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4/22/2014 7:20 am  #1


Custom IRS

Hello everyone I am new to the site. It has poped up several times in my search for answers online.

I am currently building a hot rod and would like to go with an independant rear suspension. I am not interested in salveging parts from a wrecing yard I would like everything to be new pieces.
however I am not excited about the products available from many of the purpose built guys, like Heidts, Kugel etc. These guys have some design qualitys I like but just dont have the look I am after.

I was hoping to get some help form you guy here.

what I am looking to build is a suspension that uses a Winters quick change center, and had outboard brakes, I personally prefer this look. I would prefer to use half shafts over CV but am open to thoughts on this one. I will not be producing more than 400HP likely closer to 350.

What I am looking for is some basick setup information on a JAG style, In order to buld my own.

I have found a paper from LVVTA on Jag swap basics whish is a very good outline on pivot points and what to watch out for and what to avoid in terms of suspensoin bind.

What I am looking for is:

Is there somone else other than Dutchman Rearends that builds and sells yoke style hub carriers for outboard brakes?

basic geomety for carrier/control arm/half shaft
should the lover control arm be level at ride height? should the yoke of the carrier be directly in line with the yoke in the Diff or should there be some built in angle when at ride height?
do the same rules apply to the pinion (matching pinoin andgle to engine driveline angle, 3down3up?)
I am planing to build a lower arm similar to that found in the heidts and Kugel suspensions with the forward mounted radius rod and pinion support.
ANt information would be great guys Thanks in advance.

 

4/22/2014 4:53 pm  #2


Re: Custom IRS

Wow! Now here's a guy who's done some homework! Damn so many good questions. Let's start off with, welcome longhornss. Many of your answers are here. Try using the search feature first off.

Next, should the lca be level? According to many here, yes. Your next question I'm guessing refers to half shaft angle? When the lca is level the HS should be uppward at the wheel. Refrence univesal joints best angle, 3 degrees. Now let me add, Corvette C3 runs their HS's level app. Zero degrees.  And the lca downward out. Pinion, at parallel to trans but 3 degrees univesal angle front and rear matched. Radius rod should be inline to the inner pivot point of the lca.

Ralphy

Last edited by Ralphy (4/22/2014 4:56 pm)

 

4/22/2014 5:07 pm  #3


Re: Custom IRS

https://www.infrastructure.gov.au/roads/vehicle_regulation/bulletin/street_rod.aspx
Here's a good primer which cover Jag. You need to find the sections.
Also check out the links on all my posts, lots of good stuff.

Are you wanting to use 1 or 2 coilover per side?

And I also have links for a Jag racing improvement which adds a Watts link Created for the AC Cobra guys. Maybe your unaware they probably have adapted more Jag IRS's to cars than any other group. Check out Club Cobra and be sure and use the search feature. Search Watts link. And no not the gay Club Cobra site! LOL

Ralphy

Last edited by Ralphy (4/22/2014 5:27 pm)

 

4/22/2014 5:24 pm  #4


Re: Custom IRS

http://s350.photobucket.com/user/acmjg/media/MOV04917.mp4.html

Watts video.

Have fun, that's a lot of stuff to go thru.

Ralphy

Last edited by Ralphy (4/22/2014 5:29 pm)

 

4/23/2014 5:06 am  #5


Re: Custom IRS

Ralphy wrote:

Wow! Now here's a guy who's done some homework! Damn so many good questions. Let's start off with, welcome longhornss. Many of your answers are here. Try using the search feature first off.

Next, should the lca be level? According to many here, yes. Your next question I'm guessing refers to half shaft angle? When the lca is level the HS should be uppward at the wheel. Refrence univesal joints best angle, 3 degrees. Now let me add, Corvette C3 runs their HS's level app. Zero degrees. And the lca downward out. Pinion, at parallel to trans but 3 degrees univesal angle front and rear matched. Radius rod should be inline to the inner pivot point of the lca.

