Register now to get rid of these ads!

split exaust; exausted

Discussion in 'The Hokey Ass Message Board' started by miltos68, May 10, 2013.

  1. miltos68
    Joined: Jan 29, 2013
    Posts: 94

    miltos68
    Member
    from sacramento

    I want to install a split manifold but a question in regards to manifold aft. I know powersports but stovbolts are new to me. When replacing headers on bikes I would discuss w/client 4 into 1, or 4into 2into 1,or 4into 2 into 1 into 2. All of these had +/-. My question being split manifold into 2 to 1 exaust. Is this pissing in the wind with this motor. Does the true benefit lay with true dual exaust as unrestricted as possible. If my question is completly out there I'll appologise in advance. I just want to learn from other people's experiences.
     
  2. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 9,494

    Rusty O'Toole
    Member

    As you know there are different kinds of headers and tuned exhaust. The split manifold is going to reduce back pressure but not give any tuning effect. You could get practically the same effect by installing a bigger single exhaust.

    The split manifold does 2 things. Gives a hot rod sound and is a little cheaper and easier as you can keep the original exhaust and just add a second one. This does not apply so much today, as it did back when your car was new.

    If all you change is the exhaust it isn't going to make much difference. But combined with dual carbs, or larger carb, plus a cam and a few other tricks (like milled head, shaved flywheel, ignition tuning etc) you can get another 25% HP out of your stock motor.

    By the way this may not be what you want to hear. But if the motor has some miles on it, you should overhaul it before you hop it up. An old motor may last for years if you leave it stock and baby it a little, but blow sky high in a month if you modify it. Have seen this more than once, and so have others on the board.
     
  3. dorf
    Joined: Dec 5, 2008
    Posts: 1,087

    dorf
    Member
    from ohio

    a split manifold is like organ music ,dont pass it up .
     
  4. hillbilly4008
    Joined: Feb 13, 2009
    Posts: 2,917

    hillbilly4008
    Member
    from Rome NY


  5. supervert
    Joined: Mar 8, 2009
    Posts: 433

    supervert
    Member

    i did mine on my flatty, and it made a big difference on the freeway. before it would not go over 65 know matter how much you pushed on the skinny. now it still pulls doing 75+
     
  6. supervert
    Joined: Mar 8, 2009
    Posts: 433

    supervert
    Member

    here is how i did mine

    [​IMG]

    [​IMG]

    [​IMG]
     
  7. miltos68
    Joined: Jan 29, 2013
    Posts: 94

    miltos68
    Member
    from sacramento

    My motor has great compression no more than 6% difference average 132psi. I am not looking for huge gains a 262 will be nestled in there in 3years. I have just had bad luck with the weber 32/36 and exchanged for 38/38 and I am wondering if split exaust will increase flow inorder to better accomodate the weber. What diameter exaust can stock because i believe maybe the exaust is already larger diameter than stock.rusty o'tool yousaid exactly what I want to hear the honest to goodness truth. Thank you. supervert, BEAUTYFUL!
     
  8. miltos68
    Joined: Jan 29, 2013
    Posts: 94

    miltos68
    Member
    from sacramento

    what method did you use for welding the cast iron?
     
  9. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 9,494

    Rusty O'Toole
    Member

    Milto there is an easy method of splitting the manifold I have seen recently. If you look at the bottom of your manifold there are 4 bolts where the intake and exhaust bolt together. So you make a steel plate to fit on there, and weld on a stub and flange. Then you cut into the manifold and bolt on the plate. The flange and stub you can get at any muffler shop.

    For a cool sounding exhaust you need to weld a baffle in the manifold to keep the 2 halves separate, but drill a hole in the middle.
     
  10. R Pope
    Joined: Jan 23, 2006
    Posts: 3,309

    R Pope
    Member

    The sound alone is worth the effort! Nothing raps like a split manifold on a Stovebolt.
     
