my brother a 86 trans am with a vortec 350. his car is running out of gas in the 1/4 mile! run out at the 1/8 mile marker and cuts off. here what in ran 1/8 9.482 @ 71.85 1/4 15.917 @ 66.18. anyone have any idea why its runing out of gas and cuting off?

 

How do you know it's running out of gas? What exactly does it do?

EFI or carb? Fuel pump type? Fuel line size? Dirty filter? Fuel pressure? Enough fuel in the tank?

I could go on and on guessing without a lot more information. Might as well get doctors advice on a medical problem through email.

 

[quote=Stephen 87 IROC;3451040]How do you know it's running out of gas? just cuts or like it runs out of gas and after a min u can crank it up again it just What exactly does it do? it just does at the dragstrip after the 1/8 mile marker it done it two diff days a total of 4 runs but dont do it every day driving

EFI or carb? carb Fuel pump type? he has changed it and put a new elec one 5-9 psi Fuel line size? 3/8 Dirty filter? new ones did that already Fuel pressure? what ever pump is pumping Enough fuel in the tank? frist day 1/2 tank second day 5/8 tank at dragstrip

 

Trying to decipher what you just wrote, I'd probably first have to say the float bowls are emptying by the 1/8 mile point.

Check the float levels to make sure there's enough fuel in the bowls when the engine is running.

Since it's an electric pump, do a fuel pump test. Time it to see how long it takes for the pump to pump 1 gallon of fuel into a fuel jug. Normally it should take 40 seconds or less.

Install a pressure gauge and check fuel pressure when the engine is running. Don't guess. Carburetors shouldn't have any more than 7 psi. 5 psi is a minimum.

Is there an oil pressure switch in the fuel circuit? Low oil pressure turning off the fuel pump?

Get some diagnostic information then ask more questions.

 

Most any "5 to 9 PSi"performance electric fuel pump will supply all the fuel volume needs to a 400hp motor unless its really dinky. But if its faulty or the filter is faulty, or the fuel tank is not vented properly or the fuel line feeding from the tank to the pump is collapsing when hot, the car will starve for fuel. Which pump do you have? Should have a free flow rating of 92GPH or higher.

Here is some simple math to determine if the fuel pump will feed your motor with out it starving half way down the track.
engine HP X.50 /6 =GPH fuel flow (This formula is for US gallons)

Your pump has to be able to flow that GPH @ its working pressure (5 to 9psi).
Most pumps are rated at "free flow" not at the system working pressure.
Usually the working pressure flow rate can be found by divideing the rated free flow GPH by 2.76.
Free flow rated GHP fuel flow / 2.76 = GPH fuel flow at the working pressure

So a 400hp engine needs 34GPH flow @ 5 to 9PSI
34GPH x2.76 =94GPH free flow ya need a pump that is rated at 94GPH free flow or higher for a 400hp motor.

You can bench test your electric fuel pump to find out exactly how much fuel it will flow to your carb at the working pressure (5 to 9PSI)
Remove the fuel bowls from your carb and rig up some fuel line connecting the fuel inlets to the fuel pump. Put the fuel bowls in a large bucket.
By flowing fuel from a tank, thru the pump into your carbs fuel bowls and into a bucket while measuring the fuel pressure at the pump and measuring how long it takes to pump 1 gallon of fuel from the tank to the bucket you'll know how powerfull of a motor your pump can actual supply fuel to without starving it.