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8/02/2012 2:38 am  #31


Re: IRS UPRIGHTs

http://i48.tinypic.com/10xh53n.jpg




As the rest of the posts indicated in CorvetteForum; "...they are used in racing to ensure equal tire loading. They are adjustable to ensure equal rear tire loading during launch to keep the lift of both front corners equal."

Rotating the pic 90 degrees - you can see it is more a Trailing Arm replacement and not so much an upright, per se.  Looks like a means to provide some castor/anti dive/anti squat by making adjustments independently to the heims.  And, that would be useful on launch at the drags and much like a 4-link.  I expect he went with the standard lower strut rods attached tot he C3 bearing support and the leaf spring to the trailing "tang" .  And of course the half shafts would be loaded components of the IRS.

This setup would still suffer from the C3's toe change as the single attachment point to the chassis doesn't have the 2 points like a 4 link.

Interesting find Ralphy. 

Cheers - Jim


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

8/02/2012 3:36 am  #32


Re: IRS UPRIGHTs

Ralphy wrote:

It occurred to me recently that most modern high performance manufacture IRS suspensions have a common trait. Which is a single mounted upright at the LCA and the UCA and they all use a separate toe rod behind the halfshaft. Cars included are the Corvette, Cobra Mustang and Dodge Viper. Reasoning may be to remove any twisting of the upright with higher powered motors. Corvette has been using this type of toe control since the C4.  Just thought I would throw that out there.

Ralphy

The C-4 Corvette used an adjustable toe rod, but it did not use an upper/lower control arm setup. Instead it used a double trailing arm setup similar to 4-link.

C-5 was the fist year for the upper/lower control arms.

Shiny Side Up!
Bill


Check out my latest project, "In the Company of Devils" at www.WilliamKElliott.com
 

8/02/2012 5:01 am  #33


Re: IRS UPRIGHTs

ProTouring442,

Yes I understand that, however it still used a separate toe rod behind the HS. I just became aware of the fact most of the higher output OEM cars use this design controlling toe directly behind the HS. This position would seem to me the best in controlling any flexing in the upright. The  C4 I guess under hard acceleration would want to draw the HS's inward.

If you mark the positions of the uprights pivot points say Jag Vs. C5, the triangle has a horizontal base with the Jag. The C5's points are rotated 90 degrees and of course the HS is no longer a stressed point. Ive always noticed this fact but however again I never really noticed this design in parallel to power.

Roadster Shop with C5 Uprights Rated For 1400 HP
http://img849.imageshack.us/img849/4060/screenshot20111116at915.png

http://www.roadstershop.com/products/suspension-independent-rear-unit

Ralphy

Last edited by Ralphy (8/02/2012 5:36 am)

 

8/02/2012 6:40 am  #34


Re: IRS UPRIGHTs

Ralphy wrote:

ProTouring442,

Yes I understand that, however it still used a separate toe rod behind the HS. I just became aware of the fact most of the higher output OEM cars use this design controlling toe directly behind the HS. This position would seem to me the best in controlling any flexing in the upright. The  C4 I guess under hard acceleration would want to draw the HS's inward.

If you mark the positions of the uprights pivot points say Jag Vs. C5, the triangle has a horizontal base with the Jag. The C5's points are rotated 90 degrees and of course the HS is no longer a stressed point. Ive always noticed this fact but however again I never really noticed this design in parallel to power.

Got ya...

I'm not sure it's really all about power, or if packaging and cost aren't in there somewhere. The ability to make the more complex systems work, coupled with the customer's demands perhaps? I say this because the C-2/C-3 sure had some high HP models (L-88 for example) in conjunction with the same old C-2 design. There are also NVH issues that the newer design alleviates. High HP or no, the modern consumer will not tolerate the same NVH the buyer of a C-3 or older Corvette found to be perfectly acceptable.

As far as packaging for a retrofit, I don't think you can beat the C-4 trailing arm design. Since it still uses the halfshaft as the upper control arm, you don't have the frame clearance issues you would have with a more "modern" design.

Shiny Side Up!
Bill


Check out my latest project, "In the Company of Devils" at www.WilliamKElliott.com
 

8/02/2012 2:37 pm  #35


Re: IRS UPRIGHTs

ProTouring442 wrote:

As far as packaging for a retrofit, I don't think you can beat the C-4 trailing arm design. Since it still uses the halfshaft as the upper control arm, you don't have the frame clearance issues you would have with a more "modern" design.

