SN95 IRS SWAP Thread

Discussion in 'Drivetrain' started by DropTopPony, Apr 24, 2014.

  1. DropTopPony

    DropTopPony Administrator Staff Member Admin SN95 Supporter

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    I see a lot of questions on different forums about swapping the 99-04 Cobra IRS into a 94-98. Lets see if we can't put together a thread where everyone can refer back to. I know I have looked at a dozen forums and my head is spinning.

    Tag others that you know have done the swap so we can get some pictures going.
    SIC9250 white95 Handz 330CubeGt

    Inspiration

    [​IMG]
     
  2. DropTopPony

    DropTopPony Administrator Staff Member Admin SN95 Supporter

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  3. DropTopPony

    DropTopPony Administrator Staff Member Admin SN95 Supporter

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    Go ahead, put in pics/tips/advice anything you think will help someone doing this swap.
     
  4. SVTstang96

    SVTstang96 Well-Known Member

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    I have also completed this swap. I will have some more pictures coming up soon. I had it all done, then decided to go coilover. Since then I have taken it back apart and am waiting on a machine shop to machine my shocks so i can finish the coilover setup. Then I will install them, and then I can do the exhaust. I also have a set of MM Stainless brake line for it that need to get put on soon. Once all that is done I will be able to adjust my entire setup and then it will be 100% done for now.
     
  5. SIC9250

    SIC9250 New Member

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    Very straight forward swap honestly,only a few issues to tackle that can be difficult for newbs but its really straight forward.. If your cars not extremely low you don't have to modify any brake hard lines coming from the chassis because the upper control arm will clear,when your car is very low a new fitting/line is required so the control arm will clear during travel and not smash the brake line..I also use the IRS soft caliper brake line for better fitment but the SRA calipers/lines can also be used with slight bending..Also of you don't wanna remove the gas tank and tackle the PITA job of drilling the rear IRS mount bolt provisions that bolt to the chassis in a vertical position you can use the 2 bolts from the original quad shock mount to the chassis and run a nice bead with a welder so there solid,I found this to be much faster and most of the time a IRS swap stays in the car so removal of these isn't necessary..also a pinion flange swap from the SRA to the IRS needs to be done if your using your original driveline..with wide tires you cannot use the IRS e brake cable brackets, it's impossible lol, the tire WILL rub the e brake cable..the 94-98 cars are not as wide as the 99-04 bodies in the inner quarter panels so running wide tires and NOT rubbing the e brake cable is a task in itself to get correct,I just use industrial big ass zip ties and secure them to the lower control arms as tight as possible trust me this is a must! And lastly to use the IRS cobra catback exhaust 99-04 style rear hangers need to be welded onto the rear bumper bar or a custom deal needs to be thought of to work with the sn95 rear factory tail pipe hangers,also abs sensors need to be changed to the IRS specific ones and if you want the more sought after 9/16ths lower sub frame bolts the holes do need to be opened up in the chassis,also don't forget to remove the factory bump stop..other than those items the IRS bolts into place very easy,it's the little things that hold people up..Don't forget 99 IRS's have 28 spline axles and no lower diff brace,the 01 and 03/04s have 31 spline axles and have a factory lower front diff brace..it's and amazing swap no SRA ride can compare in my o2,go for it!
     
  6. Handz

    Handz Member

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    This is not just a simple easy swap. You need to have every correct part. You either have to be able to fabricate new brake lines or, in my car, fab brake lines AND create a new form of brake splitting for the rear brakes. Fab'ing brake lines requires a special set of tools. Also, shortenting for the driveshalf and special U-joints are required. You also need to weld or drill the frame and change out exhaust hangers. Also need to change out the subframe bushings to mount into the 94-98 body. This is NOT a direct bolt in. Does require special work. I did all the special work, and it took me months of research and preparation.

    [​IMG]

    [​IMG]
     
  7. SIC9250

    SIC9250 New Member

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    Handz,please explain the specific sub frame bushings your talking about for the 94-98 chassis as I've never heard of these nor have I had an issue with the 3 other swaps I've done..I always used aftermarket FTB or MM bushings even stockers once and they work superb..is there something I'm missing,curious...also did you use the 03/04 driveshaft and had to get it shortened? Cause the SRA pinion flange to the IRS pinion and use of a stock 96-98 driveshaft is what Ive done with no issues either..(all my swaps were 96-98 cobras,2 mine and a customers car) btw your gt is very sick..
     
