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Thread: demon carb-->help<--

  1. #1
    ive got a 450hp sb chevy with a 725cfm demon on it. my buddy and i have TWEAKED on this thing for the last yr and a half. it idles great @ 800rpm. with the motor warm you stomp on it and it $hits on itself for a second then gets with it. so i got pissed and bought a new edl 750 and it idles great and the imeadiate response is way better then the demon but the top end sucks, so the demon is back on.. tweaked on the demon for a few hours.. same $hit.. F@#k this thing.. which holley to buy to match the demon? it sits on a airgap with a 1/2'' spacer.. thanks!!
    anyone else have prob with these carbs?? damn..

  2. #2
    Did you try calling Barry Grant? The tech line has been very helpful in the past.

  3. #3
    Yes, the above.
    Is this only from an idle to WOT slam?
    What happens if you just roll the throttle down slower? Does it do anything then?
    Once you are above idle (cruising at part throttle), does it have any problems being slammed WOT then?
    Sounds like a starvation just off idle to me, depending on the above answers, which is usually an accelerator pump problem.
    On a Holley (don't have a demon so I don't know) the accelerator pump is not only adjustable by output size, but actuation timing and timing volume is adjustable by the plastic cam that drives it (shape & size). Also the accel pump shooter size is adjustable (which regulates fuel shot output volume as well).

  4. #4
    The best advice I can give you is call Don @ 503 627 0728 or Email him @ Go to his website and look around. He has written a book on tuning Demons and others. Buy his book for 10.00 it explains the whole event of whats going on and how to make them work. When you buy his book he will also assist you by phone. The guy knows his ***t. Good luck its not black magic. CDBA "HOWLER" 439 Jim

  5. #5
    Throw it away and buy a Holly.

  6. #6
    im with u schiada.. nope at cruising speeds stomp it to the floor and it is GONE.. this motor is in a car. 62 nova, if i ease into the peddal it is fine!
    at 65mph on the freeway wot it kiks down into 2nd and burns em off with 3.56 gears.. ive got dominators on all my boats and they are great! this demon is the most timid pos EVER.......! what holley to buy to match the flow of this demon? 750 dbl p ? the motor is 10.75-1 with comp 280 hr set up, old set of 462x f heads with a TON of work.. thanks!
    im hanging this demon by a rope in the middle of my garage!
    when cold the demon flows enough with no choke, it doesnt die, the edl had a hard time when cold..

  7. #7
    IS the thing throwing black smoke when you stomp on it?
    If it is, it will most likely need one of two things. Drop the float levels, as this will throw too much fuel right at the hit. Or check and see if your squirters are too much for your application. Or try to increase the lash between the arm and the squirter activator. If it is dying because of too lean, then try just the opposite. Raise the floats, set less lash less, and up squirter size. I cannot see a 725 BG out of the box with squirters small enough to run this car with perfection. So my guess is you have been through that and put smaller in.
    But if you just want to toss it and get something else, then that may work too.

  8. #8
    car doesnt smoke at all.. it doesnt ever die, it seems like it pauses -flutters a sec then goes. weve gone threw the demon, floats/jets everything.. just time for a holley, which one would match the demon??

  9. #9
    Wicked Performance Boats
    Most peeps don't set the acc pump correctly. Have somebody push the acc pedal to the floor and hold it. Now check the acc pump lever to see if it has approx .030th play before it bottoms out. Just push down on it and see. If not adjust it till it does. Now is the flat spot still there? Budlight

  10. #10
    kinda went threw all that, also went threw dist, hell seems like weve been threw everything 10 times.. thought about diggin a hole in the backyard for it.. as long as that demons been on this motor the crows been hangin out at the house. thought about sending it back to BG with no return address

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