JDM rear suspension

[SoobyDoobyDoo]

Those look awesome! Even better than my Cusco ones lol. Yeah sorry those brackets are needed if you’re swapping to JDM aluminum components. I’m pretty sure spec b ones are a little different but easier to come by. Also if you want the full Cusco treatment on those vauxhall blue is a pretty darn close match.

[Cney]

11 minutes ago, SoobyDoobyDoo said:

Those look awesome! Even better than my Cusco ones lol. Yeah sorry those brackets are needed if you’re swapping to JDM aluminum components. I’m pretty sure spec b ones are a little different but easier to come by. Also if you want the full Cusco treatment on those vauxhall blue is a pretty darn close match.

Thanks. They came out pretty good. 2mm thick zink plated steel bent up to shape and welded in both sides. My plan is to fit them tomorrow so I can see if guestimating the dimensions of the end link hole placement in the pictures with the measurements taken from the holes in the trailing armed panned out. I'll post pictures of it when done.

Making them blue would have been cool but all I had was semigloss black. Makes it look OEM and I like that for this simple bracket. Plus I already have red poly bushes so that would be a little much.

My next plan is to also make it's companion bracket like the Cusco set. The one that holds the roll bar to the chassis. Same idea. Get thicker metal and borrow their design.

 

[KZJonny]

19 hours ago, Cney said:

Thanks. They came out pretty good. 2mm thick zink plated steel bent up to shape and welded in both sides. 

So, 2 things. I can confirm that the bolts are 10 x 1.25 (fine) thread pitch. About 20mm long, but they are not blind holes, so you could go a little longer if you can't find m10x20mm.

Also, your brackets look really good, but 2mm kinda seemed to ring some alarm bells to me. I measured up the brackets on my trailing arms, and they are 4.8mm, folded and welded... Might be just fine with the 2mm plate, but I would at least consider keeping an eye on that... it might be a little on the thin/flexy side with the forces being applied to it, if you drive the car hard enough. 

EDIT: For the pedantic out there. 

Edited April 20 by KZJonny

[Infosecdad]

My spare set of Cusco brackets are 4.8mm.

I would keep an eye on the 2mm; it might be fine, but there might be a good reason the others are near 5mm thick.

[Cney]

Thanks, I've ordered m10x1.25x25mm and 30mm.

Yes the 2 mm might seem thin. But the original bracket is about the same thickness but has less height. The 4.8mm of the Cusco bracket is overbuilt and my engineering colleague agreed. The 2mm in combination with the way it's folded and welded should be able to hold the forces of this bar on a street vehicle. The bracket of the front control arm is of the same thickness steel and has less bracing and that holds up fine. If not I'll fold a new one up in a thicker steel. I might add some wider steel washers to spread the load although I don't think it's necessary.

Edited April 20 by Cney

[SoobyDoobyDoo]

I’d upgrade the endlinks too while you’re back there. Moog are really nice and beefy and have zerk fittings for greasing. They’re way less than most aftermarket endlinks too. 

[Cney]

1 hour ago, SoobyDoobyDoo said:

I’d upgrade the endlinks too while you’re back there. Moog are really nice and beefy and have zerk fittings for greasing. They’re way less than most aftermarket endlinks too. 

I'm replacing the end links regardless. Those are rusted stuck normally anyway. The fronts that I removed seemed like the originals and the hex holes stripped the moment they and the Allen key got acquainted. I had to get the big boy tools to get those off. Moog end links are pretty expensive and hard to come by over here. I just ordered decent OEM style from a reputable brand. Getting those aluminium arms and bushings was expensive enough for now. I'll get some better end links in the future.

[Cney]

So I caved. Didn't feel confident at all after hearing about the thickness of the bracket. I'm also the kind of man that rather have something over engineered than minimally engineered.

So I ditched the bracket I made and went on to make a new one. This time drawing it up in actual cad and using 5mm steel plate cut on the waterjet. Cold zink sprayed and Matt black finished like the 2mm thick one. They came out better than the first one.

[Cney]

Anyone have the torque spec on these 6 bolts?

[KZJonny]

8 hours ago, Cney said:

Anyone have the torque spec on these 6 bolts?

You an engineer or what?!

4 dakkas should do, 70% of strained wrist with an 8” ratchet. But that is being kinda technical.

[Infosecdad]

8 hours ago, Cney said:

Anyone have the torque spec on these 6 bolts?

I looked through the Cusco guides to see if I could find an answer for you, half of them didn't have torque specs.  It's into aluminum; so snug, but not too much...  

[KZJonny]

11 hours ago, Cney said:

So I caved. Didn't feel confident at all after hearing about the thickness of the bracket. I'm also the kind of man that rather have something over engineered than minimally engineered.

So I ditched the bracket I made and went on to make a new one. This time drawing it up in actual cad and using 5mm steel plate cut on the waterjet. Cold zink sprayed and Matt black finished like the 2mm thick one. They came out better than the first one.

Those do look awesome btw.

Having the gear to fold and cut metal would be sweet.

I mean… gear that is not a death wheel on a grinder + a bfh.

[Cney]

9 minutes ago, KZJonny said:

You an engineer or what?!

4 dakkas should do, 70% of strained wrist with an 8” ratchet. But that is being kinda technical.

