Noses over at WOT when at operating temperature

Discussion in 'Street/strip 400/430/455' started by Smartin, Apr 11, 2010.

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  1. 69GS400s

    69GS400s ...my own amusement ride!

    Exactly why i suggested back halfing it - new fuel cell, electric pump with high volume race can filter, 1/2" braided line to the carb ... Eliminates almost all points of trouble with one fell swoop

    ... Nobody ever takes me seriuosly
     
    69GS400s, Apr 16, 2010
    #41
  2. Buizila

    Buizila GO BROWNS !!!!!!

    If there is an issue with the return system it won't come up with a fuel pressure test. What was happening with my Bro's car was to much fuel was returning to the tank. Pressure was fine but there wasn't enough volume of fuel to keep up with the demand of the engine. When the engine is warm some fuel vapors off and if there isn't enough fuel in the carb from lack of volume the car will stumble and fall on its' face. You can have 40lbs of pressure through a garden hose and 40lbs of pressure through a straw, but the garden hose will deliver and fill a 5gal bucket faster than the straw because there is more volume of fluid.
     
    Buizila, Apr 16, 2010
    #42
  3. Smartin

    Smartin antiqueautomotiveservice.com Staff Member

    The return hole in the pump is like .080...I doubt that's it, but it won't hurt to plug it for testing.

    I just have to find a gauge. The zone doesn't have them. I hope the speed shop is open tomorrow.
     
    Smartin, Apr 16, 2010
    #43
  4. Smartin

    Smartin antiqueautomotiveservice.com Staff Member

    Picked one up at O'Reilly for $18...

    Also bought $6000 worth of brass fittings to get this thing plumbed up right:Dou:

    Time to get dirty!
     
    Smartin, Apr 17, 2010
    #44
  5. Smartin

    Smartin antiqueautomotiveservice.com Staff Member

    um....


    I'm guessing that anytime the gauge drops to 0, that's not a good thing:Dou:

    What is an ideal pressure at WOT?

    At cruising speed, it is rock solid at 4.5 psi, but when I hammer it and stay on it, it will drop to zero, and struggle to return unless I let off.
     
    Smartin, Apr 17, 2010
    #45
  6. DaWildcat

    DaWildcat Platinum Level Contributor

    I like to see 2-3 psi minimum at WOT.

    Devon
     
    DaWildcat, Apr 17, 2010
    #46
  7. Jim Weise

    Jim Weise EFI/DIS 482

    You need at least 3 psi at WOT to insure the Q-jet carb bowl stays full. Holley's can get away with a little less, because they have dual fuel inlets.

    JW
     
    Jim Weise, Apr 17, 2010
    #47
  8. Smartin

    Smartin antiqueautomotiveservice.com Staff Member

    I'm going to replace the rubber lines at the tank and see what happens. I guess I didn't pass that part of the test when I dropped the tank to replace the sending unit:laugh: The tank is full right now, so I'll have to wait until I get low again to drop it, so I can take a look at the sock in the tank.

    If that doesn't fix it, then I guess I need an electric pump? (That is what I was trying to avoid with the TA pump:Dou: )
     
    Smartin, Apr 17, 2010
    #48
  9. TORQUED455

    TORQUED455 Well-Known Member

    If you take the pick-up out, remove the sock and don't install a new one.

    Did you state what filter you are using?

    Jim's billet mechanical pump would EASILY supply your engine's fuel demands.
     
    TORQUED455, Apr 17, 2010
    #49
  10. Smartin

    Smartin antiqueautomotiveservice.com Staff Member

    If it turns out to be a pump problem, why is this thing advertised to be good up to 500 hp? I'm close, but about 50 hp short of that.

    JW - if that's the case, then will your pump do the job? I would REALLY rather use a mechanical pump than have to wire and plumb an electric pump in. Plus, I've been dragging my feet on buying a convertor from you:Dou: ...hmmm
     
    Smartin, Apr 17, 2010
    #50
  11. TORQUED455

    TORQUED455 Well-Known Member

    There are pumping losses to consider too. Long, poorly bent factory lines, acceleration forces, etc, vs a pump sucking out of a bucket feeding an engine on a dyno.
     
    TORQUED455, Apr 17, 2010
    #51
  12. Jim Weise

    Jim Weise EFI/DIS 482

    I've tested just about all the 455 mechanical pumps out there, with a few exceptions. Never tested the one from Robbmc..

    But as far as what we have done, the only pump anywhere near capable of feeding 500 HP was my billet one.. The particular version of the one I use is rated at 850HP.. but with different internals, the basic pump design will feed up to 1100.. it's the Nascar Cup series cars pump, before they went to the cable drive stuff. I adapt it to fit our Buicks.


    Get some other feedback from folks out there, there may be another, somewhat less expensive mechanical pump option for you Adam. I don't have any experience, nor have I tested Rob's pump, but there are guys on here running it.

    My Billet pump is a beautiful, very capable piece of equipment, which will fuel virtually anything you can do with a 455.. but it has a price tag that goes with those attributes.

    Here's the relevant information:

    http://www.trishieldperformance.com/prod04.htm

    the manufacturer's site of my pump..

    http://www.cvproducts.com/ProdDet.aspx?PN=SPIN-MP-2509

    The basic pump design has been around since the 90's, they re-branded and re-spec'd the pumps here a couple years ago.

    The RobbMC pump

    http://www.robbmcperformance.com/products/buick550.html


    Like I said, I have no experience with that pump, but the lack of wear pad on the arm was an issue with actual in-car pump performance, that we saw with the STG 1 pumps when GM discontinued the wear pad on those pumps.

    Get some feedback from others here on that unit.

    JW
     
    Jim Weise, Apr 17, 2010
    #52
  13. TORQUED455

    TORQUED455 Well-Known Member

    Jim's pump is worth every penny, IMO. I have it on my 600+ HP convertible that runs low 11's, and if the noisey BG400 leaks one more time on my 750 HP "X", I will install it in the scrap metal bin and put one of Jim's on that car too.
     
    TORQUED455, Apr 17, 2010
    #53
  14. Yardley

    Yardley Club Jackass

    Any update Smarty?
     
    Yardley, Apr 20, 2010
    #54
  15. Smartin

    Smartin antiqueautomotiveservice.com Staff Member

    No, I parked it on Sunday after a nice drive to mom & dad's house.

    I didn't realize my engine was that thirsty.
     
    Smartin, Apr 20, 2010
    #55
  16. Smartin

    Smartin antiqueautomotiveservice.com Staff Member

    Holley red pump appears to have solved the problem. I gave up on the mechanical pump idea...since I was either going to spend $$$ on JW's pump, or hail mary a RobbMc pump and hope it worked. So I spent $100 on a Holley electric.

    The mechanical TA pump on there now doesn't seem to be able to pull through the pump if I have it off, though. It died when I was driving out of the subdivision on the first test drive...so I drove the rest of the time with the holley pump on. I wonder of the stage1 pump would pull better.
     
    Smartin, Apr 24, 2010
    #56
  17. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Adam,
    I have a Holley Red pushing up to a Stage1 mechanical. I have a shut off valve inline with the vapor return line. If I shut the valve off (plug the return line), it pulls fine on the street up to about 3/4 throttle. If I open up the valve, it noses over at less than half throttle. This is with the Holley off. At the track, it will nose over between 2nd and 3rd gear without the Holley pushing.

    I'm eventually going to upgrade to 1/2" pickup and fuel line, and either JW's or Robb Mc's pump.
     
    LARRY70GS, Apr 25, 2010
    #57
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