cobra r race configuration for rear end

sn95cobraDave · Feb 5, 2019

Those who own a r that was campaigned, what rear end set up did they run and or is under your car? Did they leave the 4 link...make it a 3 link......panhard bar and a torque arm similar to a bondurant......steeda 5 link or variant? Watts link? They had to do something...

tomshep · Feb 7, 2019

It depends on the class, but most cars that raced were in a stock-based class. In my case for IMSA, Motorola Cup, Professional Sports Car and a couple others the class required a stock diff using stock attachment points. Gears had to be 3.27 stock as equipped from the factory but you could change the limited slip. Most cars got 8.8 lockers. Coil-overs weren't allowed but you could use stock-type springs with weight jacks (screws that would let you adjust the load/height on the springs). Originally, the stock arms were required but you could use poly bushings. Later, they approved aftermarket uppers and lowers with poly. Currently, mine has Steeda aluminum upper and lower. 3 links, watts link and torque arms weren't allowed. Not sure on panhard bars. OEM brakes were used.

Tom

sn95cobraDave · Feb 7, 2019

Thanks Tom, I know the 4 link has issues with binding due to the angle of the upper arms. I put poly in the upper arms of my cobra and it stiffened things up so much I had to reinforce and box in where they attach to the under body. I have a friend who campaigned a 84 notchback in scca for years and used the steeda 5 link and loved it. That set up changes the angle of the upper arms and as the panhard bar part of it was slotted on both ends where they bolt into supports, it was easily adjusted on track. Did they leave the quad shocks as well? I imagine so if stock....Any sub frame connectors? I imagine not if stock....I do notice in tracking he Cobra r vs the cobra the understeer is not there like it is in a cobra and the rear end does not want to bind up and kick out as readily. Maybe the difference is in the spring rates.

tomshep · Feb 9, 2019

Yep, it does bind but that is what the class required. Originally, the stock arms were used with poly bushings. My belief is the arms twisted enough so there wasn't any damage in the torque boxes. Later, about 2000, they allowed non-OEM arms but they had to use the OEM attachment points. That is why I used Steeda with their bushing construction for the arms to allow everything to move without binding as bad. I also went ahead and welded all of my boxes at the same time.

The Steeda 5 link is cool, but not allowed. Quad shocks stayed. Sub-frame connectors were not allowed but remember, they had full cages, so that took care of flex issues.

I would say the decrease in understeer may be due to the extra weight of the motor making the front tires stick better and the R spring rates. They fronts are pretty stiff.

Tom

sn95cobraDave · Feb 10, 2019

Great info Tom. My feeling on the lack of understeer is a combination of factors, extra front weight, super hard springs in front, soft in back, gearing through the driveline allowing the proper torque on the rear end with the soft rear an drew stiff front enabling you to control the rotation in the corner with the throttle, at least that is how it feels to me.

If I can continue into another area I would appreciate it. The Spacer for the aluminum drive shafts...steeda has a 555-7707 17 mm spacer 11/16..
it says for c-4 only... is this the part number spacer you used? I am asking as you have done it and are using it and it is working, I just want to install the aluminum driveshaft and spacer that works .....not argue forever details with you...I promise I trust you. I am looking at Ford racing driveshaft m-4602-j or g.

tomshep · Feb 26, 2019

Sorry it took a while to get back to you. I finally got the car on a lift this past weekend and was able to look at my Steeda spacer.

My spacer is from about 2005 and it is gold anodized. A quick measurement was 3/4" so your 11/16" is spot on. I may have missed that 1/16". I would say that is the same spacer, even thought they don't show it as gold anymore on their website.

A quick note for ordering your aluminum driveshaft. The Ford Racing is a bolt-in if you are getting the spacer. The 94-95 version will work if you have the stock Tremec 3550 since it has a 28 spline yoke. If you upgrade to a TKO order the 96-98 version since it is the same length but has a 31 spline yoke which is the same as the TKO.

Your observation on the springs is correct with them set up very stiff in the front and the rear soft to allow the rear to rotate easier. The fronts in my race car are 1200 lb with the large Steeda front bar. The rears are much lighter (can't remember) with a stock sway bar. My car also has Delrin offset front a-arm bushings and X2 balljoints, which I added but would be illegal for back in the day.