I am an engineer officially. But that's as far as I'll take that. I wouldn't dare get the dakka out for a bolt that goes into aluminium threads. The thought alone makes my rectum clinch up.

4 minutes ago, Infosecdad said:

I looked through the Cusco guides to see if I could find an answer for you, half of them didn't have torque specs.  It's into aluminum; so snug, but not too much...  

That's what I did. My torque wrench set to the lowest 28nm was more than I was willing to take it. I used a good quality zink 8.8 hex bolt and self locking rings. Should be fine I think

[Cney]

3 minutes ago, KZJonny said:

Those do look awesome btw.

Having the gear to fold and cut metal would be sweet.

I mean… gear that is not a death wheel on a grinder + a bfh.

I'm lucky to work at a University as an instructor and having the mechanical engineering department as neighbors. They told me that although they have a shed of equipment/tools themselves that they rather use the shop at work. Can't blame them.

[KZJonny]

Internets suggest that 50nm should be safe for 10mm fine pitch in 20mm of aluminium no lubrication.

But not knowing the alloy type, a safer bet may be ~35nm or so.

This only based on torque charts. Many factors at play.

 

[Cney]

I have another question, I hope y'all don't mind.

The rear lower arms that I got with all the aluminium arms seem like the same stamped metal ones that are on my var right now. It has different coding stamped on them but they do seem exactly the same. Can anyone confirm they are? Because I'd rather leave the lower arms that are on the car if they are the same to not have to mess the alignment more than necessary on top of doing the extra work.

[Cney]

4 minutes ago, KZJonny said:

Internets suggest that 50nm should be safe for 10mm fine pitch in 20mm of aluminium no lubrication.

But not knowing the alloy type, a safer bet may be ~35nm or so.

This only based on torque charts. Many factors at play.

 

I'm using lube (copper grease). I wouldn't dare do the 50nm. Even 35 would be scary. I think I'm at 15/20 ish Nm. I'm gonna run it like that and check regularly. If they come loose I'm going to send it at the 28Nm.

[KZJonny]

15 minutes ago, Cney said:

I have another question, I hope y'all don't mind.

The rear lower arms that I got with all the aluminium arms seem like the same stamped metal ones that are on my var right now. It has different coding stamped on them but they do seem exactly the same. Can anyone confirm they are? Because I'd rather leave the lower arms that are on the car if they are the same to not have to mess the alignment more than necessary on top of doing the extra work.

If they are the same length from bolt hole to bolt hole, I would feel fine leaving them as they are. Plenty of examples of parts which are the EXACT same with different part codes stamped in them because they belong on different models.

Ie: the $50/each LGT rad supports which don't do the job any differently than the $15/each STi rad supports. Very literally the same dimensions in all aspects, but for some it costs $35 to stamp a different number into them....

[KZJonny]

37 minutes ago, Cney said:

I wouldn't dare get the dakka out for a bolt that goes into aluminium threads. The thought alone makes my rectum clinch up.

Haha!

I feel ya, but I *personally* feel fine running down large bolts into alumimium with my 3/8" drive gun. I've probably spend a lot more time working on motorycycles over the years where everything is aluminium so you get a feel for the trigger.

Only had to do a couple of thread inserts over time because of misjudging torque based on 'mechanics feel'. And I can honestly say the most of those screw ups were with a ratchet by hand, or a torque wrench that just didn't register quite soon enough.

Sometimes you break things even being careful.

 

Then you have people like my friends old boss who had some kind of ridiculous inability to break stuff, it was magical. Shop policy was "Tighten everything 5lbs over spec, and stake it...." How everything that entered that (motorcycle) shop didn't end it's days there some kinf of miracle, but he'd been doing it a long time and really didn't break things at all often, so who knows.

Edited Tuesday at 07:37 PM by KZJonny

[Infosecdad]

54 minutes ago, Cney said:

I'm lucky to work at a University as an instructor and having the mechanical engineering department as neighbors. They told me that although they have a shed of equipment/tools themselves that they rather use the shop at work. Can't blame them.

Nice, I teach Computer Science with some engineering department neighbors.  They are building a baja cart program that I really wish I had the time to help with.

[Infosecdad]

50 minutes ago, Cney said:

I have another question, I hope y'all don't mind.

The rear lower arms that I got with all the aluminium arms seem like the same stamped metal ones that are on my var right now. It has different coding stamped on them but they do seem exactly the same. Can anyone confirm they are? Because I'd rather leave the lower arms that are on the car if they are the same to not have to mess the alignment more than necessary on top of doing the extra work.

I think some of those "Sti" versions were more about the bushings than the metal.  I agree with KZJonny, if they look the same, I would just keep what you have depending on the bushings.

[Cney]

23 minutes ago, Infosecdad said:

I think some of those "Sti" versions were more about the bushings than the metal.  I agree with KZJonny, if they look the same, I would just keep what you have depending on the bushings.

I think that the bushings are pretty much the same. I had the arms under the car to compare length but they seemed the same. Didn't check the bushings however so I'll do that before mounting the rears.

[SoobyDoobyDoo]

Check out amayama.com-they’ll have the JDM parts and parts numbers. Shipping isn’t bad, either. I was going to order some new bushings for my JDM aluminum arms and have them installed prior to putting them on the car. Amayama also ships international.