vauxhall v6 fwd exhaust manifold

  1. so i made up a tubular exhaust manifold for a guy on another fourm and thought id stick up some pictures for all to see

    firstly had to get some flanges plasma cut from 10mm s/s and some 1 38mm pipes bent at a certin angle so i could make the 2 sets of headers.
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    i got enough material to make x2 sets of manifolds

    these are the ones i made for my own car around 3 years ago they are also s/s
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    first job was to get my round pipe fitted into the flange. it was and odd shape so i had to make a dye to press them to the shape i wanted. i cut some 8mm s/s and welded them together then grinded them into shape.
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    it wasnt perfect but did the trick ok
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    i could then start with the pipes
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    i was eventually left with this
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    when id both the front a rear headers made i could start on the connecting down pipes
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    when i was happy with the fit i welded the down pipes but i had only tacked the connecting flanges incse they need ajusting
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    i refitted the manifolds and tacked the flanges on in place when it was all bolted together so ensuring a perfect fit

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    this is it beside the standard setup
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    this gives you an idea of how restrictive the standard setup is
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    from start to finish it took 14hours so wasnt too bad
     
  2. ross27 Member

    Messages:
    79
    Glasgow, Scotland
    Excellent work mate! How much are you charging for that? (If you dont mind me asking)
     
  3. There £500 plus p&p
    You lookin a set?? :)
     
  4. AndyStobbs Member

    Messages:
    2,476
    Location:
    North West England
    How do they perform on a dyno? Did you do a back to back on your own set at all?
     
  5. Jim_gsxr1000

    Jim_gsxr1000 Mechanical Magician

    Looks realy good :)
     
  6. pedrobedro

    pedrobedro Man at Matalan

    Messages:
    10,383
    Location:
    CX Derbyshire
    Does the standard one have a flexy in the front downpipe before the union with the main exhaust ? It doesn't look to do anything and they are always a weak point in any I've had. It looks a nice set up.
     
  7. The standard setup has a flexi in the same position. And I've thought about not fitting one but some room for movement can't do any harm espically with metal expansion when it gets hot. if or when it hits the road it will always give a bit too
     
  8. DuffyBB Member

    Messages:
    265
    Central Scotland
    Going the equal lenght route i see. Would have thought you'd have sold a few sets, seen many group buy's come and go on vec forums. Usually ends up about £7-800 and interest tapers off and the thread fizzles out.

    There's even been talk of a ford probe(iirc) manifold setup being butchered to fit as their a fraction of the cost on ebay.

    Aye this one.
     
  9. AndyStobbs Member

    Messages:
    2,476
    Location:
    North West England
    I've played pretty extensively with my vec, and have come to believe its the inlet thats most restrictive in standard form - on my y26se engine in a vectra b. That and really bad mapping for WOT seem to hold mine back more so than exhaust difficulties. Hence why I would be keen to see a dyno print out - I always want that extra HP if it can be had economically.
     
  10. I've had mine on a dyno but never had a before dyno run as I built my engine with manifolds ect when I converted my cavalier from 2 ltr to 2.5 (c25xe engine) a few years ago.

    I've seen a thread on vvoc once for manifolds. I followed it for a wile but as you say I think it fizzed out after a year or so

    These are for a 3.2 with a vectra sump fitted into a mk4 Astra and all been well they fit ok ill look into makin jig and a few more sets
     
  11. AndyStobbs Member

    Messages:
    2,476
    Location:
    North West England
    Meant to say, your workmanship looks top notch at any rate.
     
  12. Thank you sir
     
  13. vst143 New Member

    Messages:
    1
    Hull England
    look really sexy :) what would be the chances and price of a pair of those sweet manifolds to fit a vec supertouring with a 3.2 conversion. ideally I wanted the manifolds to mate up with a miltek or hoffnamm sports cat/downpipes. thanks :)
     
  14. Flapdisk Member

    Messages:
    728
    Location:
    UK Warwickshire
    Absolutely beautiful, well done mate superb standard of welding
     
  15. Goldenb19 New Member

    Messages:
    1
    Location:
    Kings Lynn England
    Sweeeeet!!!
     
  16. Shakes New Member

    Messages:
    4
    Location:
    stockton
    Hello noticed this thread is a few years old but are you still making these thedondy? I'd be interested in buying one if you are.
     
  17. T0rnado69

    T0rnado69 DIY nut !!

    Messages:
    1,683
    Location:
    Basildon, Essex
    a quick check on his profile shows.

    thedondy was last seen: Jul 31, 2013
     
  18. AndyStobbs Member

    Messages:
    2,476
    Location:
    North West England
    Tell us more about your vectra
     
  19. Kent

    Kent Member

    Messages:
    10,002
    Location:
    Bowland, Lanacshire,UK
    Does this sort of thing ever alter the exhast gas sensor?
     
  20. AndyStobbs Member

    Messages:
    2,476
    Location:
    North West England
    In what respect?
    The set I made for my vectra certainly altered the location of the lambda sensors, and as my original manifolds were of the mani-verter type (built in catalytic converters) it made the post-cat lambda sensors redundant.
    As long as the location of the lambda sensor doesn't move too much that the sensor runs too hot or too cool, keeping wire length in mind too then its ok.
    Obviously it would be bad practice to situate the sensor somewhere that'll bias its reading's to one cylinder, or where condensate could drip onto it during warm up.
     
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