diff --git a/common/params_keys.h b/common/params_keys.h
index 575dcc2adc..97f23d5108 100644
--- a/common/params_keys.h
+++ b/common/params_keys.h
@@ -164,6 +164,7 @@ inline static std::unordered_map<std::string, uint32_t> keys = {
     {"BackupManager_RestoreVersion", PERSISTENT},
 
     // sunnypilot car specific params
+    {"HyundaiLongitudinalTuning", PERSISTENT},
     {"HyundaiRadarTracks", PERSISTENT},
     {"HyundaiRadarTracksConfirmed", PERSISTENT},
     {"HyundaiRadarTracksPersistent", PERSISTENT},
diff --git a/selfdrive/ui/sunnypilot/qt/offroad/settings/vehicle/hyundai_settings.cc b/selfdrive/ui/sunnypilot/qt/offroad/settings/vehicle/hyundai_settings.cc
index 693a185cde..5f0010ac33 100644
--- a/selfdrive/ui/sunnypilot/qt/offroad/settings/vehicle/hyundai_settings.cc
+++ b/selfdrive/ui/sunnypilot/qt/offroad/settings/vehicle/hyundai_settings.cc
@@ -8,7 +8,50 @@
 #include "selfdrive/ui/sunnypilot/qt/offroad/settings/vehicle/hyundai_settings.h"
 
 HyundaiSettings::HyundaiSettings(QWidget *parent) : BrandSettingsInterface(parent) {
+  std::vector<QString> tuning_texts{ tr("Off"), tr("Dynamic"), tr("Predictive") };
+  longitudinalTuningToggle = new ButtonParamControl(
+    "HyundaiLongitudinalTuning",
+    tr("Custom Longitudinal Tuning"),
+    "",
+    "",
+    tuning_texts,
+    500
+  );
+  QObject::connect(longitudinalTuningToggle, &ButtonParamControlSP::buttonToggled, this, &HyundaiSettings::updateSettings);
+  list->addItem(longitudinalTuningToggle);
+  longitudinalTuningToggle->showDescription();
 }
 
 void HyundaiSettings::updateSettings() {
+  auto longitudinal_tuning_param = std::atoi(params.get("HyundaiLongitudinalTuning").c_str());
+
+  auto cp_bytes = params.get("CarParamsPersistent");
+  if (!cp_bytes.empty()) {
+    AlignedBuffer aligned_buf;
+    capnp::FlatArrayMessageReader cmsg(aligned_buf.align(cp_bytes.data(), cp_bytes.size()));
+    cereal::CarParams::Reader CP = cmsg.getRoot<cereal::CarParams>();
+
+    has_longitudinal_control = hasLongitudinalControl(CP);
+  } else {
+    has_longitudinal_control = false;
+  }
+
+  LongitudinalTuningOption longitudinal_tuning_option;
+  if (longitudinal_tuning_param == int(LongitudinalTuningOption::PREDICTIVE)) {
+    longitudinal_tuning_option = LongitudinalTuningOption::PREDICTIVE;
+  } else if (longitudinal_tuning_param == int(LongitudinalTuningOption::DYNAMIC)) {
+    longitudinal_tuning_option = LongitudinalTuningOption::DYNAMIC;
+  } else {
+    longitudinal_tuning_option = LongitudinalTuningOption::OFF;
+  }
+
+  bool longitudinal_tuning_disabled = !offroad || !has_longitudinal_control;
+  QString longitudinal_tuning_description = longitudinalTuningDescription(longitudinal_tuning_option);
+  if (longitudinal_tuning_disabled) {
+    longitudinal_tuning_description = toggleDisableMsg(offroad, has_longitudinal_control);
+  }
+
+  longitudinalTuningToggle->setEnabled(!longitudinal_tuning_disabled);
+  longitudinalTuningToggle->setDescription(longitudinal_tuning_description);
+  longitudinalTuningToggle->showDescription();
 }
diff --git a/selfdrive/ui/sunnypilot/qt/offroad/settings/vehicle/hyundai_settings.h b/selfdrive/ui/sunnypilot/qt/offroad/settings/vehicle/hyundai_settings.h
index edf495844d..c94d40cfde 100644
--- a/selfdrive/ui/sunnypilot/qt/offroad/settings/vehicle/hyundai_settings.h
+++ b/selfdrive/ui/sunnypilot/qt/offroad/settings/vehicle/hyundai_settings.h
@@ -14,10 +14,52 @@
 #include "selfdrive/ui/sunnypilot/qt/offroad/settings/settings.h"
 #include "selfdrive/ui/sunnypilot/qt/widgets/controls.h"
 
