Moparnos (The SLP Guy)

iTrader: (55)

didn't the aeromotive FPR's have issue's with holding pressure?

LSs1Power

iTrader: (5)

Oh man i was just getting another 255 walboro pump in the tank Please keep us updated on your problem.

Anyone know where to get the 044 pumps for the best price? They are pretty expensive on the web. Also would one 044 pump be enough to flow 700-800rwhp SC'd car?

LSs1Power

iTrader: (5)

I just found this artcile which compare Walboro VS 044 pump.. http://www.stealth316.com/2-fuelpumpguide.htm#j6

They are saying there is a 255 high pressure walboro (GSS340-341-342) and 255 low pressure (GSS307-315-317). Which one are you running now?

MECHAM

iTrader: (4)

340's

LSs1Power

iTrader: (5)

In the article they are saying the 315's will flow better than the 340's at higher pressure due to different valve design whatever that is. It doesnt make sense to me because i thought the 340's was the high pressure pump.

White.Lightning

iTrader: (53)

Your car should de-pressurize itself after like 30 min or so. Mine does the same thing- turn car off at ~60 psi......come back 10 min later with key on ~56-58 psi. Etc.

As far as the pressure dropping, I saw a video on hereI think of someones Procharged car with an in-car 1/4 mile video focused on his FP gauge. It dropped pretty good. If someone has the link/knows the setup maybe they can chime in.

Good luck
Andy

LSs1Power

iTrader: (5)

Mine with a single 255 pump starts at 62psi and drops to 40psi at 6K RPM 630rwhp.

HUGGER ORANGE SS

iTrader: (2)

Not supprised.. Be careful with that 40psi of fuel pressure.


any updates Mecham...???

Old Geezer

iTrader: (3)

Aeromotive FPR... Return type system?

MECHAM

iTrader: (4)

hopefully the pic link works

http://community.webshots.com/photo/...76734921LxBlsP

using the stock line for return

MECHAM

iTrader: (4)

not clint...might dig into the fuel system tonight...to verify that both pumps are active...

Old Geezer

iTrader: (3)

That, if you have set the FPR to 50, and the vac line was off, and blocked, engine idling, that the pressure will be pulled back about 4-6psi.[Helps clean up idle]
Your math is, I think incorrect, in the subtraction of the vac value, you show as 13, will only allow the FP to rise that 4-6psi, I mentioned. This will occur as the engine progresses into boost. At that point, zero vac, zero boost, the FP should read the original set point. [50]
As the boost comes on, and rises to 13psi, the FP gauge should read 62+/-, a #, or two, not 75....

You may want to consider a larger return line, as supporting that much HP with a small return, is a bit risky.

Just my $.02...

MECHAM

iTrader: (4)

Old G

my car has 13psi of vacuum at idle...always has from the days I was supercharged.

50psi fuel regulator (vacuum line attached to regulator)
13psi vacuum
12psi boost
-----
75psi

I am intrigued as to why I would need a bigger return line?

LSs1Power

iTrader: (5)

Yes i know... We stopped there and we wanted to add another walboro pump, -8 feed line, FPR and Speed rails, but now im concerned because of the problems MECHAM having. I would like to keep my 62psi base fuel pressure and increase it by 1:1 until 13-15psi of boost. That should put me around 75-77 psi of FP. Now i see that the Walboro dont flow good at that high pressure!!!

Old Geezer

iTrader: (3)

That the car has 13" vac, but that value is not used to calculate the PSI that you will/should see at boost. [Once the vac goes to 100PKA, the engine is at the onset of boost, and vac has nothing to do with the operation of the regulator.]

I suggest you look at the gauge reading with the engine idling, vac line off, and blocked. If you do this, you will see that the 13" of vac has only a 4-6PSI effect on the pressure reading you will see, not 13 PSI.
Let's look at doing a "test" setting.
Base pressure desired is: 50PSI
So, engine idling, vac line off, and plugged, we set the regulator to 50PSI, lock it down.
Reattach the vac line, and the PSI will likely drop to 44-46.
Take the car out, and run WFO. If the 1:1 regulator is working correctly, AND the pumps are working correctly,
at 13# boost, the FP should be 62, +/- a #.

As for the fuel line sizing:
A. An OEM line that was sized to support an engine at 400HP, could be on the borderline when used on a modified system. [Except at WFO, that OEM line is expected to flow nearly twice it's intended volume.] May work, but most aftermkt systems recommend return lines near the size of the supply line.

B. Return line restrictions can cause backpressure at the regulator, pump[s]. [Causes heat, and may cause incorrect FP readings]

I'd suggest you modify the wiring to the pumps, so that off boost, you run with 1 pump. Here's a part # for a GOOD quality HOBBS switch.CCS Model 607GK.
Last fone # I had was 818-341-4610.
1 pump operation will cool things down, when you are not at "WFO"....

Lastly... Be sure your gauge is accurate. I flow check alot of the little, "mini gauges", and find them off as much as 5 psi, +/-. The best I've seen were only a # off, the worst, 7#.

HUGGER ORANGE SS

iTrader: (2)

Don't always trust what you read here... I have never had a problem with running out of fuel pressure..

I'm pushing about 14psi with my setup and over 700RWHP..

Keep us updated Mecham. Depending on how you have your pumps setup, you could just pull the fuse to the primary pump to see if you still get fuel pressure from the 2nd pump..

Good luck.

Clint

MIGHTYMOUSE

iTrader: (59)

your running too much fuel pressure, kick it back to say 3 bar (43psi) key on engine off and then re trim your injector flowrate.

less pressure will allow the pumps to flow more

LSs1Power

iTrader: (5)

But wouldnt less pressure make the injectors flow less? The way i understand is that the more FP u run the more the injectors would flow. I understand that the pump will flow better at a lower FP, but what about the injectors. For example, the 60lbs injectors will flow that much at 43psi of FP and could go to being a 85lbs injectors at 87psi of FP.

MIGHTYMOUSE

iTrader: (59)

that is true, you have to bandaid the weaker of the two by favoring fuel pressure.

but he is not using the max of the injectors right now, and therefore can run the pressure down to help the pumps

Old Geezer

iTrader: (3)

Yes, turning the FP down, will reduce flow, out of the injector. [A 60# inj at 43.5=60PPH, at 60PSI, it is 70.5PPH, at 40PSI, it's 57.5PPH.]
But, the pressure you MUST deal with is called "delta P".
That is the NET PSI the injector is working with.
IE:
Set the base, line off, to 60PSI. Reconnect reference line.
13# boost.
The FPR, if working at 1:1, should show operating PSI as 73PSI., at 13# boost.
Remember, that the outlet end of the injector is seeing the same 13# boost. Therefore, the NET, or DELTA P, is still 60PSI, and that's the flow, in #/hr, that the injector will flow.

BTW, the increase to 87PSI, from 60PSI, will not make a 60# inj flow 85#. It will flow 72.25#, if it will work at that elevated PSI....Some will not.......