diff --git a/kartduino.ino b/kartduino.ino
index b7de64da..81db157d 100644
--- a/kartduino.ino
+++ b/kartduino.ino
@@ -218,7 +218,7 @@ void loop()
       //Perform lookup into fuel map for RPM vs MAP value
       currentStatus.VE = getTableValue(fuelTable, currentStatus.MAP, currentStatus.RPM);
       //Calculate an injector pulsewidth form the VE
-      currentStatus.PW = PW(req_fuel_uS, currentStatus.VE, currentStatus.MAP, 100, engineInjectorDeadTime); //The 100 here is just a placeholder for any enrichment factors (Cold start, acceleration etc). To add 10% extra fuel, this would be 110
+      currentStatus.PW = PW_SD(req_fuel_uS, currentStatus.VE, currentStatus.MAP, 100, engineInjectorDeadTime); //The 100 here is just a placeholder for any enrichment factors (Cold start, acceleration etc). To add 10% extra fuel, this would be 110
       //Perform a lookup to get the desired ignition advance
       currentStatus.advance = getTableValue(ignitionTable, currentStatus.MAP, currentStatus.RPM);
       
diff --git a/reference/schematic.fzz b/reference/schematic.fzz
index c940aa06..d0db8e15 100644
Binary files a/reference/schematic.fzz and b/reference/schematic.fzz differ
diff --git a/utils.h b/utils.h
index 531283fc..4ff4d0bc 100644
--- a/utils.h
+++ b/utils.h
@@ -15,14 +15,17 @@ int AIRDEN(int MAP, int temp)
   }
 
 /*
-This functino retuns a pulsewidth time (in us) given the following:
+This function retuns a pulsewidth time (in us) using a hybrid Alpha-N algorithm, given the following:
 REQ_FUEL
 VE: Lookup from the main MAP vs RPM fuel table
 MAP: In KPa, read from the sensor
 GammaE: Sum of Enrichment factors (Cold start, acceleration). This is a multiplication factor (Eg to add 10%, this should be 110)
-injOpen: Injector open time. The time the injector take to open in uS
+injDT: Injector dead time. The time the injector take to open minus the time it takes to close (Both in uS)
+TPS: Throttle position (0% to 100%)
+
+This function is called by PW_SD and PW_AN for speed0density and pure Alpha-N calculations respectively. 
 */
-int PW(int REQ_FUEL, byte VE, byte MAP, int GammaE, int injOpen)
+int PW(int REQ_FUEL, byte VE, byte MAP, int GammaE, int injOpen, byte TPS)
   {
     //Standard float version of the calculation
     //return (REQ_FUEL * (float)(VE/100.0) * (float)(MAP/100.0) * (float)(GammaE/100.0) + injOpen);
@@ -32,13 +35,26 @@ int PW(int REQ_FUEL, byte VE, byte MAP, int GammaE, int injOpen)
     int iVE = ((int)VE << 7) / 100;
     int iMAP = ((int)MAP << 7) / 100;
     int iGammaE = (GammaE << 7) / 100;
+    int iTPS = ((int)TPS << 7) / 100;
 
     unsigned long intermediate = ((long)REQ_FUEL * (long)iVE) >>7; //Need to use an intermediate value to avoid overflowing the long
     intermediate = (intermediate * iMAP) >> 7;
     intermediate = (intermediate * iGammaE) >> 7;
+    intermediate = (intermediate * iTPS) >> 7;
     return (int)intermediate + injOpen;
 
   }
+ 
+//Convenience function for Speed Density 
+int PW_SD(int REQ_FUEL, byte VE, byte MAP, int GammaE, int injOpen)
+{
+  return PW(REQ_FUEL, VE, MAP, GammaE, injOpen, 1); //Just use 1 in place of the TPS
+}
+
+int PW_AN(int REQ_FUEL, byte VE, byte TPS, int GammaE, int injOpen)
+{
+  return PW(REQ_FUEL, VE, 1, GammaE, injOpen, TPS); //Just use 1 in place of the MAP
+}
 
 /* Determine the Gamma Enrichment number. Forumla borrowed from MS2 manual... may be skipped/simplified for arduino!
 WARMUP: Warmup Correction