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2/07/2012 3:42 pm  #1


IRS UPRIGHTs

I am nearing the point when I need to really consider what the uprights will look like on my new IRS.

Rather than plow entirely new ground, I took a journey courtesy Google and Bing, and found a number of example.  I will present them in a series of posting in this thread.

First, as I am designing/building a new suspension for my C3 Corvette (one owner 1978), it is probably useful to understand why I am doing this.  I am interested in initially engaging in HPDE, and eventually track days, and as energy, experience, and expenses allow, competing in either SCCA, NASA, or other forms of road racing.  I have done a number  of autocrosses in the past, and while enjoyable, I now want to move on to other events.

My first thoughts were to follow a straight Corvette approach.  I modeled and built a "Jim's Giovanni" some documents elsewhere in this forum, and then realized I wanted to eliminate the standard C3 Trailing Arms too.

My research led me to a number of alternative approaches.  One, mount a C4 rear suspension to the C3.  That has been done successfully by others, but not quite the engineering challenge I guess I was looking for.

http://i44.tinypic.com/t8p8qf.jpg



Another approach build a mounting structure (subframe) for a C5 or C6 IRS for my C3.  Not done yet really, but very do-able.  Unfortunately, my investments in a new set of 1/2 shafts (telescoping), rear differential(4.11), brakes, bearings, and spindles, sort of ruled out using a used bit of C5/6 gear.

But this research did lead me to settling on a double wishbone approach.  The question still remained, "What uprights to use?"

In the Corvette-only approach the viable uprights are based on the C3 bearing carrier.  The Greenwood,

http://i39.tinypic.com/3vldu.jpg


http://i39.tinypic.com/14kjdqd.jpg



and Pier Palou's approach (Stroker-427)

http://i39.tinypic.com/55h5vq.jpg


http://i41.tinypic.com/9rhvk9.jpg


approaches both improve the rear suspension, and still use the bearing carrier - more or less.


More results to come!
Cheers - Jim


UNDERCONSTRUCTION! Highly Modified C3 Corvette
         Dual Wishbone IRS w Subframe + Custom Uprights
 

2/07/2012 3:56 pm  #2


Re: IRS UPRIGHTs

http://i39.tinypic.com/waj6g0.jpg

Continuing my review of options, I have been frequenting the LOCOST Forums. 

http://i40.tinypic.com/ibjbrd.jpg
 
BTW, This chap has a complete layout on the LOCOST site for the entire build! (FREE!)

These are DIY-ers from around the globe building their own cars, some race. 

http://i41.tinypic.com/2vaman9.jpg

http://i39.tinypic.com/1pcvn7.jpg


Most all scratch built and somewhat replicate the Lotus Super 7 -- a car I always wanted to buy. 
http://i39.tinypic.com/8xlv2t.jpg

http://i40.tinypic.com/or5dsn.jpg


There I came across a number of approaches to the uprights - many have some distinct advantages too.
http://i41.tinypic.com/35mmio6.jpg


http://i41.tinypic.com/2itlbgp.jpg



On the down side, the LOCOST approaches, tend to be a bit low powered,
so some engineering may be required for structural integrity, and occasionally the projects go on forever - no time limit.


Again - more to follow on this review of Upright approaches!

Cheers - Jim

Last edited by phantomjock (2/07/2012 3:57 pm)


UNDERCONSTRUCTION! Highly Modified C3 Corvette
         Dual Wishbone IRS w Subframe + Custom Uprights
     Thread Starter
 

2/07/2012 4:07 pm  #3


Re: IRS UPRIGHTs

The LOCOST, being a "plans-only" approach, there naturally other  examples out there. 
In my research of other similar efforts, I came to the GT40,
http://i39.tinypic.com/15re006.jpg


http://i39.tinypic.com/2952s04.jpg


A Scratch-Built  Lola,
http://i44.tinypic.com/1b0q0.jpg


a Hemi-equipped Pantera in Sweden

http://i40.tinypic.com/28ku1wo.jpg

http://i39.tinypic.com/15whwly.jpg


Even the venerable COBRAs (smile Ralphy!)  OOPs it wouldn't post --

Each of these have some interesting Design Attributes for  consideration in choosing what shape or style of upright for my IRS.


Again, time limits are not always imposed on these self-initiated projects, but cost is frequently a  major consideration.


Just a few more to go!

Cheers - Jim


UNDERCONSTRUCTION! Highly Modified C3 Corvette
         Dual Wishbone IRS w Subframe + Custom Uprights
     Thread Starter
 

2/07/2012 4:17 pm  #4


Re: IRS UPRIGHTs

Continuing on a quest again for more innovation, the Formula SAE challenge yielded some fruit as well. 
http://i39.tinypic.com/200aa1k.jpg


In this college and university engineering students design their race cars.

http://i43.tinypic.com/15nt79g.jpg


They need to keep  costs down, being innovative,

http://i43.tinypic.com/4udqqc.jpg


very competitive, and there is always the opportunity for some breakthrough thinking.

http://i40.tinypic.com/n1tti1.jpg



The FSAE program is on a time schedule but the students frequently have access to some high quality machining and top of the line software for analysis.
http://i39.tinypic.com/2wh2ww8.jpg


OK - One more lap!

