1 Piece Rear Cradle / Moustache Bar

[240z71]

Hey Guys 

Thought id upload some photos of a little side project I’ve been working on while assembling my Z.
 

Had the idea one day to combine the rear drop down suspension cradle and moustache bar after realising how weak the standard items are and not being a real fan of the agricultural looking aftermarket solutions or the design of the standard moustache bar for that matter. 
 

I looked to the modern WRX’s which also run the r180’s and decided to use the bush out of the mid 2000’s WRX. had some sleeves machined up to suit and build a jig around the standard items. 
 

This is what I came up with in the end. Fully built out of 4130 Chromoly

 

 

 

Excuse the Poor photography. Still yet to press the bushes into the sleeves but you get the picture. 
 

The idea is to use this along with the SWM front diff member and will put the R180 in the later further back position and should significantly increase the rigidity of the suspension mounting points as well as utilise a better way of mounting the diff over the standard design. 
 

let me know what you guys think. 
 

Thanks Matt 
 

 

 

 

 

 

Edited July 5, 2020 by 240z71

[260DET]

Looks good to me, perhaps a fore/aft brace to the chassis too?

[KatoKid]

Nice!

Serious surge tank.....cos race car?

[CBR Jeff]

Nice work Matt. 

Removing the horizontal movement of the mustache bar (shock absorbing effect) may require some further strengthening or bracing to support your new structure. The forces associated with acceleration and breaking will now be transferred to other points not absorbed the spring of the mustache bar.

Jeff

[240z71]

10 hours ago, KatoKid said:

Nice!

Serious surge tank.....cos race car?

Thanks Mate.

Yup cos race car, car is solely designed for tarmac rally events but will also see the odd track day. If I even finish the bloody thing. 
 

Thanks.

[240z71]

10 hours ago, CBR Jeff said:

Nice work Matt. 

Removing the horizontal movement of the mustache bar (shock absorbing effect) may require some further strengthening or bracing to support your new structure. The forces associated with acceleration and breaking will now be transferred to other points not absorbed the spring of the mustache bar.

Jeff

Thanks Jeff.

This was the main consideration in my design, the lack of spring that is seen in the original bar.  
 

I’m pretty confident in the restraints of the member for countering the thrust force from the diff under acceleration and braking. Utilising the drop down bolts of the original moustache bar and the bolts of the drop down links using the flat plate  means there is absolutely no give in unit, but that’s only giving it the old He-man test. 
 

The other thing I though of whilst making it is that the front diff member is just as susceptible to the thrust force from the diff accelerating and braking, if there is no fore and aft movement up front (i.e the SWM mount) then little force should be transferred to the rear cradle. Also the rear control arms will provide further restraint when bolted in joining the front and rear members.?  
 

I could run a SpaceGass analysis of it if I get time. But I might just add some gussets and wait till the car is driving to give it a good shake down and go from there. 
 

Appreciate the feedback guys 

Thanks Matt  

 

[260DET]

Relevant comment on the front X member Matt, my race experience with the 280ZX 2+0 is that it's stock bolt system which is similar to a S30's comes loose, the nuts specifically. Because of that I have made some fore/aft supports hence my earlier comment, their weight is insignificant. I have bigger brakes so the loads involved when braking particularly are significant.

[240z71]

Hey guys 

ended up making a few revisions to the jig and made a version 2.0. Got it powder coated and installed the bushing and threw it in the car. Still need to get bushing for the control arms but looks the business with a set of Dave’s chromoly rear arms. 
 

still need to also get some m14 read diff studs made up. Standards are m12 so there a bit loose in the bush centres ATM. 
 

Thanks Matt 

[RLY240]

That’s a really nice solution.