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Thread: Need help on BBC alcohol tune.ROOKIES

  1. #1
    Senior Member RACING JUNKIE
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    Need help on BBC alcohol tune.ROOKIES

    My buddy has a FED with a port injection Ron's toilet bowl on it.We are having a hard time leaning it out.It is extremely rich.Milks the oil completely on a 2-3 minute warm-up.We run water in the block so as to have a temp reading.Takes about 2-2.5 minutes of idling to hit 140.Goes thru water box at 140,light burnout and still at 140.Kill time staging(we notify the other lane of our problem )and creep it up to 160-170.Make a pass(1/8 mile) and it might see 190.

    468 BBc
    12:1 static comp
    B&M 250 Powercharger putting out 12-15 lbs of boost
    Edelbrock heads
    Cam is Solid roller with specs around 660 lift and 260 [email protected]
    Exhaust is zoomies

    Toilet is setup with a 80A pump
    feed and return lines are both 6 AN and are under 4 ft long each
    nozzles are 37
    Pill is 80

    We tried a 90 pill but line pressure dropped so bad that when we burped the throttle to check the barrel valve it would spit fuel out of the nozzle(around the sponges/air bleeds).It made no boost at any rpm in nuetral with the larger pulley and we had no problem with spitting,but were rich.Wanted to try the smaller pulley(12-15 lb boost) and figured it would help lean out the engine.That pulley would make 3 lbs boost just revving in nuetral.That is when the spitting started.We put the 80 pill back in and still spit too bad.Put big pulley back on with 90 pill and it spit.Only way that the line pressure is high enough to overcome the spitting is with an 80 pill.But then we're rich.Seems we need a nozzle change,but Ron's says to run what we got and just tune around that 80 pill and keep with the 37 nozzles.

    BTW.We zoomie for #6 feels cold but plug looks consistent with the rest.Also,entire left side(cyl 1,3,5 &7)feels alot cooler than the other side.????

    Thanks for any info,we are both new to alcohol.He can have it,I think I'll stick with gas
    "The problem with quotes on the Internet is that you cannot confirm their validity"- Abraham Lincoln

  2. #2
    Senior Member RACING JUNKIE
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    I messed up.It would do fine,and not spit,with the big pulley and a 90 pill,but was still rich.90 pill and little pulley would spit back.How much should you adjust with the pill before giving up and trying another nozzle?When we went from the 80 to the 90 pill we picked up .03 and 5 mph but were stil way off what we had before.Car has ran a best of 5.17 at 140 mph.Were stuck in the 5.30s now.
    "The problem with quotes on the Internet is that you cannot confirm their validity"- Abraham Lincoln

  3. #3
    Senior Member RACING JUNKIE
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    Barrel valve is too fat. What's the leak down set at?
    -WJ Birmingham

    OneBadGMC.com

  4. #4
    Senior Member RACING JUNKIE
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    Quote Originally Posted by OneBadGMC
    Barrel valve is too fat. What's the leak down set at?
    I'll have to find out about the leak down.I know that the Rons system has a built in check valve on the return line,nonadjustable at 3 psi,if that is what you mean.You think it could just be in the barrel valveand not the pill and nozzles?
    "The problem with quotes on the Internet is that you cannot confirm their validity"- Abraham Lincoln

  5. #5
    Oh boy! You're trying to tune and you aren't using a leakdown gauge, Weeeee, are you in for some fun!

  6. #6
    Senior Member RACING JUNKIE
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    This is my buddies car.He has all the fancy toys,we just don't know how to read 'em
    "The problem with quotes on the Internet is that you cannot confirm their validity"- Abraham Lincoln

  7. #7
    Senior Member RACING JUNKIE
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    Schooled you on carbs... Guess it's time to get schooled in mech injection.

    How to leak down a BV using a 2 gauge tester:

    1. Block off all injector lines & returns except for hat nozzles
    2. Connect dual gauge tester to outlet of compressor
    3. Set Air Compressor to read 100psi on 1st gauge
    4. Connect tester to inlet of barrel valve
    5. Read % on 2nd gauge

    A good starting point for a blown motor is going to be 25% on a dual gauge. 75% on a single gauge tester.

    Now, go buy this book: http://racecarbook.com/firs.shtml
    -WJ Birmingham

    OneBadGMC.com

  8. #8
    Senior Member RACING JUNKIE
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    Quote Originally Posted by OneBadGMC
    Schooled you on carbs...
    :shock: :?: Thanks for the info on the leakdown!!
    "The problem with quotes on the Internet is that you cannot confirm their validity"- Abraham Lincoln

  9. #9
    Senior Member RACING JUNKIE
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    Got the leakdown set,leaner than Ron's reccomends,but seems to be working ok.Thanks for all the info.How do ya'll run your returns?To the tank?Pump inlet-tee?What works best?Also,who makes the best crank trigger?Thanks again!!
    "The problem with quotes on the Internet is that you cannot confirm their validity"- Abraham Lincoln

  10. #10
    Senior Member RACING JUNKIE
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    You realize that the leak down is just a base, and that you'll have to change it 2-3 times every day, right?

    Start the motor, loosen the screws, fatten it up until it surges, then lean it back out just until the surging stops.

    As for plumbing.... See below.

    -WJ Birmingham

    OneBadGMC.com


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