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 Post subject: Re: Project Canuck - 1966 Canadian Build Thread ... Finally
PostPosted: Wed Nov 30, 2016 11:27 am 
Somehow completely sideways in 4th

Joined: Thu Nov 10, 2011 11:43 am
Posts: 248
Location: Regina, SK
Last night I went back in this thread to see if there were any pictures or explanation for the fitment of rear suspension supports you just welded - Do they fit in the existing car or is the body being cut to fit them?

Very cool set up - so was just looking for the "big picture" of how it's integrating into the car. Apologies if I missed in the thread - I skimmed all the way back to 2012 (when you were messing with clay in the ports and a leaf blower...) and I didn't see any discussion.

Thanks!

Rabin


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 Post subject: Re: Project Canuck - 1966 Canadian Build Thread ... Finally
PostPosted: Wed Nov 30, 2016 1:12 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Jun 14, 2006 4:19 pm
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Location: Lethbridge, AB
Are these the images you're looking for Rabin?

Image

Image

You can see that I've hacked off the back half of the frame and welded on much stronger rear cross member. Then the shock towers go up into the trunk. I'll have to do a lot of sheet metal work to cover all this up and the brace that fits between the towers (not yet fabricated - working on it now) will be removable so that I can keep as much of the trunk as possible. This was in the early tack up phase of the build.

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 Post subject: Re: Project Canuck - 1966 Canadian Build Thread ... Finally
PostPosted: Wed Nov 30, 2016 5:31 pm 
Somehow completely sideways in 4th

Joined: Thu Nov 10, 2011 11:43 am
Posts: 248
Location: Regina, SK
Perfect - that's exactly what I was hoping to see and you didn't disappoint - looks awesome.

Did I miss it in this thread somwhere? I need to go back and re-read from the start since I'm also very interested in how the valving and spring rates for the rear coil-overs were calculated - OR is that still yet to come and those coil overs still to be reworked / set up?

Rabin


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 Post subject: Re: Project Canuck - 1966 Canadian Build Thread ... Finally
PostPosted: Wed Nov 30, 2016 8:44 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Jun 14, 2006 4:19 pm
Posts: 3131
Location: Lethbridge, AB
bean wrote:
Perfect - that's exactly what I was hoping to see and you didn't disappoint - looks awesome.

Did I miss it in this thread somwhere? I need to go back and re-read from the start since I'm also very interested in how the valving and spring rates for the rear coil-overs were calculated - OR is that still yet to come and those coil overs still to be reworked / set up?

Rabin


Probably not...I'm not sure I ever posted those shots. Valving and spring rates are PURELY start points right now. I just computed what was there and matched this set up to that. So it'll probably be far too soft. But that can be changed for a few hundred dollars and revalving these race shocks is $70 per shock. So super cheap as far as I'm concerned. Computing ride frequencies is easy enough and I've got all the data, so I consider this mostly a mock up set up at this point.

Started to mock up the shock tower brace tonight.

Image

This design takes maximum advantage of the trunk space. It's not optimal structurally...and I'm not convinced that it's worth the trunk space.

Image

Fitting it up with PCV pipe is cheaper and easier than with steel.

Image

I'll probably suck it up and just make the bar straight for greater strength. There's lots of trunk space - I've only got 18" max between the towers, so it's not a vast area we're talking about.

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 Post subject: Re: Project Canuck - 1966 Canadian Build Thread ... Finally
PostPosted: Thu Dec 01, 2016 11:02 am 
Somehow completely sideways in 4th

Joined: Thu Nov 10, 2011 11:43 am
Posts: 248
Location: Regina, SK
What about removable links from the uprights to your new frame rails, and then brace the frame rails together close to the rear seat trunk panel?

It's so robust I doubt there'd be any deflection in the structure to even warrant a brace between the uprights directly if the uprights were tied into the frame rails, and the rails were braced.

I'd imaging advantages when sheeting the trunk back in if you didn't have to work around a direct link as well.

Rabin


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 Post subject: Re: Project Canuck - 1966 Canadian Build Thread ... Finally
PostPosted: Thu Dec 01, 2016 6:42 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Jun 14, 2006 4:19 pm
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Location: Lethbridge, AB
bean wrote:
What about removable links from the uprights to your new frame rails, and then brace the frame rails together close to the rear seat trunk panel?

It's so robust I doubt there'd be any deflection in the structure to even warrant a brace between the uprights directly if the uprights were tied into the frame rails, and the rails were braced.

I'd imaging advantages when sheeting the trunk back in if you didn't have to work around a direct link as well.