Ralphy

Thanks Ralphy, I have been around cars my whole life and have set up plenty of drivelines but never in an IRS. My understanding is that a driveline like the 3 degrees due to wear characteristics of the U-joints. a static U-joint tends to wear more than a U-joint that works through a range of motion. ( a independant rear with a straight driveline would wear out uninversals faster than one that has the 3 degree angles built in) 
You are correct in saying I have done some homework but I know I have plenty more to do before I am confident in building my own custom setup.
Thanks again for the info I will be checking over the links you posted.
 

Last edited by longhornss (4/23/2014 5:15 am)

     Thread Starter
 

4/25/2014 2:27 am  #6


Re: Custom IRS

Here's a good image of a bind situation. The trailing link moves in an arc 90 degrees to the LCA. Pulling or pushing on the lower control arm.

http://car-from-uk.com/ebay/carphotos/full/ebay111305.jpg


http://car-from-uk.com/sale.php?id=10835

Here's a way to do away with any trailing link. The real issue is no control from above the Halfshafts. Once you pin/stop any fore or aft motion. The LCA can do it's job with less stress.
http://www.vettemod.com/forum/imagehosting/13874b40cb32b3277.jpg

Here's a more profesional look.
http://www.autotraderclassics.com/images/a/2011/09/10/66577797/0_1965_COBRA_006.JPG

http://www.clubcobra.com/photopost/data/500/CONTROL_ARM_COMPARISON.JPG

http://www.cobraracing.com/

http://irsforum.boardhost.com/viewtopic.php?pid=4811

Ralphy

Last edited by Ralphy (4/25/2014 2:46 am)

 

4/25/2014 2:42 am  #7


Re: Custom IRS

Here is a guy in NY posting here. With a quick change in a retired show car. Using a double wishbone design. All custom built.

http://irsforum.boardhost.com/viewtopic.php?id=574

http://oi41.tinypic.com/xf9n9i.jpg


Ralphy

Last edited by Ralphy (4/25/2014 2:45 am)

 

5/03/2014 4:14 am  #8


Re: Custom IRS

Ralphy wrote:

Here's a more profesional look.
http://www.autotraderclassics.com/images/a/2011/09/10/66577797/0_1965_COBRA_006.JPG

http://www.clubcobra.com/photopost/data/500/CONTROL_ARM_COMPARISON.JPG

I like the way this one looks.
Ralphy

 

     Thread Starter
 

5/03/2014 4:04 pm  #9


Re: Custom IRS

That's the cobraracing.com LCA.

[url=http://www.cobraracing.com/Images/XK2001_Big.jpg]http://www.cobraracing.com/Images/XK2001_Big.jpg


Upright

http://www.cobraracing.com/Images/XK2002_Big.jpg
[/url]

Ralphy

Last edited by Ralphy (5/03/2014 4:09 pm)

 

5/05/2014 2:13 am  #10


Re: Custom IRS

Ralphy -
Great updates while I've been away.  I have a lot of catching up to do. Those milled billet CAs are fantastic.

Cheers - Jim


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

5/05/2014 7:20 am  #11


Re: Custom IRS

I can't imagine how much those cost.
Still, nice, functional eye candy!

 

5/05/2014 5:07 pm  #12


Re: Custom IRS

Pretty to look at. However it looks to me like they weakened the design by putting the shock bolt through the center of the control arm. Thats the highest stressed area in that type of control arm. The design is all ready weakened by their choice to use aluminum.. The load path begins there and should have been the last place to drill a 1/2 inch hole. To have placed ears above or below the arm would have been superior. Ralphy posted a stock Jag LCA that cracked in half inches from the shock mount. The steel Jag control arms are pretty stout units.  Aluminum fatigues much faster than steel in high stress applications like Jag LCA's.  Pretty to look at, Poor design.Short service life.  

