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355 Subframe : Upper Wishbone Brackets

Discussion in '348/355' started by FourthAlfa, Mar 24, 2019.

  1. FourthAlfa

    FourthAlfa Karting
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    Hi Folks,
    If I understand well, the design of the upper wishbone brackets (on the rear subframe) evolved due to weakness where they are welded to the subframe. It seems that it is not uncommon for subframe to crack in this area. I have an early M2.7, with the start of crack so will reinforce this while the engine is out. Would someone with a later car mind posting a picture of the upper wishbone brackets (front and rear) of a later car to see what design upgrade was implemented? (I believe it was just a larger fillet radius). Below are the brackets that I am speaking of.
    Thanks! Image Unavailable, Please Login Image Unavailable, Please Login
     
  2. taz355

    taz355 F1 Veteran
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    Someone posted this before because i thought the challenge cars were all done before the raced or shortly after.
    Theywere gusseted fro what i remember.
    Maybe Tim or Fbb have that info
     
  3. krazykarguy

    krazykarguy Formula Junior
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    I checked a couple of pics from our recent engine out, and ours is a '97. The two pics below are the best images I could find of the area you're looking for.

    It looks like the mounting bracket extends quite a bit lower down the subframe tube than the early cars.

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  4. FourthAlfa

    FourthAlfa Karting
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    Thanks Matt and Tim!
    That is perfect.
    Looks like it is just the front one that got the bigger fillet
     
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  5. Dave rocks

    Dave rocks F1 World Champ
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  6. 308 GTB

    308 GTB F1 Veteran
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  7. INTMD8

    INTMD8 F1 Veteran
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    Tim, if you get a chance sometime I’m interested in the weight of that subframe :)
     
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  8. taz355

    taz355 F1 Veteran
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    What the hell are we looking at.
    Cause i cant see it.

    Is this like a Wheres Waldo game??
     
  9. taz355

    taz355 F1 Veteran
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    Before Tim posts lets get some guesses
    Mine is 64 lbs
     
  10. krazykarguy

    krazykarguy Formula Junior
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    If we're playing by Price is Right rules, my guess is 65 lbs. :p
     
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  11. SoCal1

    SoCal1 F1 Veteran
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    Just weighed it
    With crossmembers and the motor mount bushings way more then I thought, 100.8 pounds

    I got to stop messing with big girls when 100 pounds feels like 45 LOL
     
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  12. taz355

    taz355 F1 Veteran
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    Thanks Tim
    James can now lower his car 50 pounds more with chromoly tubes
     
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  13. INTMD8

    INTMD8 F1 Veteran
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    Thanks for weighing it Tim!

    Grant, you read my mind :D Probably not 50lbs but definitely some room for improvement.
     
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  14. SoCal1

    SoCal1 F1 Veteran
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    ItsI a really clunky old design that's very weak
    Aluminum, chromoly even a hybrid with different geometry would be fun to try
     
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  15. FourthAlfa

    FourthAlfa Karting
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    Thanks Barry for the confirmation of what the challenge cars have as well. Nice to know it is the same solution!
     
  16. 308 GTB

    308 GTB F1 Veteran
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    You're welcome, Andrew. Another weak point on the 1995 cars are the front shock mounts. The metal is very thin there and prone to cracking with the 2200 lb/in front Challenge springs. The 1996 cars have bolstered mounts and the Challenge Manual for that showed parts for strengthening the area. My car never had the modification when it raced. I had it done a few years ago...
     

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  17. GTUnit

    GTUnit Karting
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    Does anyone have any instructions on the recommended reinforcement?
     
  18. FourthAlfa

    FourthAlfa Karting
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    Barry, thanks again for he heads up on weak point in the front! Will check it out.

    As far as reccomendeded reinforcement, I think doing just as Ferrari did on the later subframes would be the reccomendation (but maybe there was a technical bulletin?) It is not really a difficult problem to solve, I am sure any type of gusset/fillet would basically work. I will reinforce mine just as the later cars have it, with the big fillet.
     
  19. PaulK

    PaulK F1 Rookie
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    I will have to check these mounts out. I have a '95.
     

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