NBE Racing Engines
Registered: 02/06/12
Posts: 4
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| | 02/06/12 at 06:41 PM | Reply with quote | #1 |
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My question is I had this motor tuned at one time and now I'm a little lost.
I'm having trouble with a bog right off idle. I also have a bog when I dump the clutch at 5000rpm out around the 60' mark at the track.
The motor is a 457CID Mopar w/tunnel ram, cam is 268* @ .050, 12to1 compression, B1-BS heads.
The car is a '69 Roadrunner that is fully dressed and about 3850lbs, 4.56 gears, 29" tall tire
Just a quick history of where I'm at with the carbs:
Mounted sideways
No power valves (square jetted)
The primary side has 30cc squirters
I have had problems with the float bowls as far as float level (Do I need a different float for each side?)
I have the throttle blades all but closed and the mixture screws out about a half turn.
I always get mixed up on witch way to go on the idle.
Should I go out about 2 turns and open the blades more?
Sorry I know this a long question but having a starting point again sure would be helpful.
p.s. most of the time the car is at 5000' altitude
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PRO-SYSTEMS
Moderator
Registered: 12/16/11
Posts: 302
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| | 02/06/12 at 06:59 PM | Reply with quote | #2 |
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Most of the time if you are having trouble staging and the booster is not quite making enough signal to get it up and go...richen the idle a little. OUT on the mixture screws adds fuel.
The notch in your floats go to the rear and be sure your high side line pressure is at least 26-28 psi.
If the mixture screws supply enough fuel at only .5 of a turn out go larger on idle air bleed so you can back the screw out more so its not peeing through that port. It helps break up the fuel.
Good luck.
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| Unregistered |
| | 02/06/12 at 07:09 PM | Reply with quote | #3 |
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Just to clearify what you have said, the carbs are mounted sideways on a tunnel ram and the floats are stock brass floats so I'm not sure what you mean by (THE NOTCH).
I'm lost on the high side line pressure being 26-28psi were do I need to check that?
I total makes sence to turn the idle screws out and open the butterflies more to get the idle correct.
Butterflies open, speeds up the motor, idle screws out to adds more fuel slow the motor back down correct?
Thanks again!!
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NBE Racing Engines
Registered: 02/06/12
Posts: 4
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| | 02/06/12 at 07:45 PM | Reply with quote | #4 |
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Sorry wrong part number these carbs are Holley 9379 750cfm racing carbs not 9375. |
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PRO-SYSTEMS
Moderator
Registered: 12/16/11
Posts: 302
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NBE Racing Engines
Registered: 02/06/12
Posts: 4
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| | 02/07/12 at 12:11 PM | Reply with quote | #6 |
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Thanks again, I know the idle speed and idle mixture are two different things, I believe I have the mixture screws in to far and the idle speed set to to far closed. The notched floats are something I will look into because that might be the reason the car stalls at the 60' (running out of fuel). I put the car on a limiter at full throttle when staged and leave with the throttle wide open, is there anything else I need to look at?
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PRO-SYSTEMS
Moderator
Registered: 12/16/11
Posts: 302
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| | 02/07/12 at 12:15 PM | Reply with quote | #7 |
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Install some hose extensions on the vent tubes in case its fuel slosh.
Good luck to you.
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NBE Racing Engines
Registered: 02/06/12
Posts: 4
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| | 02/07/12 at 12:16 PM | Reply with quote | #8 |
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One more thing were do I find the float on your web page? |
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PRO-SYSTEMS
Moderator
Registered: 12/16/11
Posts: 302
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| | 02/07/12 at 12:19 PM | Reply with quote | #9 |
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Just give us a call and ask for a 2-16451C and 2-16451D floats. 727.490.5717 They are $12.50 each
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