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04 IRS

  • Thread starter Thread starter fox racer
  • Start date Start date Oct 16, 2007

fox racer

Member
Jun 22, 2004
577
0
16
Staten Island, NYC
Oct 16, 2007
#1
  • Oct 16, 2007
  • #1
Hey guys, I'm new to the whole IRS scene, but I might be getting my hands on an IRS rear out of an 04 Cobra to put in my Notchback. I just have a few quick questions:
1) Is there any way to tell the difference between, say, an 03/04 IRS and a 99/01 IRS?
2) Are there any mods I should do prior to the install of the IRS?
3) What are some weaknesses of the 04 model, that I should be looking ro upgrade first.
 
U

Uncle Meat

Banned
Jun 13, 2002
0
1
0
Prattville, Alabama
Oct 16, 2007
#2
  • Oct 16, 2007
  • #2
fox racer said:
1) Is there any way to tell the difference between, say, an 03/04 IRS and a 99/01 IRS?
Click to expand...
03/04 has beefier 31-spline axles I believe and a larger torque brace than the 99/01.
fox racer said:
2) Are there any mods I should do prior to the install of the IRS?
Click to expand...
Depends on your intended use. Level 5 half-shafts, poly bushings, IRS brace, pinion snubber, etc.
fox racer said:
3) What are some weaknesses of the 04 model, that I should be looking ro upgrade first.
Click to expand...
Besides the half-shafts themselves the rear diff covers get blown out under hard launches. Again an IRS brace can help prevent this.

U.M.
 

fox racer

Member
Jun 22, 2004
577
0
16
Staten Island, NYC
Oct 16, 2007
#3
  • Oct 16, 2007
  • #3
Thanks UM. The car, for now, will be a street car, hovering around 300hp/320ft/lbs torque. I was thinking about MM Poly bushings (frame bushings), MM upper mount support (that peice of metal that is welded to the upper mount), and the Diff case brace. I read your post on how the case flexes so much that it cn break the seal, so I figure easier now then later.

I have very little hands on experience with the IRS setup, are the differences in years easil visible, or should I bring someone more knowledgeable to help me when I purchase it?
 
W

WhiningCobra

New Member
Oct 14, 2007
0
0
0
New Jersey
Oct 21, 2007
#4
  • Oct 21, 2007
  • #4
if you aren't going to road race or daily drive the car. i suggest you'd stay far away from a IRS. they're a pain, it clunks and it'll snap even on a slight launch. and it just adds weight. if i can do it again. i'd get a solid rear.
 

VR4

New Member
Mar 1, 2007
13
0
0
vancouver, wa
Oct 21, 2007
#5
  • Oct 21, 2007
  • #5
01s also have 31 spline but im pretty sure the 03/04 shafts themselves are bigger than 01s

bushings in 03/04s are slighty stiffer but i doubt youll notice the difference.


biggest weakness is the diff cover. BF IRS brace works wonders. considering youre putting it in a fairly light car i personally wouldnt worry too much about the halfshafts. i would do all the bushings in poly/delrin before installing it though.
 
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