Idle EGT temps

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by Big Steve, Apr 3, 2018.

  1. Big Steve

    Big Steve New Member

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    On a blown injected BBC with 14/71 HH what do you like seeing for EGT at idle? also what kind of fuel pressure at idle? I Know that can be nozzle dependant but just looking for something to reference
     
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  2. Mike Canter

    Mike Canter Top Dragster

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    Those are hard questions. Idle pressures can vary from 20 to 60 psi depending on how it is setup such as what is the pump loop check valve set at? Idle temps normally average about 450 but some cylinders maybe 575 if they are the back ones
     
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  3. Big Steve

    Big Steve New Member

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    Thank for the quick response Mike. Reason I asked is I did a first time start up last night on a brand new build, TBS XR1 blower JBR hat. Brand new Enderlie 110 twin gear pump BV at 75% blades at.012. Idle check at 10PSI and port at 25. Pressure was 16 psi It surged like a mofo and EGTs were 950-1050 at idle. Hat nozzles front to back are 56, 54, 52 and 48 x 4 in the blower. I think I have a vacuum leak under the hat. what was weird is I richened the BV and ithe surge got worse
     
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    Last edited: Apr 4, 2018
  4. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    With the port check at 25 it will most likely only idle on the fuel going through the hat.

    Surging usually comes from rich barrel valve. what is your idle rpm?

    I like to have the port check around 6-8 psi so it can get some fuel to the ports at idle then set the bv accordingly.
     
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  5. Mike Canter

    Mike Canter Top Dragster

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    Steve, yes agree you may have a leak above the blower. Also with your EGT temps that high on idle you might want to make your Barrel Valve leak down a couple of points richer. I agree with Will that normally too rich causes surging but your EGTs show you are lean. Also where are you reading the fuel pressure? At the pump or after the BV? Yes bring the port check valve down below 15. If you are reading fuel pressure at the pump there is a big pressure drop by the time it gets to the port check.
     
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  6. Big Steve

    Big Steve New Member

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    Will, idle was in the 2-2200 range in park, when I put it in gear it would surge so bad it would almost kill the motor. the 25psi port check seems to be the consensus from those I have talked to for a BBC in TD to on the hat only on the 2 step. High EGTs I bet is from fuel burning in the pipe. Definitely fat
     
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  7. Big Steve

    Big Steve New Member

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    Reading at the pump, also have on at the port line of the BV but its not reading for some reason, showing 0
     
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  8. kosky racing

    kosky racing Comp Eliminator

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    Port check in backward?
     
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  9. Big Steve

    Big Steve New Member

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    No it is correct and cracks right at 25
     
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  10. Mike Canter

    Mike Canter Top Dragster

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    What do you have the pump loop check valve set at. If it is too close to the idle pump pressure it may be opening and closing.
     
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  11. BB/FA 182

    BB/FA 182 Member

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    send to advanced power systems randy Anderson end all the guess ing.
     
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  12. Mike Canter

    Mike Canter Top Dragster

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    That does make easier BUT takes all the fun out if learning a fuel system and how to set it up yourself
     
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  13. Big Steve

    Big Steve New Member

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    Mike I do not have a pump sizer loop, with a 13gpm pump Jim at Enderlie didnt feel it is needed. . Made a few changes today, took some nozzle area away in the hat, reset the BV from 75 to 72. BV is 2 flats from lean. made a pill change from 125 to 135 and it idles really good at 2200 EGT temps dropped to 850-950 but still surges bad in gear, 1300-2300. Pump pressure now at 20 at idle
     
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    Last edited: Apr 4, 2018
  14. Mike Canter

    Mike Canter Top Dragster

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    What about the suspected leaks between the hat and blower?
     
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  15. Bjs344

    Bjs344 Member

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    I can't imagine getting my BBC to idle at the egts Mike mentioned above. Mine likes about 800 average. I have it setup so it surges pretty good at first but about the time I back up from the burnout, it's pretty well cleared up. I clean it up with the shutoff during warmups or if I have to sit more than a couple seconds in the bleach box.

    It used to surge all the way into the beams before I raised and cleaned my idle check. I actually got pretty good at staging with the surge, kinda preferred it that way. Not sure I really fixed anything by smoothing it out.

    2200 would drive me nuts not to mention drain my tank. I can get it clean at 1600-1700 if I mess with it a lot, but never found a reason to idle a bracket car higher than 18-1900. Pretty sure my blades are less than .010 and my bv is wherever it sounds right.
     
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  16. Big Steve

    Big Steve New Member

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    Looked good Mike, nozzle plate is o ringed both sides and making good contact, blower restraint plate siliconed and tight
     
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  17. Bob Alberty Jr.

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    Mine idles in the lower 900's with a couple of stragglers in the upper 800's at 1625 rpm with absolutely no surge. Personally I detest the surge.
    Who's leak down meter are you using, and where is the regulator set on the compress?
    I use the big moroso meter, and have a snap on also. Not a fan of the dual gauge 69 dollar ones that seem to be so popular.
    With regulated pressure of 100lbs either of mine will read (x), but, as a test i checked, and at non regulated pressure (125) the reading is different on both of my gauges.
     
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  18. Andy C

    Andy C Member

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    The air/fuel ratio is not correct at idle - we ran a BBC for long time without any problems, low idle EGT;s and smooth idle in gear @15-1600.
    The butterflies are closed too tight - not enough Air for amount of fuel coming into the engine.
    Open the butterflies - richen the BV - untill you get idle EGT
    Also 135 pill will make the engine run very very lean at high RPM. i would not run it.
     
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  19. Critical Mass

    Critical Mass Member

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    Steve,
    You never mentioned if you are using a high-speed. A high-speed will act like a pump loop if the crack pressure is low enough.
    Joe
     
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  20. Big Steve

    Big Steve New Member

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    No high speed, this is a brand new combo with all brand new parts. Just trying to keep it simple to start with
     
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