Shaftless DCOE Throttle Bodies: The EFI Upgrade

Revolutionising Induction: The Shaftless DCOE Throttle Body Explained

For enthusiasts looking to elevate their classic performance vehicles, the transition from traditional carburettors to modern Electronic Fuel Injection (EFI) systems often presents a significant leap in both efficiency and power. At the forefront of this upgrade path are the innovative DCOE Shaftless Butterfly Throttle Bodies. These precision-engineered components are not merely replacements; they represent a fundamental advancement in induction technology, offering a seamless and performance-driven solution for those seeking to modernise their classic machinery. Designed as a direct fit for iconic Weber DCOE and Dellorto DHRLA carburettors, these throttle bodies bridge the gap between vintage charm and cutting-edge fuel delivery.

The Need for EFI and the DCOE Advantage

Carburettors, while historically significant and aesthetically pleasing, often present limitations in terms of precise fuel control, adaptability to varying environmental conditions, and emissions compliance. EFI systems, on the other hand, offer unparalleled accuracy in fuel delivery, leading to improved fuel economy, smoother power delivery, and a more consistent engine response. When undertaking an EFI conversion on vehicles originally equipped with Weber DCOE or Dellorto DHRLA carburettors, the challenge often lies in adapting the manifold and throttle control. This is precisely where the DCOE Shaftless Butterfly Throttle Bodies excel. Their ingenious design mirrors the bolt patterns of their carburettor predecessors, allowing for a straightforward installation onto existing inlet manifolds. This compatibility makes them the ideal choice for manifold-mounted carburettor applications, simplifying what can often be a complex conversion process.

Unpacking the Shaftless Technology

The core innovation behind these DCOE Throttle Bodies lies in AT Power’s patented ‘Shaftless’ technology. Traditional butterfly valves, which control airflow into the engine, are mounted on a spindle or shaft. This shaft, while functional, inevitably disrupts the smooth flow of air entering the intake. The shaftless design eliminates this obstruction entirely. Instead, the butterfly valve is supported by a unique, precision-machined mechanism that allows for an unimpeded, knife-edged airflow path. This sophisticated approach has been proven to significantly enhance induction airflow speed. By reducing turbulence and resistance, more air can enter the combustion chamber more efficiently, directly translating to an increase in engine performance. The knife-edged profile of the butterfly valve further aids in slicing through the incoming air, minimising drag and maximising velocity.

Versatility and Customisation: Tailoring to Your Needs

AT Power understands that no two engine builds are identical. To cater to a diverse range of applications and performance goals, their DCOE Twin Throttle Bodies are offered in an impressive array of configurations. Bore sizes are available from a nimble 36mm, suitable for smaller displacement engines, up to a substantial 48mm for more potent powerplants. These include popular sizes such as 38mm, 40mm, 42mm, and 45mm. Furthermore, the throttle bodies can be specified for various cylinder counts, from 2-cylinder configurations all the way up to V8 and V12 applications. A critical distinction in the product offering is the choice between injected and non-injected housing designs. This allows users to select the most appropriate option based on their specific EFI system requirements. For injected housings, a one-piece billet aluminium Fuel Rail is integrated, meticulously designed to eliminate potential fuel leaks often associated with separate hose connections found in lesser designs. These fuel rails are manufactured to accommodate specific cylinder spacings, with standard options available and custom solutions offered for unique requirements. For non-injected housings, the design is optimised for direct injection applications where a separate OEM or aftermarket fuel rail and injectors are utilised.

