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Top-Down-Center (TDC) Bracket Integration Kit for: ASG Scorpion Evo Hop-up Chamber

Distributeur Airtech Studios

Product Description

The TDC (Top-Down-Centre) Trolley Converter is designed for ASG Scorpion Evos Hop-up Chamber to radically upgrade the applicable hop-up method inside the chamber.

Types of Hop the Conversion Kit can be used for

The kit may be used in unison with all bucking types and also works perfectly for R-Hop & Flat-hop setups utilizing a trolley system that applies hop perfectly downwards for the most consistent pressure distributed onto the BB. As a result, increased accuracy over longer distances.

Why TDC (Top-Down-Center)?

The idea of using a Top-down-center is a well sought after functionality in airsoft that maximizes the amount of friction allowed onto a BB round and there are third part chambers that can achieve this.  However, switching to a third party chamber could carry a series of risks such as double BB feeding, misfeeding, and inconsistent air compression. That is the reason why we opted for a an upgrade option for the original hop-up chamber that is specifically designed for ASG gun models.


We tested the performance of many types of M-nubs for its firmness, durability, and ability maintain its shape under intense pressure. We settled with a version that ticks all of these boxes. 

2x M-nubs are included that covers the length of the hop-up window to maximize the amount of exposure onto the bucking and then BB. This ensures the most stable hop, while the BB accelerates through the hop mound/ Arch. 

Micro Adjustment

The Integration Kit utilizes a grub screw with ball bearings installed that can micro adjust to the desired hop for the best shot required.

Battery Limitations

Due to the nature of adding a integration kit onto the original hop-up chamber, there will be a limitation to the battery size allowed inside the Scorpion Evo. A smaller battery may be required as compromise for the high performance this kit can offer you.  The following are some recommended battery types and limitations where the kit will fit.

  1. Small Lipo 11.1 (20 x 21 x 128 mm)
  2. AK Lipo (Long) 11.1 (19 x 21 x 128 mm)
  3. Crane or Butterfly Lipo 11.1
  4. External PEQ Box

Core Benefits After Install

  • Increase shooting distance, accuracy and consistency.
  • Micro adjustments for the perfect hop setting.
  • Using original chamber will ensure optimum BB feeding, FPS consistency, and prevent double feeding.
  • Can be used on all hop styes including a standard bucking, R-HOP, Flat-hop, and Advanced R-Hop buckings i.e. Maple Leaf Macaron.

Kit Contents

1 x TDC Flat Foot Hop-up Trolley & Spring
1 x TDC Arched Foot Hop-up Trolley & Spring
1 x TDC Spring
2 x M-Nub
1 x Back Bracket
1 x Hop Dialling Wheel
1 x M2 Bolt
1 x M2 Nut
1 x M3 Bolt
1 x M3 Nut

Good news this kit will NOT require any modification to any part of the Evo. 

Full step-by-step installation can be downloaded using this link CLICK HERE TO DOWNLOAD


FAQ Frequently Asked Questions

1. Is this difficult to install?

We recommend that you have some experience with R-hop builds before attempting and please download the instruction/ Installation manual before installing. Consult a gun tech for help if needed or contact us for any help.

2. Do I need an R-HOP patch?

This kit is designed to work with all types of hop from standard buckings to R-hop. There are many brands of R-hop in the market, much like Psionic, and Silent sniper that is easily available in the market as a drop-in patch. Alternatively, there are bucking available from companies like Maple Leaf with their macaroon buckings that perform much like a standard R-HOP does.

3. Should I upgrade my inner barrel?

It's not necessary as stock barrels are pretty good quality these days and could still function well with the R-HOP builds.

4. How do you remove the bracket?

It is possible, but not recommended once it is glued into place to prevent further deviations of the setup in the future. It is possible to still service your hop-up chamber and its components for cleaning without removing the TDC converter bracket.

5. Can it work on another hop-up chamber?

No. This is designed specifically for the ASG Scorpion Evo Stock Chamber. We have other kits available for other brands and models too though.

6. What bucking would be the best?

The stock Scorpion Evo ones are good, but other brands like Prometheus and Modify brands have boundless buckings.

7. Will this work for Flat-hop?

Yes, it will, and for G-hop too. There are plenty of videos of how-to and what you need for this setup. Once you have this in place, you will notice a huge difference in performance and accuracy.

8. How far can R-HOP travel?

For a 1J setup and the right settings, 60-70m using 0.28g BB

Unlocking the Full Potential of the Scorpion Evo Chamber

The TDC Converter Kit is specifically designed to ensure optimal vertical pressure on the inner barrel window of the Hop-up window.

The kit is specifically engineered to seamlessly integrate the existing hop-up chamber with precision-designed brackets.
These brackets effectively guide a trolley, allowing the hop force to travel in a consistent downward motion without any interruptions in axial movement.

TDC Micro Adjustment

Fine-tune the perfect spot for your build. The hop force applied strictly from Top to Bottom creating the most stable and evenly distributed exposure onto the BB spin.
As a result the most stable and consistent flight path over long distances!