Cheers - Jim


UNDERCONSTRUCTION! Highly Modified C3 Corvette
         Dual Wishbone IRS w Subframe + Custom Uprights
     Thread Starter
 

2/07/2012 4:29 pm  #5


Re: IRS UPRIGHTs

My last set of Uprights I chased down were those designed from the get-go as race equipment. 
http://i44.tinypic.com/2vx2b8o.jpg



They are off the shelf.   
http://i39.tinypic.com/16k6gid.jpg


Naturally, they tend to  work. 
http://i44.tinypic.com/15fipv5.jpg


After all, if your business is to build a race part - if you want to stay in business--it had best work and not fail first time out.
http://i40.tinypic.com/qqppn9.jpg


They tend to be high end designs, innovative, and a bit expensive.   As a design effort some could be replicated with a bit of skill.

http://i39.tinypic.com/spvfb5.jpg

Now, If I planned on a Land Speed Record - I'd want that one from Project Bloodhound!!

So, there is a start at Upright designs I found.  Please add more as you find them. 
I focused on REAR only, but realize many of the same design attributes that make a good front upright can be used in the IRS too. 
Note the Corvette C5 and C6!

Cheers - Jim


UNDERCONSTRUCTION! Highly Modified C3 Corvette
         Dual Wishbone IRS w Subframe + Custom Uprights
     Thread Starter
 

2/08/2012 7:27 am  #6


Re: IRS UPRIGHTs

PJ,
Do you have a link to this guys postings at Locost? I don't know why but both my computers crash on some pdf files. Anyone else have this problem? I think it may be older formats.

I think I found a way to view Rorty.
http://www.docstoc.com/docs/52473993/Rorty-Locost-IRS-Assembly

http://i40.tinypic.com/ibjbrd.jpg

Last edited by Ralphy (2/08/2012 8:48 am)

 

2/08/2012 3:09 pm  #7


Re: IRS UPRIGHTs

http://locost7.info/mirror/suspension.php

About 1/2 way down - download the pdf then open it?
Maybe a browser problem not supporting the pdf extension.  If mozilla/firefox theyu have a plug-in available.

Cheers - Jim


UNDERCONSTRUCTION! Highly Modified C3 Corvette
         Dual Wishbone IRS w Subframe + Custom Uprights
     Thread Starter
 

2/08/2012 3:40 pm  #8


Re: IRS UPRIGHTs

That page, I have been there before. In fact it looks like I had opened it once.

It does the same with FF or Explorer. Acrobat Reader would not update for the last two months. Saying I had no authority. Today I got the update loaded. Runs longer but still locks up. I got a message after two minutes Acrobat Crash? I don't know? I do have a 64 bit PC.

Some PDF's open some don't?

Last edited by Ralphy (2/08/2012 3:43 pm)

 

2/09/2012 6:48 pm  #9


Re: IRS UPRIGHTs

there is something  about this one that really speaks to me.  I like the quality and the obvious DIY aspect
http://i41.tinypic.com/2itlbgp.jpg


If it isn't broken..... modify it anyway!!!!
http://dazed.home.bresnan.net/JagArmssignature.jpg
 

2/09/2012 7:14 pm  #10


Re: IRS UPRIGHTs

Me too - I'm going to get some foam core this weekend and do some "folding" origami exercises. 
I want to mount with double shear but I like the depth for wheel offset too.  Its a nice build.
The integrated caliper mount is a sweet idea too.  He's done a bit of thinking for many of us!

Cheers - Jim


UNDERCONSTRUCTION! Highly Modified C3 Corvette
         Dual Wishbone IRS w Subframe + Custom Uprights
     Thread Starter
 

2/10/2012 9:51 am  #11


Re: IRS UPRIGHTs

Looks like his caliper and rotor are not matching up? Unless he plans to run bigger rotors. The C3 Calipers are big /long. Think that Wilwood is big enough for a Vette Jim? I wondered if the C3 rears were a little over stated in size?

Ralphy

Last edited by Ralphy (2/10/2012 9:56 am)

 

2/10/2012 2:56 pm  #12


Re: IRS UPRIGHTs

Good eye - the caliper does look a little oversized for that rotor.
I think there is always room for more stopping power.  Also, note the trend to putting C6 rotors/calipers on c3s too.
My Aerospace aren't as large - but will be adequate.  The caliper mount as part of the upright is a clever bit of design too.


