Limits on IRS handling/power
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Thread: Limits on IRS handling/power

  1. #1
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    Limits on IRS handling/power

    OK, first post, be kind.

    I'm considering using a 06 IRS cradle as a basis for a non competition no rules track day non CTS car.
    I expect:
    1. to fabricate my own LCA, and convert to C/O dbl adjustables, heim joint style adjustable inners
    2. Fab my own straight swaybar
    3. Change out rear bearing hubs to vette track series w/ 5x 4.75
    4. Change over to 14.4" CTS V discs
    5. Calipers, not sure if OEM or Wilwoods yet
    6. I want to keep the E brakes
    7. I will add cooling ducts
    8. I picked up a set of BMR trailing HD? arms, but I can't figure why the mid span vertical bend is absolutely necessary
    9. I will likely cut off/remove lower OEM alum shock mounts off the uprights
    10. I will use poly anywhere possible, as long as suspension does not bind
    11. rims will be 20x11 range custom
    12. And the coup de gras, I will rebuild as needed to install a Quick Change IRS rear with 930 CV's, the OEM rear is a goner, a Ford 9" is not an option

    So my questions are:
    a. Am I in the right place for these questions
    b. is this suspension up to the task of 1000hp? Road race only, with 335's?
    c. are later CTSV IRS parts interchangeable and/or more robust?
    d. Anybody gone this path and have any results to share, I am not interested in reinventing the wheel
    e, Since most wheel hop seems to be suspension compliance related, is it worth using a straight lower trailing arm if I have the needed clearances?
    f. I am concerned about using so much poly, that with all the suspension arcs built in, some will start to conflict and bind, anyone seen this?

    I finished the cradle work jig today, so I am chomping at the bit.

    Any thoughts, and If constructive, I'm ears
    Last edited by cuda-cts; 10-23-2018 at 06:39 PM.

  2. #2
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    Well, alright then!

    I'd be in for more details on the build for sure, you know, the one making 1000hp for road racing...that sounds like a good time!

    I dont know that we have a resident suspension design expert, though we do have some rather experienced road racers and the like.
    Build Thread for the Madallac

    Open and Shut - A Tranny Story (TR6060 Teardown and Rebuild)

    JRi Coilovers

    ’09 Sedan Black on Black Recaros 6MT
    Forged HED LSA 10:1 GP 2.5 Ported LSA Heads/TVS1900 Johnson 2110s 2.70/9.55 Pulleys D3 Intake Lid Spacer SW 2”/Catless/Magnaflow Resonators/Corsa Spt DIY Flex Setup ID1300Xs DW300Cs + Walbro 297 Map Ref Aux
    Low Mount D3 HX and Pump -10 Setrab Oil Cooler Diff Cooler Lowered on JRIs Subframe Reinforcement Front and Rear D3 Sway Bars Core Shifter Mantic Twin Disc Clutch Swapped/Widened Sedan Wheels

  3. #3
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    Quote Originally Posted by adam112 View Post
    Well, alright then!

    I'd be in for more details on the build for sure, you know, the one making 1000hp for road racing...that sounds like a good time!

    I don't know that we have a resident suspension design expert, though we do have some rather experienced road racers and the like.
    Thanks, I intend to share what I learn on this project here.

    On "suspension experts", I'm hesitant, they may rain on my parade., but if truth hurts, so be it

    If filtered well on my behalf, I'm sure the info I need is out there.

    We'll see.

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  5. #4
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    Youre gonna get rained on around here...if a raining is due...

    Best of luck...and wtf is this ride its going in? So secretive.
    Build Thread for the Madallac

    Open and Shut - A Tranny Story (TR6060 Teardown and Rebuild)

    JRi Coilovers

    ’09 Sedan Black on Black Recaros 6MT
    Forged HED LSA 10:1 GP 2.5 Ported LSA Heads/TVS1900 Johnson 2110s 2.70/9.55 Pulleys D3 Intake Lid Spacer SW 2”/Catless/Magnaflow Resonators/Corsa Spt DIY Flex Setup ID1300Xs DW300Cs + Walbro 297 Map Ref Aux
    Low Mount D3 HX and Pump -10 Setrab Oil Cooler Diff Cooler Lowered on JRIs Subframe Reinforcement Front and Rear D3 Sway Bars Core Shifter Mantic Twin Disc Clutch Swapped/Widened Sedan Wheels

  6. #5
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    Quote Originally Posted by adam112 View Post
    Youre gonna get rained on around here...if a raining is due...

