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Technical Help tuning a 3x2 setup on a Studebaker V8

Discussion in 'Traditional Hot Rods' started by zumrodrs, Aug 6, 2020.

  1. zumrodrs
    Joined: Nov 6, 2007
    Posts: 4

    zumrodrs
    Member

    I have a 62 Studebaker 289 V8 in a 1930 Erskine street rod. I have a 65 Stude Danna 44 posi rear with 3:73 gears and a GM 700R4 tranny. I have had a Edmunds 2x2 intake with GM and mopar WW carbs on the 289. The 289 is bored .060. I have just changed to a Smoljan 3x2s intake with Stude WW carbs. I have a 6-127 for the center carb and 6-131 and 6-130 for the end carbs. I also have an oxygen sensor and gauge in the right side exhaust. I have no experience with tuning 3x2s as I have always had AFB carbs since my first Avanti in the 70s.

    I replaced the throttle shafts with Roch 2G extended shafts from Speedway so some of the linkage could be on the passenger side.

    I am running .047 jets in the center carb based on my oxygen gauge. Runs good and spark plugs look good. The gauge tells me I am right on the line between rich and normal.

    A friend says I should be at least .005 smaller jets on the end carbs so they have .042 jets in them. At wide open throttle my gauge says mostly normal and maybe a little rich, so I think I am okay with the jets.

    But when I stomp on the gas I have a couple second bog. I have changed accelerator pump settings which did not seem to matter. I do my testing in 2nd or 3rd gear.

    Do you know what CFM these Stude carbs are and are they to big? Should I be using accel. pumps on the end carbs? Should the jets in the end carbs be bigger or smaller?

    Is there a web site that has CFM info and multi carb tune info? Any help would be appreciated.
     
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  2. carbking
    Joined: Dec 20, 2008
    Posts: 3,715

    carbking
    Member

    Stromberg never published CFM information on the type WW carburetors. Anything you may find will be as good as the tester.

    All factory 3x2 set-ups DID use accelerator pumps on the end carbs.

    Virtually all factory 3x2 set-ups sold with automatic transmissions used vacuum throttle linkage.

    Jon.
     
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  3. dana barlow
    Joined: May 30, 2006
    Posts: 5,115

    dana barlow
    Member
    from Miami Fla.
    1. Y-blocks

    This may not help,but setting here really enjoying that you have a Study V8.
    I've only played 3x2 with 97s an 94s,but linkage set up can have a lot to do with bog,not just carb tune. When trying to help out a buddy with a bad bog,he had played a lot with jets an float along with A-pump to no avail ,so we first blocked off an disconnected end carbs to see if it still bogged. No,so tried only the ends next,no center with temp linkage. Odd but that worked OK,so was thinking carbs were good an hook linkage back up an bog was back. Thinking it could be open timing,we played with when the ends opened,an later helped but still some bog.
    Jeff really wanted to have low idle ,so his auto would not being trying to move too much at a red light. He ran his end carbs full closed to get that.=nothing going on in end carbs at all tell linkage jumped them open when needed.Any end carb that is full closed,will take time to work right when popped open,,so if its part of idle=already limited flow,will start working sooner,I was told.
    Just playing around with trying to make ends also be part of idle=carbs are active stopped the bog,but we also made ends open less then full . Not sure if that really means his carbs together were too much CFM or not,but it ran smooth at full open. May not any help,but there some feed back. I love Study's too.
     
    Last edited: Aug 7, 2020
    kidcampbell71 likes this.
  4. zumrodrs
    Joined: Nov 6, 2007
    Posts: 4

    zumrodrs
    Member

    Is there a way(formula) to calculate the CFM based on throttle plate diameter?
     

  5. carbking
    Joined: Dec 20, 2008
    Posts: 3,715

    carbking
    Member

    No.

    While the throttle diameter has some effect on CFM, the primary items which determine air flow are: the diameter of the main venturi, and the restriction caused by the total volume of the booster venturii.

    As an example of the above, when Holley engineered the dual quad model 4000 carbs for Ford, spacers were designed to increase the volume of the booster venturii, thus reducing the total flow of the carburetor.

    Another example is Pontiac paying Carter to sabotage the AFB with the dummy hot idle compensator in the secondary air flow to allow the tripower engine to outrun the less expensive 4 barrel engine.

    Jon.
     
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  6. carbking
    Joined: Dec 20, 2008
    Posts: 3,715

    carbking
    Member

    Here are pictures of the above examples:

    [​IMG]

    [​IMG]

    Jon
     
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  7. saltflats
    Joined: Aug 14, 2007
    Posts: 12,594

    saltflats
    Member
    from Missouri

    Does your O2 sensor show dead rich or dead lean when you floor it?
     
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  8. aircap
    Joined: Mar 10, 2011
    Posts: 1,748

    aircap
    Member

    Have you asked over on the Studebaker Drivers Club or Racing Studebakers forums?
     
