Close



Results 1 to 19 of 19
  1. #1

    Default 8.8 or IRS set-up, Decisions

    Okay guy’s, I’m trying to decide which route to take or if in any. My ’82 GT is stock 4 lug with the original 7.5 rear. I plan on building the motor, so I’m pretty sure the 7.5 along with the 4-lug will have to go. So here is my question, my options; go with the 8.8 rear and 5-lug disc all around conversion or go with a ’03 Cobra IRS and SN95 5-lug disc front (undecided on front Susp. If using the IRS). What I plan on doing with the car when it’s finished; it would not be a daily driver, it will be worthy of being entered into a car show but NOT a show car per-say, it will not be a drag car but I may take it to the local track a few times a year just for FUN, it will mainly be driven on short cruises on back roads and day trips with the wifey on the Blue Ridge Parkway, and I could see some track days at many road course’s. I prefer for the car to handle great around corners as I like to drive them a lot more then going straight. As far as looks go, I like the wide stance look but don’t like for the tires to stick outside the fender lip. I would like to use a 10” rear or at least a 9”, I’m not even sure if that would be possible with the IRS…???... Please give me some feed back on what you guys think, and any pictures of any set-ups you might run. I really want the car to handle good but the stance and look have to be right too!!

  2. #2
    FEP Power Member In2Fords's Avatar
    Join Date
    Mar 2009
    Location
    Honolulu, Hawaii
    Posts
    2,079

    Default

    I personally think the only reason to go 5 lug is for better rim choices. I have seen 11-12 second cars on 4 lug. You would have to be making some serious power to shear off the lugs.
    As far as axle, I would stick with a 8.8, if you were going to be doing extensive road tracks then i could see going thru all the trouble of doing a IRS, but not for weekend track fun days. I have been in a couple foxes converted to IRS, seemed better in the corners then my solid axles cars but it wasnt that much softer of a ride and suspension tuning was intense to try to get it to grip on launches, of course that could have just been how the IRS was put in.

    I would build the car with a cheap 8.8, WELD THE TUBES, then after it is complete IF you feel a IRS would be needed takle it then. Nothing like tearing into a huge project then losing steam and finding something allready together to kill a project. Take baby steps

    Good luck man.

  3. #3
    FEP Power Member RichV's Avatar
    Join Date
    Aug 2003
    Location
    Elizabeth, Colorado
    Posts
    2,114

    Default

    An IRS is arguably better on a roadcourse. So either one would sujffice plenty for a fun driver. 5 lug will definitely have more wheels as options. Also, the 5 lug route is easier for cheap brake options.
    85 SVO
    94 GT CMC#71
    65 Fastback

  4. #4
    FEP Power Member qtrracer's Avatar
    Join Date
    Aug 2004
    Location
    California
    Posts
    1,849

    Default

    Been living with an IRS 01 Cobra since new. Rides a bunch better than a stick axle. BUT, leaves alot to be corrected in the handling depertment in stock trim. Tends to squat during acceleration which causes the wheels to go negative camber reducing the contact patch to the inside edges = tire spin. In turns, different forces cause the same thing. This IRS has the 31 spline shafts but the weak-link are the stubs which break if too much power is put to them. This usually occurs during axle tramp which a stock IRS does exceedingly well. Now, all this can be corrected with cubic money, but then you lose what the IRS does best - rides nicely. Also, the IRS cradle is pretty wide which means wheel-width choices when in a fox body will be limited. I'd do an 8.8 stick axle and throw the entire spectrum of MM or Griggs parts at it. The result will be a less complicated system, better handling for less money, and your choice of rim-widths up to 10" or so.
    Last edited by qtrracer; 07-03-2010 at 05:29 PM.

  5. #5

    Default

    If your plans are not road course racing, the 8.8 will more than be sufficient. Like mentioned previously, the Griggs systems are the best and the you could use the money for the IRS to pay for most of it. With the GR40 system, there won't be too many cars that will be able to out handle yours.

  6. #6

    Default

    Guys, thanks for the advice! I'm going to look into the Griggs/ GR40 system, I've never heard of it before. I would love to know/learn more about it, if you could go into some detail on it or post some links for related info.

  7. #7
    FEP Power Member RichV's Avatar
    Join Date
    Aug 2003
    Location
    Elizabeth, Colorado
    Posts
    2,114

    Default

    Get ready for a wallet beating.
    85 SVO
    94 GT CMC#71
    65 Fastback

  8. #8
    FEP Member willrst's Avatar
    Join Date
    Apr 2010
    Location
    Tulsa-ish (Inola) OK
    Posts
    294

    Default

    Quote Originally Posted by qtrracer View Post
    Been living with an IRS 01 Cobra since new. Rides a bunch better than a stick axle. BUT, leaves alot to be corrected in the handling depertment in stock trim. Tends to squat during acceleration which causes the wheels to go negative camber reducing the contact patch to the inside edges = tire spin. In turns, different forces cause the same thing. This IRS has the 31 spline shafts but the weak-link are the stubs which break if too much power is put to them. This usually occurs during axle tramp which a stock IRS does exceedingly well. Now, all this can be corrected with cubic money, but then you lose what the IRS does best - rides nicely. Also, the IRS cradle is pretty wide which means wheel-width choices when in a fox body will be limited. I'd do an 8.8 stick axle and throw the entire spectrum of MM or Griggs parts at it. The result will be a less complicated system, better handling for less money, and your choice of rim-widths up to 10" or so.
    So your saying its not worth it for a DD. Oh and if you dont mind what about dose it cost to put an IRS in a fox?? Im wanting to do it. and do you have any pics? Thinks...
    2004 gmc rst.
    1996 gt for my DD
    1986 notchback in the works... doing a 4.6 5speed swap..

