Billet Ali Rear Subframe

[BlackBeaut]

Thanks Terry, I guess a 2.5" shift forward giving around a 10degree angle will probably be within reason of the 'significant' torque. That should just be enough to get the fins tucked in nicely as well, handy!!

 

Cheers,

Rob

[cygnusx1]

I just want to add my 2cents...could it be made somewhat adjustable in the sense that you could toe in/out the rear wheels. It would add some more complexity but it would make a nice "selling point".

[S15 200sx owner]

Hi all' date='

 

 

 

Just to recap on my idea for mounting the short nose diff, here's a couple of shots of what I've been thinking on. To be honest I'm not 100% sold on the design, I'm sure it would work, but whether it's too complicated for it's needs is another question. I do like to go a bit Heath Robinson on my designs at times

Rob[/quote']

 

I like the look of your work here Rob, please keep me updated on the progress/design of the front mount for short nose R200, and when i get to offering my GTR diff unit up to the car, and designing mine, i will let you know how it all goes, I am sure between us we can come up with a strong yet simple design for a mount.

[EvilRufusKay]

I have no relavant technical info to share....I just wanted to say...

YOUR RENDERINGS ROCK!!!!

 

May I ask, are they done in solidworks?

 

Rufus

[orklc]

What about making the assembly adjustable for toe changes. My .02

[ZROSSA]

S15.... Just a quick non related question. What size are the rims on your car at the moment?

 

Douglas

[BlackBeaut]

I have no relavant technical info to share....I just wanted to say...

YOUR RENDERINGS ROCK!!!!

 

May I ask' date=' are they done in solidworks?

 

Rufus[/quote']

 

Thanks mate! They're done in Specular Infini-D 3.5 circa 1996, so old the company has gone out of business. It has just got to be one of the quickest to learn and simplest 3D packages I've ever used for simple spline based models - alas no mesh manipulation is possible in this version. I did use to use Lightwave for a while but it was a 'learn it while you work it' deal so I never ever got the best out of it and generally only had bad things to say about it

 

 

 

Back on track, there's a couple of calls for toe adjustment coming in I see. Like I said I'm planning on using Arizona Z arms so adjustment on the uprights was never in my brief but I'll have a think. I doubt there will be anything radically different than the great work that's already gone on.

 

One thought though is, would it be possible to use monoball (spherical) bearings in place of the bushes. I know Jon is quite happy running 3/16" toe with poly bushes and is still happy with the results. Am I over complicating things again?!!

 

Cheers,

Rob

[BlackBeaut]

I like the look of your work here Rob, please keep me updated on the progress/design of the front mount for short nose R200, and when i get to offering my GTR diff unit up to the car, and designing mine, i will let you know how it all goes, I am sure between us we can come up with a strong yet simple design for a mount.

 

Out of interest, does your diff have the large mounting ears that hold bushes? Mine is from an S13 any has small unbushed ears so I'll need to some up with some sort of isolator elsewhere. The big eared versions should be even easier to mount up.

 

Cheers,

Rob

[TimZ]

I see that you have addition wings that locate on to the moustache mounting bolts, did you add those so you could mount the sway bar or because you felt the four upright bolts weren't enough? Also raised is the question of vibration, I guess it would be possible to bush the cross brace/rear diff holder on to the uprights to help reduce transfered vibrations.

 

I was going to suggest something along this line of thinking - if you triangulate the assembly out to the moustache mounting bolts, you would add a ton of strength for lateral forces - Jon already mentioned the tendency of the uprights to tear out under repeated high lateral loads. This would most likely eliminate that problem.

 

You would have to mount it directly to the body, and then install the moustache bar directly to it, so you'd probably have to make a new moustache bar, like the AZ Zcar piece, but 'flatter'. Or you could come up with a way to mount it without the moustache bar as Terry suggested.

 

On the mount that you showed for the nose of the diff, don't underestimate the forces that will be presented to that mount - it will take the bulk of the stresses presented by the diff. If you figure an engine with 400lb-ft of torque hooking up through a ~3:1 first gear and 3.7:1 diff, the nose will be pushing on the mount with about 4400lbs of force.