Not really a fan of that myself - but to each his own.
The shortcoming in the C3 is the toe variation.  That can be overcome by modifying to a 4 link and more than a few do.
But the half shaft as a loaded member is just asking for trouble - if you max perform the vehicle.  Sooner or later - you'll loose it.

C5 or C6 would be a better  Corvette choice for an IRS  - IMHO,   But I'm on my own design/build and trying to take even those "One Step Beyond." And you are entirely correct - the frame does make a real clearance problem.  I've solved that with a hacksaw.  As the build progresses - I'll start loading pics in a separate thread.

Cheers-Jim


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

8/02/2012 3:12 pm  #36


Re: IRS UPRIGHTs

phantomjock wrote:

ProTouring442 wrote:

As far as packaging for a retrofit, I don't think you can beat the C-4 trailing arm design. Since it still uses the halfshaft as the upper control arm, you don't have the frame clearance issues you would have with a more "modern" design.

Not really a fan of that myself - but to each his own.
The shortcoming in the C3 is the toe variation.  That can be overcome by modifying to a 4 link and more than a few do.
But the half shaft as a loaded member is just asking for trouble - if you max perform the vehicle.  Sooner or later - you'll loose it.

C5 or C6 would be a better  Corvette choice for an IRS  - IMHO,   But I'm on my own design/build and trying to take even those "One Step Beyond." And you are entirely correct - the frame does make a real clearance problem.  I've solved that with a hacksaw.  As the build progresses - I'll start loading pics in a separate thread.

Cheers-Jim

Of course, altering the C-3 to a 4-lonk design is, in effect, making it a C-4.

I don't think I agree that the using the halfshaft as a loaded member is such a bad idea. From the L-88 to the '90-'95 ZR1, Chevrolet used such a setup with no difficulty. True, I wouldn't throw 1,000hp at it, but I think anything 600hp or less (at the crank) should be OK for a "hotrodded" IRS.

As for the hacksaw, I am going IRS in a '72 Olds 442. I think I would need to basically "back half" the car to go with a C-5/C-6 style setup. If I were going to do that, I would have gone with a custom frame... first I would need the bucks to spring for that 20K frame though! :D

Shiny Side Up!
Bill


Check out my latest project, "In the Company of Devils" at www.WilliamKElliott.com
 

8/02/2012 5:22 pm  #37


Re: IRS UPRIGHTs

Copy - and as I've mentioned before-- the suspension loads are primarily on the LCA - and so the Half Shaft gets a bit of a "pass."  Until it fails.
As for me the "hot rod" value is getting it right my way.  "Pro-touring", and this is only my second IRS mod, I'm taking a bit of a "use what I have," and mod what I need. And, I can do for a significantly less value than the $20K.  If you wanted to, I bet you could do a Team321IRS install  for 5-10% of that!  And they did all the work but the cut and install!

Yep, a complete new chassis could be in order - but for that, I'd prefer to build the entire car, chassis, body, etc.  Think I'll be saving that for a Formula 600/Ford/Mazda/Terapin/etc  approach - a purpose-built road racer - not an adaptation. 

Cheers - Jim
Cheers - Jim


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

8/02/2012 5:33 pm  #38


Re: IRS UPRIGHTs

phantomjock wrote:

"Pro-touring", and this is only my second IRS mod, I'm taking a bit of a "use what I have," and mod what I need. And, I can do for a significantly less value than the $20K.  If you wanted to, I bet you could do a Team321IRS install  for 5-10% of that!  And they did all the work but the cut and install!

Cheers - Jim

20K was a full Roadster Shop frame with C-5/C-6 front and rear suspension. And believe me, if I ever have the money (got to get those books finished!), I will be contacting them. Probably for the whole build!

I'm going to use a Jag center with C-4 halfshafts, uprights, trailing arms, etc. C-6 Z06 brakes. It's more of a Pro-"Grand Touring" car really. 6-way power seats, tilt/tele, custom console, nice stereo, etc. A bit of American Muscle Car meets BMW M6 I guess.

I'm looking forward to seeing what you come up with!

