This is a dual extruder bracket and fan cover for a Tevo Tornado, based on the Tarantula duel hot end.
I mounted two Tarantula extruder motors at the top of the frame using their own brackets, removing the Titan stock extruder from the Z frame to save a lot of weight.
The firmware needs appropriate tweaks but I have now been running this for a few months and the print quality is awesome.
31/12/17 I thought I would add a bit more detail and a couple of pictures.
I would insulate the sides of the fan cover with Kapton tape at least as they are quite close to the hot end and may warp at temperatures above about 240 deg,
The mod is based on the Tevo tarantula dual extruder upgrade which can be found here :- https://tevo3dprinterstore.com/collections/tarantula-spare-parts/products/tevo-tarantula-dual-extruder-upgrade-full-kit-dual-extruder-cooling-fan-with-two-nema-step-motor
However the Tarantula has a 12V board compared to the 24V on the Tornado, so the heating elements will need to be changed, Example can be found here :- https://www.amazon.co.uk/gp/product/B06XPDT2T6/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1
The firmware will need to be altered for the setup, I have uploaded the firmware here :- https://drive.google.com/drive/folders/1iaJfqGSp5Q7OX_au6vGL6Mc452soXLKp?usp=sharing
However you will need to be sure it works for you, I have set the steps per mm on the extruders to 228 as this gives me the correct flow. The offsets will need to be measured between the extruder nozzle tips carefully for your setup, I would suggest using some tape on the bed and marking the nozzle positions both X and Y. Mine are X= 17.97 mm and Y = 0.48 mm, for adjusting the nozzle height Z alignment I would recommend getting the primary one spot on and levelled then lowering the head against a steel plate and adjusting the other nozzle to it so that they are identical heights.
I obviously cannot be responsible for any anomaly so installation would be entirely at your risk, but this setup works for me.
The mount holes for the fan cover should be drilled for appropriate self tapping screws.