicing profile to your printer and choice of filaments. So, until you can print a good calibration box, there is little point in worrying about other printing defects you may be experiencing. Here is the step-by-step procedure for accomplishing this calibration:
1. Obtain a model for a 10 mm high box which is 20 mm on a side. ReplicatorG contains as its first example this calibration box: look under the Examples section of the File menu. It is the 20mm_Calibration_Box.stl. Alternatively, Thing #2064 at thingiverse.com contains the calibration box as the download file 20mmbox.stl. 2. Use calipers to measure the diameter of the filament with which you will be printing. 3. With the calibration box model in your slicer, slice it at a 0.3 mm layer height, 100% infill, and using the diameter ofthe filament you just measured.4 It is critical that you use 100% infill and that you measure the diameter of your filament and input that to the slicer. 4. Print the box. 5. Carefully examine the top surface of the box. While it is easy to see if the top is convex, you may need to use a straight edge to gauge how flat or concave the top is.
(a) If it is nice and flat, then you are done! (b) If it is convex, then too much plastic was extruded and your printer is over-extruding. Configure your slicing profile to put out slightly less plastic. How you will do this depends upon which slicer you use. For ReplicatorG, increase the “filament packing density” in the Dimension plugin. For MakerBot MakerWare and Desktop, increase the “feedstockMultiplier”. For Simplify3D, reduce the “extrusion multiplier”. Only change the value in small increments, such as 0.05. (c) If it is slightly hollow (concave), then too little plastic was extruded: your printer is under-extruding. Decrease the filament packing density (ReplicatorG), decrease the feedstockMultiplier (MakerWare and Desktop), or increase the extrusion multiplier (Simplify3D).6. Go back to Step 3, reslicing, reprinting, and re-evaluating the result. If you happen to have two extruders, it is recommended to do this calibration once for each extruder. Then keep distinct slicing profiles for each extruder: one for the right extruder and another for the left extruder.
Once you can print a nice calibration box, you are ready to get back to printing. Keep in mind that this calibration process should be repeated for different type of plastics. At issue is the differing hardnesses of the plastics used. The pinch gear in your printer’s extruder feed mechanism bites into the plastic filament. The depth to which it bites depends upon the hardness of the plastic. And the deeper the bite, the smaller the effective turning radius of the gear. With smaller turning radius, less filament is fed per rotation of the extruder stepper motor. This calibration is primarily to address your extruder’s handling of these variations in hardness. For example, ABS is significantly softer than PLA and so significantly different adjustments may be needed for ABS versus PLA. This will, of course, depend upon the geometry of the pinch gear and how capable it is of biting into the filament.