fuel pressure ?????????

Old 05-11-2008, 06:48 AM
  #1  
john858
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Default fuel pressure ?????????

problem started last night at the track,i turned the twostep up two hundred,car left good just before it shifts it lays down just a little . my fuel pressure 9#,this is what i was thinking ,i was going to raise flote level,maybe bump pressure to 10# or could it be reg.problem? thanks for any help, john
p.s. it is alcohol
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Old 05-11-2008, 08:43 AM
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topcat572
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7 lbs is usually plenty. Raising the float levels wont help if they are high enough already. What size fuel line are You running?
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Old 05-11-2008, 11:00 AM
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john858
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1/2 from rear # 8 to the carb
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Old 05-11-2008, 12:36 PM
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curtisreed
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Do you have a fuel pressure gauge you can watch on the gear change? On some really hard leaving cars you can stall the fuel enough to cause a drop in pressure with a rear mounted pump and it might just show up now because you are leaving harder and pulling the fuel level down at the top of first gear.

If your float level is not set right to begin with it might help to raise it. Does the carb have an extension on the rear bowl and jet extensions on the jets. It sounds like you just reached the threshold of the fuel system if you weren't having problems and now you do. Just some things to look at.

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Old 05-11-2008, 01:29 PM
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john858
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carb does have jet extensions but not a bowl extension do you think that might help?floats are set at a trickle do you think i need to raise them?
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Old 05-11-2008, 05:24 PM
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The bowl extension gives more volume to the back bowl where the fuel gets away from the jets. Most alcohol carbs have them, ours do and I wouldn't run without one. Sounds like your car might be a good candidate for one.

Float level should be fine I just think maybe you have reached a point to where you are using up the fuel in the back bowl enough to get away from the jets. It would still be good for you to know the pressure when you are having the problem though. We have data recorders that we use for that.

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Old 05-12-2008, 10:08 AM
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john858
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thanks curtis for all your help ,i never though about bowl extensions until you said something.i'm going to try that first and go from there, i'll let you know if that fix it sunday. thanks again john
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Old 05-23-2008, 09:07 AM
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it looks like the bowl extension did the trick thanks guys
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