Narrowing rear control arms

Suspension, including wheel, tire and brake.
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icehouse
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Re: Narrowing rear control arms

Postby icehouse » 17 Oct 2017 16:14

We like to mimic Apple, can't give all the goodies at once. Later version may incorporate such an ideas.
"People don't like it when shit doesn't match their rule of thumb." Sam

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datsuntech
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Re: Narrowing rear control arms

Postby datsuntech » 17 Oct 2017 16:42

510wizard wrote:
datsuntech wrote:Feel free to bitch slap me if you like, but if you're going to go to all the trouble of making a completely new control arm, why not make it so that you can use a bolt on hub like on many newer cars? This would effectively shorten the bearing area giving you more room for a longer shaft. My thought is if you are going to change this much wouldn't you want to go to CVs at the same time? The issue with CVs is always that the shafts are too long and need to be modified. This would give you more room for a longer shaft without widening the track width.
This of course is completely selfish because It's something I have wanted to do for some time but don't have the time to dedicate to this sort of project.

Brock

And also no more bearing preload stuff using the "A,B,C " spacers(as I mentioned previously) and a new nut every time you need to disassemble. It would be a lot easier to build, just a plate to bolt the hub too, no machining a housing for the bearings and no adapters for the CV's.


Exactly what I was thinking. So many advantages to this type of bearing.
Rear Wheel Drive, The way God Intended.
If a car is being pulled from the front, doesn't that mean it's being towed?

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datsuntech
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Re: Narrowing rear control arms

Postby datsuntech » 17 Oct 2017 16:44

icehouse wrote:We like to mimic Apple, can't give all the goodies at once. Later version may incorporate such an idea.



Nice... :(
Rear Wheel Drive, The way God Intended.

If a car is being pulled from the front, doesn't that mean it's being towed?

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icehouse
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Re: Narrowing rear control arms

Postby icehouse » 17 Oct 2017 23:10

datsuntech wrote:
icehouse wrote:We like to mimic Apple, can't give all the goodies at once. Later version may incorporate such an idea.



Nice... :(



I totally get what you are saying and don't disagree in the slightest. Really the first version we basically design for what we want and is achievable. I want to be able to just get some shorter VW axle like I'm currently running. I would like to upgrade later to modern axles. Me and the guys talked about exactly what you guys are saying. It's a lot of figuring just to get the packaging and the suspension characteristics we want, its hard to stay focused on such a long endeavor as it is. Which is why we haven't went into upgrading hubs and axles, ect. Plus we are just a group of friends who likes to tinker on our datsun's. When it comes to selling them who knows if we will sell enough to break even. Really it's labor of love and hopefully some good trading stock.
"People don't like it when shit doesn't match their rule of thumb." Sam

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datsuntech
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Re: Narrowing rear control arms

Postby datsuntech » 17 Oct 2017 23:34

I really appreciate all of the time and energy you guy are investing in upgrading our favorite vehicle.
I have had so many ideas and they have changed and morphed over the last 30 some years of 510 ownership. Some things I wanted to do in my 30s and 40s I wouldn't even consider now. So much more is possible these days with computer modeling and availability of CNC machining and fabrication has changed so much from when I started working on these cars. I get so excited to see all of the innovation and skills of these younger guys. Problem is that I'm not getting any younger and I still have the ability to do much of my own work and funds are a bit more than when I was a younger man, but the newer cars are so much faster and handle better than ever. This leaves me still behind the curve to keep up with daily traffic to keep these old cars current to some extent.

The point of all of this rambling? I want this stuff that you keep teasing us with... :D

Brock
Rear Wheel Drive, The way God Intended.

If a car is being pulled from the front, doesn't that mean it's being towed?

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510wizard
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Re: Narrowing rear control arms

Postby 510wizard » 18 Oct 2017 08:06

JordanTr wrote:I like s13/14/15 parts for the cartridge rear bearings. 4 and 5 lug availability. :D


Yes and theirs probably others. Another idea is to make the mounting plate also be the caliper mounting too, killing two birds at once.

