diff --git a/firmware/controllers/algo/engine.cpp b/firmware/controllers/algo/engine.cpp
index 03cad6a76c..5f3902155c 100644
--- a/firmware/controllers/algo/engine.cpp
+++ b/firmware/controllers/algo/engine.cpp
@@ -145,6 +145,8 @@ void Engine::periodicSlowCallback(DECLARE_ENGINE_PARAMETER_SIGNATURE) {
 
 	cylinderCleanupControl(PASS_ENGINE_PARAMETER_SIGNATURE);
 
+	standardAirCharge = getStandardAirCharge(PASS_ENGINE_PARAMETER_SIGNATURE);
+
 #if (BOARD_TLE8888_COUNT > 0)
 	if (CONFIG(useTLE8888_cranking_hack) && ENGINE(rpmCalculator).isCranking(PASS_ENGINE_PARAMETER_SIGNATURE)) {
 		efitick_t nowNt = getTimeNowNt();
diff --git a/firmware/controllers/algo/engine.h b/firmware/controllers/algo/engine.h
index 88238e2473..dabc4526be 100644
--- a/firmware/controllers/algo/engine.h
+++ b/firmware/controllers/algo/engine.h
@@ -216,6 +216,9 @@ public:
 	 */
 	floatms_t actualLastInjection = 0;
 
+	// Standard cylinder air charge - 100% VE at standard temperature, grams per cylinder
+	float standardAirCharge = 0;
+
 	void periodicFastCallback(DECLARE_ENGINE_PARAMETER_SIGNATURE);
 	void periodicSlowCallback(DECLARE_ENGINE_PARAMETER_SIGNATURE);
 	void updateSlowSensors(DECLARE_ENGINE_PARAMETER_SIGNATURE);
diff --git a/firmware/controllers/algo/fuel_math.cpp b/firmware/controllers/algo/fuel_math.cpp
index 0561c5c1e0..4c13d6d1a0 100644
--- a/firmware/controllers/algo/fuel_math.cpp
+++ b/firmware/controllers/algo/fuel_math.cpp
@@ -163,11 +163,9 @@ float getRealMafFuel(float airSpeed, int rpm DECLARE_ENGINE_PARAMETER_SUFFIX) {
 	float halfCylCount = CONFIG(specs.cylindersCount) / 2.0f;
 
 	float cylinderAirmass = airPerRevolution / halfCylCount;
-	
-	//Calculation of 100% VE air mass in g/rev - 1 cylinder filling at 1.2929g/L
-	float StandardAirCharge = CONFIG(specs.displacement) / CONFIG(specs.cylindersCount) * 1.2929; 
+
 	//Create % load for fuel table using relative naturally aspiratedcylinder filling
-	float airChargeLoad = 100 * cylinderAirmass/StandardAirCharge;
+	float airChargeLoad = 100 * cylinderAirmass / ENGINE(standardAirCharge);
 	
 	//Correct air mass by VE table 
 	float corrCylAirmass = cylinderAirmass * veMap.getValue(rpm, airChargeLoad) / 100;
@@ -452,6 +450,15 @@ floatms_t getCrankingFuel(DECLARE_ENGINE_PARAMETER_SIGNATURE) {
 	return getCrankingFuel3(Sensor::get(SensorType::Clt).value_or(20),
 			engine->rpmCalculator.getRevolutionCounterSinceStart() PASS_ENGINE_PARAMETER_SUFFIX);
 }
+
+float getStandardAirCharge(DECLARE_ENGINE_PARAMETER_SIGNATURE) {
+	float totalDisplacement = CONFIG(specs.displacement);
+	float cylDisplacement = totalDisplacement / CONFIG(specs.cylindersCount);
+
+	// Calculation of 100% VE air mass in g/cyl - 1 cylinder filling at 1.204/L - air density at 20C
+	return cylDisplacement * 1.204f;
+}
+
 #endif
 
 float getFuelRate(floatms_t totalInjDuration, efitick_t timePeriod DECLARE_ENGINE_PARAMETER_SUFFIX) {
diff --git a/firmware/controllers/algo/fuel_math.h b/firmware/controllers/algo/fuel_math.h
index 2680a94be3..6fe04eb355 100644
--- a/firmware/controllers/algo/fuel_math.h
+++ b/firmware/controllers/algo/fuel_math.h
@@ -37,5 +37,7 @@ floatms_t getCrankingFuel3(float coolantTemperature, uint32_t revolutionCounterS
 floatms_t getInjectionDuration(int rpm DECLARE_ENGINE_PARAMETER_SUFFIX);
 percent_t getInjectorDutyCycle(int rpm DECLARE_ENGINE_PARAMETER_SUFFIX);
 
+float getStandardAirCharge(DECLARE_ENGINE_PARAMETER_SIGNATURE);
+
 // convert injection duration (Ms/Nt) to fuel rate (L/h)
 float getFuelRate(floatms_t totalInjDuration, efitick_t timePeriod DECLARE_ENGINE_PARAMETER_SUFFIX);
diff --git a/unit_tests/tests/test_fuel_math.cpp b/unit_tests/tests/test_fuel_math.cpp
new file mode 100644
index 0000000000..4b2da7e964
--- /dev/null
+++ b/unit_tests/tests/test_fuel_math.cpp
@@ -0,0 +1,31 @@
+#include "engine_test_helper.h"
+#include "fuel_math.h"
+
+#include "gtest/gtest.h"
+
+TEST(FuelMath, getStandardAirCharge) {
+	WITH_ENGINE_TEST_HELPER(TEST_ENGINE);
+
+	// Miata 1839cc 4cyl
+	CONFIG(specs.displacement) = 1.839f;
+	CONFIG(specs.cylindersCount) = 4;
+
+	EXPECT_FLOAT_EQ(0.553539f, getStandardAirCharge(PASS_ENGINE_PARAMETER_SIGNATURE));
+
+	// LS 5.3 liter v8
+	CONFIG(specs.displacement) = 5.327f;
+	CONFIG(specs.cylindersCount) = 8;
+
+	EXPECT_FLOAT_EQ(0.80171353f, getStandardAirCharge(PASS_ENGINE_PARAMETER_SIGNATURE));
+
+	// Chainsaw - single cylinder 32cc
+	CONFIG(specs.displacement) = 0.032f;
+	CONFIG(specs.cylindersCount) = 1;
+	EXPECT_FLOAT_EQ(0.038528003, getStandardAirCharge(PASS_ENGINE_PARAMETER_SIGNATURE));
+
+	// Leopard 1 47.666 liter v12
+	CONFIG(specs.displacement) = 47.666f;
+	CONFIG(specs.cylindersCount) = 12;
+
+	EXPECT_FLOAT_EQ(4.782489f, getStandardAirCharge(PASS_ENGINE_PARAMETER_SIGNATURE));
+}
diff --git a/unit_tests/tests/tests.mk b/unit_tests/tests/tests.mk
index b48dfb3882..847a45cb59 100644
--- a/unit_tests/tests/tests.mk
+++ b/unit_tests/tests/tests.mk
@@ -50,4 +50,5 @@ TESTS_SRC_CPP = \
 	tests/sensor/test_sensor_init.cpp \
 	tests/test_closed_loop_controller.cpp \
 	tests/test_gppwm.cpp \
+	tests/test_fuel_math.cpp \