Introduction: Why a Lightweight Flywheel Transforms Your Veloster N

Upgrading to a PSA lightweight flywheel on your Hyundai Veloster N is one of the most effective bolt‑on modifications for sharpening throttle response and unlocking quicker engine acceleration. The factory dual‑mass flywheel is heavy—designed for noise and vibration dampening—but that mass also robs horsepower as the engine spins up. Replacing it with a single‑mass, lightweight unit reduces rotational inertia, allowing the engine to rev freely and drop RPMs faster between shifts. The result is a more responsive, engaging driving experience, especially noticeable on track days or aggressive street driving. This guide walks you through the entire installation process, from gathering tools to post‑installation checks. It is written for experienced DIYers with basic mechanical skills and access to a lift or sturdy jack stands.

Benefits of a PSA Lightweight Flywheel

Before you dive into the wrenching, understand exactly what you gain:

  • Faster throttle response – Less mass means the engine revs up more quickly when you hit the gas.
  • Improved acceleration – You free up drivetrain power that was previously used to spin a heavy flywheel.
  • Better engine braking – The lighter assembly helps the RPMs drop faster when you lift off the throttle, aiding heel‑toe downshifts.
  • Reduced rotational inertia – The engine reaches peak power faster, and gear changes feel snappier.
  • Minimal increase in NVH – PSA’s design includes a steel insert to control gear rattle, keeping noise levels livable for a daily driver.

Keep in mind that a lightweight flywheel will slightly change the character of the car—you may notice a bit more gear rattle at idle and a less dampened engine feel. Many owners consider this a welcome trade‑off for the performance gain.

Tools and Materials Needed

Having everything on hand before you start saves trips to the toolbox and keeps the job moving. Below is the complete list.

Required Tools

  • PSA lightweight flywheel – Make sure you order the correct model for the Veloster N (2021–2023, 2.0L turbo).
  • Socket set – metric, 3/8″ and 1/2″ drive, including 8mm, 10mm, 12mm, 14mm, 17mm, 19mm, and 21mm sockets.
  • Torque wrench – 1/2″ drive, capable of 30–150 ft‑lb (40–200 N·m).
  • Ratchet and extensions – 3″ and 6″ extensions are helpful.
  • Flywheel locking tool – a universal locking pin or a flat‑head screwdriver can be used in a pinch, but a purpose‑built tool is safer.
  • Transmission jack (or a sturdy floor jack with a wooden block) – to support the transmission during removal and reinstallation.
  • Jack and two jack stands – or a two‑post lift.
  • Breaker bar – for stubborn bolts.
  • Flathead screwdriver and pry bar – for separating the transmission from the engine block.
  • Wire brush and brake cleaner – to clean mating surfaces.
  • Thread locker (Loctite 242 or equivalent) – for flywheel bolts.
  • Engine oil (5W‑30) – to lubricate the pilot bearing and input shaft splines.
  • Safety glasses and mechanic’s gloves.
  • Shop rags and a drain pan.
  • Clutch alignment tool – if you are also replacing the clutch disc.
  • Dial indicator or torque angle gauge – for verifying flywheel runout (usually not required if using new OEM bolts).
  • Transmission jack adapter or helper – the manual transmission is around 80 lb; having a second person reduces risk.

Preparation and Safety

Park the vehicle on a level, hard surface. Disconnect the negative terminal of the 12‑volt battery and wait five minutes before proceeding to allow any residual voltage to dissipate. Use jack stands rated for at least 1.5 times the vehicle weight; never rely solely on a hydraulic jack. Chock the rear wheels to prevent rolling.

Because you’ll be working under the car and removing the transmission, ensure the engine is completely cool to avoid burns from hot exhaust components. If the car has been driven, let it cool overnight.

Draining Transmission Fluid (If Applicable)

Some installations require lowering the transmission far enough that fluid can spill. It’s wise to drain the transmission fluid into a clean container for reuse or replacement. The Veloster N’s manual transmission holds about 1.8 quarts of 75W‑85 GL‑4 gear oil. Remove the fill plug first, then the drain plug, and allow the fluid to empty.

