Diff brace thoughts?

phunk

All of this. ^^

A differential brace is a bit of a hack created as the lazy mans way to mitigate differential movement. Will it massively reduce movement in the rear differential? You bet. But like mentioned in the quote above, you are now focusing nearly all the stresses to a single mount at one corner of the differential. If you truly wanted a solid mounted differential, the proper way to do it would be to replace all 3 of the original mounts with solid bushings. This would keep the stresses spread out rather than focused at one bracket at one corner of the differential.

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NissanParty

Thanks both of you, I will take your advice!

I don't have a garage otherwise I would not hesitate to replace the bushing myself. But right now, the best I have is a parking lot with no access to 120v power. I was thinking of buying a cordless sawzall and cutting the old bushing out, that seems easier than using the bushing tool from Z1.

Also every shop I called does not have experience replacing this bushing, but said they can do it and it will cost a lot. I wish I could find a shop that was familiar with Zs and knew about the bushing issue and replaced them before.

As a guy who has done motor swaps and head swaps and lots of other stuff, how much of a pain in the "A" would it be for me to replace the bushing myself with hand tools? I don't want to get stuck somewhere in the process and not be able to finish the job.

Kzonts

With that advice, I’m going to remove the brace for now. If I replace the bushings down the road, I’ll drop it back in…

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2019 Magnetic Black Roadster
FI Exhaust | EVO-R Rear Diffuser | Artwork Bodyshop Front Splitter | Tuned By Specialty Z

phunk

Well.. let me also just state that I have not personally seen failure introduced by use of one of the differential braces. So, the practice sucks on paper, but in the real world I have not seen it cause any real consequences yet. So I dont want to sound an alarm that everyone immediately run to remove these.

If it were to eventually cause a problem... what would it be? Well, most likely mounting point failure. Whether it became cracks at the crossmember, threads torn from the differential or cracking of the differential housing or cover. Is it possible that there could be some internal wear caused by housing distortion when the differential is loaded with only 1 solid mounting point? Eh, maybe, but its a pretty beefy unit and you know its shape is round/arch which is inherently rigid, etc. I would probably be in more of a hurry to get rid of it in a 350z since they have the aluminum rear crossmember rather than the beefy steel unit the 370z has.

So if you are enjoying it or the benefits from it, I would say to keep it in and maybe just plan to one day put in a full set of solid urethane bushings. If someone doesnt already have the brace, that is where I would attempt to intercept the plan and encourage a full bushing swap instead.

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Kzonts

Thanks! I removed it anyway. It only takes a few minutes. I’ll plan to replace the bushings at some point.

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2019 Magnetic Black Roadster
FI Exhaust | EVO-R Rear Diffuser | Artwork Bodyshop Front Splitter | Tuned By Specialty Z

ZoomZ

Adding a Diff brace with stock rubber mounts on Diff. might have a different issue.

I see the other view points of moving all the load to one point and I agree to some extent.

However, I believe the brace actually becomes a hinge point.

Meaning, that the OEM rubber bushings will now deflect even more and the inner ear bushing may not deflect as much do to it's closer proximity to hinge point.

The Ear bushings may not get a vertical deflection but more of a twisting or sideways defelction . The rear subframe bushing should still have some give and maybe too much strain and lead to an early failure, as opposed to not having the brace.

Just another way to look at things. I'm not etching this in stone.

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