 

I used a similar approach with my r230 mount, except I made everything bolt up from the bottom:

 

[BlackBeaut]

I really like your diff mount approach Tim, definitely good 'un solid! I think I should point out that the renderings of my idea aren't particularly dimensionally accurate. The long braces shown would be around 20mm square, I'd most likely want to use something like 20x40mm rectangle section. Also the cross plate would be fully boxed in, not just a single piece slapped on top. At the front though, that's based exactly on the Ron Tyler mount that a few people have been using with great success, so I'm pretty sure that end of things will cope.

 

I've been thinking about how best to ditch the exisiting moustache bar design. Linking the uprights to the moustache bar mounting bolts seems like the best idea for overall strength. The tricky part is that I still want some compliance in the rear diff mount, so I can just bolt the diff up to a solid brace between the two uprights. That also means that I'll still need some sort of fixed brace between the two uprights to prevent any flexing between them which would mess a little with the toe on the wheels.

 

Nice can of worms I've found for myself here!!

 

Im getting torn between coming up with a design that can be used by anyone, with any diff, which means that it would have to leave the moustache bar well alone. And creating something nice and different, that would make a great upgrade for my particular requirements.

 

I have come up with a nice and complicated toe adjustment idea though, that would be a bitch to machine

 

Cheers,

Rob

[tube80z]

That's what I meant. I don't know if Cary was on the same wavelength.

 

Yep, that was pretty much what I was thinking.

 

It still appears to me that you'll have an interference issue with the mustache bar and the uprights. Which got me to thinking about the mustache bar. You could eliminate the stock bar, and integrate a more modern design of a shorter bar into your framework.

 

On my car I still have the mustache bar but I bolted it solidly to the uprights. I was having a lot of problems with these loosening up and cracking. This seemed to help. I then cut a sheet metal brace that made the lower portion of the X in the pic above. You will need some type of bushing in the new rear diff mount unless you solid mount the front. If you solid mount one end or the other you'll end up breaking parts down the road.

 

Making the subframe instead of modifying an existing setup gives you so many possibilities. Talk about "outside the box"...

 

I like it. The next step is a set of rear arms that connect to this and are adustable for toe. You really don't want to try and bind poly as it will develop a lot of friction and wear.

 

The renderings are really cool. I don't know what you use but my hat is off to you.

 

Cary

[BlackBeaut]

I like it. The next step is a set of rear arms that connect to this and are adustable for toe. You really don't want to try and bind poly as it will develop a lot of friction and wear.

 

It does strike me that there should be some binding issues with poly bushes but Jon is happily using them with 3/16" toe IIRC. That's why I was wondering about monoballs to replace the bushings. These would need to be installed in some cunning way to prevent the control arms moving backwards and forwards of course!

 

As for rear adjustable arms' date=' did someone mention ArizonaZ?

 

 

Anyhow, here's my nice and complicated toe adjustment idea. I've not gone for a turnbuckle as with the setup of just uprights and brace bar I haven't really got anywhere good to secure the turnbuckle to so as to prevent it just pushing one side out if the other side has stuck.

 

[center']

[/center]

 

The idea is pretty simple, well to me at least The socket cap bolt moved the bushing caps in or out, thus toe is altered. As each sides movement is independent then corrections could be made for any twisted control arms. Downside is the machining to locate the socket cap head is a bit complicated which would no doubt add to the cost. Having said that I've got no experience with modern CNC milling and it might just not be an issue at all. Ahh, I'm so innocent at times

 

Hmnm, it's just occured to me that it's a bit excessive having the brace bar bolted higher up the upright when it could be used to for the clamping bolts as well. Why didn't I think of that earlier?!!

 

The renderings are really cool. I don't know what you use but my hat is off to you.

Thanks, it's a shame I can't just hit the print button and out pops the finished article though

 

Cheers,

Rob

[JMortensen]

It does strike me that there should be some binding issues with poly bushes but Jon is happily using them with 3/16" toe IIRC. That's why I was wondering about monoballs to replace the bushings. These would need to be installed in some cunning way to prevent the control arms moving backwards and forwards of course!

 

As for rear adjustable arms' date=' did someone mention ArizonaZ?

 

 

Anyhow, here's my nice and complicated toe adjustment idea. I've not gone for a turnbuckle as with the setup of just uprights and brace bar I haven't really got anywhere good to secure the turnbuckle to so as to prevent it just pushing one side out if the other side has stuck.