Shiny Side Up!
Bill


Check out my latest project, "In the Company of Devils" at www.WilliamKElliott.com
 

8/06/2012 6:37 pm  #39


Re: IRS UPRIGHTs

Bill different but mechanically similar, the C2/C3 does control toe from a horizontal plain as the C4. Except from the front of the trailing arm. Which has two, no at least three shortfalls. The wheels toe outward with travel and the rubber bushings allow the arm mounts to move under loading and last, any suspension motion shortens the wheelbase. I've read enough posts where knowledgeable guys have drove both versions and they say the C4 is vastly superior.

Have you seen Pier's C3 conversion? Goes by Stroker 427 and he is in Italy. He can change his roll steer by moving the toe rod up or down at the upright. Also he removed the HS as a  stressed member adding an upper link.
http://www.vettemod.com/forum/showthread.php?t=3126&page=4

By the way your ride is awesome, stealth NOT! LOL!

Ralphy

Last edited by Ralphy (8/06/2012 6:51 pm)

 

8/06/2012 6:50 pm  #40


Re: IRS UPRIGHTs

Ralphy wrote:

Bill different but mechanically similar, the C2/C3 does control toe from a horizontal plain as the C4. Except from the front of the trailing arm. Which has two, no at least three shortfalls. The wheels toe outward with travel and the rubber bushings allow the arm mounts to move under loading and last, any suspension motion shortens the wheelbase. I've read enough posts where knowledgeable guys have drove both versions and they say the C4 is vastly superior.

Have you seen Pier's C3 conversion?

By the way your ride is awesome, stealth NOT! LOL!

Ralphy

Thanks for the compliment!

I haven't seen (or maybe haven't seen) Pier's conversion... is it on this board?

I pick up my Jag center on Thursday, and my 'Vette halfshafts/uprights/etc are on their way! Woohoo! LOL

Shiny Side Up!
Bill


Check out my latest project, "In the Company of Devils" at www.WilliamKElliott.com
 

8/06/2012 6:52 pm  #41


Re: IRS UPRIGHTs

Yes, I added a link. Plus type above.

Always fun getting new parts.

Ralphy

Last edited by Ralphy (8/06/2012 6:55 pm)

 

8/04/2013 9:47 am  #42


Re: IRS UPRIGHTs

Its hot outside - and I bet everyone is having a great time enjoying the summer with their IRS builds!
I'm working on the Garage remodel - and while taking an Air Conditioned break from the heat, I came across a couple of interesting suspension ideas for your consideration:


http://i39.tinypic.com/34zk188.jpg


That is a great pic of the front suspension for the Dodge Tomahawk - an 8 cylinder 4 - wheeled "scooter." 
The rear  (IRS) information is a bit spotty but came across this:
http://i44.tinypic.com/2uh35dv.jpg


And the "Type 1" has an interesting camber approach to consider:
http://i43.tinypic.com/282gp68.jpg



Enjoy - I gotta get back to the ceiling!

Cheers - Jim


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

10/22/2013 10:39 am  #43


Re: IRS UPRIGHTs

Thought I'd post what I'm doing here too - (also over on my build thread) but this is what is happening with the  C5 Corvette Uprights:
http://i44.tinypic.com/11bmg01.jpg

On order are;
1.  the new Ball joints (GM K6141  - to standardize)
2.  a reamer for the 10 degree/2 inch per foot taper to use on lower mount on upright
3.  2 of the ball joints are weld-in bodies (Coleman calls them "Integral") they go on LCA
4.  2@ "Spindle Eyes" for the upper mount - will weld-in the plates on UCA.
5.  8 fixed eye QA-1 clevis- ends RH 3/4-16  -- through bolted on the plates
6.  8 3/4" Rod Ends LH 3/4'-16 - for the inboard ends
7.  A pile of cone spacers, bolts, washers, etc

I have (on hand 8 feet) of hex tube to tap for the control arms.
I've got to fabricate the plates and am making plywood prototypes today...

I'm about to pull the trigger on new wheel bearings (SKF) are expen$ive!  But better than trying to replace trackside I guess.

Cheers - Jim


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

10/22/2013 5:42 pm  #44


Re: IRS UPRIGHTs

How much did the reamer cost?

