diff --git a/firmware/controllers/engine_controller.cpp b/firmware/controllers/engine_controller.cpp
index 3d97baeb2c..c740701a00 100644
--- a/firmware/controllers/engine_controller.cpp
+++ b/firmware/controllers/engine_controller.cpp
@@ -772,5 +772,5 @@ int getRusEfiVersion(void) {
 	if (initBootloader() != 0)
 		return 123;
 #endif /* EFI_BOOTLOADER_INCLUDE_CODE */
-	return 20190130;
+	return 20190131;
 }
diff --git a/firmware/controllers/math/config_engine_specs.h b/firmware/controllers/math/config_engine_specs.h
index 403aa77a25..4284d1e990 100644
--- a/firmware/controllers/math/config_engine_specs.h
+++ b/firmware/controllers/math/config_engine_specs.h
@@ -35,5 +35,7 @@
 #endif /* EFI_UNIT_TEST */
 
 #define get_operationMode CONFIG_ACCESS_FOR_CONFIG_HEADER_ONLY(operationMode)
+#define get_specs_displacement CONFIG_ACCESS_FOR_CONFIG_HEADER_ONLY(specs.displacement)
+#define get_injector_flow CONFIG_ACCESS_FOR_CONFIG_HEADER_ONLY(injector.flow)
 
 #endif /* CONTROLLERS_MATH_CONFIG_ENGINE_SPECS_H_ */
diff --git a/firmware/controllers/math/speed_density.cpp b/firmware/controllers/math/speed_density.cpp
index c2ddbf3735..cf0f29d21a 100644
--- a/firmware/controllers/math/speed_density.cpp
+++ b/firmware/controllers/math/speed_density.cpp
@@ -14,6 +14,7 @@
 #include "engine.h"
 #include "engine_math.h"
 #include "maf2map.h"
+#include "config_engine_specs.h"
 
 #define rpmMin 500
 #define rpmMax 8000
@@ -82,27 +83,25 @@ float getTCharge(int rpm, float tps, float coolantTemp, float airTemp DECLARE_EN
 /**
  * @return air mass in grams
  */
-static float getCycleAirMass(float volumetricEfficiency, float MAP, float tempK DECLARE_ENGINE_PARAMETER_SUFFIX) {
-	// todo: pre-calculate cylinder displacement to save one division
-	float cylinderDisplacement = CONFIG(specs.displacement);
-	return (cylinderDisplacement * volumetricEfficiency * MAP) / (GAS_R * tempK);
+static float getCycleAirMass(float volumetricEfficiency, float MAP, float tempK DECLARE_GLOBAL_SUFFIX) {
+	return (get_specs_displacement * volumetricEfficiency * MAP) / (GAS_R * tempK);
 }
 
-float getCylinderAirMass(float volumetricEfficiency, float MAP, float tempK DECLARE_ENGINE_PARAMETER_SUFFIX) {
-	return getCycleAirMass(volumetricEfficiency, MAP, tempK PASS_ENGINE_PARAMETER_SUFFIX)
-			/ CONFIG(specs.cylindersCount);
+float getCylinderAirMass(float volumetricEfficiency, float MAP, float tempK DECLARE_GLOBAL_SUFFIX) {
+	return getCycleAirMass(volumetricEfficiency, MAP, tempK PASS_GLOBAL_SUFFIX)
+			/ get_specs_displacement;
 }
 
 /**
  * @return per cylinder injection time, in seconds
  */
-float sdMath(float airMass, float AFR DECLARE_ENGINE_PARAMETER_SUFFIX) {
+float sdMath(float airMass, float AFR DECLARE_GLOBAL_SUFFIX) {
 
 	/**
 	 * todo: pre-calculate gramm/second injector flow to save one multiplication
 	 * open question if that's needed since that's just a multiplication
 	 */
-	float injectorFlowRate = cc_minute_to_gramm_second(CONFIG(injector.flow));
+	float injectorFlowRate = cc_minute_to_gramm_second(get_injector_flow);
 	/**
 	 * injection_pulse_duration = fuel_mass / injector_flow
 	 * fuel_mass = air_mass / target_afr
@@ -117,7 +116,7 @@ EXTERN_ENGINE;
 /**
  * @return per cylinder injection time, in Milliseconds
  */
-floatms_t getSpeedDensityFuel(float map DECLARE_ENGINE_PARAMETER_SUFFIX) {
+floatms_t getSpeedDensityFuel(float map DECLARE_GLOBAL_SUFFIX) {
 	/**
 	 * most of the values are pre-calculated for performance reasons
 	 */
@@ -128,10 +127,10 @@ floatms_t getSpeedDensityFuel(float map DECLARE_ENGINE_PARAMETER_SUFFIX) {
 	}
 	efiAssert(CUSTOM_ERR_ASSERT, !cisnan(map), "NaN map", 0);
 
-	float adjustedMap = map + engine->engineLoadAccelEnrichment.getEngineLoadEnrichment(PASS_ENGINE_PARAMETER_SIGNATURE);
+	float adjustedMap = map + engine->engineLoadAccelEnrichment.getEngineLoadEnrichment(PASS_GLOBAL_SIGNATURE);
 	efiAssert(CUSTOM_ERR_ASSERT, !cisnan(adjustedMap), "NaN adjustedMap", 0);
 
-	float airMass = getCylinderAirMass(ENGINE(engineState.currentVE), adjustedMap, tChargeK PASS_ENGINE_PARAMETER_SUFFIX);
+	float airMass = getCylinderAirMass(ENGINE(engineState.currentVE), adjustedMap, tChargeK PASS_GLOBAL_SUFFIX);
 	if (cisnan(airMass)) {
 		warning(CUSTOM_ERR_6685, "NaN airMass");
 		return 0;
@@ -142,7 +141,7 @@ floatms_t getSpeedDensityFuel(float map DECLARE_ENGINE_PARAMETER_SUFFIX) {
 #endif /*EFI_PRINTF_FUEL_DETAILS */
 
 	engine->engineState.airMass = airMass;
-	return sdMath(airMass, ENGINE(engineState.targetAFR) PASS_ENGINE_PARAMETER_SUFFIX) * 1000;
+	return sdMath(airMass, ENGINE(engineState.targetAFR) PASS_GLOBAL_SUFFIX) * 1000;
 }
 
 static const baro_corr_table_t default_baro_corr = {