Starving for fuel?

I went to the track yesterday to run my car (ZZ4, 200-4r, 4.10's and a truetrac) and it was doing awesome off the line with a 2.1sec 60' time but at about 1/2 track it kept on losing all power for a second until i backed off the gas and hit it again.

At first i thought it might be the ignition cutting out but then I thought it might be starving for fuel. The car is new but the drivetrain is from my last wagon. It didn't nose over in the last wagon, but the old wagon had 3.42's instead of 4.10's. Also the fuel line is really rusted in places on the new wagon, and about 7' of it had been replaced with a 3/8's hose. And I had at least 1/2 a tank of gas.

I'm thinking either the line has a small blockage or its sucking air. It hasn't showed any signs of nosing over on the street, just at the track. I also drove the 70 miles home at 2800-3000 rpm with out problem.

So I was wondering if any knows or thinks if I should just run a 3/8 hose from front to back and get rid of the metal line or if I need to upgrade do a 7/16" or a 1/2" line.

Thanks  
`

It may not be the fastest or prettiest, but i can pretend

i've had fuel tanks rust from the inside...the rust can and will go thru the fuel line and clog the filter...mine got so bad that i had to carry a spare filter on long drives...

can you take the fuel feed line loose from the pump and pressurize the tank with compressed air and run some fuel into a container to see if you are getting rust thru the line

i would also replace the rusted fuel line with new meatl line of at least 3/8" diameter

may readjust the float level also

just some thoughts...hope they help  
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the red-headed step-child of the mailing list

fuzzy dice, air shocks & N50's rule

OOPS
g..d..computer running in circles
wasn't there a movie about that  
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the red-headed step-child of the mailing list

fuzzy dice, air shocks & N50's rule

I actually did empty out 1/2 a tank of 87 octane by plugging the return line and pressurizing the vent line. Plus I have to drop the tank anyway cause the fuel float sensor is screwed up.

And do I raise the floats? or should I raise em just for racing?  
`

It may not be the fastest or prettiest, but i can pretend

if the problem isn't rust/clogs...

i'd raise the float level(s) in small incriments until the problem goes away...
then see if it acts normal on the street or if it starts to load up...
if it acts up on the street, then back off the float levels a little ***

i've never known of anyone that had to adjust floats just for racing and then reset them for the street...

if this is the same combo (engine, trans, carb), i just can't see the float level being a problem all of the sudden

what you described sounds like fuel starvation, like you said...are you running an electric pump or a pressure regulator?  something that would/could decrease flow or get weak and reduce flow

again, i'm thinking out-loud  
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the red-headed step-child of the mailing list

fuzzy dice, air shocks & N50's rule

Just running the stock ZZ4 pump. Today I am going to check the fuel filter (8an Trick Flow filter). Also I am going to replace what is left of the really rusty gas line with 3/8's hose. I also have to drop the tank and replace the sending unit anyway due to the faulty fuel level sender.

I didn't have any fuel problems in the last wagon this drive train was in, the only difference is this one has 4.10's instead of 3.42's. and my 60ft went from 2.4sec to 2.10.

My buddy said I might be sucking air through the line, so hopefully the hose will fix that problem.

I also added 2 gallons of 110 leaded racing fuel to about 17.5 gallons of super, but I have done that before with even less super and never ran into a problem.  
`

It may not be the fastest or prettiest, but i can pretend

your 8an filter may be causing the problem. it may have a air bubble in it. the stock pump can not pump enough fuel volunm, up grade to a performance pump and 1/2 or 8an lines. the 4.10`s are letting that motor spin and you have to feed that horse  

Can I put in an electric pump near the tank and only turn it on for racing? Will the mech. pump still pull fuel through the electric pump when it is off?  
`

It may not be the fastest or prettiest, but i can pretend

mechanical pump acts like a restriction, i found its run  one or the other. put it close to the tank and try to mount it below the fuel level. eletric pumps push better then they pull. remember its part of the fun to figure out the problem.  

Changed the fuel line to a single rubber hose and changed a 5\16" 90deg fitting to a 3\8 fitting.

Ran down the track with no stumble or anything. All fixed.  
`

It may not be the fastest or prettiest, but i can pretend

glad to hear you got it figured out  
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the red-headed step-child of the mailing list

fuzzy dice, air shocks & N50's rule