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PostPosted: February 28, 2017, 5:26 pm 
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More non-picture updates. I have finally gotten the front suspension mounts done. The last two need to be drilled and welded on the chassis. When these are welded, I will send along beautiful full color photographs of much work and otherwise basically nothing.

Good thing my watch works on geologic time.

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PostPosted: February 28, 2017, 6:10 pm 
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I'm watching this, keep at it.


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PostPosted: February 28, 2017, 8:19 pm 
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Not to worry. It will get done. Between baby, parents with health issues and work, it is not fast, but the work is so satisfying I can't see stopping. And thanks for the support. Good to know there is interest from other enthusiasts.

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PostPosted: March 1, 2017, 6:07 pm 
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We are Slotus!
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Good thing my watch works on geologic time.
Is that just a joke, or are you a geologist?

Quote:
And thanks for the support. Good to know there is interest from other enthusiasts.
This group has always been very supportive. They supported Team Slotus from Day 1... If pointing and laughing counts as support!?!?! :mrgreen:

:cheers:
JDK
FL P.G. #3166

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PostPosted: March 1, 2017, 7:57 pm 
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No joke JD. They have these watches in sidereal time (time measured from a point in space, like a star), and I thought, what the heck! Maybe they got one of those Timexes that moves its hands every thousand years or so, with the little hand moving during the next ice age. Figured I'd need one for my build.

But no, I am a recovering chemist. Geologists work with things I don't understand.

As for support, this place is great, and pointing and laughing are helpful in their way too, and so to prove, on with the next post!....

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PostPosted: March 1, 2017, 8:11 pm 
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OK all, I've been all along thinking of double wishbone rear suspension. But as with everything else, nothing is clear. Packaging, given the length of the trams, could make getting the engine in and out of the bay tricky, etc. ad the usual nauseum.

So I would like to explore other suspension designs, especially trailing arm types, but being utterly new to the field, have no clue how to design one that won't randomly dump me into the weeds. Lotta weight in the back of this thing, and swapping ends was great in snowy parking lots when I was in high school, but not so much at speed on the road or track. I could really use some pointers to learn how to design something effective.

Thanks in advance.

Terry

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PostPosted: March 2, 2017, 10:50 pm 
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OK, I'll bite. There's probably 2 big areas to look at. There's structure, strength kind of things and there's geometry stuff.

Trailing arms are also a big subject and I'm not sure off the top of my head the names or categories of them all. We are not going to talk about the kind used in the front suspension of a VW Beetle or the semi trailing arms in a BMW 2002 or early Datsun Z car ( showing my age here :rofl: ).

I have not spent much time looking at or thinking about transverse midship cars. They make sense these days because of the large amount of donor hardware available. On the other hand when they go sideways maybe that is mother nature trying to straighten them out? I don't know.

For geometry, at least to start, I think you can use tools like Vsusp or other and consider them like double wishbone designs. The lateral links control the camber, toe and roll centers, just like wishbones. Depending on the design there may be toe changes with bump and droop as the trailing arms move the uprights fore and aft, due to their length.

A big issue here is finding places to mount the suspension to the car. With the rear suspension there are also the halfshafts to consider which may make the frame more difficult or require offset of the coilover/pushrod mounting to the upright. This later issue can be considerable, I worked on a car where issues were traced to flex of the control arm caused by this offset of the coilover mount. FEA showed the arm was warping by a couple of inches.

I chose trailing arms with a reverse lower wishbone for Car9 and I have recommended this and similar style setups a couple of times. This was useful in this case because it only required two inboard mounting points on each side, ignoring the coilover anyway. The bulkhead behind the driver easily supplies these, you could cut off all the rear tubing behind the driver and the car would work fine. This bulkhead can be made very strong for sideways loads. The trailing arms mount to the sides of the cockpit somewhere and this also can be very strong for fore and aft loads.

The trailing arms take all the torque from the brakes and coilover, the IRS diff takes all the torque loads from the engine. To me this seems easier to figure than the twisting loads you deal with in pure wishbone style setups. Not that that can't be done, but many people just build something that looks right and that can lead to trouble.

Next step is to look at your car and maybe think out load with 2x2 wood and look at how you're going to mount your motor and look for places to mount control arms...

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PostPosted: March 3, 2017, 7:27 am 
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The semi-trailing arm irs is the exact reason I started hanging around here! I was trying to figure out how to shoehorn a 2004 GTO rear into a '33 Vicky. The factory control arms aren't very friendly to being narrowed. This was before I was completely taken in by this site... :twisted: Then I had not even thought about fabricating my own arms. Now, thinking about what Horizenjob has said, it does actually make sense. My issue was track width. The GTO was 66", hub to hub, and had a reputation of being, shall we say, twitchy without much modification. As many of the factory bushed suspensions are. If you were to find a rear with the attributes you desire, gearing, dimensions, etc., setting up a fixture on the acorn platen would be a piece of cake, you could cut off the bushing ends, and install rod ends, or use the cradle as a fixture, and fabricate tubular arms and your own attaching points. It would certainly aid in the fitment of the engine!