 

5/06/2014 3:39 am  #13


Re: Custom IRS

tyrellracing wrote:

Pretty to look at. However it looks to me like they weakened the design by putting the shock bolt through the center of the control arm. Thats the highest stressed area in that type of control arm. The design is all ready weakened by their choice to use aluminum.. The load path begins there and should have been the last place to drill a 1/2 inch hole. To have placed ears above or below the arm would have been superior. Ralphy posted a stock Jag LCA that cracked in half inches from the shock mount. The steel Jag control arms are pretty stout units.  Aluminum fatigues much faster than steel in high stress applications like Jag LCA's.  Pretty to look at, Poor design.Short service life.  

Well if you go to their web site. The design is used for racing applications, however? They also use only 1 coilover at the front. Which would increase the stress. So if your to go with double coilovers for the street?  Half the stress? Aluminums life varies dependent on what type used. One of lifes trade offs! I'm sure if you contacted them they would tell you what material they use and life expectancy.

The OEM Corvette C4 IRS is mostly aluminum! However not the same.

http://www.cobraracing.com/

What would concern me? If someone were to think they could use that LCA and not pin/control the upright above the halfshaft. Myself, I'll stick with steel.

http://www.clubcobra.com/forums/attachments/shop-talk/3221d1022819200-salisbury-billet-arm-link-anyone-amp-fullassylorzpg2.gif

http://image.kitcarmag.com/f/9117156+w750+st0/142_0505_daytona_09_z.jpg

Ralphy

Last edited by Ralphy (5/06/2014 12:49 pm)

 

5/11/2014 12:51 pm  #14


Re: Custom IRS

The likelyhood of failure is dependant on many factors. The most damaging would be vehicle weight and engine torque. When that is combined with sticky tires even Jag LCA's can fail.  I can see how these LCA's could survive happily under a Cobra with their light weight. I just see a weak load path where they chose to counter bore the CA with a 3/4 x 3/4 hole combined with I am assuming to be a concentric 1/2 inch hole with 1/2-13 threads.  I am well aware that Aluminum isnt free so they chose to go with a plate thickness that gave the most bang for the buck. It looks like 1.5"  6061 T6 plate using the parts around it for scale and guessing on the alloy.  2.5" plate would have provided enough material for the ears but that would be a high price to pay when the majority of the difference  would have ended up as shavings in the auger of their CNC mills chip evacuation system.  Ralphy, do you know off hand what the rear weight of an average Cobra is?  I am aware that question is vague but it would give me a starting point for some rough calculations.   I cant seem to find this info on line. No one seems to be willing to disclose F/R vehicle weights.only gross weight.  The company I work for now has just purchased a new Haas VF5, They allready had 2 VF4's 2 VF5's and a VF6. They are nice machines and opperator friendly. I have been spending the last 4 months getting my feet wet with the software. We do alot of 3D work with them for a testing lab near our location.  The control arms would be a piece of cake to make. Its kind of funny how people show so much intrest in parts that are so simple to make.  (access to the CNC mill is the hard part)  With a greater understanding of the G codes and general programming,  I can see how simple the Billet cobra would have been to make.  Nearly all of the machine work was done on two planes, X and Y. I didnt see any compounded curves anywhere on it.  Kind of like the the aluminum work supporting the quick change in the 68 vette. All done on two planes and as simple as CNC milling gets.  This is not an insult to these cars just an observation from a new understanding of the programming involved.  As far as the latest designs of Vette rear suspensions. They are all far superior to the Jag design. Period. No more BS half shaft UCA.  They resemble a front suspension with out the rack and pinion. Having an upper control arm, not a fake one that only supports one plane but a real wish bone three point CA makes them leap years ahead of the Jag design as well as the old type vette IRS. No argument.  There only draw back is packaging. They take up more space.

Last edited by tyrellracing (5/11/2014 1:12 pm)

 

5/11/2014 1:29 pm  #15


Re: Custom IRS

Tyrell, a good starting point weight wise would be 2,600 at the high. And almost all Cobras being 50/50 weight bias. So were at 1,300 lbs. Divided by 4 coilovers, were at 325 lbs. at each. Now 2,600 is high, you can easily lower weight to 2,100. Then as I mentioned before they have used this setup with 1 coilover per side.