    Will

  9. #9

    Default IRS in 82

    Quote Originally Posted by willrst View Post
    So your saying its not worth it for a DD. Oh and if you dont mind what about dose it cost to put an IRS in a fox?? Im wanting to do it. and do you have any pics? Thinks...
    I just got finished with my car doing exactly what you are thinking about doing. I can answer everything you might have questions about. Just hit me up.....I have not adjusted the coilovers at all corners yet, that's why it's sitting nose high..... and I can take more IRS pics if you need them, just tell me what you want to see......
    Attached Images Attached Images   
    Last edited by halffast82; 07-18-2010 at 08:48 AM. Reason: added pic

  10. #10

    Default

    Who has pic's of their set up, 8.8, 9", IRS, or Griggs? Choice of Control arms, springs etc?? Would like to see your car's set-up/stance and wheel size options!

  11. #11
    FEP Member
    Join Date
    Jun 2007
    Location
    Sunny Arizona
    Posts
    147

    Default Dont forget about...

    Maximum Motorsports!! I am not a fan of Griggs. Too many times I spoke with them and they were anything but friendly. I actually wasted a very pretty penny on their sway bar (against my better judgment but they were the only ones I knew of with that type) for my Modular 82 GT project which wouldn't work so I had to sell it at a big loss. I waited weeks for them to send me the correct hardware too. I just don't have anything good to say...except they do have some nice stuff. Not necessarily better than MM. Its kinda like Ford vs. Chevy. Both have good and bad.

    FWIW...I too have the IRS in my 82 with MM coilovers and bone stock IRS otherwise. I LOVE the way it rides and handles. It used to beat me to death with the solid axle. I wouldn't hesitate to do it again given the chance. Of course, I don't take my handling too serious as in racing of any kind. Its a fun car that I drive occasionally. And I believe you could easily run a 9" wheel given the correct offset. I'm just not sure what that is since I have never tried. I am using 05 GT wheels.

  12. #12
    FEP Member
    Join Date
    Jun 2007
    Location
    Sunny Arizona
    Posts
    147

    Default

    Quote Originally Posted by JOEFIVEOH View Post
    Who has pic's of their set up, 8.8, 9", IRS, or Griggs? Choice of Control arms, springs etc?? Would like to see your car's set-up/stance and wheel size options!

  13. #13

    Default wheels

    Quote Originally Posted by 73z-6sp View Post
    Are those 17's off an 06 gt....

  14. #14
    FEP Power Member RichV's Avatar
    Join Date
    Aug 2003
    Location
    Elizabeth, Colorado
    Posts
    2,114

    Default

    That sounds like a fun project. The 82 looks sweet with those S197 wheels. OT, why did the modular swap not work?
    85 SVO
    94 GT CMC#71
    65 Fastback

  15. #15

    Default

    I went with a built up .045 over 351w/69 block..Just a little old school.....
    Attached Images Attached Images  

  16. #16
    FEP Member
    Join Date
    Jun 2007
    Location
    Sunny Arizona
    Posts
    147

    Default

    The wheels are from an 05. Probably the same as 06. Not sure.

    It wasnt the mod conversion that wouldnt work...it was the sway bar. With my new suspension, it hit the wheels and severely limited my turning radius. The mod engine is awesome!

  17. #17
    FEP Member
    Join Date
    Jun 2007
    Location
    Sunny Arizona
    Posts
    147

    Default

    Quote Originally Posted by halffast82 View Post
    I went with a built up .045 over 351w/69 block..Just a little old school.....
    Nice!

  18. #18
    Banned
    Join Date
    Feb 2009
    Location
    Goldsboro/Pikeville, NC
    Posts
    1,267

    Default

    my friends 275 drag radial class car runs 4 lug and its expected to go in the 4's in the 8th mile with the new setup....

    my 82 has a 5 lug conversion which give me more wheel choices and way better brakes...im planning on doing the IRS swap since i dont plan on running my car at the strip more than a few time a month

  19. #19

    Default

    Joe,

    Here is a link to our Torque Arm tech page for solid axle 8.8 applications:

    http://www.maximummotorsports.com/st...h_rear_susp_ta

    Here is a link to a write up comparing the IRS performance to the performance of the solid axle 8.8 with a TA and PHB.

    http://www.maximummotorsports.com/st..._irs_faq_royce

    The solid axle has an advantage in forward grip from a dead stop, due to the greater amount of antisquat. The IRS has a significant advantage in ride quality due to the much lower unsprung weight.

    When you install both rear suspensions with all of the fixes, the overall cost ends up being about the same, depending on what options you use. If you have any specific questions, just ask.

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •