Car Tuning Drivetrain and Transmission 2 — Questions and Answers
Question 1: What is the primary purpose of a short-throw shifter kit in a manual transmission car?
- Increases gear ratios
- Reduces the distance the shifter travels between gears (Correct answer)
- Adds an extra gear to the transmission
- Strengthens the clutch disc
Correct answer: Reduces the distance the shifter travels between gears
A short-throw shifter reduces the throw distance between gears, enabling quicker and more precise gear changes.
Question 2: Which differential type is most commonly used in performance AWD tuning builds because it actively distributes torque between axles?
- Open differential
- Torsen differential
- Electronic limited-slip differential (eLSD) (Correct answer)
- Spool differential
Correct answer: Electronic limited-slip differential (eLSD)
An eLSD uses electronic controls to actively vary torque distribution, making it the top choice for AWD performance applications.
Question 3: When upgrading a transmission for high-horsepower use, what does 'gear dog engagement' refer to in a dog-ring gearbox?
- The clutch's bite point
- Positive interlocking teeth that lock gears to the shaft for fast shifts (Correct answer)
- A synchro ring that smooths engagement speed
- The differential spider gears
Correct answer: Positive interlocking teeth that lock gears to the shaft for fast shifts
Dog-ring gearboxes use positive-locking dog teeth instead of synchros, allowing near-instant gear engagement under load.
Question 4: A tuner is upgrading a RWD car and wants to run a Ford 9-inch rear axle. What is the main advantage of this axle housing?
- It is lighter than modern differentials
- Its drop-out center section allows ring and pinion changes without removing the axle (Correct answer)
- It has a built-in torque vectoring system
- It supports electric motor integration natively
Correct answer: Its drop-out center section allows ring and pinion changes without removing the axle
The Ford 9-inch's removable center section (drop-out) allows gear ratio and differential swaps without pulling the entire axle assembly.
Question 5: What happens to driveshaft angle (U-joint operating angle) when you lower a RWD vehicle significantly?
- The angle decreases, reducing vibration
- The angle increases, potentially causing vibration and U-joint wear (Correct answer)
- The angle stays the same due to flex joints
- The CV axles self-adjust automatically
Correct answer: The angle increases, potentially causing vibration and U-joint wear
Lowering a vehicle steepens driveshaft operating angles, increasing vibration and accelerating U-joint wear if not corrected.
Question 6: Which transmission fluid type is generally required in modern dual-clutch transmissions (DCT) to protect wet clutch packs?
- Standard gear oil (GL-5)
- Engine oil (5W-30)
- Dedicated DCT or wet-clutch compatible ATF (Correct answer)
- Power steering fluid
Correct answer: Dedicated DCT or wet-clutch compatible ATF
DCTs with wet clutch packs require specialized DCT/wet-clutch ATF; standard GL-5 gear oil lacks the friction modifiers needed.
Question 7: In drivetrain tuning, what is the effect of using a numerically higher final drive ratio (e.g., 4.10 vs. 3.55)?
- Better highway fuel economy and lower RPM at cruise
- Faster acceleration at the cost of lower top speed and higher cruise RPM (Correct answer)
- Increased top speed with no effect on acceleration
- Reduced torque multiplication at the wheels
Correct answer: Faster acceleration at the cost of lower top speed and higher cruise RPM
A numerically higher axle ratio multiplies torque more, improving acceleration but raising engine RPM at any given speed, reducing top-end potential.
Car Tuning Drivetrain and Transmission 2
What is the primary purpose of a short-throw shifter kit in a manual transmission car?