Tom

1993R · Feb 26, 2019

FYI....
on my 93R I'm running poly bushings and I welded the torque boxes .
Also added the Steeda extra rear sway bar. I believe these mods were legal and period correct according to the rule book I have from IMSA for the series. While the extra sway bar doesnt seem to be a very stout piece it did help with the rear end wanting to move around in the corners..........
Its been on there about 15 years now

sn95cobraDave · Feb 26, 2019

tomshep said:
Sorry it took a while to get back to you. I finally got the car on a lift this past weekend and was able to look at my Steeda spacer.

My spacer is from about 2005 and it is gold anodized. A quick measurement was 3/4" so your 11/16" is spot on. I may have missed that 1/16". I would say that is the same spacer, even thought they don't show it as gold anymore on their website.

A quick note for ordering your aluminum driveshaft. The Ford Racing is a bolt-in if you are getting the spacer. The 94-95 version will work if you have the stock Tremec 3550 since it has a 28 spline yoke. If you upgrade to a TKO order the 96-98 version since it is the same length but has a 31 spline yoke which is the same as the TKO.

Your observation on the springs is correct with them set up very stiff in the front and the rear soft to allow the rear to rotate easier. The fronts in my race car are 1200 lb with the large Steeda front bar. The rears are much lighter (can't remember) with a stock sway bar. My car also has Delrin offset front a-arm bushings and X2 balljoints, which I added but would be illegal for back in the day.

Tom

Than she for sharing lots of God intel to consider as I get into shaking her out how I want. I am doing a few autocross events to warm up for some hpde events this summer. Should be interesting. I will update. I am putting new poly bushings in the front end, the drive shaft, drive it a bit and decide how to proceed with the rear end suspension.

sn95cobraDave · Feb 26, 2019

1993R said:
FYI....
on my 93R I'm running poly bushings and I welded the torque boxes .
Also added the Steeda extra rear sway bar. I believe these mods were legal and period correct according to the rule book I have from IMSA for the series. While the extra sway bar doesnt seem to be a very stout piece it did help with the rear end wanting to move around in the corners..........
Its been on there about 15 years now

Thanks, I intend on boxing in the control arm connection points. I am a Griggs disciple as I have a griggs sent up under my 95 cobra convert. I want to stay true to the original but griggs makes a great solution to the rear end with torque arm, pan

tomshep · Feb 27, 2019

Dave,

One quick note on the aluminum Ford Racing driveshaft. It is a larger diameter than the steel unit. Make sure you have clearance on the parking brake bracket. Mine rubbed slightly and I bent the offending piece of metal slightly up and no more rub.

I also had a 95 conv/ht with a full griggs rear and coil overs all the way around. Never did the K-member or a-arms. In retrospect, I wish I would have done MM. I had friends run their stuff and they were as pleased as I was with griggs. I believe the MM items were more robust and I liked the extra clearance on the torque arm. I was also never very comfortable with the way the griggs torque arm attached. I always had visions of the tab breaking and it turning into a pole vault.

Tom

sn95cobraDave · Feb 27, 2019

tomshep said:
Dave,

One quick note on the aluminum Ford Racing driveshaft. It is a larger diameter than the steel unit. Make sure you have clearance on the parking brake bracket. Mine rubbed slightly and I bent the offending piece of metal slightly up and no more rub.

I also had a 95 conv/ht with a full griggs rear and coil overs all the way around. Never did the K-member or a-arms. In retrospect, I wish I would have done MM. I had friends run their stuff and they were as pleased as I was with griggs. I believe the MM items were more robust and I liked the extra clearance on the torque arm. I was also never very comfortable with the way the griggs torque arm attached. I always had visions of the tab breaking and it turning into a pole vault.

Tom

The hardtop convert I have is an untouched or modified original trailer queen. I have a second 95 cobra convert , that had 2 things happpen, the mileage creeped above 130k and then I hit a deer taking out the right side and windshield. So I had the entire car repainted the right way- all doors hood rear dexklid come off. Strip it down to metal and start over and add in a new top. Since I have everything apart......then while apart...why not switch out interior...so I found a 2001 cobra interior and installed it. Put in a 4 point roll cage, since everything was apart, then figured, as everything is apart,why not get a griggs sla, coil overs and k member for the front end......since that was all apart...why not take the 302, stroke it and make it a 347 to solve the slowbra problems.....for the rear end, griggs panhard bar and a custom built torque arm mirroring the roush bondurant design, boxed in tubular upper and lower control arms poly bushings on bottom arms cobra bushings on the top arms..eibach lowering springs , that was an expensive deer and now I have the world's most expensive 95 cobra convert.

cobra r race configuration for rear end

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