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430 Removing Cats from OEM Headers and Repairing Them

Discussion in '360/430' started by strongx, May 29, 2020.

  1. strongx

    strongx Karting
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    Mar 20, 2009
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    Rock Thompson
    Has anyone drilled/knocked out the cats from their intact, non-leaking headers? If your headers don't leak, but you want them to run cooler and eliminate a failure point, it might be nice to remove the cat. While I've seen this done on motorcycles, those have a straight, relatively easy access to drill and chisel their cats. The F430 headers would require more contortions to get all the cat material out.

    And I know people with leaking headers have cut the heat shields off, cut the manifolds open to remove the cats, then welded everything up again. I've also read that there's a shop that does that, but I can't find who. Does anyone know?

    I have leaking headers, but I can see they leak from a warped flange (I have a machining center that can fix that) and I'm not sure they are leaking internally (but I'll test them and find out). I'm weighing all the options, including just installing aftermarket. But I'd like the sound to change as little as possible (yes, I know it will be louder/different without the cats) and it's kind of nice to stay OEM, if you can do so minus the destroy-your-engine debacle.

    Thanks for any help.
     
  2. Sean F.

    Sean F. F1 Rookie

    Feb 4, 2003
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    Yes someone here did just what you are describing on a 360. Removed both headers, cut back the insulation shields around the cat area, cut open the header and cut out the precat material. Thy welded the header back together, put the insulation back around, welded up the shield and put it all back together.

    You have to remember that once you remove the precat you’ll likely get an error on the dash light.


    Sent from my iPhone using FerrariChat
     
  3. EastMemphis

    EastMemphis Formula Junior
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    >> Has anyone drilled/knocked out the cats from their intact, non-leaking headers?

    I asked this exact question to a master Ferrari tech and he pointed out that by removing the (pre) cat material, the aerodynamic properties of the header are changed due to the formally filled area being empty. Turbulence in the exhaust stream at particular RPM's would rob the car of power and cause a flat spot. I think he said it was 6k RPM's. He recommended against using a header that's been modified in that way.
     
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  4. strongx

    strongx Karting
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    That is very interesting and makes sense. Thanks for the info, before I spent 20 hours figuring out how to do it, only to decrease performance.
     
  5. Dean Palmer

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    Seems like you would be doing a crazy amount of work only to have the factory headers still crack at some time later. I'd understand this if there were no alternatives but there are plenty of headers made for these cars that don't have a history of cracking and failing.
     
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  6. strongx

    strongx Karting
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    But I think there are two reasons the headers crack. First, and increasingly well-known, the factory mounting is terrible, too rigid and won't allow for the considerable length expansion that comes with the high heat, so something has to suffer and that is the headers. Second, the internal cats result in extra high temperature and that further weakens and strains the header welds.

    If the system could allow for expansion, like the Capristo mounts, or just deleting the factory mounts, the OEM headers might well last a very long time. Removing the internal cats might not be necessary, but would have the additional benefit of lowering the heat.

    We know there are some cars with blown engines from ingesting broken material, but it's a relatively rare problem (although very expensive if it happens). Most headers (including the two needing replacement on my car) only crack, and that relieves the stress and probably that's all that happens. Catastrophic ingestion is only possible if a piece of the manifold, or the cat, actually breaks off. If that occurs, the piece cannot escape and will rattle around until it is sucked back into the exhaust.

    Anyway, I'm not going to try and remove my cats. I'll test my headers and if there's a cracked weld I'll go aftermarket. But if the cause of the leak is only a warped flange, I may machine it flat and put them back in, with a new arrangement that allows for expansion.

    My advice to anyone running MkII manifolds: Do not use the factory mounting; modify it now. I wondered if I should change mine after my 1st manifolds were replaced under warranty, but I didn't, after a tech told me they never saw the later manifolds go bad. Now I wish I had, because then I'd be off driving instead of taking minuscule turns with a 12mm wrench and spending enough money to pay for a number of annual services.
     
