Well boys and girls, I just spent the last 15 hours in the car. Drove out and bought a 2003 IRS with 820 miles on it for 1100 bucks then drove it down to Kenny Brown Performance, then drove home. I hate traffic!!! But anyway I am going to drive my stang down in mid Aug. to get it installed and I have two options that I can go with. I can either get :
Lower control arms
Coil over shocks
Springs (back)
mounting bracket
Or I can have them rework the geometry to get better stability at higher speeds and a differential cooler. Then wait to have the above put in next summer.
I am leaning toward this option because if I have the geometry redone and the Diff cooler put in next summer the labor or taking it out and putting it back in will cause me to basically pay for the install twice, The first things I mentioned won't require the whole unit to get taken out so I can get that done with no problem. What do you guys think and what would you do?
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Home made CAI, Pro 5.0, Steeda clutch adjuster kit, Raised gass pedal, GT take off's, white gauge face, Aluminum pedals, Aluminum driveshaft, underdrive pully, 03 cobra IRS with bushings and rear steer kit, 10th ann. Cobra rims wrapped in 275 Eagle F1's, 3/8 intake spacer.
Congrat on the IRS. I wish I had one. Go with the control arms and coil overs. Do the diff cooler any way. Those things get HOT!
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Black,79 Mustang mostly carbon fiber/kevlar body, M-2300-k brake kit, full roll cage, maximum motorsport suspension, custom geared 6 speed, 2 inch rear fender flares, 1 inch front, motor being built (no eta). Looks like the Mad Max interseptor and weighs about 1800lbs w/o motor (450hp 351w installed to move the car around)
Black, 82 Capri RS 5.0L, B303, 1.7 rockers, World 180 heads, +150hp N.O.S, Turbo coupe rear end, T-56(tremec tko would be beter), 80 cobra nose
If I get the control arms and coil over now I have to pay for them to pull the whole thing apart do the install then put the whole thing back together again next year. As I understand it the control arms and the coil over don't require the whole thing getting pulled out and I could even do that myself.
Thanks on the congrats it only look me 2 months to find a good 03. The diff cooler is a must because I am planning on taking her on road tracks and I can't have her butt roast out on me. I am definatly getting the coil overs though, just a question of when.
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Home made CAI, Pro 5.0, Steeda clutch adjuster kit, Raised gass pedal, GT take off's, white gauge face, Aluminum pedals, Aluminum driveshaft, underdrive pully, 03 cobra IRS with bushings and rear steer kit, 10th ann. Cobra rims wrapped in 275 Eagle F1's, 3/8 intake spacer.
keep in mind I am basically getting stock springs and shocks on there until I can save up the money to get coil overs in the front and back. I am now looking at possibly going with griggs instead.... still got time though. I just want to get that thing in there..... I know, get your mind out of the gutter! But ya, I want that IRS on my car asap. Hopefully within the next 3 weeks....
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Home made CAI, Pro 5.0, Steeda clutch adjuster kit, Raised gass pedal, GT take off's, white gauge face, Aluminum pedals, Aluminum driveshaft, underdrive pully, 03 cobra IRS with bushings and rear steer kit, 10th ann. Cobra rims wrapped in 275 Eagle F1's, 3/8 intake spacer.
Hey everyone, sorry I wasn't able to get a pict of the IRS but I finally got it in!!!! She drives like a charm and I don't know what kenny Brown's people did but there seems to be much more pickup and the clutch seems much more sensative, and I can take turns much faster with no wheel whine. I can't say enough great things about it. Now I just have to get some tower braces, subframe connectors, and coil overs and I'll be set!
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Home made CAI, Pro 5.0, Steeda clutch adjuster kit, Raised gass pedal, GT take off's, white gauge face, Aluminum pedals, Aluminum driveshaft, underdrive pully, 03 cobra IRS with bushings and rear steer kit, 10th ann. Cobra rims wrapped in 275 Eagle F1's, 3/8 intake spacer.
Home made CAI, Pro 5.0, Steeda clutch adjuster kit, Raised gass pedal, GT take off's, white gauge face, Aluminum pedals, Aluminum driveshaft, underdrive pully, 03 cobra IRS with bushings and rear steer kit, 10th ann. Cobra rims wrapped in 275 Eagle F1's, 3/8 intake spacer.
Riddic116, Calric is right, IRS in car terms stands for Independent Rear Suspension... just a few more quick points of reference and info for ya:
- IRS is generally considered superior technology for road racing and ultimate handling because the car will usually handle bumps, dips and other road irregularities with less drama than a traditional straight axel rear wheel drive car... But drag racers still need straight axels... Mach 1s are a prime example.
- The key trade-offs are cost and simplicity, which often correspond to strength and reliability. Almost all amateur road racers, even the big buck guys like Griggs are still using traditional straight axels due to the proven strength, reliability, and ultimate cost.
- The key benefits to most street driven Mustangs, even those taken on the track, are ride quality and car controllability at the limit over rough roads. Due to cost, only 1999 and newer Cobra Mustangs have IRS from the factory. As indicated above, besides rough driving and abuse, the quickest way to kill ANY rear end, straight but especially IRS, is to subject it to extended high temperatures from high-torque acceleration and high speeds, like on a road coarse. Thus, the addition of a fluid cooler for the rear end for those hard-core open track and racers is recommended. Usually just checking and changing the rear end fluid more regularly and often is enough for most street and moderate open track driving.
Stick axles also tend to be a bit more forgiving than IRS.
The big reason that an IRS needs more attention to the rear end oil is that there is less of it, and it doesn't have the axle tubes to slosh around in and cool itself. A good cooler with a good pump is a must.
The stock control arm bushings should be replaced with less compliant ones such as the Griggs Racing de-alum bushings. The front cross brace and bushings are also a worthwhile upgrade. Bumpsteer is a problem on the 99s for sure, and I believe the 01s, they fixed the problem in 2003.
IRS for me 
it only look me 2 months to find a good 03. The diff cooler is a must because I am planning on taking her on road tracks and I can't have her butt roast out on me. I am definatly getting the coil overs though, just a question of when.