    Best of luck...and wtf is this ride its going in? So secretive.
    Sorry as new member, don't want to throw any shade on the CTS crowd.

    1972 Barracude w/440" SB Alum A8 w8 EFI centrifugal SC to get to 1K

    Stumbled on this FWIW:

    Old 10-27-2016, 08:29 PM #102
    FuzzyLog1c
    TECH Junkie
    Join Date: Mar 2011
    Location: Connecticut
    Quote:
    Originally Posted by hefftone View Post
    If the suspension layout of the 2nd gen helps with traction..... then cradle swap with 8.8 would be where it's at. Cmon Creative Steel !
    The V2 subframe geometry is identical to the V1 and so is the geometry of the control arms, tie rods, and trailing arms. I have a half dozen V1 and V2 rear control arms and spindles and they're virtually indistinguishable. The trailing arms are rotated 90 degrees for easier access to the bolts. Not a big deal unless you want to migrate your old trailing arms.

    The only interesting differences between the V1 and V2 subframes are the dual front differential mounts and the metal shaping/welding process improvements. The quality is a little better and it looks a little cleaner due to the reduction in the number of welds.
    adam112 and Wrecked Em like this.

  7. #6
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    I don't see how 1000HP on 335s is a good idea regardless of how good the suspension and diff are. On my V, the car is loose at high throttle with 305s in the back. You're talking about ~2x the HP with a 10% increase in the amount of rubber to get that power to the road. I'm sure you intend to be lighter than the Cadillac but even so, this seems like a sub-optimal combination. My 02Z06 made 600HP and I also ran 305s and aggressive throttle was downright dangerous in the turns, the rear end would come loose in a heartbeat.

  8. #7
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    The V1 differential will not hold power if you plan on using it. The V2 diff would be a much more durable choice unless you are just using the subframe as a base to fab in your Ford 8.8?

    Post up some pics of this monster you're creating!

    Sent from my SM-G965U using Tapatalk

  9. #8
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    Quote Originally Posted by RocketSled View Post
    I don't see how 1000HP on 335s is a good idea regardless of how good the suspension and diff are. On my V, the car is loose at high throttle with 305s in the back. You're talking about ~2x the HP with a 10% increase in the amount of rubber to get that power to the road. I'm sure you intend to be lighter than the Cadillac but even so, this seems like a sub-optimal combination. My 02Z06 made 600HP and I also ran 305s and aggressive throttle was downright dangerous in the turns, the rear end would come loose in a heartbeat.
    I agree, the 1000hp target is probably more for bragging rights. One of the reasons I leaned towards a centrifugal, as anything in the lower rpms is not going to the ground. However I am not shy about Aero/Wing usage, but will find my limit in trying to get enough front DF to make the rear wing a useful balance.. I play a lot with CF, so low weight is essentially free hp.
    I weighed the OEM cradle complete last night, without wheels/rims, not sure what the fluid level was, approx 352lbs, which is heavier then I expected. OEM Rotors 1" 5x114 included in above weigh 15.4 lbs, they will be up sized. I expect when complete with my changes, I'll be adding somewhere 65-75 lbs, which IMO ,will be easier to accept because its all(?) below COG and near/over rear axle.
    Last edited by cuda-cts; 01-17-2019 at 08:08 AM.
    adam112 likes this.

  10. #9
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    So I decided on X tracker SKF-BR930555 bearing hubs, no tone ring, 5 x 4.75", 14mm studs, 33 spline, .54" flange, first brand new one to arrive feels like gravel replaced the grease.

    Not sure how this could get by quality control. I'm not impressed.

    Its being returned.

  11. #10
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    Oct 2018
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    Winters IRS Quick Change Showed up, Sweet. 930 CV, Gear Diff 1350, internal oil pump, now I get make it fit.


 

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