IKnowtheFuture

iTrader: (5)

dual walbro 255s each with -6an line y-blocked into a single -6an, then up to the front, -6 crossover, aem fpr to stock feed as the return.

alot of what i have read says -6 is too small and get -8. i have heard from a couple reputable people that -6 line will support 1200 whp. its about the pressure not the line size, larger line was used to reduce pressure loss between the pump and the carburator since they are only running a couple psi. now a days we can over come the couple psi pressure loss by running the extra psi.

cjmatt

iTrader: (4)

What transmission? thats cutting it close, I ran out of fuel on a 255 walbro at 519rwhp, so in theory, 2 pumps may be able to support 1000. But why not run -8 instead of -6? its only like a $15 dollar difference in materials

IKnowtheFuture

iTrader: (5)

i have 30 ft of -6, i know the pumps will support it, im wondering about the -6 line.

cjmatt

iTrader: (4)

people have done it, but its not ideal

IKnowtheFuture

iTrader: (5)

anybody successfully run -6 feed and use stock feed as return, what power level?

PRAY HRD

iTrader: (119)

i've seen a couple do -6 and complain of pressure drop but haven't seen why. personally, i'd sell the -6 and grab some -8 and call it a day.

Slowhawk

iTrader: (12)

That setup will handle a no load dyno pull but I wouldn't trust it to feed a car in high gear on the road/track.

bug man nrg

NO NO NO !!!!!!you do not do this with that pump set up on -6 you will need two pumps with to -8 feed line's and a -6 back to a surge tank this is what we had to do on a 1JZ take a look at the link
! hope this will help you with your set up
http://www.supramania.com/forums/sho...ed-setup/page4

Nasty N8

iTrader: (33)

You will want -8 for the volume and heat. Do it right once.

qqwqeqwrqwqtq

I personally see no problem with the -6 line at 1k rwhp. We've used the stock feed line on a few cars at well over 1000rwhp and running mid/low 8's in the 1/4.

IKnowtheFuture

iTrader: (5)

"some people have it stuck in their heads that they must increase their line size when making big HP numbers like a thousand or more. A #6 AN line can easily support 2000 HP as long as you have enough pump head !!!"

http://forums.corvetteforum.com/c4-f...line-size.html

IKnowtheFuture

iTrader: (5)

your saying the -6 is acting as such a large restriction that it will heat the fuel a significant amount, so much so that -8 is necessary?

you don't think the -8 is more susceptible to heat soaking the fuel being a larger surface area.

I am starting to feel like -8 line is like carrying a 5 gal drum of water with you to drink everyday. It's just not necessary.


Anyone else have experience they'd like to share?

fast

iTrader: (24)

I dont know Nasty N8 ... So dont mean to step on his toes
But I do know Jim M. And trust his advice

Thanks for posting this and for answers

dville_gt

iTrader: (5)

over build and never have to replace good parts. i did -12 to my pump, then -10 from the pump to a Y block under the hood, then -8 to each rail, then -8 from each rail to the regulator and -8 from the regulator to the cell. works perfect and will support gobs of power.

stevieturbo

Walbro pumps cannot push a lot of pressure. SO I would say a single -6 line is not safe or sufficient for a genuine 1k+
Although that does depend on the dyno. Some do read much higher than others.

If you have so much -6 hose, just run 2 x -6 lines from pumps to rails and a single -6 return.

Job done, and no chance of lack of fuel flow ability.

IKnowtheFuture

iTrader: (5)

I am running stock feed and a -6 return. will anything bad possibly happen if the line is too small? I'm assuming the fuel pressure will drop a noticeable amount. I've never personally had a car with too small line so this is new to me. If it's not going to pop my motor I might run it and see.

I am only going to make around 800whp (+/- 100) for a while, but I've heard and was wondering about the 1000whp with -6.

Wicked69

I run -10's to the twin A1000'S. The second pump is on a hobbs switch and also has a one way check valve after the pump and filter. From there both pumps connect to a Y block and a single -10 line to the firewall where it meets another Y block. I then run -8 to each rail and a -8 return line back to the trunk. I am running E85 which is a bit different but I am still worried I should have -12 lines. I am only 600rwhp right now but plan to be 800 to the wheels when all is done. I personally would not run -6.

Orr89rocz

iTrader: (13)

I think its more of a function of pump heat due to being run harder with smaller lines. Smaller line is more restrictive so you need to increase pressure in the line to pass the flow required to feed the motor. The higher pressure the pump operates at, I believe it causes more heat in the pump because it takes more power to push the fuel required. Its being worked harder, thus heating the fuel in the lines more. I could be wrong but as said up above, walbros only can push out so much pressure. Higher the pressure, the less gallons per minute/liters per hour ( or whatever unit of measure you wish to use) there will be.

Like on carbs, they run lower pressure and larger lines to get the volume rate or mass rate of fuel required. Carb pump at low pressure may support 800 hp lets say, but at higher EFI pressures it may only be good for 600. Look at the charts Aeromotive gives for instance. Higher pressures cause less lbs/hr of flow = less hp potential.

That said, i have dual walbros for now. -6 feeding a Y into -8 supply to -6 return. ~700 whp so far pump gas only thru 5000+ stall Th400 on stingy mustang dyno. Plenty left in it, I think it will easily do 1000whp. Only 48psi base pressure and 15-18 psi boost on old setup and the new setup is much much nastier so it should push the fuel system.

IKnowtheFuture

iTrader: (5)

correct me if i'm wrong: say the -6 adds an extra 3 psi resistance over -8. If you have a base fuel pressure with -8an @48 psi and you turn up the fuel pressure to 51 psi, isnt that the same as having -6an in the sense of working the pump harder and heating the fuel more? and for that matter, if a base pressure is at 48 psi with -6 ("45" with -8) wouldn't I be working the pump alot less than at 58psi, so it would solve the problem of heating the fuel.

Orr89rocz

iTrader: (13)

Not 100% sure on that but its not only pressure related, but volume flow or mass flow related as far as speed delivered.

I took this from another forum.

The fine balance is pump flow rate in gallons/hr or liters/hr vs pressure. If you need 90 gpm of fuel, you may need more pressure to deliver that flow fast enough for the motor to handle without having pressure loss in the system. But as you increase pressure more and more, the flow rate drops say 75 gpm. Now you may not have enough fuel period to produce the power you are at.