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IRS to SRA....the whole shabang

Discussion in 'Driveline' started by LSwat, Oct 9, 2009.

  1. LSwat

    LSwat Member Established Member

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    So I broke my drive shaft and broke my diff cover, now I am faced with the dilema to either go SRA or (re)build the IRS...

    [​IMG]

    Few things I need to know right off is the following

    1. IF I switch to a SRA would one out of a 2000-2004 GT be better then one out of an 03/04 Mach?

    2. I need a Posi unit, or "traction lok" as ford refers to it, both tires spinning simotaniously and receiving equal power, correct me if I am wrong but didn't the 2000-2004 GT's come with limited slip? which is NOT the same thing? My understanding is limited slip is a "one tire fire" that slips the other wheel in and out of power to get traction....similar to the posi, yet different.

    3. Do I keep my same lowering springs and other suspension parts? what needs to be changed?

    4. What other major components need to be changed? say I get my hands on a 03/04 Mach rear end, what needs to be done to actually make this work?

    5. Is there an indepth guide, or any guide for that matter on doing this swap on here or any other forums?

    6. Is it the 03/04 cobra driveshaft? or the driveshaft from a mach/GT?

    7.new sway bar?

    8. Is it really better to swap to SRA or to just repair the IRS, slam, brace, and add some bushings?

    9. What are the major pros and cons of this operation?

    If there is anything I missed or something that comes to mind, toss it on in here :rockon:
     
  2. mu22stang

    mu22stang [_==[_=_][_=_3[_=_< /_=_\ Established Member

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    It really depends on your goals for the car. It's not just about swapping parts and "eliminating" the problem(s). Some people love their solid swapped Cobra, others wouldn't be caught dead with one. Whatever you choose, don't just dive into it without clearly thinking about what it means to do such a major componentry changeover. There is a lot of information, reviews, and opinions on the subject.
     
  3. yellowgt02

    yellowgt02 New Member Established Member

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    See above in red.

    -Jason
     
  4. BlownAway03

    BlownAway03 Active Member Established Member

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    As a person who has gone solid and now gone back to IRS.....I say keep the IRS. It'll be cheaper to just repair your current problem unless you have a solid swap lined up already. IMO the IRS is easier to launch with, it rides 100 times better, and it's what these cars should have. After all, your only real IRS specific problem was the diff cover breaking. And if you get a brace you won't have to worry about it on the next go round.
     
  5. LongshotSVT

    LongshotSVT I piss excellence Established Member

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    The solid is really only good for completely eliminating wheel hop regardless of tire and weight reduction. I know that may sound good but you're giving up more than you realize. You'll need a new exhaust, new springs, control arms (factory control arms are garbage), ABS sensors, Cobra pinion flange (you need to rebuild the rear end to replace this CORRECTLY), and other odds and ends. I priced it myself, but after installing bushings in my IRS I'm happy with my decision to stick with the IRS.

    Also you're giving up the strong 31 spline diff in the IRS for the 28 spline diff and axles in the SRA, unless you intend to build it, which will be $$$.
     
  6. whyte_03

    whyte_03 I got your HEMI hanging!! Established Member

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    gee lets see. I WENT SOLID! the IRS was drama to my driving style, i never broke a diff cover tho. If you decide to go solid be sure to use the ford C=springs... they are kick ass amd are not priced like the rest...you might need to trim the rear springs a tad for your desired height. I have over 40k miles on my solid and have not ever needed to get under the car to replace anything that i had to deal with when I had the IRS. From 14k miles to 55k miles I replaced one halfshaft (boot went bad) and sealed the diff 3 times. That is total crap and obviously the flaw of the IRS. If you go solid get 3.73's. I noticed a better pull when they were installed. If you find a stock GT rear from 99 and up just bolt it right in and go. I drove with a untouched stock 03 rear for 15k miles and the gas mileage was great. I got 395 miles to a tank of gas with the 3.27's. The solid axle swap was EASY..I picked up all the lil hardware crap from the junk yard off a V6 but ordered all the good stuff like control arms from a good source. And truthfully.. i don't really notice any driving condition differences.....car still hangs corners great and I have yet to install a sway bar. I recommend it PLUS the weight reduction of 100+ pounds is free. My car weighed 3490 after the switch with spare tire and 1/4 tank of gas. It's what this car should of come with from the factory!!
     
    Last edited: Oct 11, 2009
  7. cobrasvtcoupe25

    cobrasvtcoupe25 Active Member Established Member

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    Went solid and never looked back...
     
  8. rotor_powerd

    rotor_powerd Well-Known Member Established Member

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    1. IF I switch to a SRA would one out of a 2000-2004 GT be better then one out of an 03/04 Mach?

    Mach comes with 3.55 gears, same as in your IRS. I believe the Mach is 31 spline as well (Could be wrong here). 94-98 rearends are a bit shorter, and will allow you to run wider rubber. I have a '98 rearend under my car, and I am fitting 345 width tires under the fenders just fine.

    2. I need a Posi unit, or "traction lok" as ford refers to it, both tires spinning simotaniously and receiving equal power, correct me if I am wrong but didn't the 2000-2004 GT's come with limited slip? which is NOT the same thing? My understanding is limited slip is a "one tire fire" that slips the other wheel in and out of power to get traction....similar to the posi, yet different.

    A limited slip diff will lock the wheels together. When either side spins, the clutches lock up and essentially act as a locker. All GT's come with LSD's since forever... all the one you will be looking at had Trac-Lok diffs, same as in your IRS. Only difference is 28 vs. 31 spline, but you can swap the side gears out in a 28 spline diff to make it a 31 spline.