As far as material type we can only guess unless we call. However 6061 T6 is not the strongest aluminum. Aircraft wings flex millions of times through their life span. We from what I've seen use 6061 and 7000 series. I forget the exact # on the 7000 but it must be 7075. I would call if I were interested but I'm not.

Anyhow read the diff.

7075 Aluminum
7075 is the other "aircraft grade" aluminum that is carried by OnlineMetals. Its principal alloying ingredients are zinc and copper, which make it one of the highest-strength aluminum alloys that are available. In fact, its typical strength in the T6 temper is higher than most mild steels. 7075 also has average-to-good ratings for machinability, corrosion resistance, and anodizing response. Like 2024, however, it is not considered to be weldable.

7075-T6 AluminumPhysical and Mechanical PropertiesUltimate Tensile Strength, psi83,000Yield Strength, psi73,000Brinell Hardness150Rockwell HardnessB87ChemistryAluminum (Al)87.1 - 91.4%Zinc (Zn)5.1 - 6.1% maxCopper (Cu)1.2 - 2.0%Chromium (Cr)0.18 - 0.28%Iron (Fe)0.5 maxMagnesium (Mg)2.1 - 2.9%Manganese (Mn)0.3% max

6101 Aluminum
6101 is best suited for applications involving moderate strength and maximum electrical conductivity. It is similar to alloy 6063, but with minor chemistry changes which enhance electrical conductivity. Although slightly lower in conductivity than alloy 1350, it offers greater strength. Its most typical application is bus bar.

6101-T6 AluminumPhysical and Mechanical Properties Ultimate Tensile Strength, psi32,000Yield Strength, psi28,000Brinell Hardness71Electrical Conductivity57% IACSChemistryAluminum (Al)97.6%Chromium (Cr)0.03%Copper (Cu)0.10%Iron (Fe)0.50%Magnesium (Mg)0.35 - 0.80%Manganese (Mn)0.03% maxSilicon (Si)0.3 - 0.7%Boron (Si)0.06%

http://www.onlinemetals.com/aluminumguide.cfm

Then let's go to Cobra Racings Statement

All of our Cobraracing™ products are race proven and built in-house on our own state-of the-art CNC mills. We use a very "nuts and bolts" approach to our engineering. No magic here. We have an idea. We build it. We install it on a real car. And we drive the heck out of it on a real track.We analyze the performance. Tear the thing down. Look at the wear on the parts. Go back to the drawing board. Buld it... an so on until the product meets out exacting standards of performance, appearance and durability. As a result we don't sell a thousand pretty good products. We sell just a few products and we make sure that each one is the best engineered, highest quality, most attractive product in its category. Kit cars are our passion. We try our best to make sure each of our products reflects that passion.

http://www.cobraracing.com/Company.html

So let's suppose AH HA! They did have problems!

Well would you think they know the weak areas from experience? Yes Do you think they they found where to improve the product? Yes

But a Cobra is so much lighter! Hmmm...... Maybe with a little tweeking, rewrite/edit a new program and thicker material they could increase the strength. Or maybe if they're using 6061 they can make a set out of 7075.

I'm gonna go out on a limb here Tyrell. The stressed points you mention? They do not have issues at these points. Why, because as a machinist myself, it's just to easy to fix/modify, so they would have. Your questioning is great, I see the same right away. Makes me go Hmmm............

Ralphy
 

Last edited by Ralphy (5/11/2014 2:12 pm)

 

5/11/2014 2:15 pm  #16


Re: Custom IRS

I am familliar with 7000 series aluminum. I got a Tremec 5 spd.out of a 2007 mustang GT for cheap at a swap meet. It had the bell housing integral to the front half of the trans case. The mod engines as well as the coyote 5.0l have a different bell housing bolt pattern from the old classic small block ford. I machined a new front casing with its bearing bores and three rail shifter detented bores minus the bell housing. I did this to make the trans compatable with old school seperate bell housing ford used for decades. The problem I ran into was the foot print was bigger than the old top loader bolt pattern so an adapter was  required. I made the new case out of 7075 for the strength and it was what my boss/ company owner recomended I use. He had a remnant big enough and only wanted $25 for it so how could I refuse?  It was also my first personal project on the Haas mills at work. Learning how to program and getting practice by doing personal projects after hours is encouraged. As long as I pay for any tooling I break out of ignorance. 

