follow ft86club on our blog, twitter or facebook.
FT86CLUB
Ft86Club
Speed By Design
Register Garage Members List Calendar Search Today's Posts Mark Forums Read

Go Back   Scion FR-S Forum | Subaru BRZ Forum | Toyota 86 GT 86 Forum | AS1 Forum - FT86CLUB > FT86CLUB Shared Forum > Member's Car Journals

Member's Car Journals Car journals by our members.


User Tag List

Reply
 
Thread Tools Search this Thread
Old 05-12-2017, 05:39 AM   #15
DIY
Senior Member
 
DIY's Avatar
 
Join Date: Jul 2016
Drives: BRZ, WRX
Location: Sydney, Australia
Posts: 172
Thanks: 57
Thanked 255 Times in 116 Posts
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Work has begun on the rear suspension, I have done my research and I think I have figured out how to do it but there will be some changes made as I go.

It starts with making a welding jig for the rear suspension cradle. The idea is to locate all the suspension arm pivot points in space including the position of the rear diff.



I am using these bits of tube to locate the pivot points which have been cut such that they will slide into a piece of 50 x 2.5mm square box (SHS). The box sections will be cut to create brackets for the rod ends on each control arm. The rest of the frame will be CDS tube.



I hope to build most of it on the bench but at some point it will need to be placed in the rear of the car as it will not be bolt-in to save some more weight. I will use the original 4 bolt points to locate the tube frame in the correct position, however, I will raise it up about 80mm using spacers so the the car is lowered by this amount without affecting the suspension geometry.

Joel.

Last edited by DIY; 07-01-2017 at 07:11 AM.
DIY is offline   Reply With Quote
The Following 2 Users Say Thank You to DIY For This Useful Post:
jubella2 (05-12-2017), Psilox (05-14-2017)
Old 05-14-2017, 08:34 AM   #16
DIY
Senior Member
 
DIY's Avatar
 
Join Date: Jul 2016
Drives: BRZ, WRX
Location: Sydney, Australia
Posts: 172
Thanks: 57
Thanked 255 Times in 116 Posts
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Some more progress today, I have got the main frame of the jig welded up and test fitted it in the back of the car to make sure that it fits between the frame rails. You may notice the use of washers in the control arm mounts, this is because the rod ends I intend on using are a lot more narrow than the factory rubber bushings.



This is as far as I got today, the frame is welded up and the rear diff mounts are finished.



Joel.

Last edited by DIY; 07-01-2017 at 07:14 AM.
DIY is offline   Reply With Quote
The Following User Says Thank You to DIY For This Useful Post:
RJasonKlein (07-06-2017)
Old 05-18-2017, 07:22 PM   #17
DIY
Senior Member
 
DIY's Avatar
 
Join Date: Jul 2016
Drives: BRZ, WRX
Location: Sydney, Australia
Posts: 172
Thanks: 57
Thanked 255 Times in 116 Posts
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Last night I finished off the diff mounts in the jig.





Control arm pivot locations will be next which are slightly more difficult as I have to attach square to round tube.

Joel.

Last edited by DIY; 07-01-2017 at 07:19 AM.
DIY is offline   Reply With Quote
Old 05-20-2017, 04:35 AM   #18
DIY
Senior Member
 
DIY's Avatar
 
Join Date: Jul 2016
Drives: BRZ, WRX
Location: Sydney, Australia
Posts: 172
Thanks: 57
Thanked 255 Times in 116 Posts
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
A little bit more done last night and this afternoon. Started joining bars to the pivot points, I used a step drill on the square tube first to match the outer diameter of the tube that locates the pivot points. This way you get a nice tight fit for welding.



The rear most pivots were a little awkward to reach, I've got to think ahead and make sure I can remove the jig from the frame when its finished and also get good enough access to get a weld on first so nothing moves.

I had to flip it over to get to some of the welds.



The next pivot points moving forward were much easier and access was good so I just attached the bar straight to it.



Final photo is of a car that I am getting ideas from to join the tubular rear cradle to the roll cage.



Joel.

Last edited by DIY; 07-01-2017 at 07:22 AM.
DIY is offline   Reply With Quote
Old 05-27-2017, 05:38 AM   #19
DIY
Senior Member
 
DIY's Avatar
 
Join Date: Jul 2016
Drives: BRZ, WRX
Location: Sydney, Australia
Posts: 172
Thanks: 57
Thanked 255 Times in 116 Posts
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Lots of progress today, I have just completed all the pivot locations on the jig.

The last one was a little tricky as I wanted to include a little anti-squat reduction into the design.

It started by making some drilled angle which would move the pivot down and slightly forward.



Then this was simply bolted into the factory location and squared off the table.



