308 QV fuel pump specs ?

Hey boys,

Looking for a little input RE: 308 QV CIS fuel pump pressure and volume specs and testing. Here is the latest on my supercharger fueling issue.

http://www.ferrarichat.com/forum/showthread.php?p=136902956#post136902956

Thank you in advance for any help/comment/opinion here.

-Lou

 

wow. I am amazed at the incredible response from the tech guys.

 

you probably already have this, but my qv factory repair manual says:

Fuel pump delivery: 1000 cm3 per 30 sec
Primary Pressure: 5.0 - 5.6 bar (72 psi - 81.24 psi)
Minimum operating voltage is 11.5 Volts (this might be part of the problem)

Edit: took this off of an on line forum on Bosch K-jetronic:

http://www.auto-solve.com/mech_inj.htm

Based on your other post stating you delivered 850 cc/30sec, then by the book you have a fuel delivery problem. Would recheck with a new filter, and check the voltage at the pump.

 

I recently measured the two Bosch CIS FP on my TR, and your 850 mL in 30 sec does seem wimpy (I haven't reviewed your saga, but shouldn't you be able to do some fairly straight forward calculations based on RPM*AF ratio*intake absolute pressure to guesstimate/compare if the stock unit is enough?). I was using a 1000 mL graduated cylinder without much spare room for my volume measurement so I couldn't run for the full 30 sec -- my results (at battery voltage, not alternator voltage):

FP1-6
time to deliver 1000 mL = 23 sec (measured)
estimated delivery for 30 sec = 1300 mL (calculated)
(system pressure = 5.55 bar)

FP7-12
time to deliver 1000 mL = 25 sec (measured)
estimated delivery for 30 sec = 1200 mL (calculated)
(system pressure = 5.60 bar)

 

Thank you, my freind for the confirmation.

I am in spec in all but volume, blew out the fuel lines with compressed air and replaced the filter with new. Voltage to the pump is confirmed @ 12.0 on my digital Fluke meter (birdmans fuseblock rocks). I will check current draw (amps) with my old analog multimeter in series today.

Fuel pump delivery: 900 cm3 per 30 sec
Primary Pressure: 100+psi (at the CIS inlet)
System pressure: 74psi
Resting pressure: 41psi
Voltage @ fuel pump: 12.0 volts (will recheck today)
Amperage draw: ?.? (will check today @ relay and fuse terminals)

Thanx again,

-Lou

 

The 1100ccpm in 30 sec. that I gave you is from the Bosch K-jet service guide. Bear in mind Bosch says this is a minimum number. I think they might be the best source don't you think?

Larry

 

Yes, Larry, probably the most reliable source. Thanks.

If my voltage and current draw are in spec (which I will confirm) my lines are clear and filter new, and I still only pump 900 or so, then the pump is proven to be deficient. (nearly brand new or not)
If that is the case and a new pump is in order, what would your (and I mean Larry, Carl, and anyone with a educated opinion) recommendation be? Since I will have to spend the money anyway, and I am supercharging, a higher volume than stock pump seems in order. (then again, trying to build a bolt on kit would require that we stay with stock specs ?!?) Carl ? Larry ?

 

confirmed information:

Fuel pump delivery: 900 cm3 per 30 sec (@ 12 volts confirmed)
Primary Pressure: 100+psi (at the CIS inlet)
System pressure: 74psi
Resting pressure: 41psi
Voltage @ fuel pump: 12.0 volts (10.8 battery/12.0 w/alternator)
Amperage draw: 7.2 amps

I ran the pump wired direct to a confirmed 13v source (my other car) to take the Ferrari wiring out of the equation. Only ran 950cm3 @13 volts. Pump is way out of spec, end of story.

 

SOLUTION, FYI http://www.fiveomotorsport.com/FuelPumps.asp

 

Requirement is an inline pump.
Your distributor has a pressure regulator, with return line, so pressures should be near or above the stock 120 psi

To roughly calculate flow required:
Stock requirement @260 hp is 1.0 liter/ 30 sec, or 2.0 liters/min, or 120 l/h
Assume double the hp, double the volume, i.e. 240 l/h

Choices:
The Walbro inline GSL 392 - 255 LPH @ 150 psi
Bosch 0580254984 - 255 LPH @170 PSI

JMHO and SWAG, but does jive with the Walbro recommendation for hp support