diff --git a/config/avrsim.cfg b/config/avrsim.cfg
index e8b18717..9fbcfb7c 100644
--- a/config/avrsim.cfg
+++ b/config/avrsim.cfg
@@ -42,6 +42,8 @@ step_pin: ar19
 dir_pin: ar18
 enable_pin: ar25
 step_distance: .004242
+nozzle_diameter: 0.500
+filament_diameter: 3.500
 max_velocity: 200000
 max_accel: 3000
 heater_pin: ar4
diff --git a/config/example-delta.cfg b/config/example-delta.cfg
index 1155a06f..41e238ec 100644
--- a/config/example-delta.cfg
+++ b/config/example-delta.cfg
@@ -46,6 +46,8 @@ step_pin: ar26
 dir_pin: ar28
 enable_pin: !ar24
 step_distance: .0022
+nozzle_diameter: 0.400
+filament_diameter: 1.750
 max_velocity: 200
 max_accel: 3000
 heater_pin: ar10
diff --git a/config/example.cfg b/config/example.cfg
index 1113351b..75684d16 100644
--- a/config/example.cfg
+++ b/config/example.cfg
@@ -109,6 +109,12 @@ step_pin: ar19
 dir_pin: ar18
 enable_pin: !ar25
 step_distance: .004242
+nozzle_diameter: 0.500
+#   Diameter of the nozzle orifice (in mm). This parameter must be
+#   provided.
+filament_diameter: 3.500
+#   Diameter of the raw filament (in mm) as it enters the
+#   extruder. This parameter must be provided.
 max_velocity: 200000
 #   Maximum velocity (in mm/s) of the extruder motor for extrude only
 #   moves. This parameter must be provided.
diff --git a/config/makergear-m2-2012.cfg b/config/makergear-m2-2012.cfg
index 78e32968..83deee9b 100644
--- a/config/makergear-m2-2012.cfg
+++ b/config/makergear-m2-2012.cfg
@@ -48,6 +48,8 @@ step_pin: PC3
 dir_pin: PL6
 enable_pin: !PA4
 step_distance: .004242
+nozzle_diameter: 0.350
+filament_diameter: 1.750
 max_velocity: 200000
 max_accel: 3000
 pressure_advance: 0.07
diff --git a/klippy/extruder.py b/klippy/extruder.py
index 31f66cd6..23ed7f54 100644
--- a/klippy/extruder.py
+++ b/klippy/extruder.py
@@ -10,9 +10,11 @@ class PrinterExtruder:
     def __init__(self, printer, config):
         self.heater = heater.PrinterHeater(printer, config)
         self.stepper = stepper.PrinterStepper(printer, config, 'extruder')
-        self.pressure_advance = config.getfloat('pressure_advance', 0.)
+        nozzle_diameter = config.getfloat('nozzle_diameter')
+        filament_diameter = config.getfloat('filament_diameter')
         self.max_e_velocity = config.getfloat('max_velocity')
         self.max_e_accel = config.getfloat('max_accel')
+        self.pressure_advance = config.getfloat('pressure_advance', 0.)
         self.need_motor_enable = True
         self.extrude_pos = 0.
     def build_config(self):