 

5/11/2014 2:29 pm  #17


Re: Custom IRS

Cool!
Ralphy
 

 

5/11/2014 2:32 pm  #18


Re: Custom IRS

As far as the failure of aluminum parts. Any one that has worked with Aluminum in high stress environments knows that the issue is number of cycles and their sevearity of  deflection the part must endure before work hardening occurrs. The wings you described may go through millions of cycles but never bend to the point of deformation. Thats where things go bad and work hardening sets in. Typically this is not an over night problem. It takes time. They may only deform the LCA once in a while but the deformations all add up to a crack in the long term.  I agree with you as far as using steel in app's like this one. If I were racing and had these LCA's under my car, I would just have one more thing to inspect before every race for cracks.  The weight savings may or may not justify the effort. Lower unsprung weight has its advantages on rough tracks but have no real advantages on a smoothe track. Rough tracks would be where the damage takes place so it looks like a catch 22. Weather or not these could be an  advantage would depend on where you race.

Last edited by tyrellracing (5/11/2014 2:42 pm)

 

5/11/2014 2:49 pm  #19


Re: Custom IRS

In the over view I do admit the billet LCA's look sweet. I think they look lonely with out upper control arms of the same quality... LOL

 

5/11/2014 3:35 pm  #20


Re: Custom IRS

I'm just sayin, takes a licken. lol

http://www.cyclepedia.com/wp-content/uploads/2011/05/kawasaki_kx250r_swingarm_shock_absorber_linkage_bearings_pivot.jpg


Ralphy

Last edited by Ralphy (5/11/2014 3:35 pm)

 

5/11/2014 4:03 pm  #21


Re: Custom IRS

tyrellracing wrote:

In the over view I do admit the billet LCA's look sweet. I think they look lonely with out upper control arms of the same quality... LOL

Something to say about 2 coilovers for looks. Wonder if someone makes a superlight dual setup?

Ralphy
 

 

5/11/2014 7:06 pm  #22


Re: Custom IRS

Wings don't plastisize, they?

http://m.youtube.com/results?q=777+wing+test&sm=1

Last edited by Ralphy (5/11/2014 7:08 pm)

 

5/11/2014 8:24 pm  #23


Re: Custom IRS

The motorcycle swing arm you posted has more engineering in the slotted slack adjusters than the entire LCA we were disgussing.Do you see how the design made the swing arm thicker where the load is greatest and tapers down in both directions. That is how the billet LCA should have been made and was the basis of my original statement. As far as the airplane wing. Thousands of man hours go in to the engineering of the spar's and other related parts of any commercial airplane wing. By design they are intended to flex.

Last edited by tyrellracing (5/11/2014 8:43 pm)

 

5/12/2014 1:44 am  #24


Re: Custom IRS

But aluminum does flex as you said, that's my point. And it does not fatigue as much as common thought, if made right. If it can stand the rigors of Moto X's constant pounding and a wing flexing millions of times?

By Tyrell, "Nearly all of the machine work was done on two planes, X and Y. I didnt see any compounded curves anywhere on it. Kind of like the the aluminum work supporting the quick change in the 68 vette. All done on two planes and as simple as CNC milling gets."

Where have you seen a CNC "profile" parts? Maybe custom wheel manufactures? That would require many hours with little value.

Question: What is a defect?
Answer: Anything that adds cost that adds no value!


If the guy spent countless hours massaging a practical part you can't see anyhow. Trying to turn it into a show piece/ Gold Bricking? He would have to way up the price. Eliminating buyers and not selling much of anything. This market is limited anyhow.

Ralphy

Last edited by Ralphy (5/16/2014 4:07 am)

 

10/17/2014 11:25 am  #25


Re: Custom IRS

Does anyone have any dimensions of an upright off a 2009-2013 Corvette ZR1?

