Finally finished it today after spending around 20 hours on it and changed the design multiple times during the process. But still feel like an achievement, especially during the lock down period.
I do not expect any significant impact to my daily driving, I do not track her after all.

The story started from the very over-priced Mitsubishi branded rear strut tower bar, $400 for a piece of aluminum alloy tube is just too much to me. After investigating its design as well as the power braces, I decided to build my own from steel square tubes. The tubes are pretty cheap, 3/4 by 36 in one is $10 from homedepot. I used two to build the rear strut bar, and around 20 in flat bar. Considering the bolts and nuts, steel wire, propane. etc, the total cost should be less than $50.

First of all, the final result. The plastic cover can be kept untouched if I noticed its depth at the first place, but I did not want to make any adjustments anymore, so I cut several slits and bent it to fit the brace.




Without the plastic cover.





I ignore all the bad attempts and focus on the final decision.

First of all, I need four feet to be installed on the rear strut bolts. It was not really a "forge", but heat and hammer one end of the square tube to flat. Extra adjustments are needed, like grinding the final piece thinner. Though the strut bolts are long, there are only 3/8 in extra threads to use.



Then, two legs, H-sharped to slightly enforce the strength.



Install the feet onto the legs with flat bars and bolts. The flat bars won't hold strength, but I still used 1/8 thickness one.



The "brace" or the "bar" itself will be installed onto the legs by using two long bolts (cut from a threaded rod) and 9mm steel round tube, as I cannot quite accurately measure the angle. Should be pretty close to this one. Though the final design has been adjusted, I gave up the spring washers and used steel wire to fill the gaps between two "hips" and the brace.



Then I installed the legs onto the struts. Not necessary to remove the glass water tank and battery, as the design should co-exist well with them, but uninstalling them provided a slightly larger working space. I placed two washers under each "toe" / bolt hole of the feet.
Left:


Right:



I can measure the length of the brace, e.g. the distance between the two steel round tubes after installed the legs, and prepared the last brace. Two square spacers were installed at each end - If I installed only one longer spacer, the plastic cover could be kept unchanged. Between the spacers, two 3/8 in holes were drilled to fit the 9mm steel round tubes.



The final step was installing the brace onto the legs. Glass water tank and the battery should be restored before installing it.




It was more complex than my initial thought, but still doable with basic home tools, like grinder, drill, impact driver, ratchet wrench, propane torch.
I do have concerns if the nuts would loose soon or late, the good news is three out of four nuts can be checked through the battery changing and glass water refilling windows. The left rear one is not accessible through the glass water refilling window.


Finally, the enforced differential brace.



Coated with rust-proof paint



And my double-deck wing. Unfortunately, I scratched her wing badly before, have to cover it with stickers.




Thank you for reading.

 

I give you points for originality, inventiveness, and frugality. I also like the fact that you did all of this without welding. I am not so sure about the shape and your claim that it's the strongest rear strut bar in the world. However, it's definitely stiff enough to work for what you want to do.

As I look at this I am thinking that with your ingenuity you could build a trunk cage to tie in with this strut bar. What do you think?

 

Props for creativity and ambition. If you really think this is a good structural piece, let alone the "strongest in the world" then I think you are suffering from a big case of "You don't know what you don't know" syndrome. That's ok though, with a healthy dose of humility you can easily learn and improve. The evo is a great muse to inspire fun learning projects too, which it looks like you have already discovered.

 

WUT?!? I think a half hearted kick and this whole thing deforms.

No offense OP.

 

You sure that double wing isnt going to add to much downforce and flex your custom strut tower?

 

I don't understand how that makes any difference since that whole chassis structure directly above it is a strut bar in the Evo X.

 

It's made by a 1/8 in wall steel square, should be much stronger than the frame above which is a 1/16 aluminum. And it's not a rectangle.

But, I am just trying to build something during the lockdown period.

 

The frame is not aluminum