Fuel pumps

[hiy_po]

I have a Low pressure high volume intank Pierberg fuel pump.
130 LPH at 0.25 Bar (3-1/2 PSi)
220 at When used as a pre pump
I am looking at adding a second external pump.
What would be the better choice for use with the Quadrajet. Keeping in mind it is a boosted engine so at 15psi WOT it does suck down the juice.
1) 102 LPH flow at 5-9 Psi, and will self prime and lift 500mm
2) 100 LPH flow at 3-5 PSi, and will self prime and lift 500mm

Both pumps are German Pierberg

I am leaning toward number 2.
The other consideration is my fuel tank has an internal swirl pot. This is kept full by the returning fuel being fed threw a ventury that draws the fuel from main tank into the pot. The pot stays full regardless of fuel level in main tank

What yas reckon???

[hiy_po]

also this one with a big jump in price but notice the others are 3/8 in and out, this one is 1/2 in 3/8 out

3) 95 LPH at 1 Bar (14 PSi) 1.8 Bar (max)

[Cliff Ruggles]

What is the carburetor part number that you are going to use?

[hiy_po]

 17059595

 Is the simple answer but such an easy question can get a complicated answer. That is the carby I have fitted up now and is nicely tuned for its purpose.
The problem I have with it that is low vacuum at cruise not operating the APT circuit.
 I have collected a few  7045281 earlier carbs and am thinking one of these without the power piston and needles and feed blocked, 68 main jets with MAB reduced to suit will work better. I would be more reliant on the secondaries for enrichment and aim for around 15:1 AFR cruising on the primary main curcuit. I dont know if that makes a difference to my original question on adding the second pump but just putting it out there.

Is fitted with 0.135 N/S I also have 0.150 spare parts.

[Kenth]

Sounds like you are running boost at cruising speeds?
Is the carb pushed thru or pulled thru by boost?

[hiy_po]

yes it runs at 1psi at cruise. Its a draw threw turbo system.

My theory about that is my extremely low compression  ratio.
It seemed like a good idea to invest in a 72cc Aftermarket Alloy turbo head, and bolt it onto a fresh bottom end with dishtop pistons and standard deck height of around 0.040'. o.040' copper head gasket.
I should have used flat tops and decked block so pistons came out 0.005' Maybe next engine.
Would go from 7:1 now up to about 8.5:1 and run a better tune.
Pic is in top gear at about 50mph.

[Cliff Ruggles]

The factory routed the vacuum supply to the power piston in externally for "pull-thru" turbo set-ups and put a check valve in line so the PP was not boost referenced or at least no boost to the PP.

This can be done to the later baseplates without much effort, blocking the internal hole and drilling in from the front for external vacuum supply to the PP.

I've done a few pull-thru turbo set-ups but really don't have a lot of time spent with them. 

Another option is to eliminate the power piston and pull straight off the jets.  These carburetors work fine like that an the A/F ratio will still change proportionally to throttle position and engine load.  Rochester even set up the 1970 Olds W-30 4 speed carbs to run straight off the jets......Cliff

[hiy_po]

Cliff what fuel pump would you chose???

My Carb is boost referenced power piston to Inlet manifold after the turbo and I do run a check valve.
I am surorised by how many Holley users dont reference there Holleys. A low pressure under the carb when turbo is spooled is not what these carbs were manufactured for.

[lightning boy]

hiy-po, how much horse power is your engine making?

[hiy_po]

Its a fresh build. Boost is turned down to 7 psi and rev limit is set at 6000rpm. Once I get a few more miles on it I will turn it up and see how it feels.
Last Dyno run I had was 10 years ago plus. Was same turbo setup but was using twin 1 3/4inch SUs.
Had a GM cast Iron 12 port head I opend the chambers from 56cc to 62cc by removing material from the spark plug side. Ran a huge exhaust valve slightly bigger Inlet valve, 5 angle seats, pocket port and short turn opend and ported roof. I do all my own port work.
440 lift cam on a 112 lobe centre. Compression about  8.5 maybe 9 to 1
Pulled 233 rwhp then 235rwhp @ 10 psi


https://www.facebook.com/112808622092369/videos/1501437580981/

[hiy_po]

Fuel pumps anyone

[Kenth]

One of these may do the job?:

https://www.summitracing.com/search/product-line/carter-universal-rotary-vane-electric-fuel-pumps/part-type/fuel-pumps?SortBy=BestKeywordMatch&SortOrder=Ascending

[lightning boy]

Okay, 230 hp at the wheels means 275 at the crank, lets just say a little more in case you want to turn it up later-300 hp. A 300 horse motor on boost will use 124 liters per hour of fuel. So you are right the pumps you have shown are not going to work. Instead of staging the pumps together or running twin pumps, you dont need to, not at the power you're making. There are so many factory installed pumps to do what you need the choice is yours. Any Denso pump off a similar hp car will do.They are factory Toyota parts. Walbro pumps are installed on thousands of GM products and it wont be hard to find one that flows 124+ per hr. If you are stuck on a German pump, a Bosch 040 or 044 would do anything you will need. Just be sure to run a regulator on the back (downstream) side of your carb and then return back to the tank.

[hiy_po]

 Yer I was using a high pressure EFI pump for quite some time. but I ran two regs. first had the return and was set to 25psi fuel pressure then ran a second reg that regulated it down to 4 psi to feed the SUs.
I want to use less. I want to use the OEM style pumps because they need to run at full flow at all times. I still run a single reg but is before the Quadrajet and has the return.
I am thinking if two inline pumps both high flow rated and 1st one tank fed cant keep up  with the demand will go up a fuel pipe/hose size. Change to half inch or bigger.

So maybe the 102 LPH flow at 5-9 Psi maybe a better choice than 100LPH @ 3 -5 psi I was leaning towards the later of the two.. The one in the tank runs the car now at 5psi. I dont think I have maxed this system out yet. But when I do put a demand on the fuel supply it still needs enough to go back via return to keep the swirl pot full

Another option is buy a Pierberg chinese copy for half price and road test it.

[Cliff Ruggles]

The later Q-jets will handle high fuel pressure w/o issues so I'd go with the higher pressure pump. 

I use a 1977 Pontiac carb on my own engine with a 140 GPH electric pump feeding it thru 8AN fuel lines.  I use a regulator set at 7.5 psi and it has a return line to the tank.

That system effectively feeds over 550hp/600tq w/o the first hint of a fuel delivery issue.  I use a .145" fuel inlet seat, but tested it with .125", .135" and .149" seats as well.  I only ran into an issue with the .125" seat when I tried running less than 5psi fuel pressure.......Cliff

https://www.youtube.com/watch?v=6zVdoLR-VzM