 

[center']

[/center]

 

The idea is pretty simple, well to me at least The socket cap bolt moved the bushing caps in or out, thus toe is altered. As each sides movement is independent then corrections could be made for any twisted control arms. Downside is the machining to locate the socket cap head is a bit complicated which would no doubt add to the cost. Having said that I've got no experience with modern CNC milling and it might just not be an issue at all. Ahh, I'm so innocent at times

 

Hmnm, it's just occured to me that it's a bit excessive having the brace bar bolted higher up the upright when it could be used to for the clamping bolts as well. Why didn't I think of that earlier?!!

 

 

Thanks, it's a shame I can't just hit the print button and out pops the finished article though

 

Cheers,

Rob

A couple points:

First off is the fact that even with AZC arms, you'll still have poly bushings on the inside. Cary wants no poly ANYWHERE, and with good reason. For a race car, it isn't a problem to have no bushings and the lack of stiction in the suspension means more accurate movement and less bind. For a street car, different story.

 

Second, it should be fairly easy to convert a normal rear control arm to monoballs, but I've never seen it done. I know there are kits to replace the stock bushings in 911 semi-trailing arms with monoballs, so I know it is possible and I'm pretty sure I understand what is involved. Basically you just have to machine a monoball holder that fits the bushing cup and rides on an axle. The outer axle would be easily made with a 5/8" bolt, maybe even the stock spindle pin could be made to work. The inner pivot is larger, might be 3/4". I remember Terry had messed around with cutting the inner pivots off the stock control arm and then welding a big bolt into the stock control arm. I think that was a 3/4" bolt, but I'm not sure. He was already 1/2 way there though. Just weld in those bolts, make spacers, slide the monoballs in and bolt the spacers into the bushing cups. Viola.

 

As to my setup, when I first bought my Z I had a close friend who worked at a Z shop do ALL the initial work on my car. At the time I hadn't been wrenching for a while, and he was the expert on Datsuns. When I just took all this stuff apart I found that I had GMachine inners and stock rubber outer bushings. So I haven't been running poly in the back on the outers, much to my surprise.

 

Regardless, I am confident that the bushings won't be significantly bound at my 3/16" setting, because the toe change will be handled by both the front and the rear bushings. So 3/16 = 3/32 per side, and that = 3/64 deflection per end. I've seen poly bushings last a VERY long time under much worse conditions than that.

 

I'm going to stick with poly because I don't have the means to manufacture the necessary spacers to run monoballs on the control arms. If someone made those spacers I'd run the monoballs, but it wouldn't be for fear of wearing out the bushings.

[tube80z]

A couple points:

First off is the fact that even with AZC arms' date=' you'll still have poly bushings on the inside. Cary wants no poly ANYWHERE, and with good reason. For a race car, it isn't a problem to have no bushings and the lack of stiction in the suspension means more accurate movement and less bind. For a street car, different story.[/quote']

 

True, I'm a biggot about poly. My eyes were really openned when I learned about how much stiction kills grip. I even spin my balljoints, tie-rods, and heims to lower the friction in them. It's a little anal but I'm trying to get the max out of what I have. Another area where you get a lot of friction is the sway bar mounts. I now hang mine from heims rather than using a ploy or other type of plastic bushing.

 

For a street car poly is probably a good way to go because it is tough and will last a long time. In the back fo a 510 I've seen the poly wear pretty quickly but they may have more bind to get the alignment sorted. I would think about fitting a zerk so you can periodically grease them. And on the sway bars I wrap them in teflon tape before putting them on to help minimize the squeakes you sometimes get.

 

If I were to make new arms I'd look at welding some tube that is similar to what is on the inside of the stock arms already. I'd then hook the heims to this. I'd also do some kind of bracing under the diff to make this stiffer with the additional bracing in the back. This would be similar to the bolt on lower in the pics above but with more bracing. So instead of seperate pieces you end up with a diff cradle. If you look at the back of most rally cars you'll find that's how they usually do it.

 

For the shorter diff I think additional bracing will be needed to take the force from the nose of the diff. Unless this some how hooks to the floor of the car. I've managed to pull the bolt and washer through the crossmember on my race car a few times before reinforcing this area.

 

Cary

[BlackBeaut]

Well I've been busy again, got under the car and measured up the mounting points for the uprights and their relationship with the moustache mounting bolts. What's the deal with them? Start at 16mm then taper to 12mm for most of their length. The poly bushes I've got for the moustache bar have got a sleeve for 16mm, don't they just rattle around on the smaller bolt? Weird!