Here is a photo of the completed pivot location in its new lower position.



and a couple of photos of the completed pivots. I'm getting better at using the MIG welder, this job has given me a lot of practice.





The final part involves locating the four main subframe attachment points. This is a little tricky as I have to make them removable with bolts otherwise I will not be able to separate the cradle from the jig. More on that later....

Joel.

Last edited by DIY; 07-01-2017 at 07:28 AM.
DIY is offline   Reply With Quote
Old 05-28-2017, 06:18 AM   #20
DIY
Senior Member
 
DIY's Avatar
 
Join Date: Jul 2016
Drives: BRZ, WRX
Location: Sydney, Australia
Posts: 172
Thanks: 57
Thanked 255 Times in 116 Posts
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
More done today, actually I have finished the jig.

As mentioned yesterday I have to make the main subframe attachments removable as I need to locate the top of the holes which is where it bolts up to the main chassis rails in the car. When the jig is complete the idea is to lift the factory cradle straight up and off the jig so permanent mounts would stop me doing that.

To make it removable I am using some bolts. I used some slightly smaller box section that slides into the 30mm stuff I have been using. To make the fit really tight I put some small tacks with the welder first and then filed them down until the fit was very snug.



Then slid it inside the larger box section and did another tack to hold it firm while I drilled some holes for the bolts.





Same thing on the rear of the frame just with taller posts.



With those four points located it was time to lift the cradle off the jig and finish some of the welds I could not reach with the cradle in place. This is where I had some trouble, I could not get the cradle off as it was stuck where the rear diff mounts are recessed into the frame a little. I'm not too surprised this happened as its my first time doing anything like this.

After some thought I decided to cut one of the diff mount post off, it was the only solution really. I used a hacksaw as the blade is very thin and my grinder could not cut it in one clean pass.



So I welded that back on, it will drop the hole position less than 1mm which is ok as the diff mounts are slotted anyway. Then I finished the rest of the welds and the jig was finished. I will put a coat of paint on it when I get a chance.



Joel.

Last edited by DIY; 07-01-2017 at 07:33 AM.
DIY is offline   Reply With Quote
Old 06-01-2017, 07:35 AM   #21
DIY
Senior Member
 
DIY's Avatar
 
Join Date: Jul 2016
Drives: BRZ, WRX
Location: Sydney, Australia
Posts: 172
Thanks: 57
Thanked 255 Times in 116 Posts
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Success!

The jig fits into the car, what a relief when your ideas turn out how you imagined.


Last edited by DIY; 07-01-2017 at 07:34 AM.
DIY is offline   Reply With Quote
The Following User Says Thank You to DIY For This Useful Post:
Trust86 (06-01-2017)
Old 06-01-2017, 11:35 AM   #22
BigFatFlip
sleep, drive, eat, repeat
 
BigFatFlip's Avatar
 
Join Date: Mar 2012
Drives: '13 BRZ, '12 Outback
Location: Sack of Potatoes
Posts: 4,428
Thanks: 2,629
Thanked 3,779 Times in 1,973 Posts
Mentioned: 186 Post(s)
Tagged: 4 Thread(s)
Subbed for the Fab Pr0n!
BigFatFlip is offline   Reply With Quote
The Following User Says Thank You to BigFatFlip For This Useful Post:
DIY (06-01-2017)
Old 06-01-2017, 12:53 PM   #23
DustinS
Senior Member
 
DustinS's Avatar
 
Join Date: Apr 2014
Drives: 2013 Ultramarine FR-S
Location: Springfield, MO
Posts: 1,873
Thanks: 2,388
Thanked 1,289 Times in 749 Posts
Mentioned: 29 Post(s)
Tagged: 3 Thread(s)
Really excited to see the progress. Looks great so far.
__________________
DustinS is offline   Reply With Quote
The Following User Says Thank You to DustinS For This Useful Post:
DIY (06-01-2017)
Old 06-04-2017, 03:59 AM   #24
DIY
Senior Member
 
DIY's Avatar
 
Join Date: Jul 2016
Drives: BRZ, WRX
Location: Sydney, Australia
Posts: 172
Thanks: 57
Thanked 255 Times in 116 Posts
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Thanks for the comments guys.

Coming up with a design for the rear suspension integrated into the roll cage is not easy, I don't have any experience in this area but I understand the basics which is triangulation keeping all tubes in compression or tension with no bending.

Drawing it on paper only got me so far with all the depth and complex angles etc. I don't have access or the skills to use fancy software other than Photoshop. So I decided to mock the whole thing up with 1.25" electrical conduit so I could properly visualise the whole design and show other people my idea. I ended up using around 13 meters of conduit which also helps me to know how much steel tube I need to buy.

