diff --git a/firmware/controllers/algo/advance_map.cpp b/firmware/controllers/algo/advance_map.cpp
index 6624af3fae..b94d0ce23f 100644
--- a/firmware/controllers/algo/advance_map.cpp
+++ b/firmware/controllers/algo/advance_map.cpp
@@ -107,3 +107,43 @@ void prepareTimingMap(DECLARE_ENGINE_PARAMETER_F) {
 	iatAdvanceCorrectionMap.init(config->ignitionIatCorrTable, config->ignitionIatCorrLoadBins,
 			config->ignitionIatCorrRpmBins);
 }
+
+/**
+ * @param octane gas octane number
+ * @param bore in mm
+ */
+float getTopAdvanceForBore(chamber_style_e style, int octane, double compression, double bore) {
+    int octaneCorrection;
+    if ( octane <= 90) {
+        octaneCorrection = -2;
+    } else if (octane < 94) {
+        octaneCorrection = -1;
+    } else {
+        octaneCorrection = 0;
+    }
+
+    int compressionCorrection;
+    if (compression <= 9) {
+        compressionCorrection = 2;
+    } else if (compression <= 10) {
+        compressionCorrection = 1;
+    } else if (compression <= 11) {
+        compressionCorrection = 0;
+    } else {
+        // compression ratio above 11
+        compressionCorrection = -2;
+    }
+    int base;
+    if (style == CS_OPEN) {
+    	base = 33;
+    } else if (style == CS_CLOSED) {
+    	base = 28;
+    } else {
+    	// CS_SWIRL_TUMBLE
+    	base = 22;
+    }
+
+    float boreCorrection = (bore - 4 * 25.4) / 25.4 * 6;
+    float result = base + octaneCorrection + compressionCorrection + boreCorrection;
+    return ((int)(result * 10)) / 10.0;
+}
diff --git a/firmware/controllers/algo/advance_map.h b/firmware/controllers/algo/advance_map.h
index 47bec86fc4..6efd11b9de 100644
--- a/firmware/controllers/algo/advance_map.h
+++ b/firmware/controllers/algo/advance_map.h
@@ -13,5 +13,6 @@
 angle_t getAdvance(int rpm, float engineLoad DECLARE_ENGINE_PARAMETER_S);
 void setDefaultIatTimingCorrection(DECLARE_ENGINE_PARAMETER_F);
 void prepareTimingMap(DECLARE_ENGINE_PARAMETER_F);
+float getTopAdvanceForBore(chamber_style_e style, int octane, double compression, double bore);
 
 #endif /* ADVANCE_H_ */
diff --git a/firmware/controllers/algo/rusefi_enums.h b/firmware/controllers/algo/rusefi_enums.h
index 37b2ff859b..d9b9682c82 100644
--- a/firmware/controllers/algo/rusefi_enums.h
+++ b/firmware/controllers/algo/rusefi_enums.h
@@ -628,4 +628,13 @@ typedef enum {
 	Internal_ForceMyEnumIntSize_timing_mode = ENUM_32_BITS,
 } timing_mode_e;
 
+typedef enum {
+    CS_OPEN = 0,
+    CS_CLOSED = 1,
+    CS_SWIRL_TUMBLE = 2,
+
+	Internal_ForceMyEnumIntSize_chamber_stype = ENUM_32_BITS,
+} chamber_style_e;
+
+
 #endif /* RUSEFI_ENUMS_H_ */
diff --git a/firmware/rusefi.cpp b/firmware/rusefi.cpp
index 4ce57a60e4..6db015cbd2 100644
--- a/firmware/rusefi.cpp
+++ b/firmware/rusefi.cpp
@@ -275,5 +275,5 @@ int getRusEfiVersion(void) {
 		return 123; // this is here to make the compiler happy about the unused array
 	if (UNUSED_CCM_SIZE[0] * 0 != 0)
 		return 3211; // this is here to make the compiler happy about the unused array
-	return 20151218;
+	return 20151224;
 }
diff --git a/java_console/ui/src/com/rusefi/logic/IgnitionMapBuilder.java b/java_console/ui/src/com/rusefi/logic/IgnitionMapBuilder.java
index 16d93d4647..07e9ca4c72 100644
--- a/java_console/ui/src/com/rusefi/logic/IgnitionMapBuilder.java
+++ b/java_console/ui/src/com/rusefi/logic/IgnitionMapBuilder.java
@@ -8,7 +8,7 @@ public class IgnitionMapBuilder {
     public enum ChamberStyle {
         OPEN_CHAMBER(33),
         CLOSED_CHAMBER(28),
-        SWITL_TUMBLE(22);
+        SWIRL_TUMBLE(22);
 