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icehouse
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Re: Narrowing rear control arms

Postby icehouse » 18 Oct 2017 09:06

datsuntech wrote:I really appreciate all of the time and energy you guy are investing in upgrading our favorite vehicle.
I have had so many ideas and they have changed and morphed over the last 30 some years of 510 ownership. Some things I wanted to do in my 30s and 40s I wouldn't even consider now. So much more is possible these days with computer modeling and availability of CNC machining and fabrication has changed so much from when I started working on these cars. I get so excited to see all of the innovation and skills of these younger guys. Problem is that I'm not getting any younger and I still have the ability to do much of my own work and funds are a bit more than when I was a younger man, but the newer cars are so much faster and handle better than ever. This leaves me still behind the curve to keep up with daily traffic to keep these old cars current to some extent.

The point of all of this rambling? I want this stuff that you keep teasing us with... :D

Brock



When the guys at work ask me what I'm doing over the weekend my comment is usually "I'm going to make my car stop like a rac.... stop like the cars you guys drive, or have rack and pinion steering like your car, or EFI ect.." Yes we fight to keep our cars dailyable and competitive that's for sure. At the last autoX there was a new Camaro that beat me. He was a 30 year SCCA autox driver so he had so serious skills. I thought I should look up the car though to see the specs. Turns out it has a 10 speed automatic transmission and 650 HP!!!! He almost hit 100MPH in the straight away....... He was only a couple ten's away from me. Blows my mind a car that big can do so well, until I saw the specs.
"People don't like it when shit doesn't match their rule of thumb." Sam

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icehouse
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Re: Narrowing rear control arms

Postby icehouse » 18 Oct 2017 09:06

510wizard wrote:
JordanTr wrote:I like s13/14/15 parts for the cartridge rear bearings. 4 and 5 lug availability. :D


Yes and theirs probably others. Another idea is to make the mounting plate also be the caliper mounting too, killing two birds at once.


Which calipers though..
"People don't like it when shit doesn't match their rule of thumb." Sam

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DADZSUN
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Re: Narrowing rear control arms

Postby DADZSUN » 30 Oct 2017 09:47

Pardon my naivety on this topic, but what is the objective to this exercise? Better anti squat/articulation/adjustment, or more selection of rear axles?

Or is it to fit a wider rim? I've been under the impression the rear already fits up to a 15x8 +10'ish rim, at least one did on my 510 when I tested it years ago. With that sized rim I'm assuming a fat 225 could live back there already. My issue is maintaining a non-stagger setup and the front appears to be the limiter w/o flaring the fender or hitting my 280zx strut.
'72 Datsun 510 - KA24E/R1 carbs/EDIS 4 Megajolt
'76 Datsun 280z

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icehouse
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Re: Narrowing rear control arms

Postby icehouse » 30 Oct 2017 10:31

To fit wide rims and not run 8 degrees of camber is the goal. Not to say you have bad memory but I don't believe you fit 15x8 plus 10 on your car with 225's. I have 15x7 plus 16 and have to run 3.9 degrees of camber with 195 50 15's at my ride height or I will get fender rubbing on hard cornering. I also got ride of the square inner fender lip. By my calculations a 13x8 zero should fit with basically no camber with 225's with our narrowed arms. Also virtually no toe change, and the roll center should be better. O and bolt in with minor trimming.

I have a buddy that said the same thing you said. With further inspection it turned out someone had narrowed his control arms, maybe someone did that to your car.
"People don't like it when shit doesn't match their rule of thumb." Sam

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DADZSUN
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Re: Narrowing rear control arms

Postby DADZSUN » 30 Oct 2017 14:48

Lol, I do have a shitty memory so I looked up my old post on the Realm and it was a 15x8 et15 rim, not et10. No tire was fitted at the time but the rim cleared nicely out back (1/4"), not a chance up front though...