UNDERCONSTRUCTION! Highly Modified C3 Corvette
         Dual Wishbone IRS w Subframe + Custom Uprights
     Thread Starter
 

2/11/2012 12:43 pm  #13


Re: IRS UPRIGHTs

Yep looks like the diameter is off by about 2" but I am sure whats in the pic is just there for mock up.  As to the wilwood parts I am a wilwood dealer and can hook you up with anything wilwood sells, at good price so let me know if you need anything.


If it isn't broken..... modify it anyway!!!!
http://dazed.home.bresnan.net/JagArmssignature.jpg
 

2/15/2012 6:23 am  #14


Re: IRS UPRIGHTs

I have a pair of billet aluminum upright blanks that I had waterjet cut if anyone is interested in them. I had them made up similar to the layout of the T-Bird but flat, I think the billets are a little over 2" thick. They need to be finish machined of course. I'll take a hundred bucks plus another 25 for shipping for them, which is less than they cost me. When I decided not to use a top link they became redundant but I figure it would be a good start for one of you guys.

Jim

 

2/15/2012 6:30 am  #15


Re: IRS UPRIGHTs

Can you post a picture Jim? What type of material are they made of?


Ralphy

Last edited by Ralphy (2/15/2012 6:47 am)

 

2/15/2012 4:47 pm  #16


Re: IRS UPRIGHTs

Yes! Pictures Please. And details! 
I sense a bidding war?
Also, if you could  offer some dimensions too. 
Maybe a diagram/engineering drawing used for the water jet setup?

Cheers - Jim


UNDERCONSTRUCTION! Highly Modified C3 Corvette
         Dual Wishbone IRS w Subframe + Custom Uprights
     Thread Starter
 

2/16/2012 3:28 pm  #17


Re: IRS UPRIGHTs

http://i40.tinypic.com/8ye5bc.jpg

I've got no clue what ever happened to the cam file and don't recall dimensions except that they were rough-out dim to match the Ford parts. Hope this works, I laid a yardstick across one of them.

Jim

 

2/16/2012 4:12 pm  #18


Re: IRS UPRIGHTs

Hey Jim
Thanks for posting.  They look plenty stout. 
I bet someone will find a good home for them too.
Cheers - Jim


UNDERCONSTRUCTION! Highly Modified C3 Corvette
         Dual Wishbone IRS w Subframe + Custom Uprights
     Thread Starter
 

2/16/2012 4:38 pm  #19


Re: IRS UPRIGHTs

I was hoping for enough meat at the outer bearing to use the C3 bearing. But? Looks a little close don't you think PJ? The size I am referring to is the OD, looks to be app. 4".

You can put the pic and description in the classified section also.

Ralphy

 

2/17/2012 5:46 pm  #20


Re: IRS UPRIGHTs

Ralphy, the OD of the bearing boss area is 4-1/2" plus maybe ten. What is the diameter of your C3 bearings?

Jim

 

2/18/2012 9:23 pm  #21


Re: IRS UPRIGHTs

Ralphy? You there?

Jim

 

3/02/2012 9:40 am  #22


Re: IRS UPRIGHTs

I couldn't find that other post. Anyway if the hub bearing BC is 4 to 4.25" it should work out depending on the bolt size. I measured the distance from the bearing bore to the LCA pivot and 2-1/4" would put everything at about center. Of course it could be moved up or down about +- 1/2" or so. Distance to the UCA pivot would be about 4 to 6". These could be sculpted and polished into extremely nice show pieces if someone wanted to take the time to do it, and like I mentioned they were intended for inboard brakes and maximum length control arms to get as much suspension travel as practical.

Jim

 

3/02/2012 2:21 pm  #23


Re: IRS UPRIGHTs

Jim,
If my BC was 4" and the bolts were 3/8". The outer edge of the 3/8' tapped holes would be 4 3/8". Looks to me like you have an OD of 4 3/8" to 4 5/8". Then I would have to counter bore or pocket the ID out to at least 4 5/8" I'm guessing. To clear the bolt head. That leaves little to none for wall thickness.

Here is a pic of an aftermarket upright, you can see I would need more like 5" plus OD.
http://finnshark.com/gallery/displayimage.php?imageid=2847


Ralphy

Last edited by Ralphy (3/02/2012 2:35 pm)

 

3/02/2012 4:09 pm  #24


Re: IRS UPRIGHTs

You got a better link to that - and the aftermarket source?
Not fond of the "mounting in single sheer" but nice looking product. 
Looks ready-madefor a C3 application too.

Cheers - Jim


UNDERCONSTRUCTION! Highly Modified C3 Corvette
         Dual Wishbone IRS w Subframe + Custom Uprights
     Thread Starter
 

3/02/2012 4:30 pm  #25


Re: IRS UPRIGHTs

Yes, go to the chevy IRS thread. Fourth post, with link and all. Dick Guldstrand design. And yes it is a C3 swap. I also see they raised the price, it was $2,700 now $3,300. It's sold as a leaf or coil-over design. However TT at VM said they told him not to use the coil-over setup.

Last edited by Ralphy (3/02/2012 4:37 pm)

 

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