hot plugs with good gpm and air throttle

Discussion in 'PSI Superchargers Tech Questions' started by overkill69, May 24, 2016.

  1. overkill69

    overkill69 Member

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    We have a BAE5 129% c rotor combo that runs ok with no hurt parts but requires a LOT more gpm than normal to keep reasonable cad on the plugs.
    On our best 201 mph lap the plugs were frosty/chalky and burned down past the first thread.
    We made 330 hits recently and I would call the plugs happy/safe at that point so its building heat pretty early.

    Our egt on the 2 step averages 600 and we leave with about 18 psi at 4400 rpm.
    The air throttle is the big difference between us and most other outlaw promods. I'm wondering if it gets a quick hot spot when the blades come open?

    We also run the R6571a-11 plug which seems to read a little hotter than the 6061.
    We've run a wedge and 2 hemi screw fuel systems and they have all tended to want excess fuel and ran hot egts and plugs.
    I think the wedge really required a lot of fuel but the hemi should be comparable to others that run good.
     
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  2. Mike Canter

    Mike Canter Top Dragster
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    The plugs only show what happened in the last few hundred yards so the problem is it being lean at the end of the run and most likely not the air throttle. If you have 100% frosty on top and down past the first thread then you need to go at least 10 main jet sizes smaller. You need fuel for power especially in the back half. How much timing is in the car towards the end of the run?
     
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  3. overkill69

    overkill69 Member

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    I've never really been able to run fast with good cad on the plugs. On my 330 hits there was 25% on the face of the plug which would be great if it didn't have to make it another 330ft. Lol. I shut all my timers off at 3.2 seconds and give it a bunch of fuel but by 3.8 they are frosty.
    The g Meter didn't seem to care about the additional fuel either.
    I run 23-25 degrees of timing out the back. I launch with about 13 out and feed it in within 2 seconds.
     
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  4. rb0804

    rb0804 Active Member

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    You could add a little fuel leaving while leaving the rest of your tuneup the same and see if it makes a difference. How do the bearings look? The plugs only show the most amount of heat during the run, where that occurs is up to you to figure out. Usually the most heat is at the end of the run, but not always. Good luck.
     
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  5. blownapex

    blownapex Member

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    ill find a comparable run if you send me
    wheather and
    gpm 8000
    9000
    10000 or your highest rpm
    boost at each rpm
    all in high gear
    I had the same engine combo as you
    I actually had the same type car as you it was red and heavier
    and slower (good job on the 3.70s)
    when my plugs are frosty 2-3 runs and it kills the top rings
    leak down gets bad
    we went 3.69 @2550 in the Camaro with brad 5s
    so it should be very comparable if we match the air and boost
    duane
     
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  6. overkill69

    overkill69 Member

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    thanks Duane sent you a PM
     
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  7. Mike Canter

    Mike Canter Top Dragster
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    Duane, Yes plugs will show frosty after 2-3 runs on them but that is not a true reading.
     
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  8. Joad Donnelly

    Joad Donnelly Member

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    I didn't take it that Duane meant that the plugs look frosty after running the same set for 2-3 runs. I took it that if he makes 2-3 runs where the plugs get frosty, with a fresh set of plugs on each run, that the rings end up getting damaged due to the excess heat.
     
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  9. blownapex

    blownapex Member

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    i only run 1 run on plugs
    i wish i didnt have too
     
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  10. WIDEOPEN231

    WIDEOPEN231 Member

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    First rule of tuning.The motor will tell you waht it wants..If plugs,egt's and bearings tell you you need more fuel then give to it.Worst thing to happen would be slower run.Remembering what Newberry told me one time "the idea is to make the motor burn more fuel ,not see how lean you can run it".

    Not all plugs read the same,not all egt's are in best postion in pipe and fat bearings are not always detonation.All 3 meabn your lean.When was pump flow last checked?Is something stupid going on with fuel system would be my first checking points.
     
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