Rabin


I've thought a lot about this over the years. The primary issue with joining any part of this cradle to the frame of the car is that the diff is hard mounted to the cradle and I'd rather not have differential noise transmitted through the car. Also, I would agree that I'd need to tie the frame together (though the sheet metal back there would work if I have the right shape), so there is no weight saving to be had from joining them the other way. The solution that I've seen on cars like the F40 and the RS200 is to just join the two towers.

Image

Image

The design was not really inspired by either of these cars, but they both sport IRS's with high mount coil overs that are similar to what I'm working with. It's a little "old school" compared with how it would be done today and I could have switched it up to have either cantilevered or offset coil overs, but packaging was harder.

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 Post subject: Re: Project Canuck - 1966 Canadian Build Thread ... Finally
PostPosted: Thu Dec 01, 2016 7:21 pm 
Somehow completely sideways in 4th

Joined: Thu Nov 10, 2011 11:43 am
Posts: 248
Location: Regina, SK
I had overlooked the hard mounted diff - definitely want it isolated.

In both cars you referenced - the support between the uprights is trangulated to the base of the upright as well - will you be doing that as well?

Total aside - but I worked on an RS200 Evo at Pikes Peak in 2004. It's the automotive highlight of my lifetime so any segue I can get to mention it - I use. :)

Rabin


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 Post subject: Re: Project Canuck - 1966 Canadian Build Thread ... Finally
PostPosted: Thu Dec 01, 2016 9:26 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Jun 14, 2006 4:19 pm
Posts: 3131
Location: Lethbridge, AB
bean wrote:
I had overlooked the hard mounted diff - definitely want it isolated.

In both cars you referenced - the support between the uprights is trangulated to the base of the upright as well - will you be doing that as well?

Total aside - but I worked on an RS200 Evo at Pikes Peak in 2004. It's the automotive highlight of my lifetime so any segue I can get to mention it - I use. :)

Rabin


You win the cool story for that one. Not that I've had a tape measure on any of this junk, but my sense (please forgive this transgression) of things is that both these cars are: 1. Made from lighter gauge material than I'm using. 2. Designed by someone that knows what they are doing. 3. The towers on both of them are taller and further apart than I'm dealing with. My towers are only 24" apart and all this tube is 120 wall - not exactly the 4130 of the RS200 or I'm sure the 60 wall of the F40. It's also full penetration welded.

I really have tried to read up on everything that I can get my eyes on - but who can tell you the right way to do any of this stuff? It's been a real struggle. I don't have the CAD skills to model the deflection of this stuff or really fully understand the forces that this part will see. My guess, is that if it wont actually be as bad as I think as it sees just suspension loads. If my thinking is completely off - someone chime in.

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 Post subject: Re: Project Canuck - 1966 Canadian Build Thread ... Finally
PostPosted: Fri Dec 02, 2016 11:22 am 
Somehow completely sideways in 4th

Joined: Thu Nov 10, 2011 11:43 am
Posts: 248
Location: Regina, SK
Hi Craig,

I'm just going to preface the following comments: While my Engineering studies weren't exactly successful degree/diploma wise, every class I took that had to do with building or fabrication and analysis I was REALLY good at. While at SIAST in Mechanical Engineering Technology my 2nd year design project was the finite element analysis of a bike I designed using an early version of Pro-E. I may be a bit rusty but I'm hoping you find this of value or at the very least interesting discussion:

Attachment:
Forces v1.jpg


Excuse the crude MS Paint - but I'm hoping this helps convey what I'm seeing. Shock forces (Sf) are essentially push pull along the mounting points of the coil over. The top mount forces will create a moment of force to the top of the assembly (Sf * distance to mount= Tf), and that force will then be creating a moment of force on the base of the upright (Tf *distance to base). What I see is that the welds opposing that force are ~2" apart which would be a lot of force acting on those welds. Add to this that the loads are going to be constantly cyclical, with the potential for some pretty high impact loads should the coil over have the bump stop integrated into it.

Attachment:
Cross bar forces v1.jpg


With just the cross bar I see it being essentially a box, and without any triangulation the forces incurred on one upright will transmit to the other upright in the same fashion stressing the base welding even more. While I'm sure the welds are likely fine for the loads it will see, they will still be very high, and with the constant and varying cyclical loads I'd worry about fatigue on the upright welds attaching to the subframe.

Attachment:
Bracing ideas v1.jpg


By trangulating the two uprights together the shock forces seen by the uprights would then get transmited and dispersed to other areas, and by spreading the loads to different areas of the sub frame any concerns would be considerably reduced.

Now I'm not there, and so much can be missed with just what I've seen in your posts. You could be absolutely right in saying it's been over built - and it should be fine, but I'm just offering ideas based on what I see and advice I would offer based on that.