  7. Jgivoo

    Jgivoo Formula Junior
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    @strongx
    The Ferrari OEM sport exhaust, made by Tubi, is the only real solution. It has zero hard mounting brackets. It allows the entire exhaust system to expand properly. No worries about CEL's with aftermarket headers.
    This exhaust should have been put on all F430's.
    My $0.02
     
  8. 360+Volt=Prius

    360+Volt=Prius Formula 3

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    What about after market headers without pre-cats, Wouldn’t they decrease performance as well?


    Sent from my iPhone using FerrariChat
     
  9. ttforcefed

    ttforcefed F1 World Champ
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    you could do the same with the factory exhaust no, jsut remove the mounting brackets and live without them? i think the factory exhaust and the sport exhaust are the same, just the sport isnt valved.
     
  10. 24000rpm

    24000rpm F1 Rookie
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  11. 9650max

    9650max Karting
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    The Ferrari sport exhaust has valves. They are vacuum operated just like the stock exhaust. The sport exhaust has two small mufflers whereas the stock exhaust is the giant suitcase that is center mounted. As stated above the sport exhaust has rubber mounts. It is also a much cleaner look and you lose the weight of the stock unit. It’s easy to find pictures of both systems, new or installed.
     
  12. Jgivoo

    Jgivoo Formula Junior
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    +1
     
  13. one4torque

    one4torque Formula 3

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    Nice work 24k!
     
  14. Flea7

    Flea7 Formula 3
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    Don't waste your time.
    The only good thing about the stock Ferrari headers are that they make good wall decorations. This is what I did with mine......Garage art!

    Image Unavailable, Please Login
     
  15. RedTaxi

    RedTaxi Formula 3
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    What you say does make sense. But I have F430 challenge headers on my car which I believe are also Scud headers. (Difference being Scuds have air rails) They are simply 430 headers without the cats. The large cavity where the cat would be is still there. I don't think Ferrari would do this on a factory race car if it impeded performance. I can guarantee there is no flat spot. But a proper merge collector in place of the cavity would be better.
     
  16. EastMemphis

    EastMemphis Formula Junior
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    As far as I know, the 430 doesn't have pre-cats installed in the headers.
     
  17. 24000rpm

    24000rpm F1 Rookie
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    euro & US & china versions do
    take a look at your vin?


     
  18. RedTaxi

    RedTaxi Formula 3
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    Euro 360's and US '99 MY 360's don't have precats. But I'm pretty sure all other 360's and all 430's have them. (not scuds though)
     
  19. CoreyNJ

    CoreyNJ Karting

    Apr 17, 2006
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    so why don’t more people do this option? Seems like a good alternative using OEM parts.
     
  20. 24000rpm

    24000rpm F1 Rookie
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    reason is too expensive


     
  21. RedTaxi

    RedTaxi Formula 3
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    I stole my 430 headers for $500 from a wrecked challenge car. But I imagine they would otherwise be hard to come by or if available from Ferrari the price would be exorbitant. It would not be too expensive to just hack the whole cat section off the header and weld on a new collector. The heat shields are a little tricky getting off and back on though.
     
  22. 24000rpm

    24000rpm F1 Rookie
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    if you cut them in the middle like what i did in the pics, its not tricky at all. actually its quite easy

    the hard part is to take the cat materials out, it is , watch my pink lips: HARD TO EVEN MAKE A DENT

    taking out the cat material takes 80% of the whole job's time.


     
  23. CoreyNJ

    CoreyNJ Karting

    Apr 17, 2006
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    don’t seem to be hard to come by or expensive. https://www.scuderiacarparts.com/part-finder/ferrari/430/oe/13/25/982

    If I’m reading the Scuderia parts website correctly, seems like a set would be under 2K USD and wouldn’t need blankets, ceramic coating or wraps and would look stock.
     
  24. 24000rpm

    24000rpm F1 Rookie
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    lots of people think aftermarket are better than oem all around. i am against this idea.

    the oem shield is a work that none of the welders have yet to imitate.

    so that's partially why people don't use scud headers.

    it costs me under $100 of labor to gut the precat and weld it back again.





     
  25. ttforcefed

    ttforcefed F1 World Champ
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    So i think im confused. If one had a late 07+ 430 with the second generation headers what wld you do? Just add a tubi sport exhaust and be done?
     

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