1.8 Miata Differential Housing Reinforcement Plates
Are you DIYer who can weld aluminum? Do you want to reinforce your 1.8 NA or NB Mazda Miata differential housing yourself? These reinforcement plates are for you! These are the same plates we use on all of the differential housings we reinforce in house. The set of plates includes 4 total plates to reinforce the left and right side of the differential. Although the stock differential housing has an engineered weak spot only on one side, in our experience at higher power levels, both sides of the differential can and do break! The only way to reinforce the differential housing the right way is to reinforce both sides.
The kit includes 4 reinforcement plates CNC cut by us in house here in North Carolina. The plates are cut from 0.190" thick 5052 aluminum. We chose 0.190" thick material because this is at the reasonable limit of what can be welded with a full penetration weld. These welds require a lot of current. We have found that even with 250amps of current, it is not a guarantee that you will get a full penetration weld on anything thicker than 0.190" thick material.
Lastly, we do not cut out a notch in the plates to go around the raised casting vias on the differential housing. In our experience welding 50+ differentials, we find that these casting vias contain considerably more contamination than the rest of the housing. Best practice is to grind these bosses off prior to welding and that is what we do.