Suspension Information and Upgrades – 2.5L NA

Overview

This guide provides an overview of suspension dynamics and upgrade options for the Porsche 944 (8-valve engine configuration) for pre-1985.5 (1983–1985.5) and 1985.5 onwards (1986–1988) variants. It explains key concepts like understeer and oversteer, their causes, and how to adjust the suspension to improve handling for street or track use. Upgrading the suspension enhances cornering stability, reduces body roll, and improves overall driving performance, making it essential for enthusiasts looking to optimize their 944’s handling.

Pink and blue text represent links to additional resources, tools, parts, and partner websites.

Tools Required

• 10mm (3/8 inch) wrench
• 13mm (1/2 inch) wrench
• 17mm (11/16 inch) wrench
• 19mm (3/4 inch) wrench
• Socket set (10mm to 19mm)
• Torque wrench (capable of 20–100 Nm / 15–74 ft-lbs)
• Jack and jack stands
• Spring compressor (for front springs)
• Torsion bar indexing tool (for rear torsion bars, if replacing)
• Adjustable spanner wrench (for coil-over adjustments, if applicable)
• Camber/caster alignment tool
• Tire pressure gauge

Parts Required

• Front springs (200–275 lb. rate, e.g., 944 343 531 00 for 220 lb. sport setup)
• Rear torsion bars (27mm–29mm, e.g., 944 333 531 00 for 27mm, 220 lb. rate)
• Front sway bar (30mm, e.g., 944 343 701 00)
• Rear sway bar (19mm, 3-way adjustable, e.g., 968 343 701 00)
• Optional: Coil-over shocks (front/rear, adjustable, e.g., 944 343 031 00 for Koni Sport)
• Optional: Adjustable sport shocks/struts (e.g., 944 343 031 01 for Bilstein)

Step-by-Step Procedure

Step 1: Understand Suspension Dynamics

1. Learn the concepts of understeer and oversteer:Understeer (Pre-85.5 and 85.5 Onwards):

   • Occurs when the front tires lose traction before the rear during cornering, causing a wider turn radius. The stock 944 setup has understeer for safety.

   Oversteer (Pre-85.5 and 85.5 Onwards):

   • Occurs when the rear tires lose traction before the front, causing a tighter turn radius. Oversteer requires careful correction to avoid spins.

2. Understand slip angle:• Slip angle is the angular difference between the tire’s contact patch and the wheel’s direction during a turn, caused by tire distortion. Higher slip angles increase understeer (front tires) or oversteer (rear tires).

3. Recognize how acceleration and braking affect handling:• Acceleration in a rear-wheel-drive 944 increases rear tire slip angle, potentially causing oversteer.

   • Braking shifts weight forward, increasing front tire slip angle and inducing oversteer.

Step 2: Assess Stock Suspension Setup

4. Review the stock suspension specifications for your 944 (8-valve engine):For Pre-85.5 (1983–1985.5):

   • Front springs: 160 lb. rate.

   • Front sway bar: 20mm (21.5mm optional).

   • Rear torsion bar: 23.5mm (126 lb. rate).

   • Rear sway bar: 14mm (optional).

   For 85.5 Onwards (1986–1988):

   • Front springs: 2946N (approx. 200 lb. at operating height).

   • Front sway bar: 21.5mm (25.5mm tubular optional).

   • Rear torsion bar: 23.5mm (126 lb. rate).

   • Rear sway bar: 18mm (optional).

5. Identify handling characteristics:• Pre-85.5 models have softer front springs, leading to more body roll and understeer.

   • 85.5 onwards models have stiffer front springs, reducing body roll but still favoring understeer.

Step 3: Choose a Suspension Upgrade Setup

6. Select a setup based on your driving needs:Sport Suspension (Street):

   • Front springs: 220 lb. (944 343 531 00).

   • Rear torsion bar: 27mm, 220 lb. rate (944 333 531 00).

   • Front sway bar: 30mm (944 343 701 00).

   • Rear sway bar: 19mm, 3-way adjustable (968 343 701 00).

   High Performance (Street/Track):

   • Front springs: 260 lb. (944 343 531 01).

