Kia Stinger rear differential brace

This is an evolution of a common brace design for the Kia Stinger rear differential. This brace is intended to prevent wheel hop and reduce deflection of the differential under hard acceleration conditions, and with tuned vehicles, limiting slop that is provided by the stock rubber bushing mounting points. This DIY option with lasercut parts and hardware cost me <$80 shipped to my door.  

My force simulations (pictured) are based on CAD designs based on pictures of the BMS design, not measurements from the actual brace, however I believe the increase in stiffness between the two designs to be more than marginal gains from a difference in geometry. They also show an earlier revision of my brace design that is weaker than the current version.

If you do not want to source your own laser cut parts and hardware, and perform some measuring and drilling, the BMS part is a good option and is available here for $180: https://burgertuning.com/products/differential-brace-for-2018-kia-stinger

Out of respect for this company, I am not selling this design, rather making it freely available, and i do not authorize others to reproduce this for anything other than personal use on your own car. 

My development has been performed on my own car, and the 3D printed part fit with good tolerance, but I recommend printing the part and test fitting everything on your own vehicle before ordering a lasercut part, and measuring your own print for shrinkage/deviation from the model. I have also tested assembly and dissasembly with steel parts and real hardware, there is proper clearance for tools as needed.

Assembly Notes:

For more access, remove the stock exhaust cross brace with two 14mm nuts.

Flatten the removed cross brace tube or make a replacement piece out of flat bar. This is not a normally loaded component and is not a precision fit either, it is designed to hold the two mufflers a fixed distance apart.

Autodesk fusion file has exact dimension for the 2-1/4" angle iron, but it is not needed to be this exact. You can extend beyond either end a small amount and make a cut with an angle grinder if needed.https://www.mcmaster.com/products/9017k714/

Source High Quality Flanged Hex Hardware, m10x1.5 25mm long, 5 pieces nuts/bolts.https://www.mcmaster.com/products/93474a222/

Drill holes located in the angle iron according to the model dimensions. Use the 3D printed hole template (3mf file) for precise 72mm distance between holes. Use a 13/32" or 7/16" drill bit if you only have SAE drills like me. 

Pre-install two nuts in the 3D printed nut holding tool and insert up into the subframe. This is to hold the top nut from spinning and increase your reach because you cannot reach your hand into that hole in the subframe far enough to hold the nut by hand.  After it is hand tight you can remove the plastic part and reach a open spanner wrench in the hole. After installing the top bolt you can do the bottom one easily by hand. The BMS kit solves this issue by including two nuts welded to a bracket, I have removed this complexity.

Use the 3D printed piece for the flat plate to trace a template. Tape the dovetail pieces together, as it is too long for a 250x250 print bed. You can cut and drill your own piece out of 1/4" steel sheet if you have the tools or order a lasercut piece as I have done. ($15-40 depending on steel grade)

Both pieces should line up when assembled correctly. Use the holes on the flat piece to locate 3 holes on the angle iron. These are not pre-designated with dimensions to allow for differences in your vehicle.  These holes are placed where they are to avoid interference with flanged m10 fasteners on the inside of the angle iron part. 

You will need to remove the angle iron bracket and drill the 3 marked holes before reinstalling.

Torque all 5 new fasteners to 72Nm/53ft-lbs, this is based on clean M10x1.5 Class 10.9 hardware. Use medium strength thread locker if desired.

Torque diff case bolts to Kia spec. You can source bolts that are slightly longer to account for the 1/4" material but it is not necessary. You may see a few drops of diff fluid leaking from around these 3 bolt holes when removed. I recommend cleaning off the surface and applying a small amount of new gasket maker (oil resistant/black) to each of the factory bolts behind the brace before reinstalling.