|
|
|
 |
 |
 |
You are not logged in. Would you like to login?
Offline
New guy here with some questions about my cobra IRS. First off the project car is my 1989 mustang notch that i am putting a 2003 cobra IRS in. The easy part was getting the IRS in the car and everything working, but now with using this wider setup on the smaller fox body, my wheel size choices are very limited. I had factory 1994 cobra 17x8 wheels and they fit ok, but stuck out almost flush with the quarter panel. I would like to run a 17x11 or 12" wheel with maybe a 335 tire on the back which is impossible. So i ended up minitubbing the car and now have all the room i need, but lost my factory coil over mounts. I am thinking about building some new tubular upper and lower control arms with heim joints on the ends to be adjustable, and shorter on the overall arm length with some shorter CV shafts, and the move the coilovers inboard like i have seen on the TEAM 321 IRS they have. Would there be any pitfalls to doing this setup??? Second, i am not a engineer or suspension designer, so if you were going to build you own control arms, what material would you use, what O.D., I.D. wall thickness, what heim joints would you use and recommend on sizes. Lastly, just wanted to say thanks for any information and for a great site, the info here is fantastic, still have lots of posts to read and pics to drool over, thanks Chris
Offline
cobra94svt,
Welcome to the IRS board. Is this similar to what you have? If you were to put 12" wheels on what all interferes? Got any pics with the 8" wheels and tires on? Any wheel offset can be had. It may require having them made. They are a little more $$$$$$.
First always remember, Team 321 frame needs to be rigid and strong. The shorter distance that the coilover is from the pivot means running much higher spring rates. If you half the distance from the inner pivot, that means doubling the spring rate. All your spring forces will be taken on by the frame below.
Ralphy
Last edited by Ralphy (1/12/2012 7:03 am)
Offline
First of all welcome to the forum!!! Would love to see some pix of your project!!! couple things to consider first of all wider tires will connect the road to the suspension a lot more aggressively so the arms will have to be even stronger. Second the closer you can get your coil over to the centerline of the wheel the better. that will give you better leverage on the suspension and allow your coil over to do its job more effectively. as to what materials to use, I work on the concept of find something similar and then make it stronger. in other words find out what aftermarket tubular control arms are made of (size wise) and then make it out of something a little stronger. keep in mind that some metals like cromemolie take tig welding, where a good quality DOM steel tubing will be fairly strong and can be stick mig or tig welded .
Offline
I think DOM is fairly common to use, 1 1/4" would be a good place to start, not sure on wall thickness.
A tip about steels, the second two numbers designate how much carbon content is in the steel. So say 1020 steel would have approximately .2 percent carbon, 1040 has approximately .4 percent. Chrome-moly 4130 is a higher carbon steel than DOM. The carbon is what can make steels brittle, it also makes them stronger. If you heat 4130 too much and it cools fast, the carbon goes to the heated area. High carbon steels are materials used for heat treating, such as bearings. DOM 1020 is what you would probably want to use. I measured my aftermarket Mustang II A arms and they are 1" OD. The rear takes more loading so that's why I would say 1 1/4". DOM stands for Drawn Over Mandrel.
Last edited by Ralphy (1/12/2012 10:28 pm)
Offline
WOW thanks for the info already. Im glad to have found this site has. Ralphy, the picture of under shot of the mustang with the IRS is what i have. As far as interference, the rear mount of the IRS to the frame rail, and the coil over is the biggie. Im going to just cut off the rear mount on the outside of the frame rails and make a new hard mount that is between the rails to get room there. But fords factory shock/coil over location is on the bottom control arm close to the wheel. I can not go out for more wheel and have to go in, and as you do that hit the shock, i thought about just leaning the shocks inward towards the center section and making new upper shock mounts. Once i find away to deal with the shock/coil over, i will have all the room i need. As far as the Team 321 part, i was just wanting to use the idea of the tubular upper and lower arms, and moving the shock/ coil over in board and in front of the CV shafts in the open area i have there and keep my ford sub frame as it seem to be a rather robust piece and i can modify that as needed. I do no want to have to run some extremely high spring rates, with the stock location coil over, i was running a 600lb coil over spring on the rear. Im getting ready to buy a TIG welder so i can weld chrome moly, have mig already, im not worried about being light weight, i want strength and heavy duty. As far as seeing whats out there and then up sizing, the only aftermarket control arms i have seen for this IRS is the Kenny Brown stuff and its high dollar if you can find it and still uses the same shock location and same length, as i would like to shorten mine. I will post up some pics tonite after work. Thanks Chris
Thread StarterOffline
here a couple of pics of my IRS in my 89 mustang notch, in the process of mini tubbing the right side now.
Thread StarterOffline
more pics
Thread StarterOffline
left side with wheel and tire and at about ride height, these are the factory 94 cobra wheels, 17x8 with a 275 tire, and about a half inch clearance between the wheel and and the inner wheel house
Thread StarterOffline
here is a modified pic of the one that was posted by Ralphy that is of a IRS in a 1967 mustang fastback from DVS. Whats marked out in red on the right side is what im getting rid off, and trying to move the coil over to where the green is at.
Last edited by cobra94svt (1/16/2012 3:38 pm)
Thread StarterOffline
So is the spring pocket on the LCA in the way? What I first see you would need to tub the wheel wells and narrow the IRS cross member. You may be able to add upper spring mounts to a modified cross member. The green area marked seems way inward for the lower shock/coilover mount. Need to keep it as far out as possible.
Last edited by Ralphy (1/16/2012 3:36 pm)
Offline
the spring pocket will have to be cut out, the front of the IRS cross member mounts to where the factory straight axle lower control arm mounts, i think i can keep that there, and the rear part of the mount at the frame rail will have to be cut off and mounted to the inside of the frame rail.As far as the shock i meant for that to be where it may end up on the car, will have to cut out the factory upper arm mounts and make a cross member for that, the shock may end up somewhere close to where the factory spring pocket is at with the coil over leaned in a little to clear the frame rail. I am working on the mini tubs now, the new tubs i have for the inner are almost 11" so i will have plenty of room, and will also have to modify the frame rail too, yippie lots of fun with the plasma cutter lol 
Thread StarterOffline
Have you looked for aftermarket LCA's?
Offline
Kenny Brown does make some tubular upper and lower arms that are the factory length
Here are the lowers
and the uppers
But for almost $1500 id rather make my own and be able to shorten them up, and i hardly ever see them on the forums for sale used or anything like that.
Thread StarterOffline
Can you get by with only the lowers modified and not narrow?
Last edited by Ralphy (1/17/2012 8:35 am)
Offline
Id really like to be able to narrow these down about 2". With help from other members i think i have found everything i need to make my arms, big thanks to Ralphy, Phantomjock and Daze for there help and knowledge. I found some DOM 1020 in 1.25" .120 wall here locally, and HP world has some PTFE line rod ends and the camber adjusters i need. Now to rack up that credit card a little lol.
Thread StarterOffline
I have an 89 vert that I want to do this swap with. I like this thread. It address's all the short coming s of a 03 Cobra IRS swap. The additional 1.5" width to each side of the fox axle width kills it. I want to fit 00R wheels on my vert. Do you think you can stretch the quarters 1" outward with a port a power? I want to see more pics.
I care about handling, drag raacing not so much with my vert. This is what I want, but I need to see how to make a large tire work. I too want a large wheel and tire in the back. I can see how shortening the arms would give you the additional clearance, the upper mount as well. Keep us updated.
Offline
Any updates?
1 of 1