350z Targa Top Conversion Kit

The Nissan 350Z, a modern classic sports car, has always been admired for its sleek lines and performance capabilities. While factory-produced convertibles exist, some enthusiasts desire an open-air experience that balances rigidity and open-top driving: the Targa top. This article delves into the world of 350Z Targa top conversion kits, exploring their design, engineering considerations, installation challenges, and the compromises involved in transforming a fixed-roof coupe into a Targa.

Understanding the Targa Top Concept

Before diving into the specifics of the 350Z, let's clarify what defines a Targa top. It's a semi-convertible car body style featuring a removable roof section, typically leaving the B-pillars and rear window in place. This configuration offers a compromise between the structural rigidity of a coupe and the open-air feeling of a convertible. Targa tops generally improve chassis stiffness compared to a full convertible because the B-pillars still connect the chassis. Famous examples include the Porsche 911 Targa and the Chevrolet Corvette T-tops of the 70s and 80s.

The 350Z's Structural Integrity: A Critical Factor

The 350Z was designed as a coupe, meaning its structural integrity relies heavily on the roof. The roof panel is welded to the A-pillars, B-pillars, and the rear section of the body, creating a strong, enclosed cage. Cutting into this structure to create a Targa opening necessitates reinforcement to compensate for the lost rigidity. Failure to properly reinforce the chassis can result in:

Chassis Flex: The body twists and bends under stress, particularly during cornering or over uneven surfaces.

Compromised Handling: Chassis flex negatively affects suspension geometry and tire contact, leading to unpredictable handling.

Increased Noise and Vibration: Gaps and movement in the body panels can amplify noise and vibrations inside the cabin.

Potential Cracking: Stress concentrations around the cut edges of the Targa opening can lead to metal fatigue and cracking over time.

Components of a Typical 350Z Targa Top Conversion Kit

A comprehensive 350Z Targa top conversion kit generally includes the following components:

Reinforcement Structure:

This is arguably the most crucial aspect of the kit. It usually consists of steel bracing, typically made from high-strength steel tubing or sheet metal, that is welded into the existing chassis to reinforce the Targa opening. This structure aims to redistribute the loads previously carried by the roof, preventing chassis flex. The design of the reinforcement structure is critical; it must be carefully engineered to maintain the car's structural integrity without adding excessive weight.

Targa Top Panel:

The removable roof panel is usually made from fiberglass, carbon fiber, or a combination of materials. Fiberglass is a cost-effective option, while carbon fiber offers superior strength-to-weight ratio. The panel must be rigid and weatherproof to prevent leaks and wind noise. It typically features a locking mechanism to secure it to the car and seals to prevent water intrusion. The design needs to be aerodynamic to avoid excessive wind noise.

Sealing System:

A robust sealing system is essential to prevent water leaks and wind noise. This typically involves a series of rubber seals around the Targa opening and on the Targa top panel itself. The quality of the seals significantly impacts the overall driving experience. Weather resistance is a key factor here, to prevent damage during changing seasons.

Locking Mechanism:

The locking mechanism secures the Targa top panel to the car. It usually consists of a series of latches or clamps that engage with corresponding points on the roof frame. The mechanism must be robust and reliable to prevent the panel from coming loose during driving. Usually these are aftermarket clamps that can handle high levels of torsion.

Headliner and Interior Trim:

The kit may include replacement headliner and interior trim pieces to accommodate the Targa opening and provide a finished look. This is mostly for aesthetics, but it does impact the driving experience.

Installation Hardware and Instructions:

A complete kit should include all necessary hardware, such as bolts, nuts, and washers, as well as detailed installation instructions. However, given the complexity of the conversion, professional installation is highly recommended. Due to the nature of aftermarket parts, always test fit before welding or installing any components.

Installation Process: A Technical Overview

Installing a 350Z Targa top conversion kit is a complex and time-consuming process that requires significant mechanical skills and specialized tools. Here's a general overview of the steps involved:

Preparation: The car must be completely stripped of its interior, including the headliner, seats, and trim panels. This is to provide access to the roof structure.
Cutting the Roof: This is a critical step that requires precision and accuracy. The roof panel must be carefully cut along the marked lines, leaving enough material for welding the reinforcement structure.
Welding the Reinforcement Structure: The steel bracing is then welded into the chassis, reinforcing the Targa opening. This requires skilled welding techniques to ensure strong and reliable welds. Improper welds can compromise the structural integrity of the car.
Installing the Targa Top Panel: The Targa top panel is fitted to the car, and the locking mechanism is installed. The panel must fit snugly and securely to prevent leaks and wind noise.
Installing the Sealing System: The rubber seals are installed around the Targa opening and on the Targa top panel. The seals must be properly aligned and seated to ensure a watertight seal.
Reassembling the Interior: The interior is then reassembled, including the headliner, seats, and trim panels.
Testing and Adjustments: Finally, the car is tested for leaks, wind noise, and structural integrity. Adjustments are made as necessary to ensure proper fit and function.

Challenges and Considerations

Converting a 350Z to a Targa top is not without its challenges and considerations:

Structural Integrity: As mentioned earlier, maintaining structural integrity is paramount. The reinforcement structure must be carefully designed and installed to prevent chassis flex.
Water Leaks and Wind Noise: Sealing the Targa top can be challenging, and water leaks and wind noise can be a common issue. High-quality seals and proper installation are essential.
Cost: Targa top conversion kits can be expensive, and the cost of professional installation can further increase the overall expense.
Complexity: The installation process is complex and requires significant mechanical skills. It's not a project for novice DIYers.
Resale Value: Modifying a car can affect its resale value. While some enthusiasts may appreciate a Targa top conversion, others may prefer the original factory configuration.
Legality: Depending on local regulations, modifying a car's roof structure may not be legal. It's essential to check local laws before undertaking such a project.

Alternatives to a Full Targa Conversion

For those who are hesitant to commit to a full Targa conversion, there are alternative options to consider:

Sunroof Installation: Installing a sunroof can provide a similar open-air experience without significantly compromising the car's structural integrity.
Convertible Top Conversion: While more expensive and invasive than a Targa conversion, a convertible top conversion offers a fully open-air driving experience.

Conclusion

A 350Z Targa top conversion can be an exciting and rewarding project for enthusiasts who desire a unique open-air driving experience. However, it's essential to understand the engineering considerations, installation challenges, and compromises involved. Proper planning, careful execution, and professional installation are crucial to ensure a successful and safe conversion. It's a significant undertaking that requires a deep understanding of vehicle structure and a commitment to quality. The result, however, can be a truly unique and head-turning 350Z.