Engine animation curve

Hello, i'm making a racing game with only EVs, right now, I have the torque in a float value. But i want to use a animation curve in which the torque will evoluate according to the engine RPM (like you get 700 pound/feet of torque from 0 to 1000 rpm but from 1000 to 2000 it drops to 400 pound/feet of torque). So the torque is on the vertical axis and the rpm is on the horizontal axis. PS : i also need a simple way to calculate the wheel rpm. There is the script :

 using System.Collections;
 using System;
 using System.Collections.Generic;
 using UnityEngine;
 
 public enum Axel
 {
     front,
     rear
 }
 
 [Serializable]
 public struct Wheel
 {
     public GameObject model;
     public WheelCollider collider;
     public Axel axel;
 }
 
 [RequireComponent (typeof(InputManager))]
 public class CarController : MonoBehaviour
 {
     public InputManager inputManager;
     public List<Wheel> wheels;
     public Rigidbody localRigidbody;
 
     [Header("Throttle system")]
     public float torque;
     public float torqueMultiplier = 1;
     public float finalTorque;
     public float level = 1;
     public float currentSpeed;
     public float topSpeed;
 
     [Header("Steering system")]
     public float maxSteerAngle = 20;
     public float responsiveness = 1;
 
     // Start is called before the first frame update
     void Start()
     {
         
     }
 
     // Update is called once per frame
     void FixedUpdate()
     {
         finalTorque = torque * torqueMultiplier;
         currentSpeed = localRigidbody.velocity.sqrMagnitude;
 
         ThrottleSystem();
         SteeringSystem();
         AnimateWheels();
     }
 
     void ThrottleSystem()
     {
         foreach(var wheel in wheels)
         {
             if (currentSpeed > topSpeed)
             {
                 wheel.collider.motorTorque = 0;
             }
             else if (currentSpeed < topSpeed)
             {
                 wheel.collider.motorTorque = ((inputManager.throttle * finalTorque) * level) / 4;
             }
         }
     }
 
     void SteeringSystem()
     {
         foreach (var wheel in wheels)
         {
             if (wheel.axel == Axel.front)
             {
                 wheel.collider.steerAngle = inputManager.steer * maxSteerAngle * responsiveness;
             }
             else
             {
                 wheel.collider.steerAngle = 0;
             }
         }
     }
 
     void AnimateWheels()
     {
         foreach (var wheel in wheels)
         {
             Vector3 wheelColliderPosition;
             Quaternion WheelColliderRotation;
             wheel.collider.GetWorldPose(out wheelColliderPosition, out WheelColliderRotation);
             wheel.model.transform.position = wheelColliderPosition;
             wheel.model.transform.rotation = WheelColliderRotation;
         }
     }
 }