Ralphy

 

10/24/2013 2:23 am  #45


Re: IRS UPRIGHTs

Its over a hundred bucks. 
I could have done some more shopping around - but everywher I check it was about the same.
It thought about taking to a machinist - but that would be that at least.
Wazup - need to borrow one?  Let me know. 

Cheers - Jim


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

10/24/2013 6:29 am  #46


Re: IRS UPRIGHTs

Ouch!
But I figured as much, yeah, consider that cheap. That's a rare animal, even in a machine shop. I'm guessing it's made of HSS/High Speed Steel. Charish it like a child always use a cutting oil and spin it slow maybe 50 RPM. I may need to rent it someday!

Ralphy

Last edited by Ralphy (10/24/2013 6:29 am)

 

10/24/2013 6:48 am  #47


Re: IRS UPRIGHTs

Just like me to think of it later. I have three EDM machines at my disposal. Turrning an electrode or two is a snap. Duh!

Ralphy

 

10/24/2013 3:18 pm  #48


Re: IRS UPRIGHTs

Hey Ralphy - Wanna cut some steelplate (3/16 or 1/4) for those 8 pieces I'll need to make the upper and lower ball jint attachments?  The RED plates in the diagram.  I can provide pdf, stl, stp, gcode (but out of practice).  My drawing is Rhino - but can export. 

Interested in making some pocket money over lunch?

Cheers - Jim


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

10/24/2013 5:08 pm  #49


Re: IRS UPRIGHTs

What's the width and length? Also how many pieces? I'll do as a favor! One issue is if it needs lots of band saw work, I don't have a decent b saw near by.

Ralphy

Oops I see, 8 pieces as I counted. All I need is a sketch. Can you supply the 8 separate pieces near size? 3/16 would seem a ok thickness to me, are you welding the two pieces together at the balljoint with solid round? 1020 CRS?

Last edited by Ralphy (10/24/2013 5:23 pm)

 

10/24/2013 5:55 pm  #50


Re: IRS UPRIGHTs

Cool - We can take this off line to PM.  I  need to get the Ball Joints (Coleman Wed-In place)  in to spec the holes for the lowers and the ""weld-In" "SLUGS" for the ppers.  Shortly -- I hope - shipping says tomorrow.  Then we can look at the drawings and see if do-able. 

Cheers - Jim.
 


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

10/25/2013 1:14 am  #51


Re: IRS UPRIGHTs

Check your Inbox.

Ralphy

 

10/25/2013 7:52 am  #52


Re: IRS UPRIGHTs

But guys, if you take this discussion to a PM, we won't have nail biting updates http://cdn.boardhost.com/emoticons/tongue.png

Just kidding.
Post pics when you're done, this should look great!

 

10/25/2013 1:17 pm  #53


Re: IRS UPRIGHTs

Now where's the like button on this site?

Ralphy

 

10/25/2013 2:27 pm  #54


Re: IRS UPRIGHTs

Ralphy pointed out - I didn't show the shock/spring mount -- here is an update for that:


BTW - there are some great discussions over on the Lateral-G.net regarding suspensions too.  Ken sutton knows his stuff!  Here are the three key stickies if you are interested:

1.  Overview of handling and his background  -- http://www.lateral-g.net/forums/showthread.php4?t=42423

2.  IRS - very key for this forum -- http://www.lateral-g.net/forums/showthread.php4?t=42568

3. for the front end -- http://www.lateral-g.net/forums/showthread.php4?t=42467

Cheers - Jim

Last edited by phantomjock (10/25/2013 2:27 pm)


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

10/25/2013 2:43 pm  #55


Re: IRS UPRIGHTs

http://i39.tinypic.com/2lxedfl.jpg


Added the Pushrod and widened the plates - help ensure no interference.
CAD is nice to sort out these details - but it pays to build a prototype - I'm using 1/8" ply for the plates and will bolt up this weekend to see where we are.

There is a SIGNIFICANT challenge with using C5 - or C6 uprights.  They are meant to be replaced if/when the ball joint goes bad.  And there are NO replacement Ball Joints to be had - buy a new UPRIGHT!  What Idiot thought that up?!!