So I am sharing the photos just in case someone can see some obvious flaws in my design. A couple of things to keep in mind before you comment:

1. Everything coming forward will be attached to the main hoop of the roll cage (not shown), there are no dead nodes, all loads are transferred forward.

2. Some gussets will be added in areas where the control arm attachment points are a little further away from the corners or junctions.

3. Almost everything in yellow will be removed from the forward most point of the rear wheel arch moving toward the rear of the car. The main chassis rail will be cut off and boxed at this point.

I have included photos from every angle possible.













I have not decided on what size tube to use yet but I am leaning toward 1 1/2 x .102 (38.1mm x 2.6mm) 350 Grade CDS/CDW/DOM 1020 Hi-tensile Mild Steel.

Joel.

Last edited by DIY; 07-01-2017 at 07:39 AM.
DIY is offline   Reply With Quote
Old 06-05-2017, 08:17 PM   #25
DIY
Senior Member
 
DIY's Avatar
 
Join Date: Jul 2016
Drives: BRZ, WRX
Location: Sydney, Australia
Posts: 172
Thanks: 57
Thanked 255 Times in 116 Posts
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Great news!

I have received a generous offer to do full FEA on my design so I will be spending some time measuring everything, no fancy laser just with a plumb bob and ruler so we can load it into the computer. Then I should be able to come up with the strongest design possible whilst keeping it to a minimum weight.

I'm very excited about this, it will add a professional touch to what is a very low budget build.
DIY is offline   Reply With Quote
Old 06-05-2017, 09:27 PM   #26
surfwaxsmitty
Member
 
Join Date: Aug 2016
Drives: '14 BRZ 6MT
Location: NO, LA
Posts: 66
Thanks: 47
Thanked 34 Times in 22 Posts
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quote:
Originally Posted by DIY View Post
Great news!

I have received a generous offer to do full FEA on my design so I will be spending some time measuring everything, no fancy laser just with a plumb bob and ruler so we can load it into the computer. Then I should be able to come up with the strongest design possible whilst keeping it to a minimum weight.

I'm very excited about this, it will add a professional touch to what is a very low budget build.
Fantastic news!!!
surfwaxsmitty is offline   Reply With Quote
The Following User Says Thank You to surfwaxsmitty For This Useful Post:
DIY (06-05-2017)
Old 06-12-2017, 03:44 AM   #27
DIY
Senior Member
 
DIY's Avatar
 
Join Date: Jul 2016
Drives: BRZ, WRX
Location: Sydney, Australia
Posts: 172
Thanks: 57
Thanked 255 Times in 116 Posts
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Just a small update today, I spent a few hours measuring the location of all the pivot points and tube junctions on my rear suspension design for the FEA analysis. No fancy laser system, just a ruler and plumb bob to get the data we needed.

I'm at a point now where I need to determine the ride height before any of the fabrication begins. WTAC rules state that minimum clearance to the ground from any un-sprung part of the car excluding the exhaust is 50mm and I aim to get as close to that as possible.

Here is a photo of the height I have settled on, a call to MCA suspension last week did help a lot when determining this height. The front end will be a challenge as under the rules I must retain the front strut towers.



​​​​​​​Joel.

Last edited by DIY; 07-01-2017 at 07:40 AM.
DIY is offline   Reply With Quote
Old 06-17-2017, 04:24 AM   #28
DIY
Senior Member
 
DIY's Avatar
 
Join Date: Jul 2016
Drives: BRZ, WRX
Location: Sydney, Australia
Posts: 172
Thanks: 57
Thanked 255 Times in 116 Posts
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Today was a great day for this project! we had a little back and forth this week sending the node measurements over to my friend Dave at davidbenekeconsulting.com/ who not only does FEA for a living but owns and races time attack with a very tidy MY10 wrx hatch in our local wrx club.

Today I went to visit Dave at his work and we played around with my design by adding extra tube, changing tube sizes, connection points etc. I think we ran nine different configurations in total before coming to the conclusion that my original design was actually very good to start with. This was great news for me as I have zero experience in this field and have spent many months reading and researching before coming up with what you saw mocked up with the electrical conduit.

I feel much more confident moving forward now and also really excited by what this means for the build. Reasons to be excited? the whole thing weighs around 30kg and includes a substantial portion of the roll cage, it allows me to remove a lot of sheet metal from the back of the car as this design carries all the loads. To put it in perspective the OEM cradle, just the center part alone without the control arms weighs around 23kg. Then there are the ride height, COG and suspension geometry benefits as well.

In terms of numbers the design gave a result of 16310Nm/

DIY is offline   Reply With Quote
 
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 12:31 AM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
Garage vBulletin Plugins by Drive Thru Online, Inc.