    3. Do I keep my same lowering springs and other suspension parts? what needs to be changed?

    No. Everything. New springs, shocks, brakes (Unless you get the adapter plate). You need to swap the Cobra pinion flange onto the SRA, or get the adapter U-joint to still use your driveshaft. You will need the brake lines and ABS sensors (If you get a rear with ABS) that came with the SRA.

    4. What other major components need to be changed? say I get my hands on a 03/04 Mach rear end, what needs to be done to actually make this work?

    See above. It's an easy job. You need the rear, brakes, shocks, springs, pinion flange or adapter U-joint, exhaust, ABS sensors, brake lines, upper/lower control arms.

    5. Is there an indepth guide, or any guide for that matter on doing this swap on here or any other forums?

    Not sure.... search. It is really simple once you're into it though.

    6. Is it the 03/04 cobra driveshaft? or the driveshaft from a mach/GT?

    Have to use the 03/04, the tail shaft output is different. As I said, you will need to swap the pinion flange or use the adapter U-joint.

    7.new sway bar?

    I assume they are different, the SRA will come with the factory sway bar though.

    8. Is it really better to swap to SRA or to just repair the IRS, slam, brace, and add some bushings?

    I love my SRA. When I was swapping it out, I was afraid I was going to regret it........ not a chance. Best modification I've done to my car.

    9. What are the major pros and cons of this operation?

    Pros... -120lbs, no wheel hop, no braking axles/diff covers.

    Cons.... no cool looking exhaust from the back.
     
  9. Jomo1994z71

    Jomo1994z71 Can I get a KB WooWee! Established Member

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    Good thread...OP, how did this happen...details please? Track? Tires? PSI? Launch? I assume you don't have a Billetflow Diff Brace.
     
  10. ous2418

    ous2418 Member Established Member

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    i had an 03 mach 1 sra and switched to a 98 sra. the post 98 sra's are wider and my 315's were rubbing bad. so if you are wanting to run a 315++ id go with a 98 sra
     
  11. ac427cobra

    ac427cobra FULLTILTBOOGIERACING.COM Staff Member Super Moderator

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    You broke the rear cover on your differential housing because you haven't been paying attention to the precautions IRS owners should be taking. Bracing and stabilizing the differential housing are paramount!

    Don't put a stick axle in a Cobra! :nonono: Unless you're going to trailer the car to the drag strip and never drive it on the street. :-D

    Research this site, there is a LOT of good information here.

    Good luck!

    :thumbsup::coolman::beer:
     
  12. FuzzyDiceRule

    FuzzyDiceRule Member Established Member

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    Where you should go depends on what you want to do with the car. If you have, or are planning to be a drag only, Sub 10 second car, then by all means, go with an SRA, but if you like turning, or its your daily, or you like a nice ride, keep the IRS. theres a ton of debate, but from what ive seen, its best to stick with what came in the car stock (for turning, i was looking into an IRS swap for my fox) as it takes roughly the same amount of mods to get the SRA to handle well, as the IRS (about a grand each...) and then the IRS has the benifit of a smoother ride, and the ass end isnt as affected by bumps as an SRA...

    but in the end, its your decision
     
  13. SlowSVT

    SlowSVT Well-Known Member Established Member

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    Do you mind telling us how you accomplished to do all that damage? Something tells me it got hopped to hell, didn't back-off and exploded the rear end which is something that can happen with an SRA as well. Hard to tell from your sig but I see 390 hp and I see no diff brace in photo with all that carnage which leads me to believe your car is basically stock.

    If you go solid I suggest "not looking back" because it will regret the fact you just downgraded the handling of your car (an the re-sale value). Solid axles are pretty much the domain of heavy haul trucks and vintage muscle cars and that is for a reason.
     
  14. ac427cobra

    ac427cobra FULLTILTBOOGIERACING.COM Staff Member Super Moderator

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    SRA is also an excellent choice for your tow vehicle! ;-)

    [​IMG]
     
  15. SlowSVT

    SlowSVT Well-Known Member Established Member

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    What? No SRA for the red one? :nonono:
     
  16. rotor_powerd

    rotor_powerd Well-Known Member Established Member

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    This is just ignorance. Take a look at AI, and AIX cars then come back and let me know what you find.
     
  17. SlowSVT

    SlowSVT Well-Known Member Established Member

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    Edit: Googled AIX Americam Iron Series.

    Mostly Mustangs, Camaros. OK, so what point are you trying to make?
     
    Last edited: Nov 11, 2009
  18. ac427cobra

    ac427cobra FULLTILTBOOGIERACING.COM Staff Member Super Moderator

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    Did it ever occur to you that NO* modern sports car comes from the factory with an SRA?!?! :read::idea:


    * zero, zilch, zip, nada
     
  19. ous2418

    ous2418 Member Established Member

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    huh???? gt's and gt500's come with sra's
     
  20. ac427cobra

    ac427cobra FULLTILTBOOGIERACING.COM Staff Member Super Moderator

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    Neither a GT nor a GT500 is a "Sports Car". :read:

    They are BOTH "Pony" cars. :idea:

    Sports cars are:

    Corvettes, Ferraris, Lamborghinis, Vipers, Porsches etc. etc. NONE of these HIGH performance sports cars (that all handle very well I might add) come with an SRA. Why?!?! Shouldn't be too hard to figure out actually!
     

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