Ps, I know a guy about an hour North of you that has just the setup you need! He works cheap too! :cheers:

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PostPosted: March 3, 2017, 8:10 am 
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Too early, not enough caffein yet... :BH: I'm in front / rear mode. You're middie!
Anyway, Much of my pre-coffee post applies. Less the differential, of course! :roll:

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PostPosted: March 3, 2017, 11:03 am 
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Kimini and Midlana use rear lateral/trailing links. I complicated things a bit by using a separate reaar toe control link, as using a reverse wishbone in my setup caused what may have been excessive toe change. Would it have been noticeable? Who knows but I didn't want to find out the hard way. The trailing link portion of it is parallel to the centerline of the car and as mentioned, handles all the fore/aft forces, while the lateral link part of it handles cornering and camber control. The upper link is a proper A-arm.

Is the setup perfect? No, I'd have liked to use an upper A-arm as well, but given the width of FWD drivetrains it's the most practical packaging solution that allows good wheel control - tire wear is very even. The shock is bolted to the outboard end of the lower arm, offset enough to miss the upper A-arm and half-shaft. Someday I'd like to build a longitudinal V8 setup with a proper transaxle, but the cost is just too much for me right now.

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PostPosted: March 3, 2017, 9:58 pm 
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Thanks for the input.

Dismantalus, oddly enough, at 66", the GTO is still too wide for my (64") track needs. Who'd have imagined? But I should stop up and actually see it, as it might give ideas. Old BMWs and Porsches need looking into.

Kurt, this is not surpisingly, the trouble I am in. Given I'm using your book as loose guide, doing similar stuff with even bigger engines, I should not be surprised. I pretty much thought I could fit the lower A arm where I wanted it, given 2" more track than Toyota used. To be fair, I still can, but keeping the engine low and triangulating for stiffness, holding the tapley meter straight and ensuring the gas law uses the right constant is not as obvious as it might seem. If I stay double wishbone, the solution on one side MAY NOT be the same as the other, as access is very different side to side. Of course, if I go there, the amount of measurement, jigging and goofing around will go up by an order of magnitude or so. It will make a better story at DMV though.

Keep the ideas coming, more design ideas are welcome.

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PostPosted: March 4, 2017, 5:49 pm 
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Front suspension mounts are done! Well, unless and until I find out if they are wrong. Pictures enclosed.

The seat mounts are in and welded as well. No photos. They are just seat mounts.


Attachments:
IMAG00564[1].jpg
IMAG00564[1].jpg [ 1.76 MiB | Viewed 3399 times ]

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PostPosted: March 5, 2017, 8:59 am 
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Yo, Terry-
First thing, the standard disclaimer applies, "I ain't no enga-neer!"

However, those suspension mounts look like they're hanging out there a good distance from the frame. I realize that a lot of the load on the suspension travels through the coilovers, but there's still some that's supported by those mounts. Iffen it wuz me, I'd triangulate those mounts with another piece of tubing that goes upward and inward from the ends of the mount to the frame rail above.

I lack MV8's ability with MS Paint, but I put a couple of green lines on your picture in the areas I'm talking about. The new tubes would attach just inboard of the actual mounting "ears" on the ends of the mounts and sit at some convenient angle. (45*, maybe?)
Attachment:
Terrys Susp Mounts.jpg
Terrys Susp Mounts.jpg [ 125.07 KiB | Viewed 3375 times ]
Please refer back to the disclaimer above. But think about it... And maybe some of the Smart Kids in here will chime in... :mrgreen:

:cheers:
JDK

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"Gonzo and friends: Last night must have been quite a night. Camelot moments, mechanical marvels, Rustoleum launches, flying squirrels, fru-fru tea cuppers, V8 envy, Ensure catch cans -- and it wasn't even a full moon." -- SeattleTom


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PostPosted: March 5, 2017, 9:53 am 
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And while you are putting Gono's gusset in, please add a horiziontal cross brace between the two stand offs and two more gusset. Dave W


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PostPosted: March 5, 2017, 10:57 am 
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Ah, you guys are great, and as they say, way ahead of me build-wise. Indeed, you point out a critical flaw in designing the upper area of the font. I just didn't make it wide enough. :roll: So now I have these suspension thingies sticking out that need bracing.

But to be fair, I also have to triangulate the sides and front of the front chassis box. Ideally, that solution will solve the suspension mounts hanging in the breeze at the same time.

All of which to say, don't worry, I'm thinking about it.

On second thought, worry might be in order. 8)

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