Birdie2000

iTrader: (15)

FWIW, the 420 I had was hardly even noticable until the fuel got really hot and made it tempermental. A properly designed system shouldn't have that problem though.

onfire

iTrader: (17)

They would have independent pressure drops if they fed each rail even though they would y after the rails. What you're doing should work, but I would field test it since it's easy. Good luck.

stevieturbo

2 check valves wouldnt make any difference. If the Bosch overpowers the Walbro, the Walbros check valve would almost stay shut, and you would become reliant on the Bosch pump..

I wouldnt be concerned about overpowering the reg. As your pumps are essentially on demand, most of the fuel should be going into the engine when both are running, not through the reg. ( assuming you get the pumps matched to run together )

RyanJ

I'm no expert...but it looks pretty lop-sided to me. Can you insulate the pump(s) at all (to cut noise)?

stevieturbo

On the noise front, if both pumps ( preferably Bosch ) were mounted in-tank, noise would be much reduced.

The intank pump I referred to before was fitted to a 80's90's Saab 900 Turbo. It is simply a Bosch inline pump, 12mm inlet, 8mm outlet, placed in tank. I see no reason why the 044 couldnt do the same.

Come to think of it...I even think I seen somewhere, where an A1000 was used in tank ???

MIGHTYMOUSE

iTrader: (59)

the walbro has an internal check (i had a brain fart)

also, i would not need the shown check valve after the 420 if the 420 has its own internal check like i am sure it does.. can someone confirm?
if it didnt have its own internal check then it would not hold fuel pressure when primed...which would not work for us

i think you are thinking what would happen if i dead headed the system which i am not,? i have a return line so excess fuel will come back to the tank. when the second pump comes on it will just return more (and less and less as i make more power) it's not going to stall out the 255. it wouldnt do that unless my return line or regulator was so small that it could not return the fuel i sent to it (remember the 420 will only come on under high load)

i know my return line can handle (2) 255lph's running at 13.5 volts at a 39psi idle. so what i am asking it to do now should be significantly easier

stevieturbo

For peace of mind, I would be using 2 x bosch pumps. But.....

you mention 70psi fuel pressure. Your other post re-injectors said you were using about 35psi to try and get the get the 96lb's to work low down.
So with a 1:1 boost ref regulator, will you ever see 70psi fuel pressure ??
If you have 35psi base ( no vac ), then you would need 35psi of boost to get 70psi fuel pressure, which is unlikely you are doing that ( but it would be cool to see what power it produced )

So perhaps if max fuel pressure is kept to around 50-60psi, then the Walbro/Bosch combo will be fine.

MIGHTYMOUSE

iTrader: (59)

the base pressure will def. be 3 bar and at idle it will be that - vacum which turns out around 39psi.

i really doubt i would ever go over 25psi boost for a grand total of near 70psi


i was running upwards of 80psi with the old injectors at 20psi boost, 4 bar base

MIGHTYMOUSE

iTrader: (59)

anyone think i will have trouble sucking air through the line each time the 420 pump cuts on.. will it even prime the first time?

thinking i might only have the option of putting a sump bulkhead in.

anyone have pics of a bulkhead fitting just bolted to the bottom of the stock tank?

xssive

iTrader: (123)

Ls1 Speed posted pics of a bulkhead on a plastic tank. Maybe ask Tom to post up a pic again?

stevieturbo

Mount the external pump lower than the fuel level, and once initially primed, it should be ok.
Or place a suitably large check valve on the pickup at the lowest pount in the tank.

Or mount it in-tank.

What actually are the differences betwwen an in-tank pump, and an external ??
Here this HKS in-tank pump, looks incredibly like an 044 Bosch in-line pump...
http://www.hksusa.com/products/?id=717
http://www.abtivan.com/hks/hks_intankfuelpumps.htm

While searching, I found another idea, listed for some Supras

Its a bracket that mounts 3 Walbros in tank.

I guess you could use 1 Walbro most of the time, then under load, bring on another 2.
http://store.yahoo.com/ntnsracing/tesbitrfupua.html

Having a quick read through this article does seem to suggest HKS's pump is a Denso unit, and virtually identical to an in-tank Supra turbo pump. Their paics are also very different to the one in their advert.
http://www.stealth316.com/2-fuelpumpguide.htm

MIGHTYMOUSE

iTrader: (59)

http://www.ls1speed.com/pictures/dualpumps.jpg

that is a speed inc. car. apparently this is working just as good for them as a sump. looks easy. i need to know what fittings they are.

only thing i found so far from russell
http://www.russellperformance.com/au...mages/22-5.jpg

670850 -6 Fuel Cell Bulkhead

670860 -8 Fuel Cell Bulkhead

670870 -10 Fuel Cell Bulkhead

670880 -12 Fuel Cell Bulkhead

MIGHTYMOUSE

iTrader: (59)

that triple pump bracket is bad ***.

stevieturbo

It would work out cheap too, 3 x $100 pumps to support 1500bhp !!! ( pressure permitting )

Searching a bit more, the HKS pump in the picture may not be the actual in-tank pump listed, so may be misleading, but I have found at least 2 people running an A1000 in-tank.

MIGHTYMOUSE

iTrader: (59)

this was my original idea, lots of mustangs use this.
http://www.paxtonauto.com/fuel_detail.asp?ID=6

vortech must not be worried about sucking in air with an intank pickup to an external pump either http://www.vortechsuperchargers.com/...el_system.html

if they can suck the fuel up that to an external pump then no reason why i can't do the same thing.. i dont wanna drill a hole in my tank even worse weld in a sump

stevieturbo

A fitting bolted thru the tank would probably work, but there would be no internal baffling at the pickup point, so surge may become a problem if fuel is low.
And once drilled, there is no going back....

Your original plan is sound, the only thing not sure about is the compatability of the 2 pumps when running together. Once the external is primed, it would work fine thereafter.

Could you do 3 Walbros in tank ? or does that become difficult getting wires into the tank ??

Id ask around with people who know more ( pump manufacturers ) about running another Bosch in-tank, in place of the Walbro.

MIGHTYMOUSE

iTrader: (59)

two pumps is real real tight.. i gotta say 3 would be impossible.. ill have a look

MIGHTYMOUSE

iTrader: (59)

this is what they posted



i would still much rather run a pickup tube from the stock sending unit since it looks like i wont have any priming problems

MIGHTYMOUSE

iTrader: (59)

fuel flow = crank hp* bsfc
fuel flow for 1200 horse at .6bsfc is 720#/hr
gasoline is 6#/gal
fuel flow is 120 gal/hr

walbro gss340 at 13.5v and 70psi is 210lph = 55.4 gal/hr each = 110.8 gal/hr

also
720#/hr / 8 injectors = 90# injectors at 100% dc at 43.5psi


please put this stuff under review.. kurt told me to use .6 for bsfc for my motor.

onfire

iTrader: (17)

Just playing with your numbers....

gss340 @ 16.5v and 70psi is 258lph = 68gal/hr. ea = 136 gal/hr or 816 lb/hr or 1360 crank hp....hotwire kit plus MSD...is that enough margin of safety for your hp goal?