diff --git a/board/boards/black.h b/board/boards/black.h
index c860d1401d..ae6e0160df 100644
--- a/board/boards/black.h
+++ b/board/boards/black.h
@@ -162,6 +162,7 @@ board board_black = {
   .has_spi = false,
   .has_canfd = false,
   .fan_max_rpm = 0U,
+  .fan_max_pwm = 100U,
   .avdd_mV = 3300U,
   .fan_stall_recovery = false,
   .fan_enable_cooldown_time = 0U,
diff --git a/board/boards/board_declarations.h b/board/boards/board_declarations.h
index a9ff9297ba..22f55883f4 100644
--- a/board/boards/board_declarations.h
+++ b/board/boards/board_declarations.h
@@ -29,6 +29,7 @@ struct board {
   const uint16_t avdd_mV;
   const bool fan_stall_recovery;
   const uint8_t fan_enable_cooldown_time;
+  const uint8_t fan_max_pwm;
   board_init init;
   board_init_bootloader init_bootloader;
   board_enable_can_transceiver enable_can_transceiver;
diff --git a/board/boards/cuatro.h b/board/boards/cuatro.h
index 43a5dfc505..720077def6 100644
--- a/board/boards/cuatro.h
+++ b/board/boards/cuatro.h
@@ -57,6 +57,10 @@ uint32_t cuatro_read_current_mA(void) {
   return adc_get_mV(3) * 2U;
 }
 
+void cuatro_set_fan_enabled(bool enabled) {
+  set_gpio_output(GPIOD, 3, !enabled);
+}
+
 void cuatro_init(void) {
   red_chiplet_init();
 
@@ -93,6 +97,7 @@ void cuatro_init(void) {
 
   // fan setup
   set_gpio_alternate(GPIOC, 8, GPIO_AF2_TIM3);
+  register_set_bits(&(GPIOC->OTYPER), GPIO_OTYPER_OT8); // open drain
 
   // Initialize IR PWM and set to 0%
   set_gpio_alternate(GPIOC, 9, GPIO_AF2_TIM3);
@@ -108,7 +113,8 @@ board board_cuatro = {
   .has_obd = true,
   .has_spi = true,
   .has_canfd = true,
-  .fan_max_rpm = 6600U,
+  .fan_max_rpm = 12500U,
+  .fan_max_pwm = 99U, // it can go up to 14k RPM, but 99% -> 100% is very non-linear
   .avdd_mV = 1800U,
   .fan_stall_recovery = false,
   .fan_enable_cooldown_time = 3U,
@@ -121,7 +127,7 @@ board board_cuatro = {
   .check_ignition = red_check_ignition,
   .read_voltage_mV = cuatro_read_voltage_mV,
   .read_current_mA = cuatro_read_current_mA,
-  .set_fan_enabled = tres_set_fan_enabled,
+  .set_fan_enabled = cuatro_set_fan_enabled,
   .set_ir_power = tres_set_ir_power,
   .set_siren = unused_set_siren,
   .set_bootkick = tres_set_bootkick,
diff --git a/board/boards/dos.h b/board/boards/dos.h
index 0164f2b262..62e83c6882 100644
--- a/board/boards/dos.h
+++ b/board/boards/dos.h
@@ -190,6 +190,7 @@ board board_dos = {
 #endif
   .has_canfd = false,
   .fan_max_rpm = 6500U,
+  .fan_max_pwm = 100U,
   .avdd_mV = 3300U,
   .fan_stall_recovery = true,
   .fan_enable_cooldown_time = 3U,
diff --git a/board/boards/grey.h b/board/boards/grey.h
index 516d0fa70f..cbbd8e9c89 100644
--- a/board/boards/grey.h
+++ b/board/boards/grey.h
@@ -11,6 +11,7 @@ board board_grey = {
   .has_spi = false,
   .has_canfd = false,
   .fan_max_rpm = 0U,
+  .fan_max_pwm = 100U,
   .avdd_mV = 3300U,
   .fan_stall_recovery = false,
   .fan_enable_cooldown_time = 0U,
diff --git a/board/boards/red.h b/board/boards/red.h
index 746c54b622..3a12fdb705 100644
--- a/board/boards/red.h
+++ b/board/boards/red.h
@@ -174,6 +174,7 @@ board board_red = {
   .has_spi = false,
   .has_canfd = true,
   .fan_max_rpm = 0U,
+  .fan_max_pwm = 100U,
   .avdd_mV = 3300U,
   .fan_stall_recovery = false,
   .fan_enable_cooldown_time = 0U,
diff --git a/board/boards/tres.h b/board/boards/tres.h
index 91b94f68e2..fdd4cb19d5 100644
--- a/board/boards/tres.h
+++ b/board/boards/tres.h
@@ -76,6 +76,7 @@ board board_tres = {
   .has_spi = true,
   .has_canfd = true,
   .fan_max_rpm = 6600U,
+  .fan_max_pwm = 100U,
   .avdd_mV = 1800U,
   .fan_stall_recovery = false,
   .fan_enable_cooldown_time = 3U,
diff --git a/board/boards/uno.h b/board/boards/uno.h
index a2e1e98354..8e86c98fac 100644
--- a/board/boards/uno.h
+++ b/board/boards/uno.h
@@ -197,6 +197,7 @@ board board_uno = {
   .has_spi = false,
   .has_canfd = false,
   .fan_max_rpm = 5100U,
+  .fan_max_pwm = 100U,
   .avdd_mV = 3300U,
   .fan_stall_recovery = false,
   .fan_enable_cooldown_time = 0U,
diff --git a/board/boards/white.h b/board/boards/white.h
index 8d22afbc9b..08f62e5226 100644
--- a/board/boards/white.h
+++ b/board/boards/white.h
@@ -191,6 +191,7 @@ board board_white = {
   .has_spi = false,
   .has_canfd = false,
   .fan_max_rpm = 0U,
+  .fan_max_pwm = 100U,
   .avdd_mV = 3300U,
   .fan_stall_recovery = false,
   .fan_enable_cooldown_time = 0U,
diff --git a/board/drivers/fan.h b/board/drivers/fan.h
index 15296079ae..e0946aac34 100644
--- a/board/drivers/fan.h
+++ b/board/drivers/fan.h
@@ -86,7 +86,7 @@ void fan_tick(void) {
       float error = fan_state.target_rpm - fan_rpm_fast;
       fan_state.error_integral += FAN_I * error;
     }
-    fan_state.power = CLAMP(fan_state.error_integral, 0U, 100U);
+    fan_state.power = CLAMP(fan_state.error_integral, 0U, current_board->fan_max_pwm);
 
     // Set PWM and enable line
     pwm_set(TIM3, 3, fan_state.power);
diff --git a/board/stm32h7/llfan.h b/board/stm32h7/llfan.h
index dce622503a..04f0fc11c8 100644
--- a/board/stm32h7/llfan.h
+++ b/board/stm32h7/llfan.h
@@ -8,8 +8,8 @@ void EXTI2_IRQ_Handler(void) {
 }
 
 void llfan_init(void) {
-  // 5000RPM * 4 tach edges / 60 seconds
-  REGISTER_INTERRUPT(EXTI2_IRQn, EXTI2_IRQ_Handler, 700U, FAULT_INTERRUPT_RATE_TACH)
+  // 12000RPM * 4 tach edges / 60 seconds
+  REGISTER_INTERRUPT(EXTI2_IRQn, EXTI2_IRQ_Handler, 1000U, FAULT_INTERRUPT_RATE_TACH)
 
   // Init PWM speed control
   pwm_init(TIM3, 3);