diff --git a/buoy_gazebo/src/ElectroHydraulicPTO/ElectroHydraulicPTO.cpp b/buoy_gazebo/src/ElectroHydraulicPTO/ElectroHydraulicPTO.cpp
index 590c1346..97bb8bc6 100644
--- a/buoy_gazebo/src/ElectroHydraulicPTO/ElectroHydraulicPTO.cpp
+++ b/buoy_gazebo/src/ElectroHydraulicPTO/ElectroHydraulicPTO.cpp
@@ -376,6 +376,9 @@ void ElectroHydraulicPTO::PreUpdate(
   const double N = this->dataPtr->x[0U];
   double deltaP = this->dataPtr->x[1U];
   double VBus = this->dataPtr->x[2U];
+  const double eff_m = this->hyd_eff_m.eval(fabs(N));
+  const double eff_v = this->hyd_eff_v.eval(fabs(deltaP));
+
   VBus = std::min(VBus, this->dataPtr->MaxTargetVoltage);
   double BusPower = this->dataPtr->functor.BusPower;
 
@@ -436,6 +439,8 @@ void ElectroHydraulicPTO::PreUpdate(
   latent_data.electro_hydraulic.motor_drive_switching_loss = pto_loss.motor_drive_switching_loss;
   latent_data.electro_hydraulic.motor_drive_friction_loss = pto_loss.motor_drive_friction_loss;
   latent_data.electro_hydraulic.battery_i2r_loss = pto_loss.battery_i2r_loss;
+  latent_data.electro_hydraulic.eff_m = eff_m;
+  latent_data.electro_hydraulic.eff_v = eff_v;
 
   _ecm.SetComponentData<buoy_gazebo::components::BatteryState>(
     this->dataPtr->PrismaticJointEntity,
diff --git a/buoy_gazebo/src/LatentData/LatentData/LatentData.hpp b/buoy_gazebo/src/LatentData/LatentData/LatentData.hpp
index f8fd3cec..0a579158 100644
--- a/buoy_gazebo/src/LatentData/LatentData/LatentData.hpp
+++ b/buoy_gazebo/src/LatentData/LatentData/LatentData.hpp
@@ -106,10 +106,12 @@ struct ElectroHydraulic
   double inst_power{0.0};  // Watts
   double rpm{0.0};
   double force{0.0};  // Newtons
-  double motor_drive_i2r_loss{0.0};
-  double motor_drive_friction_loss{0.0};
-  double motor_drive_switching_loss{0.0};
-  double battery_i2r_loss{0.0};
+  double motor_drive_i2r_loss{0.0};  // Watts
+  double motor_drive_friction_loss{0.0};  // Watts
+  double motor_drive_switching_loss{0.0};  // Watts
+  double battery_i2r_loss{0.0};  // Watts
+  double eff_m{0.0};  // mechanical efficiency
+  double eff_v{0.0};  // volumetric efficiency
 
   bool operator==(const ElectroHydraulic & that) const
   {
diff --git a/buoy_gazebo/src/LatentData/LatentData/LatentDataPublisher.cpp b/buoy_gazebo/src/LatentData/LatentData/LatentDataPublisher.cpp
index 49705430..64984200 100644
--- a/buoy_gazebo/src/LatentData/LatentData/LatentDataPublisher.cpp
+++ b/buoy_gazebo/src/LatentData/LatentData/LatentDataPublisher.cpp
@@ -279,6 +279,12 @@ void LatentDataPublisher::PostUpdate(
     latent_data.electro_hydraulic.motor_drive_friction_loss;
   this->dataPtr->latent_data_.electro_hydraulic.battery_i2r_loss =
     latent_data.electro_hydraulic.battery_i2r_loss;
+  this->dataPtr->latent_data_.electro_hydraulic.eff_m =
+    latent_data.electro_hydraulic.eff_m;
+  this->dataPtr->latent_data_.electro_hydraulic.eff_v =
+    latent_data.electro_hydraulic.eff_v;
+
+
 
   this->dataPtr->latent_data_.wave_body.buoyancy.force.x =
     latent_data.wave_body.buoyant_force.X();
diff --git a/buoy_gazebo/src/PolytropicPneumaticSpring/PolytropicPneumaticSpring.cpp b/buoy_gazebo/src/PolytropicPneumaticSpring/PolytropicPneumaticSpring.cpp
index 5f392ffe..0f995e86 100644
--- a/buoy_gazebo/src/PolytropicPneumaticSpring/PolytropicPneumaticSpring.cpp
+++ b/buoy_gazebo/src/PolytropicPneumaticSpring/PolytropicPneumaticSpring.cpp
@@ -40,6 +40,8 @@
 #include "SpringState.hpp"
 #include <LatentData/LatentData.hpp>
 
+#include <buoy_utils/Constants.hpp>
+
 
 using namespace std::chrono_literals;
 
@@ -528,8 +530,8 @@ void PolytropicPneumaticSpring::PreUpdate(
   const int dt_nano =
     static_cast<int>(std::chrono::duration_cast<std::chrono::nanoseconds>(_info.dt).count());
 
-  static const double PASCAL_TO_PSI = 1.450377e-4;  // PSI/Pascal
-  const double pressure_diff = (spring_state.lower_psi - spring_state.upper_psi) / PASCAL_TO_PSI;
+  const double pressure_diff =
+    (spring_state.lower_psi - spring_state.upper_psi) * buoy_utils::PASCAL_PER_PSI;
 
   if (spring_state.valve_command) {
     openValve(
@@ -597,6 +599,7 @@ void PolytropicPneumaticSpring::PreUpdate(
     latent_data.upper_spring.dQ_dt = this->dataPtr->Q_rate;
     latent_data.upper_spring.piston_position = x;
     latent_data.upper_spring.piston_velocity = v;
+    latent_data.upper_spring.mass = this->dataPtr->mass;
   } else {
     latent_data.lower_spring.valid = true;
     latent_data.lower_spring.force = this->dataPtr->F;
@@ -604,6 +607,7 @@ void PolytropicPneumaticSpring::PreUpdate(
     latent_data.lower_spring.dQ_dt = this->dataPtr->Q_rate;
     latent_data.lower_spring.piston_position = this->dataPtr->config_->stroke - x;
     latent_data.lower_spring.piston_velocity = -v;
+    latent_data.lower_spring.mass = this->dataPtr->mass;
   }
 
   _ecm.SetComponentData<buoy_gazebo::components::LatentData>(
diff --git a/buoy_gazebo/src/buoy_utils/Constants.hpp b/buoy_gazebo/src/buoy_utils/Constants.hpp
index 68810e92..49d5e21d 100644
--- a/buoy_gazebo/src/buoy_utils/Constants.hpp
+++ b/buoy_gazebo/src/buoy_utils/Constants.hpp
@@ -27,6 +27,7 @@ static constexpr double NM_PER_INLB{0.112984829};
 static constexpr double INLB_PER_NM{8.851};
 static constexpr double INCHES_PER_METER{39.4};
 static constexpr double NEWTONS_PER_LB{4.4482};
+static constexpr double PASCAL_PER_PSI = 6894.757;  // Pascal/PSI
 }  // namespace buoy_utils