Well, leave it to DIY and AI (American Ingenuity): one fellow came up with this creative approach - that I will copy for the upper BJ:

http://i42.tinypic.com/ae2yva.jpg
That is an aluminum "slug" milled to press fit into the Upper Ball Joint Reciever, then drilled/tapeered for the Ball Joint - pretty cool huh?  I'll be copying that approach.  Here is his upright set up:
http://i41.tinypic.com/30wlc88.jpg


Cheers - Jim


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

10/25/2013 6:36 pm  #56


Re: IRS UPRIGHTs

phantomjock wrote:

There is a SIGNIFICANT challenge with using C5 - or C6 uprights.  They are meant to be replaced if/when the ball joint goes bad.  And there are NO replacement Ball Joints to be had - buy a new UPRIGHT!  What Idiot thought that up?!!

Much of this has to do with pressing the ball joint in and out of aluminum. Many auto manufacturers who use aluminum arms or uprights do not sell the joints as serviceable parts. My BMW M5 (E34) has aluminum control arms in the front suspension and the ball joints are not replaceable for that reason.

I would think, to properly replace them, you would have to do as I must when replacing the bearings in my Triumph Bonneville's engine cases, heat up the aluminum until the bearing (or in the case of the control arm or upright, the ball joint) nearly falls out or drops in. Otherwise, pressing them in may gall the aluminum to the point where the interference fit is of too little tension.

Just my .02... take it for what it is worth.

Bill
 


Check out my latest project, "In the Company of Devils" at www.WilliamKElliott.com
 

10/26/2013 3:24 am  #57


Re: IRS UPRIGHTs

Jim, that's what I'm talking about in your new drawing. Do you think putting the pushrod on top of a multi-part A-arm, may flex and possibly fatigue the clevis area? Would it be better to have a welded one piece at the outer lower A-arm? Or second, somehow mount the pushrod on/to the upright?

ProTouring442, good post!http://cdn.boardhost.com/emoticons/happy.png


Ralphy


http://oi39.tinypic.com/2lxedfl.jpg

Last edited by Ralphy (10/26/2013 4:20 am)

 

10/26/2013 3:50 am  #58


Re: IRS UPRIGHTs

SO that may well explain the number of C5 uprights that are routinely for sale on eBay.  Not all from wreckers - just left overs following replacement for a bad ball joint.  Also, I  suppose the system doesn't encourage ball joint replacement (using heat as you have suggested - for liability reasons - and so no replacement ball joint is made available.  It has been declared Non-Servicible and the lawyers would love to sue  if some shop did replacements!

That TR-Bonneville wouldn't be the same as Steve McQueen's ride in the Great Escape, would it Bill?

Cheers - Jim


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

10/26/2013 4:12 pm  #59


Re: IRS UPRIGHTs

phantomjock wrote:

SO that may well explain the number of C5 uprights that are routinely for sale on eBay.  Not all from wreckers - just left overs following replacement for a bad ball joint.  Also, I  suppose the system doesn't encourage ball joint replacement (using heat as you have suggested - for liability reasons - and so no replacement ball joint is made available.  It has been declared Non-Servicible and the lawyers would love to sue  if some shop did replacements!

That TR-Bonneville wouldn't be the same as Steve McQueen's ride in the Great Escape, would it Bill?

Cheers - Jim

Well, that one was doctored up a bit to look like a Wehrmacht BMW. Mine, on the other hand, is currently in several pieces...

But sometime in the next five years, if all goes well, it will be back together and better than ever. 270 degree crank, Yamaha XS650 dual disc front end (properly doctored of course), and a custom electric start system. Why? Because just like my Jeep and my 442, I simply cannot leave well enough alone.

On a related note, my wife says she is quite happy that women do not come apart for modification so easily...

Bill
 


Check out my latest project, "In the Company of Devils" at www.WilliamKElliott.com
 

11/30/2014 4:03 am  #60


Re: IRS UPRIGHTs

Over the past few years there has been a minor movement to DIY/CNC manufacturing of Alumiinum Billet Uprights.  The nice part about some of the designs, they can be modular and assebled rather than welded saving on fabrication, and easing manufacturing complexity.  This is a set built by a fellow who is building a Formula 1000.  Ok it weighs between 1000-1400 pounds wet, but the DIY work was done without a CNC as I understand.

Cheers - Jim
http://i58.tinypic.com/2ldu73b.jpg


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

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