engine hwlp

my buddy built a 30 over 429 with stock dove heads roller rockers solid lift 605/605 the car is using a stock 3/8 fuel line idles at 8 lbs. fuel pressure when the motor goes under a load presure drops to 3-4 pounds the fuel filter stays full of gas and fuel in the bowls does not drop i think fuel line is to small what do you guys think?

How does it run, does it act like it's starving for fuel? Electric pump? My self, I'd prefer 1/2" minimum from tank to engine, but, if it's not running out of fuel, he's probably ok.

3000 rpm it pops thru the mufflers bad car wont turn over 3500 rpm or so runs like shit stock mechanical fuel pump

That sounds like starvation to me. I doubt the mechanical pump is doing it's thing. Sounds like it's time for him to spend a little money

thanx we will try it keep you posted

Nevs wrote:That sounds like starvation to me. I doubt the mechanical pump is doing it's thing. Sounds like it's time for him to spend a little money

I always make sure it will fill a gallon jug in 15 seconds or less. If not, you need more volume. just my opinion!!

Yep. I think so.

Had a stock fuel line on my boy's 350ci camaro. We put a blow thru turbo on it and until we upgraded the line the car felt like you hit a wall at 4500rpm. Shift and it'd pull again, the fall over again at about 4500.

dirtbogger wrote:

Nevs wrote:That sounds like starvation to me. I doubt the mechanical pump is doing it's thing. Sounds like it's time for him to spend a little money

I always make sure it will fill a gallon jug in 15 seconds or less. If not, you need more volume. just my opinion!!

That's an easy way to check. Good idea

1 gallon in 15 seconds? That's 4 gallons per minute. 240 gallons per hour.

There's no reason to need that much flow unless you're running 1000 HP.

Overkill in this case.

If the fuel pressure is still 3-4 lbs at WOT then your problem lies somewhere else. That pressure exists because the pump is pushing more fuel than the carb can use.

Greg

Greg, that amount of fuel is at a "no pressure" level. When a fuel pump starts having to "push" pressure that flow amount will go down considerably. At WOT my 600hp motor had a fuel consumption of 80 gal/hr on the dyno. I would think that the pump has an issue of some sort, either the line is too small, or the pump isn't capable of delivering the amount of fuel required.

I hear what you're saying, BUT....

If the carb wanted more fuel than the pump could push, wouldn't the fuel pressure be zero?

Not necessarily, as there is a restrictioin at the needle and seat, and that is where the 3 or so psi is. More psi is needed to keep the fuel bowls full at WOT.