Rabin


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 Post subject: Re: Project Canuck - 1966 Canadian Build Thread ... Finally
PostPosted: Fri Dec 02, 2016 11:14 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
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Joined: Wed Jun 14, 2006 4:19 pm
Posts: 3131
Location: Lethbridge, AB
That's excellent Rabin. Thanks. I've worked out a couple of models for this as I've been developing the frame and the more I have thought about the towers the more they need a brace. I am not sure if I will stay the the internal bump stop in the Bilsteins or put a limiter on the suspension somewhere. Either way, a quick run through the corner weights plus the anticipated cornering loads don't have me concerned, but as you've pointed out, it's the sudden bump loads where things get serious. I've worked out the bracing with 1" 100 wall DOM tube and will put it in play over the weekend. I will brace it towards the seat back to maintain a little cubby space in between the towers. Maybe a custom tool kit and place for my race helmet. Smugglers cove or something. We'll see how it all works out tomorrow.

I will do some deflection testing as well as I move along.

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 Post subject: Re: Project Canuck - 1966 Canadian Build Thread ... Finally
PostPosted: Sat Dec 03, 2016 5:23 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
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Location: Lethbridge, AB
OK - here's what I've done. I made an exact scale replica of the rear shock towers using 3/32" TIG rod. Then I analysed the various stresses as I added parts. Sorry I didn't take pictures of the entire thing, you'll get the idea.

So as it stands without any cross bracing at all, the "towers" were very easy to move in bump or droop. They could be bent in every direction. Then with the addition of just the cross brace, all that happened was motions on one side were transmitted to the other side. it was a little stiffer, but I don't think I could characterise it as better, in fact worse in some ways as the motions were translate which would add to the stresses over time.

Then I added some 1/16" TIG diagonal braces following what was shown in the F40 and RS200 (I used 1/16" as they used smaller tube and I happen to have some 1" 100 wall DOM that I bought as I was thinking a head the last time I was in YYC. Bam - I can not make this move laterally at all. Or at least not with just simple hand movements. If I went full gorilla on it - sure, but the only thing you can do with this shape is twist it a bit which is not a force that it would see unless something catastrophic went wrong. It was shocking how much of a difference this made.

Image

I'm now making the parts to execute this design. Stay tuned for more tube awesomeness.

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 Post subject: Re: Project Canuck - 1966 Canadian Build Thread ... Finally
PostPosted: Sun Dec 04, 2016 12:11 am 
Somehow completely sideways in 4th

Joined: Thu Nov 10, 2011 11:43 am
Posts: 248
Location: Regina, SK
Sweet - looks great. Very curious to see if you go welded or bolted... It's like a cliff hanger... :)

Rabin


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 Post subject: Re: Project Canuck - 1966 Canadian Build Thread ... Finally
PostPosted: Sun Dec 04, 2016 4:41 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
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Location: Lethbridge, AB
Still going bolted. Made the parts to slug the ends of the tube today. Started with a stock bracket that I have in the garage. Needed to add a tab to the bottom. So welded this up.

Image

Then found tube that fits into the cross tube.

Slot, cut, repeat.

Image

Then I fit the tubes I made yesterday to the uprights. Nothing welded at this point.

All welded up.

Image

These have now been ground and finished off and are ready to go in the tube. I have little caps for the tops. They will be button welded and welded to the tube before the caps go on. They're going no where.

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 Post subject: Re: Project Canuck - 1966 Canadian Build Thread ... Finally
PostPosted: Thu Dec 08, 2016 9:21 am 
Haha, I just built a W24 Octo-Turbo, now what?!
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Time for a little update. Here's where I'm at with the tower brace so far.

I've constructed some extensions that will be welded onto the uprights/cross bar basically inline with the uprights and angled in. The bar will then go straight between these (not as the picture suggests from the bar ends) and the diagonal bracing will weld to the main cross bar and go down to the frame rail attachment points (whatever those end up looking like).

Image

You can see it a little better this way.

Image

Image

This gives me easy access to the shock bolt and other potential service items and I don't think sacrifices strength where needed. It also does meet my objective of getting the bar up and out of the way a little so the space isn't gratuitous.

I haven't tacked it on yet or build the bar - so the case is not yet closed.

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 Post subject: Re: Project Canuck - 1966 Canadian Build Thread ... Finally
PostPosted: Thu Dec 08, 2016 9:47 pm 
Haha, I just built a W24 Octo-Turbo, now what?!
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I tacked it up tonight. Still have to move it around to get it fit properly, but that's the cross bar in place.

Image

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