   • Rear torsion bar: 28mm, 254 lb. rate (944 333 531 01).

   • Front sway bar: 30mm (944 343 701 00).

   • Rear sway bar: 19mm, 3-way adjustable (968 343 701 00).

7. Consider coil-over shocks for easier adjustments:• Replace rear torsion bars with adjustable coil-over shocks (944 343 031 00) to simplify ride height tuning.

   • Use adjustable spring perches to balance front and rear spring rates.

Step 4: Install Suspension Components

8. Prepare the vehicle:• Park on a level surface and engage the parking brake.

   • Jack up the car and secure it on jack stands at all four corners.

9. Replace front springs:• Remove the front wheels using a 19mm (3/4 inch) socket.

   • Use a spring compressor to compress the stock front springs.

   • Remove the strut assembly using a 17mm (11/16 inch) wrench and socket.

   • Install new 220 lb. or 260 lb. springs (944 343 531 00 or 944 343 531 01).

   • Reassemble and torque bolts to 40 Nm (30 ft-lbs).

10. Replace rear torsion bars (if not using coil-overs):For Pre-85.5 and 85.5 Onwards:

    • Remove the rear wheels using a 19mm (3/4 inch) socket.

    • Access the torsion bar housing and remove the stock 23.5mm torsion bar.

    • Install a new 27mm or 28mm torsion bar (944 333 531 00 or 944 333 531 01).

    • Index the torsion bar using a torsion bar indexing tool to set ride height (may require trial and error over 1–2 days to settle).

    • Torque mounting bolts to 50 Nm (37 ft-lbs).

11. Install coil-over shocks (optional):• Remove the stock rear shocks and torsion bars.

    • Install adjustable coil-over shocks (944 343 031 00) with adjustable spring perches.

    • Adjust ride height to match front suspension using a spanner wrench.

    • Torque mounting bolts to 60 Nm (44 ft-lbs).

12. Replace sway bars:• Remove the stock front sway bar using a 13mm (1/2 inch) wrench.

    • Install a 30mm front sway bar (944 343 701 00) and torque bolts to 25 Nm (18 ft-lbs).

    • Remove the stock rear sway bar (if equipped).

    • Install a 19mm, 3-way adjustable rear sway bar (968 343 701 00) and torque bolts to 20 Nm (15 ft-lbs).

13. Install adjustable shocks/struts (optional):• Replace stock front struts with adjustable sport struts (944 343 031 01).

    • Replace stock rear shocks with adjustable sport shocks (944 343 031 01).

    • Torque mounting bolts to 50 Nm (37 ft-lbs).

Step 5: Adjust and Test Suspension

14. Adjust suspension settings:• Set the 3-way adjustable rear sway bar to the middle setting for neutral handling.

    • Adjust coil-over spring perches (if installed) to achieve a ride height of approximately 25.5 inches (64.8 cm) from the ground to the fender lip.

    • Set adjustable shocks/struts to medium firmness for street use or firmer for track use.

15. Perform an alignment:• Use a camber/caster alignment tool to set front camber to -1.0° (street) or -2.0° (track).

    • Set rear camber to -0.5° (street) or -1.5° (track).

    • Adjust caster to +5.0° for improved stability.

16. Test drive the vehicle:• Drive 5 miles (8 km) at low speed to settle the suspension.

    • Check for unusual noises or vibrations.

    • Test cornering at moderate speeds to assess understeer/oversteer balance.

17. Fine-tune as needed:• Adjust sway bar settings, shock firmness, or tire pressure (32 psi / 2.2 bar front, 34 psi / 2.3 bar rear) to achieve desired handling.

    • Recheck ride height and alignment after 50 miles (80 km) of driving.

Post Procedure Checklist

• Verify all bolts are torqued to specifications (20–60 Nm / 15–44 ft-lbs).
• Check ride height is consistent across all four corners.
• Ensure no unusual noises or vibrations during test drive.
• Confirm alignment settings match desired specifications.
• Inspect for proper tire contact and wear after 50 miles (80 km).

Sources

• Clark’s Garage
• Pelican Parts
• Porsche 944 Workshop Manuals
• YouTube