  9. TCTND
    Joined: Dec 27, 2019
    Posts: 543

    TCTND
    Member

    I'd suggest you get it running perfectly on the center carb only first. The outer carbs don't need much (anything really) in the way of low speed accommodation (idle circuit, transition, enrichment valves or needles etc). Set them to open fairly late in the game and be fully open with the center. Then it's just a matter of setting the mains slightly rich for power and engine protection then the acc pumps to cover any bog. Hope this makes sense and helps.
     
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  10. Mike VV
    Joined: Sep 28, 2010
    Posts: 3,029

    Mike VV
    Member
    from SoCal

    Nooo...

    By reading the answers so far, it's obvious that no one knows anything about the Smoljan "manifold" that you are using.
    That..."manifold"...is NOT a manifold. It's just a huge plenum chamber with VERY short runners.
    It's a VERY tough "manifold" to tune, no matter who's holding the screwdriver.
    There IS a reason that you don't see these on anything but show cars...
    You'll need a huge accelerator pump shot for a medium to hard acceleration, at any engine RPM.

    You'll NEVER get very good milage, you'll NEVER get very good power, except maybe at about 100mph and higher..!

    Your car, your money...but I'd...put something else on the engine to hold the carburetor(s).
    Or do as another guy did (in the Stude Racing Site)...that "manifold" is a good basis for building a supercharger manifold, which he did. A VERY nice job, VERY expensive to buy.

    I hope you have a LOT of hair...you'll be pulling it out trying to make the engine run well with it.

    Best of luck.

    Mike
     
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  11. carbking
    Joined: Dec 20, 2008
    Posts: 3,715

    carbking
    Member

    After reading Mike's post above, I Googled the Smoljan manifold. Some very interesting comments, although I take most of the internet with a large dose of salt! ;)

    One post stated that Dave Thibeault in Massachusetts purchased the molds, and was reproducing the manifold. Haven't been in contact with Dave for years; but when I knew him, he was really a stand-up guy. If the internet is correct, and he is reproducing these things, maybe a call to him for diagnostics would be useful. He probably would know more about them than virtually anyone else.

    Jon.
     
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  12. Mike VV
    Joined: Sep 28, 2010
    Posts: 3,029

    Mike VV
    Member
    from SoCal

    Yes, Dave is or was going to reproduce them. Haven't heard if he ever got to it or not, he's had the molds for a while now.
    Many years back, I was going to buy one. After close examination, and seeing that the port runners are only about 1-1/4" long, I knew what I was in for, and decided against it.

    There's a fair amount of Stude hot rods on the road if you know where to look. There's twin two barrel manifolds if your lucky enough to find one, and most work fairly well.

    Mike
     
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  13. Mike VV
    Joined: Sep 28, 2010
    Posts: 3,029

    Mike VV
    Member
    from SoCal

    Zomrodrs -

    Here's another option...MUCH better than your first thought.
    There's a guy on the Studebaker Racing site that is making adapters to install Chevrolet manifolds onto the Stude heads. Not cheap, but they are there.

    Now you buy the manifold of choice, cut all of the thermostat and water passages off, front and rear, give it a sand blasting, and bolt it onto your Stude engine.
    Single four barrel all the way to six two barrel carburetors...your choice.

    Here's what I did -
    https://public.fotki.com/-Mike-/studebaker-int-manifolds/
    Pictures #6 thru #12
    This manifold is going on a very high dollar, 299" Stude engine. It was a "Renegade" intake for the Corvette. It's an after-market manifold to replace the Chevy dual throttle body manifold of the mid-80's as I recall. Been reported to be worth about 50hp over the original GM manifold. Plus I've made changes to the interior myself.

    Mike
     
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  14. jimmy six
    Joined: Mar 21, 2006
    Posts: 14,802

    jimmy six
    ALLIANCE MEMBER

    I did not know this was a non conventional 3-2 manifold. I deleted my post.
     
  15. lippy
    Joined: Sep 27, 2006
    Posts: 6,825

    lippy
    Member
    from Ks

    Mee too. Should have known it wasn't a normal intake. lol We'll let you experimenters fix it. Hell I can't even find a pic of one!!
     
  16. Mike VV
    Joined: Sep 28, 2010
    Posts: 3,029

    Mike VV
    Member
    from SoCal

    Here's a picture of the Smoljan manifold. Not my engine.
    Actually I don't know if this is an original or a copy, in any case, they are all the same.
    Notice the runner legs, that IS...the entire runner length.
    Notice the big box under the carburetors, that is a completely empty box (plenum). No runners, no divider walls, no humps or bumps...no nuthin.

    IF...one were to cut the top off, install a divider down the center, front to rear, then add plates to lengthen the runner ports...as much as possible, then weld the top back in place...
    It MAY be a sorta usable part.