 
         private final int advance;
@@ -16,10 +16,6 @@ public class IgnitionMapBuilder {
         ChamberStyle(int advance) {
             this.advance = advance;
         }
-
-        public int getAdvance() {
-            return advance;
-        }
     }
 
 
diff --git a/java_console/ui/src/com/rusefi/logic/test/IgnitionMapBuilderTest.java b/java_console/ui/src/com/rusefi/logic/test/IgnitionMapBuilderTest.java
index 5e0b832616..d2204a38b5 100644
--- a/java_console/ui/src/com/rusefi/logic/test/IgnitionMapBuilderTest.java
+++ b/java_console/ui/src/com/rusefi/logic/test/IgnitionMapBuilderTest.java
@@ -27,7 +27,7 @@ public class IgnitionMapBuilderTest {
         assertEquals(35.0, getTopAdvanceForBore(OPEN_CHAMBER, 98, 8, 101.6));
         assertEquals(33.0, getTopAdvanceForBore(OPEN_CHAMBER, 98, 11, 101.6));
 
-        assertEquals(22.0, getTopAdvanceForBore(SWITL_TUMBLE, 89, 9, 101.6));
-        assertEquals(32.2, getTopAdvanceForBore(SWITL_TUMBLE, 89, 9, 145));
+        assertEquals(22.0, getTopAdvanceForBore(SWIRL_TUMBLE, 89, 9, 101.6));
+        assertEquals(32.2, getTopAdvanceForBore(SWIRL_TUMBLE, 89, 9, 145));
     }
 }
diff --git a/unit_tests/main.cpp b/unit_tests/main.cpp
index d64509a087..afef1a38c9 100644
--- a/unit_tests/main.cpp
+++ b/unit_tests/main.cpp
@@ -140,6 +140,7 @@ int main(void) {
 
 	testMenuTree();
 	testMafLookup();
+	testIgnitionMapGenerator();
 	testMafFuelMath();
 
 	testPidController();
diff --git a/unit_tests/test_engine_math.cpp b/unit_tests/test_engine_math.cpp
index b0737b8a83..1f08a66b59 100644
--- a/unit_tests/test_engine_math.cpp
+++ b/unit_tests/test_engine_math.cpp
@@ -13,6 +13,7 @@
 #include "speed_density.h"
 #include "engine_test_helper.h"
 #include "maf.h"
+#include "advance_map.h"
 
 void testIgnitionPlanning(void) {
 	printf("*************************************************** testIgnitionPlanning\r\n");
@@ -45,6 +46,17 @@ void testEngineMath(void) {
 	assertEquals(327.6667, getTCharge(4000, 100, 300, 350));
 }
 
+void testIgnitionMapGenerator(void) {
+	printf("*************************************************** testIgnitionMapGenerator\r\n");
+
+	assertEquals(35, getTopAdvanceForBore(CS_OPEN, 98, 8, 101.6));
+	assertEquals(33, getTopAdvanceForBore(CS_OPEN, 98, 11, 101.6));
+
+    assertEquals(22.0, getTopAdvanceForBore(CS_SWIRL_TUMBLE, 89, 9, 101.6));
+    assertEquals(32.2, getTopAdvanceForBore(CS_SWIRL_TUMBLE, 89, 9, 145));
+
+}
+
 void testMafLookup(void) {
 	printf("*************************************************** testMafLookup\r\n");
 
diff --git a/unit_tests/test_engine_math.h b/unit_tests/test_engine_math.h
index f507d17e19..d7b4e4fd90 100644
--- a/unit_tests/test_engine_math.h
+++ b/unit_tests/test_engine_math.h
@@ -11,5 +11,6 @@
 void testEngineMath(void);
 void testIgnitionPlanning(void);
 void testMafLookup(void);
+void testIgnitionMapGenerator(void);
 
 #endif /* TEST_ENGINE_MATH_H_ */