kogt85 Posted January 14, 2006 Share Posted January 14, 2006 I own a 1999 Cobra with 18,000 miles. I love the car, but would like to eliminate or at least greatly reduce the wheel hop. I have purchased, but not installed as of yet polyurethene bushing for the differential center section and the Ford IRS brace off of a 2004 Cobra. It is my understanding that Ford installed 12mm bolts in 14mm holes in the rubber bushing in the subframe of the IRS. Can I install 14mm bolts to replace the 12mm and where do I get the bolts. I checked with Ford after hearing that the 2004 Cobra used these bolts with a grade of 10.8 or 12.9., with no luck. Does anyone have a part number for the 14mm button bolts? I also understand you can replace the rubber bushing in the IRS with polyurethene, but I am not interested in this. If I want to drag race I will race the 85 GT that I own. Any help would be appreciated. Thanks Larry Quote Link to comment Share on other sites More sharing options...
2FST4GM Posted January 16, 2006 Share Posted January 16, 2006 (edited) Definitely get the poly IRS subframe bushings before swapping the bolts. The bolts are the same part number as the front control arm bolts on a GT. But, I didn't notice any difference when I did the bolts st a later time after the bushings, though. Now, last year I completely rebuilt my rear end (see sig) and I really don't have any wheel hop. but mostly I did what I did for strength since I grenaded my stock Ford differential in two (literally down the middle). Edited January 16, 2006 by 2FST4GM Quote Link to comment Share on other sites More sharing options...
kogt85 Posted January 16, 2006 Author Share Posted January 16, 2006 :D Definitely get the poly IRS subframe bushings before swapping the bolts. The bolts are the same part number as the front control arm bolts on a GT. But, I didn't notice any difference when I did the bolts st a later time after the bushings, though. Now, last year I completely rebuilt my rear end (see sig) and I really don't have any wheel hop. but mostly I did what I did for strength since I grenaded my stock Ford differential in two (literally down the middle). Thanks for the info and I like your license plate Quote Link to comment Share on other sites More sharing options...
1999BlackSnake Posted January 19, 2006 Share Posted January 19, 2006 Hey 2FST4GM, if it isn't too personal, what was the total you spent on redoing your rear end with those parts? And, how is the handling, is it still stock-ish, or is it very, very stiff? Quote Link to comment Share on other sites More sharing options...
2FST4GM Posted January 19, 2006 Share Posted January 19, 2006 (edited) The handling is absolutely mind boggling! A daily driver shouldn't handle this well. Its stiff but not unbearable at all. However, everybody's tolerence levels are different. I love it. The total cost would have been A LOT CHEAPER if I just bought an '03/04 rearend from someone swapping to a live axle. But then I'd b buying a used rearend from a car that had a blower with stock internals. However, I was more interested in strength becuase I didn't want this to happen to me again. So here is a breakdown of the costs (by memory). B&M Ripper ($90 used eBay) '03 half-shafts ($330) Eaton ($450) Motive Gear 4.30's ($170) Steeda IRS cover brace ($135) IRS poly pumpkin bushings ($40) '03 IRS brace ($110) Fidanza aluminum flywheel ($220) SPEC stage 1 ($220) Steeda quadrant & firewall adjuster (& cable) ($35 used eBay) Labor $700 TOTAL $2500 Edited January 19, 2006 by 2FST4GM Quote Link to comment Share on other sites More sharing options...
kogt85 Posted January 29, 2006 Author Share Posted January 29, 2006 :D 99 Cobra I installed the Steeda IRS brace and polyurethane bushings.............very happy. I would say it eliminated 95% plus of any wheel hop I would experience. Put on a sticky set of tires and leave at 4500 and I would guess you have to change the springs and shocks to cure the wheel hop from that type of launch. Quote Link to comment Share on other sites More sharing options...
2FST4GM Posted January 30, 2006 Share Posted January 30, 2006 (edited) koqt85, Its pretty worth the money for sure! I already have coil-overs and Bilsteins/Tokicos. Its a rare day if I get wheel hop. They usually just spin. I'm happy with my IRS. Its rock solid. And remember, the part that failed on me was the stock Ford Traction-Lok differential. The same peice that comes in a stick axle. I no longer fear that I might break something. That peice of mind is worth every penny I spent! :D Edited January 30, 2006 by 2FST4GM Quote Link to comment Share on other sites More sharing options...
REDLYNE Posted March 30, 2006 Share Posted March 30, 2006 I am happy with the IRS brace and bushing as well. However, witht he 4.30 gears, the wheelhop came back with a vengence! Overall though, I think the IRS brace is helping...since before the gears it allowed me to launch about 2200 rpm higher without hop. Therefore, if I didn't have it installed...it would probably even worse now, with the gears. Quote Link to comment Share on other sites More sharing options...
supercruise Posted April 1, 2006 Share Posted April 1, 2006 (edited) :D 99 CobraI installed the Steeda IRS brace and polyurethane bushings.............very happy. I would say it eliminated 95% plus of any wheel hop I would experience. Put on a sticky set of tires and leave at 4500 and I would guess you have to change the springs and shocks to cure the wheel hop from that type of launch. I was just looking at the Steeda online catalog, did you install the "Cobra IRS Subframe Bracket Kit" (555-5405) and the "Cobra Differential Bushings (555-4015) or the "IRS Subframe Bushings" (555-4016) or all three? Did you install everything yourself or... how many hours of shoptime would you have to pay for? Thanks in advance. Edited April 1, 2006 by supercruise Quote Link to comment Share on other sites More sharing options...
REDLYNE Posted April 25, 2006 Share Posted April 25, 2006 My brace was the PHP BRace, so I can't speak to that...but I can tell you the bushings I installed were te Cobra Differential Bushings (555-4015). Quote Link to comment Share on other sites More sharing options...
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