+enum class LongitudinalTuningOption {
+  OFF,
+  DYNAMIC,
+  PREDICTIVE,
+};
+
 class HyundaiSettings : public BrandSettingsInterface {
   Q_OBJECT
 
 public:
   explicit HyundaiSettings(QWidget *parent = nullptr);
   void updateSettings() override;
+
+private:
+  bool has_longitudinal_control = false;
+  ButtonParamControl *longitudinalTuningToggle = nullptr;
+
+  static QString toggleDisableMsg(bool _offroad, bool _has_longitudinal_control) {
+    if (!_has_longitudinal_control) {
+      return tr("This feature can only be used with openpilot longitudinal control enabled.");
+    }
+
+    if (!_offroad) {
+      return tr("Enable \"Always Offroad\" in Device panel, or turn vehicle off to select an option.");
+    }
+
+    return QString();
+  }
+
+  static QString longitudinalTuningDescription(LongitudinalTuningOption option = LongitudinalTuningOption::OFF) {
+    QString off_str = tr("Off: Uses default tuning");
+    QString dynamic_str = tr("Dynamic: Adjusts acceleration limits based on current speed");
+    QString predictive_str = tr("Predictive: Uses future trajectory data to anticipate needed adjustments");
+
+    if (option == LongitudinalTuningOption::PREDICTIVE) {
+      predictive_str = "<font color='white'><b>" + predictive_str + "</b></font>";
+    } else if (option == LongitudinalTuningOption::DYNAMIC) {
+      dynamic_str = "<font color='white'><b>" + dynamic_str + "</b></font>";
+    } else {
+      off_str = "<font color='white'><b>" + off_str + "</b></font>";
+    }
+
+    return QString("%1<br><br>%2<br>%3<br>%4<br>")
+             .arg(tr("Fine-tune your driving experience by adjusting acceleration smoothness with openpilot longitudinal control."))
+             .arg(off_str)
+             .arg(dynamic_str)
+             .arg(predictive_str);
+  }
 };
diff --git a/sunnypilot/selfdrive/car/interfaces.py b/sunnypilot/selfdrive/car/interfaces.py
index 2c27e960e9..f2019f5ed7 100644
--- a/sunnypilot/selfdrive/car/interfaces.py
+++ b/sunnypilot/selfdrive/car/interfaces.py
@@ -11,6 +11,7 @@ from opendbc.car.car_helpers import can_fingerprint
 from opendbc.car.interfaces import CarInterfaceBase
 from opendbc.car.hyundai.radar_interface import RADAR_START_ADDR
 from opendbc.car.hyundai.values import HyundaiFlags, DBC as HYUNDAI_DBC
+from opendbc.sunnypilot.car.hyundai.longitudinal.helpers import LongitudinalTuningType
 from opendbc.sunnypilot.car.hyundai.values import HyundaiFlagsSP
 from openpilot.common.params import Params
 from openpilot.common.swaglog import cloudlog
@@ -25,6 +26,21 @@ def log_fingerprint(CP: structs.CarParams) -> None:
   else:
     sentry.capture_fingerprint(CP.carFingerprint, CP.brand)
 
+def _initialize_custom_longitudinal_tuning(CI: CarInterfaceBase, CP: structs.CarParams, CP_SP: structs.CarParamsSP,
+                                           params: Params = None) -> None:
+  if params is None:
+    params = Params()
+
+  # Hyundai Custom Longitudinal Tuning
+  if CP.brand == 'hyundai':
+    hyundai_longitudinal_tuning = int(params.get("HyundaiLongitudinalTuning", encoding="utf8") or 0)
+    if hyundai_longitudinal_tuning == LongitudinalTuningType.DYNAMIC:
+      CP_SP.flags |= HyundaiFlagsSP.LONG_TUNING_DYNAMIC.value
+    if hyundai_longitudinal_tuning == LongitudinalTuningType.PREDICTIVE:
+      CP_SP.flags |= HyundaiFlagsSP.LONG_TUNING_PREDICTIVE.value
+
+  CP_SP = CI.get_longitudinal_tuning_sp(CP, CP_SP)
+
 
 def _initialize_neural_network_lateral_control(CI: CarInterfaceBase, CP: structs.CarParams, CP_SP: structs.CarParamsSP,
                                                params: Params = None, enabled: bool = False) -> None:
@@ -61,10 +77,11 @@ def _initialize_radar_tracks(CP: structs.CarParams, CP_SP: structs.CarParamsSP,
           CP.radarUnavailable = False
 
 
-def setup_interfaces(CI: CarInterfaceBase, params: Params = None):
+def setup_interfaces(CI: CarInterfaceBase, params: Params = None) -> None:
   CP = CI.CP
   CP_SP = CI.CP_SP
 
+  _initialize_custom_longitudinal_tuning(CI, CP, CP_SP, params)
   _initialize_neural_network_lateral_control(CI, CP, CP_SP, params)
   _initialize_radar_tracks(CP, CP_SP, params)
 
diff --git a/system/manager/manager.py b/system/manager/manager.py
index fde85f0f7c..90df415a8c 100755
--- a/system/manager/manager.py
+++ b/system/manager/manager.py
@@ -45,6 +45,7 @@ def manager_init() -> None:
     ("AutoLaneChangeTimer", "0"),
     ("AutoLaneChangeBsmDelay", "0"),
     ("DynamicExperimentalControl", "0"),
+    ("HyundaiLongitudinalTuning", "0"),
     ("Mads", "1"),
     ("MadsMainCruiseAllowed", "1"),
     ("MadsPauseLateralOnBrake", "0"),