Removing the Transmission

Accessing the flywheel requires dropping the transmission. This is the most labor‑intensive part of the job. Proceed methodically.

Step 1: Raise and Support the Vehicle

Lift the front of the car high enough to work under it comfortably. Place jack stands under the subframe or frame rails. Remove the front wheels for easier access to the transmission bell housing bolts.

Step 2: Remove Under Engine Covers and Components

Remove the plastic splash shield under the engine if equipped. Unbolt the rear engine mount bracket (the dogbone mount) and set it aside. You may also need to detach the intercooler pipe and air box for clearance—refer to a service manual for your model year.

Step 3: Disconnect Electrical Connectors and Sensors

Unplug the backup light switch, speed sensor, and any other connectors on the transmission. Carefully zip‑tie them out of the way. Also disconnect the shift cables from the transmission housing by removing the retaining clips.

Step 4: Remove the Starter Motor

Unbolt the starter from the bell housing (two or three bolts). Support the starter and disconnect the main power wire and signal wire. Set the starter aside.

Step 5: Support the Transmission and Unbolt the Bell Housing

Place a transmission jack under the transmission pan. Secure the transmission to the jack with a strap or chain. Remove the bolts connecting the bell housing to the engine block—typically 12 to 14 bolts of varying lengths. Note their positions for reassembly.

Step 6: Lower the Transmission

Check that nothing is still attached (e.g., hydraulic line for the clutch). Carefully lower the transmission a few inches. This can be a tight squeeze on the Veloster N; you may need to rock the engine slightly by hand. Once the transmission clears the engine, lower it completely and slide it out from under the car.

Removing the Old Flywheel

With the transmission removed, the flywheel is now visible on the rear of the crankshaft.

Inspect the Condition

Before you remove it, take note of the dual‑mass construction and any visible wear. The factory flywheel is quite heavy (around 26 lb vs. ~10 lb for the PSA unit). Use a flashlight to check the friction surface for glazing, cracks, or hot spots.

Lock the Flywheel

Install the flywheel locking tool into the hole on the flywheel ring gear. If you don’t have a dedicated tool, a large flat‑head screwdriver can be wedged against the bell housing bolt hole—but be careful not to damage the ring gear teeth. This prevents the crankshaft from turning when you break the flywheel bolts.

Remove the Flywheel Bolts

Using a 21mm socket and breaker bar, loosen each flywheel bolt in a crisscross pattern. The bolts are often torqued to around 74–85 ft‑lb (100–115 N·m) and may have thread locker applied. Remove all six bolts and discard them—factory flywheel bolts are single‑use and should not be reused.

Pull the Flywheel Free

Grasp the flywheel by its edges and pull it straight off the crankshaft flange. If it’s seized, tap it gently with a rubber mallet or use a puller. Do not pry against the crankshaft seal. Once the flywheel is off, inspect the crankshaft pilot bearing. If it shows signs of wear or if you are installing a new clutch, replace it now.

Installing the PSA Lightweight Flywheel

Cleanliness is critical here. Any debris between the flywheel and crankshaft can cause runout and vibration.

Clean the Mating Surfaces

Use brake cleaner and a lint‑free cloth to thoroughly clean the crankshaft flange and the back of the new flywheel. Remove any oil, dirt, or old thread locker residue from the bolt holes. A wire brush can help dislodge stubborn deposits.

Position the New Flywheel

Align the six bolt holes of the PSA flywheel with the crankshaft flange. The flywheel will only fit one way because of the offset dowel pins or bolt pattern. Gently slide it onto the flange until it sits flush. Do not force it.

Install New Flywheel Bolts

Use new bolts that come with the PSA flywheel or purchase OEM‑spec bolts from a reputable supplier. Apply a small amount of medium‑strength thread locker (Loctite 242) to each bolt thread. Hand‑tighten them.

Torque the Bolts in Sequence

Lock the flywheel again. Using the torque wrench, tighten each bolt to the manufacturer’s specification. For most Hyundai applications, the spec is 74–78 ft‑lb (100–106 N·m) plus a 30‑degree angle, but always verify with the PSA installation instructions. Torque in a star pattern in two or three steps. After the final torque pass, check that each bolt is properly seated.