 

10/18/2014 2:18 pm  #26


Re: Custom IRS

Sorry, I'm a little to join the party, but Ralphy has a wealth of information available - and terrylracing has a lot of experience to offer as well as many others here.  For all things IRS - this is the place!

I have been working with the C5/6 uprights in my suspension design for my track/race car for the past few years.  Maybe I can offer a point or 2 you might find useful.
1. The geometry of the pick up points on the frame from C5 to C6 are the same, the uprights and control arms as well (As I all my research has found.)
2.  Also, they are the same from base C6 to C6Z06. We'll have to assume that for the ZR1.  Have you a source for those?  May be just different materials - not design.  I understand that is the difference with the stock vs Z06.
3.  Suspension Analyzer V2.4 has a 2001 vette file in its library (C5). Because the position of the pick up points is the same, you can use that information to locate the control arm pivot points and balljoints if that fits your need.
4.  When you start your build, unfortunately, you'll need to do some work on the uprights to get them to be useful - GM didn't make the Ball Joints replaceable - that is why you see them on eBay. There are approaches you can use, I've posted mine here on this site, as well as vettemod.  I post there as phantomjock. 
I have some dimensions - somewhere - I'll look.http://cdn.boardhost.com/emoticons/grin.png


Cheers - Jim
 


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

10/20/2014 2:51 am  #27


Re: Custom IRS

Here is a quick link to GrabCad - There are some control Arms and Upright in the database:
https://grabcad.com/library/corvette-c5-control-arms-1

Cheers - Jim


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

10/21/2014 7:00 pm  #28


Re: Custom IRS

Lets back track a little bit here. The primary reason I like using two coil overs per side at the rear of my rig is two fold. I have rebuildable shocks and lots of internal parts( pistons and shims) to play with to find what works best for me. Its real easy to over dampen any suspension if you get too gung ho with the spring shims in the rebuild process. I have found a setting that works best for me with the poor road quality and the way I drive. I dampen the rear shocks more on compression and dampen the fronts more on extension.  This seems to reduce some of the wheel hop. The other reason is I like a fairly soft spring heavy shock type setup. I have always used about 75lbs/in greater spring rate on the rear coil overs than the fronts attached to the LCA for reasons we have covered in other posts. I feel having support both ahead and behind the LCA reduces loading on the inner bushings. I am still using needle bearings at all pivot locations and have zero free play. So far.. I understand how simplicity can be a draw to the single C/O shock per side lay out. If it works for you,and you like the valving, by all means go that route.  I however,spend way too much time on E-bay, I have a tough time letting 2.5 id coil springs go when they are in the range I use and are,listed at $5.00 a pair buy it now  and have cheap shipping. I have accumulated more than a dozen pairs that way. So.. I use them LOL.

 

10/26/2014 10:45 am  #29


Re: Custom IRS

One more thing. I used a hybred Klaus Arning T5 suspension for about 2yrs. The suspension worked great but suffered one critical problem. It limited my rim width to 8"  This was a real problem with the new engine I built for the car. I just couldnt get the traction I needed to hook up the engines torque. In fact it got kind of scary lighting the rear tires unexpectedly at 65mph and above. This was the driving force behing narrowing the old Jag XJ6 LCA's 2" per side and shortened 2 chev 1 ton drive shafts to make suitable half shafts. This allowed me to put 12.5x19" rear rims in the stock 67 mustang rear wheel well. This resulted in better traction but wheel hop presisted on wet asphalt.  I tried using the watts link on top of my uprights but that didnt solve it.  Rather than fight it. I drive it in dry weather.

 

10/27/2014 7:05 am  #30


Re: Custom IRS

Tyrellracing - Did you ever have any luck with the widened LCA's to combat or change any wheel hop?
You had a post about how overcoming the large disk brake for the in board brakes caused the LCA's to twist like spongy corkscrews and while the shock setup helped a bit, the shocks acted like a torque coupling.
I've been curious if anything came from the information.

 

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