Component Options for a Complete Solution

Beyond the core throttle body units, AT Power provides a comprehensive suite of optional extras and supporting components to ensure a complete and integrated EFI conversion. This includes:

• Throttle Linkage Configurations: Options range from traditional mechanical linkages to advanced Drive-By-Wire (DBW) systems, offering modern electronic throttle control.
• Throttle Positional Sensors (TPS): Mounting kits for TPS are available, with choices of rotary contact or Hall Effect contactless sensors for accurate throttle position feedback.
• Extension Tubes (Runners/Velocity Stacks): Precision machined from billet aluminium, these components are crucial for optimising airflow and can be specified in various lengths to suit packaging requirements and enhance performance. For boosted applications, SLS 3D printed extension tubes are offered for enhanced durability.
• Ram Pipes (Trumpets): Similar to extension tubes, these billet aluminium components can be selected in different lengths to fine-tune airflow characteristics and sound.
• Fuel Rails and Injector Compatibility: For injected housings, the one-piece billet aluminium fuel rail is designed for seamless integration with aftermarket fuel injectors, with options available to suit various injector types.
• Anodising Colours: To match your vehicle's aesthetic or engine bay theme, a choice of 18 different anodising colours is available for the billet aluminium components.

Ancillary Support for Seamless Integration

To facilitate a complete EFI conversion, AT Power also offers a range of ancillary supporting parts. This includes high-quality fuel injectors, various air filtration solutions, motorsport-grade cables, essential tuning aids, fuel pressure regulators, and crucially, aftermarket Engine Management Systems (ECU's). The correct ECU is fundamental for the operation of any EFI system, and AT Power provides options to complement their throttle bodies. It is important to note that while base maps are often provided with aftermarket ECUs, dyno tuning is highly recommended to ensure optimal performance and prevent potential engine damage.

Installation and Ordering Considerations

The DCOE Shaftless Butterfly Throttle Bodies are designed for direct bolt-on replacement of Weber DCOE and Dellorto DHRLA carburettors. Inlet manifolds with the standard DCOE (Weber) bolt pattern are readily available from specialist suppliers such as Webcon.co.uk. When ordering, it is essential to carefully select the correct configuration based on your specific engine and desired performance characteristics. This includes choosing the appropriate bore size, cylinder configuration, and whether an injected or non-injected housing is required. For bespoke Drive-By-Wire applications, contacting the sales team for assistance is advised. As with all aftermarket engine management systems, careful consideration and professional tuning are paramount for achieving the best results and ensuring the longevity of your engine.

Frequently Asked Questions (FAQ)

Q1: Can I use these throttle bodies with my original Weber DCOE manifold?
Yes, the DCOE Shaftless Butterfly Throttle Bodies are designed with fixing bolt patterns that match standard Weber DCOE and Dellorto DHRLA carburettors, making them a direct replacement for manifold-mounted applications.

Q2: What is the benefit of the 'Shaftless' design?
The shaftless design eliminates the air obstruction caused by the traditional throttle spindle, leading to improved induction airflow speed, reduced turbulence, and ultimately, increased engine performance.

Q3: Do I need a new ECU for these throttle bodies?
Yes, these throttle bodies require an aftermarket engine management system (ECU) for correct engine fuelling operation. AT Power offers a range of compatible ECUs.

Q4: Are these suitable for carburetted engines?
No, these are designed for Electronic Fuel Injection (EFI) conversions. The non-injected housings are for direct injection applications, while injected housings include fuel rails for port injection.

Q5: What are Extension Tubes (Runners/Velocity Stacks)?
These are components that fit between the throttle body and the inlet manifold, designed to optimise airflow velocity and volume into the engine. They can be specified in different lengths to suit packaging and performance needs.

Q6: Is dyno tuning necessary?
While base maps are provided with ECUs, dyno tuning is highly recommended to achieve optimal performance, ensure correct fuelling, and prevent potential engine damage.

Conclusion

The DCOE Shaftless Butterfly Throttle Bodies by AT Power represent a significant advancement for classic performance vehicle enthusiasts undertaking EFI conversions. Their innovative shaftless technology, direct fitment capabilities, and extensive customisation options provide a compelling solution for unlocking enhanced performance and efficiency. By bridging the gap between iconic carburettor designs and modern fuel injection, these throttle bodies offer a clear path to a more responsive, powerful, and refined driving experience.

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