HELP ME!!! running out of fuel---FIXED

Any type of technical questions or info

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Buzzin'7
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Re: HELP ME!!! running out of fuel---FIXED

#31 Post by Buzzin'7 » Wed Dec 13, 2017 8:57 pm

bumpstart wrote:ok here you go
i stole these and trimmed it up
but its backing up what i was trying to point out above


For Dead-Head type regulators:

Multiply maximum horsepower by .23 to calculate minimum pump size in "free flow" GPH.
Example: 400 HP x .23 = 91 GPH "free flow"

For Return-Style regulators:

Multiply maximum horsepower by .17 to calculate minimum pump size in "free flow" GPH.
Example: 400 HP x .17 = 68 GPH "free flow"

Image
dead head ---
p1 > p2
the picture in posts above mine is actually this set up, but hybrid with a restricted bleed going to tank from the carb supply line
( further de-rating the flow coming from the reg )
--------------------------

Image
bypass set up
P1 seen by pump is lower ( the FPR set point ) flow is higher
provided the line diameter supports that flow at that pressure
my pic is a variation of this, though a dead head was used in reverse
( all we had at the time )
and the return line is in fact a little small compared to supply
( still working with minimum 4.5 psi )

-------------------------

Image
the dual FPR set up that will let the carb see a low set dead head, yet pump see a bypass
- unfallible
( yet still has a minor inlet restriction )
Hey bumpstart,

Do you still have the pictures for the fuel system utilising two regulators for a true bypass setup for a 12a bridge?

I'm still a little confused as to where the regulators need to be positioned in the setup.

Also, where would you recommend mounting a carter gold/black fuel pump in a gen 1 rx7, and which pump is best suited?

Thanks.



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Re: HELP ME!!! running out of fuel---FIXED

#32 Post by bumpstart » Tue Dec 19, 2017 4:08 pm

you will have to google.. meanwhle i like carter black . it is higher flow rated ( 100 V 70 GPH ) . at double the delivery pressure. ( 15 V 6 psi ) and has 3/8 fuel barbs ( compared to 1/4 )

3/8 minimum diameter is required to keep the supply up in a bypass system for a worked carbed rotor at 4.5 psi

( the dead head uses instead a much higher pressure back to the pump in a stock line , but derates the pump flow, and puts the reg in the way as the flow restriction ) .

if using the cheaper AN fitting , be aware you often lose one dash size internally through the fitting . and in that case a dash 8 line would run front to rear and rear to front ( and in out of tank )

a bypass system is significantly more parts, and requires the tank outlets modded .
it will keep up with the carb at full throttle all gears, long as you like , run the pump quieter with less wear, boil the fuel less , and give no hot start drama


when the going is hard, don't retard, remember your lubrication
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Re: HELP ME!!! running out of fuel---FIXED

#33 Post by Buzzin'7 » Tue Mar 06, 2018 10:28 pm

bumpstart wrote:
Tue Dec 19, 2017 4:08 pm
you will have to google.. meanwhle i like carter black . it is higher flow rated ( 100 V 70 GPH ) . at double the delivery pressure. ( 15 V 6 psi ) and has 3/8 fuel barbs ( compared to 1/4 )

3/8 minimum diameter is required to keep the supply up in a bypass system for a worked carbed rotor at 4.5 psi

( the dead head uses instead a much higher pressure back to the pump in a stock line , but derates the pump flow, and puts the reg in the way as the flow restriction ) .

if using the cheaper AN fitting , be aware you often lose one dash size internally through the fitting . and in that case a dash 8 line would run front to rear and rear to front ( and in out of tank )

a bypass system is significantly more parts, and requires the tank outlets modded .
it will keep up with the carb at full throttle all gears, long as you like , run the pump quieter with less wear, boil the fuel less , and give no hot start drama
Thanks for the reply!

I'll do some more research on the bypass setup and if I have anymore questions post them here.

Cheers.



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