Anyone fancy a manifold project?

  1. mjrally Member

    Messages:
    88
    uk
    Hi guys and gal's,

    Im putting bike throttle bodies on my rally car, and so therfore would like an aluminium manifold making to attach these to. Its a bit of a odd ball as its for a hyundai coupe so isnt an item that could be picked off the shelf.

    So my question is, would anyone be able to asist or point me in the directon of someone or somewhere that would take on the project with me?

    I can produce 2D cad drawings, and have no issue in paying for services (if sensibly priced) and I'm open to offers from businesses or general forum members. Im in no great rush as the car is currently in primer.

    The design will be pritty simple, a back plate with four tubes swept up. like the picture below.
     
    • Manifold.jpg
  2. rtbcomp

    rtbcomp Moderator Staff Member

    Messages:
    18,615
    Location:
    Sheffield UK
    Where in the UK are you?
     
  3. chimpface Member

    Messages:
    15
    oxford
    Get hold of a standard inlet and cut it down as a starter , much easier than trying to draw it from scratch. If the bodys are going to be held on with sillicon tube all you need is a small stubb of alu tube welded on . It will be cheaper and less likely to break as well .
     
  4. Pete.

    Pete. Member

    Messages:
    9,427
    Location:
    Kent, UK
    I bloody hate silicone tube. Ok it's not so bad on a car where you have room to get around and see stuff but on a bike it can be a real pain for rolling up where you can't see or get at it!

    I used a much more better solution for mounting throttle bodies to custom manifolds/plenums using o-rings to seal. Quick, perfect fitment and looks much better too:

    [​IMG]

    [​IMG]

    [​IMG]
     
  5. mjrally Member

    Messages:
    88
    uk
    I live in hinckley, but im often back home to chesterfield and work in warwick so can travel anywhere around the midlands really.

    Yeah Ive seen some cut down ones but id like something a bit more engineered, dont get me wrong its a good idea that would work but im after something thats designed for the job. Also the standard inlets have the injectors next to the head which i dont require, so would need blanking. Ive already done the CAD anyhow so not a problem.

    Those sealing flanges look really nice, how was your plenum held on though? i assume it most be bolted to the frame?
     
  6. Pete.

    Pete. Member

    Messages:
    9,427
    Location:
    Kent, UK
    No, I made some brackets to anchor it to the throttle bodies. You could easily anchor your TB's it to the manifold plate by a similar method.

    [​IMG]
     
  7. chimpface Member

    Messages:
    15
    oxford
    Just thought it would be cost effective as well . I would be a bit worried about constant vibration on welded alu pipes especially with the xtra weight of the throttle bodys hanging off them. Best of luck anyway.
     
  8. Pete.

    Pete. Member

    Messages:
    9,427
    Location:
    Kent, UK
    Total non-issue IMO.
     
  9. mjrally Member

    Messages:
    88
    uk
    Cheers Chimp! Pete, whats an non-issue, the vibration? Those brackets look a great idea and would most likely work too. Depends on if i can get them manufactured? still no offers/ idea's anyone? Im quite happy to have the back plate made somewhere and it welded up somewhere else?
     
  10. KennyC Member

    Messages:
    95
    Derry, Ireland
    My mate has made a few of these before. I'll sort you out with his contact details in a few days if nodoby else offers. Postage from NI may be a deal breaker though :(
     
  11. Pete.

    Pete. Member

    Messages:
    9,427
    Location:
    Kent, UK
    Yes, the vibration is a non-issue. Throttle bodies are a lot lighter than carbs. YOur best bet for the intake plate is to have one water-jet cut.
     
  12. Julian I need medication

    Messages:
    68
    Kent
    My son-inlaws is made from stainless and his mates is just made from steel alley is fairly good but dont count out the steel options as it may be cheaper and does do the same job, we fitted 1 to 20ltr golf that has a crossflow head on it and had twin 40s on prior it goes better with the bike carbs and we did not have to change any of the jets which you may need to do, we do kn ow of another mates escort needing bigger jets which also had to be drilled out to 6 mm.
    Which ever route you go down you will find that you car does go better so also make sure you main bearing is sound we found out the hard way and had to re-build the 20ltr bottom end, unfortunately our mate did not replace the clutch which is now slipping due to the increase of power.
     
  13. mjrally Member

    Messages:
    88
    uk
    I did think about a steel one as i could weld it myself, but it would weigh alot more than an aluminiun one and im trying to keep the car as light as possible, Yeah what research ive done on them i should get good gains. Ill probably run with standard injectors to start and go from there!
     
  14. mjrally Member

    Messages:
    88
    uk
    Right then, latest is ive found a company to machine the back plate for a very sensible price, so hopefully have that done soonish. Im now thinking about the runners, do i have them welded on the inside or outside? im planning on having them inserted into the back plate so lips, but im woundering what will give the most flush fit to the head? Any suggestions?
     
  15. tommy dunlop Member

    Messages:
    121
    uk south east
    manifold flange

    hi i think you can buy a pre cut flange on ebay
     
  16. stuvy

    stuvy Member

    what management will you be running mate, megasquirt or similar?
     
  17. mjrally Member

    Messages:
    88
    uk
    Any links? Im looking at DTA i think stuvy, but looking out for anything that comes up cheap. ive seen megasquirt but seem abit hit or miss to be honest. Also not many rolling roads seem to like it.
     
  18. mjrally Member

    Messages:
    88
    uk
    This is mainly a reply to tommy's Pm but anyones advice is more than welcome.

    After looking at the head and throttle bodies last nite, i agree i will have to taper the runners, so that a get a good flow through the system.

    The tb's are 36mm bore and are off a gxr750 (pic1). one good thing about this is that the diameter of the outer sides of the ports are the same, therefore i should be able to use a 36mm ID tube. My thoughts are then, are to cut down the middle of the tube and bend out the two half's to the same width as the port. Then a small "V shaped" plate will have to be welded in. ill then have to "port" it, to a nice smooth tube. What do you think to that?

    In terms of TB angle, i want to make the runners as straight as possible to the angle of the ports, which i have measured to be 67degrees from the port face. Also as im looking at using them on injection so not worried of flooding and have plenty of room from the baulkhead.

    One issue i have got which if you look at pic 2 of the standard manifold, is that the head has a machining in the port for where the injector heads poke through. So to match the ports i would have to make an extra "hump" in the end of the runners/ manifold backplate. Ideally I'd like not to do this as it means the backplate and runners become alot more difficult to fabricate and match the head exactly.
     
    • hyundai (32).JPG
  19. mjrally Member

    Messages:
    88
    uk
    :laughing:pic2
     
    • IMG_0954.jpg
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