    Another thing. Notice the blocks under the carburetors. Not sure why this guy (normally a VERY qualified guy) did this, but the Stude engine is at about an 8° tail down angle. So that means that the carburetors will be tilted back, 8°. By design, that MAY not be too big a deal for the Rochester carburetors. It may well affect the way that the fuel enters the emulsion tubes and falsly richen the carburetors with a high fuel level. Then lower the fuel level to fix that, and mess with the rest of the system, including possibly starving the accelerator pump well.
    It's still another bad design configuration.

    [​IMG]

    Mike
     
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  17. clem
    Joined: Dec 20, 2006
    Posts: 4,190

    clem
    Member

    Would that not work better with two end carbs as primary, and middle carb as secondary on progressive linkage ?
    Curious as to your opinions.
     
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  18. hrm2k
    Joined: Oct 2, 2007
    Posts: 4,842

    hrm2k
    ALLIANCE MEMBER

    DAMN !!!!!!!!! This is why I love the HAMB.
    Thank you Mike !!!!!!
     
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  19. TCTND
    Joined: Dec 27, 2019
    Posts: 543

    TCTND
    Member

    Sorry, I knew nothing about your manifold. Just trying to throw out some basic triples setup info.
     
  20. aircap
    Joined: Mar 10, 2011
    Posts: 1,748

    aircap
    Member

    I think you mean Jeff Rice. He posts here on the HAMB.
     
  21. zumrodrs
    Joined: Nov 6, 2007
    Posts: 4

    zumrodrs
    Member

    It is dead Lean..

    I probably won't work on it any more this year as I got hit by a flying deer on the way home from the Symco Hot Rod Weekender. I will fix the car over the winter once I have all the parts I need.
     
  22. zumrodrs
    Joined: Nov 6, 2007
    Posts: 4

    zumrodrs
    Member

    I knew the manifold is for high RPM but I am trying to use Studebaker stuff if I can. The car seems to run good on the center carb. I got 17 MPG going to Symco over the weekend before the flying deer hit the car.
     
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  23. Peanut 1959
    Joined: Oct 11, 2008
    Posts: 2,179

    Peanut 1959
    Member

    Oh, no! Serious damage?
     
  24. I have that Intake. I got mine from Dave Thibeault a few years back. I bought mine as Cast (un-machined) I would be curious to hear the results of this build up. I am planing on modifying mine to install on a '50 Cad 331.
     
  25. carbking
    Joined: Dec 20, 2008
    Posts: 3,715

    carbking
    Member

    Sorry about the deer. When a deer decides to hit your ride, you have virtually no chance to prevent the occurance.

    As to your set-up:

    Not sure you will ever get that set-up really streetable with all carburetors functional; however: if that were a conventional manifold, I would SUGGEST the following:

    (1) replace the end carbs with those from the early 1950's Studebaker 233 engine. Still type WW, but flow between 24 and 25 percent LESS air than those you are running. Retain the center carb.
    (2) acquire a set of the Pontiac GTO progressive linkage from one of the Pontiac vendors (I have personally used Ames Performance for decades, but there are others). Modify this linkage to fit the WW carburetors. It is going to take some machine work; but MUCH superior linkage.
    (3) modify the pump circuits on the end carbs to deliver the maximum amount of fuel. This may require the use of stronger pump springs, haven't looked on one in awhile.
    (4) set the carbs up so that you IDLE ON ALL THREE!
    (5) set the progressive GTO linkage such that the ends do NOT open until maybe 75 percent center carb throttle.

    And remember that Mr. Granatelli used dual quads, NOT tripower, on the Studebaker V-8's; I believe he probably knew what he was doing. ;)

    Jon.
     
  26. This builder added the blocks to level the tops of the carbs to use the chosen air cleaner. The intake it self has 8° built into each carb base. But because the intake has equal runners that places the rear carb lower than the front carb.
     
  27. Mike VV
    Joined: Sep 28, 2010
    Posts: 3,029

    Mike VV
    Member
    from SoCal

    No, this intake manifold does "not" have the angle built into it.
    You can see it's NOT there in the photo above, plus, I've had one in my hands, no built in angle.
    Think for just a second...about it...if there WERE the 8° built into it, the spacers would NOT...be required..!

    Mike
     
  28. saltflats
    Joined: Aug 14, 2007
    Posts: 12,594

    saltflats
    Member
    from Missouri

    If it's going dead lean you need to get accelerator pump shot to cover the loss of air flow tell it speeds up and can pull fuel from the boosters. Sorry to hear of the deer incident.
     
  29. I think you need to look at the pictures again!
     
  30. Mike VV
    Joined: Sep 28, 2010
    Posts: 3,029

    Mike VV
    Member
    from SoCal

    Jr. -

    I see said the blind man. I had to move the photo so I could blow it up larger, but yes, there are wedges under the carburetors. Not sure they are the 8° that the engine sits at, but yes.

    This still doesn't alter the fact that this manifold is a bastard to tune, to make power and to get mileage out of though.
    Still a wall hanger in my opinion.

    Mike
     

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