 

Anyway, I've come up with an new, bigger, badder and definitely madder design that combines the uprights and moustache holder. Here's a first pass:

As you can see I'm using a much shorter moustache bar that's bush mounted in to the uprights to retain some compliance. It also moves the diff forward, although I'm not too sure how far as the moustache bar I've got seems pretty wonky so I don't know if I should consider the measurements taken from it as correct. If they are though then the diff should be about 45mm further forward then stock, so obviously on good for shortnose diffs and CV axles.

 

Probably need to look at the bracing between the uprights some more again, and if anyone would care to suggest better triangulation in the wings, please do. I'm never quite sure where to stick them!

 

Cheers,

Rob

[TimZ]

That's pretty much exactly what I was thinking of - the implementation of the moustache bar is a nice touch. Just keep in mind that the shorter you make the bar, the more bushing deflection you will get, and I'm pretty sure the less NVH isloation for a given bushing. The length you have there will probably be fine, but I don't think I'd go much shorter. You could probably use a standard suspension bushing to limit the amount of deflection. One question - does this setup put the m-bar bushing in single shear, or does the m-bar have another mounting ear on the backside (like a clevis)? I can't tell from the pic. If the bushing is in single shear, you'll put a twisting moment on the bushing.

 

Also, 45mm? Is that a typo?

[BlackBeaut]

Hi Tim,

 

Yes the bar is in double shear, here's a couple of clearer pics:

Had a little experiment with material removal on the bar there. I based the bushing sizes on one of the control arm bushes, so at least I know it's the right length! Down side is that they are sleeved for 1", where as I'd probably be looking around 14mm bolt to mount the minibar.

 

As for 45mm, yes that's possibly right. The problem I've got is that the moustache bar I have seems to have been through the wars and is bent in slightly odd ways, so I'm not sure if I can rely on measurements I've taken from it for my datum.

 

 

The mystery measurement I've got from my bar is around 12mm, can anyone confirm or deny that? What I don't understand is the ArizonaZ bar which, from the pic on the site, seems to be entirely flat, and so would logically move the diff back but apparently doesn't as I haven't read any posts about people having problems with them.

 

Cheers,

Rob

[TimZ]

Hi Tim' date='

 

Yes the bar is in double shear, here's a couple of clearer pics:

[center']

[/center]

Had a little experiment with material removal on the bar there. I based the bushing sizes on one of the control arm bushes, so at least I know it's the right length! Down side is that they are sleeved for 1", where as I'd probably be looking around 14mm bolt to mount the minibar.

 

As for 45mm, yes that's possibly right. The problem I've got is that the moustache bar I have seems to have been through the wars and is bent in slightly odd ways, so I'm not sure if I can rely on measurements I've taken from it for my datum.

 

 

The mystery measurement I've got from my bar is around 12mm, can anyone confirm or deny that? What I don't understand is the ArizonaZ bar which, from the pic on the site, seems to be entirely flat, and so would logically move the diff back but apparently doesn't as I haven't read any posts about people having problems with them.

 

Cheers,

Rob

 

Very nice, Rob.

 

The bar does bend pretty much as you described - you can kind of see it in this pic:

 

Unfortunately you can't quite tell the mystery dimension from this. However, in this pic, you should be able to get a feel for how far the diff protrudes behind the uprights:

 

I'll try to get under the car tonight and get a pic with a better perspective on this.

 

Seems like once you know the correct offset you should just be able to change the offset in the 'minibar' to accomodate - it almost looks like you could just flip the existing one over, provided it clears the pumpkin.

[BlackBeaut]

Thanks for the pic Tim, looks like the rear of the uprights is only a couple of mm forward of the moustache bar/diff mounting surface, it would be awesome if you get another pic though.

 

I like the idea of being able to flip the minibar over so that it would work for a long nose R200, that would be pretty cool and I can't see it being too hard to achieve either.

 

Back on the 3D front, I've been fiddling with the design of the wings a bit:

I kinda prefer this open design to the first. I have shot myself in the foot a bit though as it's made access to the outer upright bolt a lot harder. Longer bolt is probably the simplest solution there, back to the drawingboard

 

Cheers,

Rob

[JMortensen]

I think what you've got there is way overkill, and I don't think it would hurt to remove the green link. Remember the initial structure was 2 4" wide pieces of 1/8" plate attached by 4 bolts and now you have these massive ribbed aluminum pieces that tie into the mustache bar bolts. The only downside I can see to this design is that it's going to take a lot of material and a lot of milling.