Link to PSA official torque specs: PSA Installation Guide

Optional: Check Flywheel Runout

If you have a dial indicator, mount it to the engine block and check runout on the friction surface. Runout should be less than 0.005″ (0.13 mm). If it’s excessive, recheck cleanliness and bolt seating.

Reassembling the Transmission and Clutch (If Applicable)

If you are replacing the clutch at the same time (highly recommended while everything is apart), follow the clutch manufacturer’s procedure. Align the clutch disc using an alignment tool, then install the pressure plate and torque to spec. The PSA flywheel is designed to work with the OEM clutch or upgraded discs. For the stock clutch, no modification is needed.

Reinstall the Transmission

Lift the transmission back onto the transmission jack. Ensure the input shaft splines are lightly greased with a thin coat of moly‑based grease. Slide the transmission forward, aligning the input shaft with the clutch splines. Rotate the output shaft slightly if necessary. Engage the bell housing onto the engine dowel pins. Do not use bolts to pull the transmission together—if it doesn’t slide easily, stop and check alignment.

Once the transmission is fully seated, install the bell housing bolts. Torque them to factory spec (typically 40–50 ft‑lb for the M10 bolts). Reinstall the starter motor, shift cables, electrical connectors, and the rear engine mount.

Refill Transmission Fluid

If you drained it, refill with fresh 75W‑85 GL‑4 fluid through the fill hole until it runs out. Replace the fill plug. Reinstall the drain plug with a new crush washer.

Final Checks and Test Drive

Before lowering the car, double‑check all fasteners and connections.

Visual Inspection

  • Verify that no tools or rags are left in the engine bay or under the car.
  • Check that the negative battery terminal is reconnected.
  • Look for any fluid leaks around the drain/fill plugs.
  • Make sure wiring harnesses are routed away from hot or moving parts.

Start‑Up Procedure

Start the engine with the car still on jack stands. Listen for any metallic scraping or unusual gear rattle. A slight rattle at idle is normal with a lightweight flywheel. If the noise is excessive, stop the engine and inspect. Allow the engine to reach operating temperature, then shut it off and recheck the flywheel bolt torque (only if you have access from below).

Road Test

Lower the car and take it on a quiet road. During the first few miles, perform gentle acceleration and deceleration to let the clutch and flywheel bed in. Then test harder pulls. You should notice immediate improvements: a quicker rev rise and a more direct feel. Downshifts become more rewarding as the RPMs drop quickly. If you hear a grinding or vibration that worsens with RPM, pull over and reevaluate the installation. Common issues include a misaligned clutch disc or loose flywheel bolts.

Tips for a Smooth Installation

  • Work in a well‑lit area – The flywheel bolts are hard to see without a light.
  • Take photos during disassembly – Especially of bolt locations and wiring routing. It saves time later.
  • Use a helper for transmission removal – The transmission is heavy and awkward. A second set of hands prevents injury and damage.
  • Replace the pilot bearing – This is inexpensive and easy to do while the transmission is off. A worn bearing can cause vibration.
  • Consider a lightweight flywheel‑specific clutch – Some aftermarket clutches have different damping characteristics that pair better with a single‑mass flywheel.

Long‑Term Considerations

The PSA flywheel is built from billet steel and is designed to last. However, because it’s lighter, the engine may need a slightly higher idle RPM to prevent stalling when coming to a stop with the AC on. Some owners adjust the idle with an aftermarket tune. Additionally, if you do many miles of stop‑and‑go traffic, the increased gear rattle may become a minor annoyance. For most drivers, the performance gain far outweighs these trade‑offs.

Regularly inspect the flywheel’s friction surface during clutch changes. With aggressive driving, it may show wear faster than the heavier factory unit. But that’s a small price for a more responsive Veloster N.

Conclusion

Installing a PSA lightweight flywheel transforms your Hyundai Veloster N into a sharper, more engaging machine. The DIY process is challenging but rewarding—you’ll gain not only a performance upgrade but also a deeper understanding of your car’s drivetrain. Follow each step carefully, use the right tools, and don’t rush the torque sequence. The result is a car that feels alive every time you press the throttle. For further reading and community support, check out the Veloster N forum or the official PSA product page.