My current setup is 195/60r14 Azenis 14x7 et0 with mild fender rolling (still looks stock), inner fender 'step' is still OEM. I checked a 2014 alignment print-out and I'm running only -1 deg in the rear. It's a tight squeeze though, my first solo2 outing with the tires I lightly shaved the sidewalls lol. Still, there looks to be enough inboard room for a 3cm wider tire hence the reason for my question (I do like the idea of better toe control though!).

I suspect I am running some kind of tampered setup... I know when I installed Byron' s brackets I had to run max toe-in to clear the rear arches with exact same wheels/tires.
'72 Datsun 510 - KA24E/R1 carbs/EDIS 4 Megajolt
'76 Datsun 280z

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icehouse
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Re: Narrowing rear control arms

Postby icehouse » 30 Oct 2017 21:09

Also alignment is based on ride height, so what works on your car may not work on other cars. We chose 2" because of what I want to run on my car. If the work out like we plan and others like the setup they can buy it.
"People don't like it when shit doesn't match their rule of thumb." Sam

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jeffball610
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Re: Narrowing rear control arms

Postby jeffball610 » 07 Nov 2017 12:43

I'm nobody and have no idea what I'm talking about, but I would think you might want to start with the rear crossmember itself. I think the large box design has a LOT of room for improvement. Moving the pickup points upward, removing the restrictive box around the diff mount, better clearance for the exhaust etc. In doing so, you can move the arms in (like what you're doing) and find better geometry that can then be used to make adjustable arms. There might even be enough space under the car to move the pickup points further forward to give the suspension "slower" changes in geometry.

For the record, what you're doing is completely badass. I just think that you'll be fighting the stock crossmember and need to change that at some point. You've already stated that there would be an issue with finding stock size bushings and the way the arms mount to the stock pick up points. Eliminate the area of interference and move forward from there.

Also for the record, I'm not an engineer or anyone who knows enough to form an educated opinion.
1972 Datsun 510
7-bolt 4G63T, EVO 9 pistons & rods, Garrett GT3076R, "Flipped" Stock Intake Manifold, Toyota R154, Z31 R200 w/ CVs

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icehouse
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Re: Narrowing rear control arms

Postby icehouse » 07 Nov 2017 16:31

Yeah Jeff we've talked about doing that before. There are a few problems. The main problem is dual A arms are the best and there is no way to fit them without loosing the back seat, me and Sam both have kids so fuck that. The second problem is that strays away from our goal of making it 99% bolt in. Once a competent on sight welder is required all bets are off as far as all the FEA goes. So we've decided to go this route. More pics to come tonight.
"People don't like it when shit doesn't match their rule of thumb." Sam

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icehouse
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Re: Narrowing rear control arms

Postby icehouse » 07 Nov 2017 18:02

Sam updated some stuff on Ratsun. Figured I should port it over here, plus he's the smart guy so his stuff is fun to read.



sam wrote:A peek into the decision process, obviously not much meaning easily visible from the raw data but it shows the nearly 35 suspension point iterations tested in CAD before going ahead with fabrication.

Image


A point of interest brought up by Jeff in our conversations about the trailing arm angle and resulting forces. He wagered the front suspension made nearly the same angle as our rear suspension and therefore would carry cornering loads similarly. I didn't think they were too similar until I overlaid the front on the rear! New perspective, haha.



Image


With the final geometry worked out we turned to FEA for the detail design, lots of iterations resulted in some additional gussets and bends on the trailing arms but, more drastically changed the mustache box which is looking more like a bow-tie box these days. We had to reduce/eliminate the in situ access of the diff mounting bolts but it was that or make the box the lowest point of the car :hmm:


Image


Image


Image


Image


Image


The last major change those far is a bolt on shock mount, this will be a bit more work to implement but gives us a lot of future proofing for some ideas we've been toying with implementing :D



"People don't like it when shit doesn't match their rule of thumb." Sam


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