  11. paintman27
    Joined: Apr 23, 2011
    Posts: 287

    paintman27
    Member
    from new jersey

    here's how I'm doing my 292
    [​IMG]
    [​IMG]
     
  12. supervert
    Joined: Mar 8, 2009
    Posts: 433

    supervert
    Member


    heat for a hour in the oven at 400 deg

    mig weld

    put back in oven for about a half an hour, then turn off oven and just let it sit in their till cool

    the trick is to not let it cool to fast or it will pop and crack

    i have done lots of cast this way and never had a problem with it cracking

    the best way is with nic. rod on a stick welder, but you should still heat and let cool slow
     
  13. supervert
    Joined: Mar 8, 2009
    Posts: 433

    supervert
    Member

    that is a beautiful header, and i dig the control arm, looks like a nice setup

     
  14. reds headers does some nice work as well
     
  15. miltos68
    Joined: Jan 29, 2013
    Posts: 94

    miltos68
    Member
    from sacramento

    Those are very nice. stainless?
     
  16. N8B
    Joined: Sep 28, 2009
    Posts: 476

    N8B
    Member

    I have a triple split exhaust on a 235 in an old chevy circle track racer which raced through the antique nationals until 1996.
    It is the fastest and best sounding I6 I have ever had the pleasure of driving.

    I will snap some pictures when I get the chance.
     
  17. miltos68
    Joined: Jan 29, 2013
    Posts: 94

    miltos68
    Member
    from sacramento

  18. miltos68
    Joined: Jan 29, 2013
    Posts: 94

    miltos68
    Member
    from sacramento

    is a stock exaust diameter 2in?
     
  19. N8B
    Joined: Sep 28, 2009
    Posts: 476

    N8B
    Member

    Sorry for the crappy picture but it's the best I can do for now.
    [​IMG]

    You can see the first and last exhaust ports are connected towards the rear port.
    They continue with a single exhaust tube to the rear of the car.
    The middle two exhaust ports are both single down pipes and run about 3/4 of the way to the rear of the car before combining into a single tail pipe.

    It's not the prettiest setup in the world but this was done in 1946.
     
    Last edited: May 12, 2013
  20. N8B
    Joined: Sep 28, 2009
    Posts: 476

    N8B
    Member

    Here is another immaculate way of doing it. Almost likes Paintman's above but into lakes megaphones.
    This was designed and built buy a friend of mine on his Chevy Sedan.
    [​IMG]
     
  21. miltos68
    Joined: Jan 29, 2013
    Posts: 94

    miltos68
    Member
    from sacramento

    N8B is that cast iron? looks like it would do the trick
     
  22. its the sound boys
    2 in is fine
    i should fire up the glass pack factory and make some 3 in cased ones again but my domer is stuck hig up in a grainery on farm
    i made a tripple split for a 216 long ago when iwas about 16, buzz box will weld a lot of cast when you dont care
     
  23. miltos68
    Joined: Jan 29, 2013
    Posts: 94

    miltos68
    Member
    from sacramento

    N8B is that cast iron? I do think regardless of looks will do the trick.
     
  24. N8B
    Joined: Sep 28, 2009
    Posts: 476

    N8B
    Member

    On mine, yes those are the original cast iron flanges cut & welded to the additional tubing.
    Like most have said before you can weld it with preheating of the cast iron.
    I have seen preheating done with a torch between 375 and 400 degrees (red hot) then MIG it. Let it cool naturally and slow.

    I will get better pictures tomorrow from multiple angles.
     
  25. miltos68
    Joined: Jan 29, 2013
    Posts: 94

    miltos68
    Member
    from sacramento

    I have heard that if its cold enough outside, you can weld cast iron but only about a half inch at a time then let cool.If it is cold out then cooling happens rapidly. I would only test this on scrap first.
     
  26. Unsafe6
    Joined: Dec 7, 2007
    Posts: 129

    Unsafe6
    Member

Share This Page

Register now to get rid of these ads!

Archive

Copyright © 1995-2021 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.