383backinblack

ok.....it appears im now pulling the fuel out of the system on the launch, and my pump isn't powerful enough to push againt the g force.

aka, im getting 1.65 short times.....hard launch, then nasty bog right off the tree

im getting an a1000 fuel pump wed, but then i was thinking "oh S***, i have a return style regulator at the front, so the line pressure is going to equal the regulated pressure right?

if the pressure starts to drop, will the bigger pump make up the difference???

or am i going to end up putting a bypass at the pump, and running a dead head regulator under the hood in order to get big line pressure to the front?

just lookin for some opinions, pickin peoples brains

AlkyIROC

It's always best to use a bypass regulator. That way the pump isn't loading up. If the fuel cell and pump are in the back, install both. Use a bypass regulator in the back to keep the pressure at about 15 psi. Use a deadhead regulator at the carb to bring the pressure down to 7 psi.

Pressure and flow are too different things. Right now it sounds like you have a flow problem. The pump can't push enough fuel from the back of the car during high accelleration. Installing a bigger/stronger pump will help. You should also have a minimum of 3/8" fuel line to provide enough fuel. I'm not sure what size the factory lines are.

I had some fuel supply problems until I moved my fuel system to the front of the car. When I switched to alcohol, I used a BG280 pump. I upgraded to a BG400 when I got a good deal on Ebay for it. Back when I was still running gasoline, my fuel system was in the rear with a Holley blue pump then the BG280. I used 1/2" fuel line under the car.

Are you sure it's a pump supply problem and not a fuel in the float bowl problem? The needle and seats may be too small to fill the bowls fast enough. Install a minimum of a .110 needle and seat. I run the .150 titanium ones on my bowls.

383backinblack

i have -8 line from front to back.....the pump should be flowing enough total, but the pressure it puts out might be enough....cause pressure is like voltage in an electric circuit....its how much force is pushing the fluid.......my tank is in the back, with pump, and i have a bypass regulator up front right now....hopefully the bigger pump will solve the problem, we'll find out i guess.

i never even thought about the needle and seat, i'll have to check those

onefast85

in what i have read it sounds like you have a carb on it.do you have jet extensions in the rear of the carb?well if its a double pumper you need them.also check the float level.

i have ran a 140gph pump dead headed to a holley regulator to a 850hp motor.leaving off the brake it cuts 1.3 60fts.

383backinblack

ya its carbed, it has extensions.......its street driven too, so its not getting dead headed with no bypass lol.

the float level is good as well

IHI

iTrader: (1)

If it's bogging right out of the box, I have to ask if you have the vent slosh tube installed. piece of rubber fuel line pushed over the front vent tube and arched over onto the rear vent tube with a small section sliced out of the peak of the arch to allow venting, but not allowing fuel to slosh out of the front bowl vent and directly into your carb casuing a flooding condition.

This is the FIRST thing I would do before dropping the coin on a new pump since it's simple, fast, and very cheap and fixes 100% of the problems that you describe.

383backinblack

yup its on there

it doesnt bog right off the line, it leaves hard, then falls on its face about 40' out id say, then takes off again strong

IHI

iTrader: (1)

I know different cars like different things, but we've got plenty of cars here running 3/8" stock lines with blue pumps well below 1.6? 60's and no problems-dead head units I might add

Hopefully since the pump is on order that's the problem. What is your FP doing at that point? I know with the Holley blue I have now out of the bosx it's a slow loss until it gets to 6psi (down from 8.9psi at idle) and just flutters there till the stripe.

383backinblack

thats the problem.....its all over the place it will sit at like 8.5

then a half hour later you start it up, and its at like 4

so you turn it up......then another half hour later its like 14 lol

IHI

iTrader: (1)

With readings like that I assume that's a 1" or 1 1/2" Summit, Jegs, or Holley fp gauge that's mounted to the regulator? If so disregard that reading as the guages are all junk and are affected by engine bay temps more than fuel pressure.

Get a good Autometer guage that mounts either under your cowl hood or use an isolater and mount it in your car, this will be the only way your gonna ever get a accurate fp reading that's not tarnished by ambient temps.

383backinblack

while this is true.......the thing varies so widely that its impossible for it to be just the gauge at this point

im talking like a 12 psi swing......regardless though, i took off the fuel line (-8) before the regulator, and free flowed the pump into a jug....after over 50 seconds it was approximately 1/3 of a gallon......thats no ****in good

onefast85

buy you a new pump..yours is junk.

IHI

iTrader: (1)

new pump in order...wow, suprised you hav'nt leaned it out on the big end with that dismal pump.

And yes, those little junky 1.5" gauges WILL vary that much. Everybody in our group has had problems until they switched to the regular gauges, some would come back at 0psi and stillbe running, others would be pegged. Then it would vary between first start up, after pre racing warm up, and end of run....they are not an accurate guage by any means.

383backinblack

well ya.....i had already ordered the a1000 anyways

we'll see what happens......i have an inkling sensation that pump needs pressure in order to prime itself though.....perhaps thats why it was pumping like that......but who knows

the voltage is good checked it today, reads 12.45 volts with the car off, and its wired direct to the battery so it should see 14 with it running no problem

AlkyIROC

Do you have a filter before the pump or does the pump have some sort of inlet filter?

My BG400 pump was having problems pumping fuel before I even had a chance to get the car to the track. I had some sort of inline stainless mesh filter before the pump and it was plugging up with something. Cleaned out the screen and the pump could empty my 4 gallon cell in less than 30 seconds. I've since changed to a BG5000 filter and have had no more fuel flow problems.

383backinblack

ya it has one of those summit aluminum filters on there, its a stainless screen inside....i'll check it when i pull the pump out

i picked up some -10 hard line at the hydraulic shop today, and i was toying with the ideal of welcing it into the tank sending unit for a pickup.....i think i'd have to heat it up to put the kind of bend it needs in there though

Motor City Mike

As long as you mount your pump at or below the lowest part of the fuel tank, it should self prime. Ideally it should be mounted towards the rear of the tank also. You should really consider putting a sump with a fitting(s) on your tank at the bottom rear area though.

I just realized this, but you could very possibly have a partially plugged sock on the end of your pick-up giving you your problems.

My fuel system consists of a Magnaflow Pro-star 500 pump with an integral filter and fuel return. It puts out 36 psi to my 4 port regulator, which is mounted directly in front of my carbs. Fuel pressure is then reduced to 6-7 psi which is then fed to the carbs. The pump is a little overkill for my combo, but it has never given me any problems, and I have lots of room to grow (hp wise).

383backinblack

there is no sock on the end of the pickup

theres really not much room to put a sump down there, and a new tank (which i would much rather weld on) is like 250 bucks plus a sump, maybe in the future.

i have the a1000 installed.....so we'll see how it all works