  8. Win

    Win Legend

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    actually. Yes while the 01 has 31 spline the circumference of the 01 shaft is not the same as the 03/04 so you would want to upgrade to a 03/04 axles.
     
  9. hondarocks61

    hondarocks61 Active Member

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    Idk what he is talking about either? I still have the stock driveshaft in my 95, it fits perfect, I just used the SRA pinion flange on the IRS differential... That's literally all.
     
  10. Handz

    Handz Member

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    The driveshaft for this swap needs to be shortened 1 inch. The 99 cobra had the T45+IRS combo and the factory 99/01 driveshaft was exactly 1 inch shorter than the GT combo with the T45+SRA combo.

    The stock driveshaft will mount up with force, but it puts strain on the rear trans bushing inside the tailhousing. The proper way to do it is by shortening the driveshaft by 1 inch to match the driveshaft length of the 99/01 cobra.

    I ordered a FRPP driveshaft and it would only mount up by hammering it into place with no play whatsoever. I had to shorten the driveshaft to prevent wear on the trans bushing.
     
  11. SVTstang96

    SVTstang96 Well-Known Member

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    Thats odd because I used my stock one also and it slid in no problem even with about 1/2" of movement left at the tail shaft.
     
  12. SIC9250

    SIC9250 New Member

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    Mmm weird,never had an issue myself with driveshaft issues..
     
  13. Handz

    Handz Member

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    I doubt it was a 1/2 inch of movement. Maybe an 1/8th. Some stock ones fit but this is only because of manufacturing inconsistencies.

    My stock 98 GT driveshaft fit, but was VERY difficult to install and remove. the FRPP aluminum driveshaft didnt even fit. It was very close, but still didnt fit.

    There is a reason 99/01 cobras have a shorter driveshaft than GTs.
     
  14. SVTstang96

    SVTstang96 Well-Known Member

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    Nope, definitely more then 1/8". If it was that tight I would have had it shortened, but there was still enough room that I felt comfortable with it. If I get a moment I will take the bolts out and get a video. It was still a decent amount of room to slide. I can still remove and install the driveshaft with the IRS in the car. This means that I can clear the lip on the pinion flange which is around 1/4" if I remember right.
     
  15. Handz

    Handz Member

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    My driveshaft had zero room to slide the yoke. had to literally hammer the driveshaft off if i wanted to remove it.
     
  16. Handz

    Handz Member

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    The hardest part about the IRS swap is fab'ing brake lines and finding the proper T-fitting splitter.
     
  17. SVTstang96

    SVTstang96 Well-Known Member

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    I agree. I got my splitter from www.belmetric.com and also picked up some lines from them. just had to bend them up. I was going to build my own lines but their lines are cheap and coated so I just said f*** it and ordered them. Total I think it cost me $45 for 2 lines, and the fitting.
     
  18. hondarocks61

    hondarocks61 Active Member

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    I literally still have a good 3/4" of plunge left I can go into on my tailshaft housing. Pretty much exactly the same as stock.

    Very strange Handz had the issues he did? I suppose its a good warning to those swapping to just verify the length of their stock driveshaft, and make sure everything is peachy.
     
  19. hondarocks61

    hondarocks61 Active Member

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    Lol, for my brake lines I just bought a tee and fittings at Advanced auto parts and got the copper nickel brake line for everything while I was there. They should carry everything you need, I believe its 3/16" line.

    Then I got the braided stainless brake line kit from MM, Which is probably the best idea because it includes brackets you MAY NOT HAVE with the IRS you are swapping in.

    - 3/16 brake line

    - 3/16 three way tee

    - 3/16 male flare nuts (x5)

    - MM irs braided line kit (just get the front/rear kit if you don't already have braided front lines, its worth it.)

    I think that's all that's really needed guys.
     
  20. DropTopPony

    DropTopPony Administrator Staff Member Admin SN95 Supporter

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    Did some thread cleaning, good info this should help others searching in the future.


    Post up pics if you have them.