s-cam

I was running the stock fuel pump with a BAP (boost a pump) on it to increase fuel delivery on my CTS-V. I have added a Inline Walbro 255 LPH to the car. I have the BAP still in the car but not hooked up at the moment depending if i have enough fuel or not. when i hook up both pumps i am getting 95 lbs of fuel pressure. Are there any options around this? guys who have put the inline pumps in are they running them off hobbs switches? (only activating with boost?) Just trying to get the gremlins out before i go back to the dyno. I am trying for 750-800 rwhp so i dont want to rely (hope) that a stock pump with a BAP would support it and want to make the second pump work. HELP !!!!

98cobra

iTrader: (32)

The return line is too small to do what you are trying to do.

jenks40

iTrader: (3)

I don't know squat about fuel pumps, but I know this. If i put two air regulators inline to feed compressed air to something and set them both to 80psi.... I don't get 160 to my target. This kindof sounds like what you are trying to do.

itsslow98

iTrader: (18)

A lot of boosted guys run hobbs switches but i doubt thats your problem. May want to throw an adjustable regulator on there.

s-cam

This is the set up i went with...
http://www.cadillacforums.com/forums...maggied-v.html

Same set up and i have read quite a few guys using this but have no read anything about the fuel pressure they are running with the system or pressure regulator to decrease the pressure.

I have a hobbs switch plumbed in for my boost a pump and could use it to activate the second pump but not sure if it would create mapping issues or not.

And it is a returnless system.....

itsslow98

iTrader: (18)

Maybe try switching out the fuel filter. I know on my msuatng swap the corvette fuel filter has a built in regulator so if that has gone bad maybe thats your issue. It looks like the same exact filter in the link above.

s-cam

i put a new filter in when i did the 2nd pump. Looks like the cadillac filter does not have an internal regul;ator like the corvette filter does.

System runs 60 lbs with the second pump not powered then goes to 95lbs when the second pump is powered.

aurora40

iTrader: (1)

I guess I don't get it? How is the pressure from the in-line pump regulated? It doesn't look like it is, from that other thread. The stock regulator is in the tank, isn't it?

I don't think the Corvette has a pressure regulator incorporated into the fuel filter. I've never heard of any car having that.

s-cam

Agreed- the pressure from the tank pump is regulated to 60 psi but the inline is not regulated. That being said i am trying to find if the people who have done this are just running a high fuel psi or are they regulating it in another way or only running it off a hobbs switch that activates it when it hits boost.

I dont know if injectors will take 95 lbs of fuel pressure on a continuous basis?

Chris0nllyn

iTrader: (1)

http://www.svtsnake.com/forum/archiv...p/t-40672.html

Maybe a dual pump controller?

punishmentcycle

iTrader: (6)

what i would do is run the inline off the hobbs switch and set it to say 3-5 psi so your only increasing pressure when under boost only.. just like how the magnavolt or boostapump works. im setting my dual stage meth kit up like that..it comes on light at 3 psi and full at 6.. goes on the dyno this weekend .. previous numbers 475/453

greddy91

iTrader: (2)

Running the 255 in-line walbro for approximately 4000 miles now... no issues thus far. No additional regulators in the system and the pump is on full time with the in-tank pump.

aurora40

iTrader: (1)

Wouldn't the pump running at the max pressure it can produce have some variability in the actual pressure delivered?

Also, wouldn't it be rough on the pump to have no return line, as it means it's constantly fighting to move fuel?

I mean, obviously it's working for you, but it sounds like an odd setup, especially when you reach the point that it's not like you are afraid to cut up the car a little bit.

DMM

Are you getting your fuel pressure readings static or under load? At any rate, you will have a hard time controlling the pressure of a pump downstream of a regulator.

I am looking into an over sized pump that is normally powered through a resistor block to reduce the voltage (reducing output) during normal driving and when under boost the pressure switch will allow full voltage thereby increasing the output of the pump.

In theory, this will greatly extend the life of the pump without having to worry about hacking dual pumps in a module, causing cavitation in a downstream boost pump, or having to worry about wild uncontrollable fuel pressures. This is also the basic architecture of the supercharged 3.8 V-6's that worked reliably in OE form.

vmapper

iTrader: (8)

There is no return line.

vmapper

iTrader: (8)

yes, the regulator is part of the assembly in the tank, your pump is post regulator, and you will be fighting varying pressures based on injector pulse loads...
you need to use an Aeromotive 1000 regulator or something similar, then incorporate return lines...
Or you can use the Huge Denso Kyosan type 300lph or 390lph in tank pump... (-1020)

s-cam

I am getting my fuel pressure off the passenger side rail.

with the stock pump 60lbs static (i am thinking you mean key on?)
with the inline pump also connected 95 lbs static

under load it was 60lbs when i had the BAP but i have not run the new engine combo with the old fuel pump set up under load as i was afraid i never had enough fuel.

The inline pump set up has not been run under load on the dyno yet as i was a bit nervous about running that much fuel pressure on a continuous basis.

greddy91

iTrader: (2)

I could be completely wrong here folks... but I don't think I am.

The Vette and the V share a fuel filter that also acts as a regulator. The V doesn't have a traditional return line from the fuel rails - that's true, but review the fuel filter and you'll notice that it has two lines from the tank. From my understanding one of those lines is the return. Plumb the 255 between the in-tank unit and the fuel filter/regulator and your solution is complete.

Where is your 255 currently plumbed? After the fuel filter?

s-cam

i have it plumbed prior to the filter. I read about the regulator part of the filter on a corvette but could not find or verify that the cts-v did the same thing but yes it has a return line on it. I did replace the filter with a non GM filter when i did the pump so maybe that is the issue?

I will see if i can find a brand name one and try it.......

greddy91-Did you ever check the fuel pressure at the rail after the install?

itsslow98

iTrader: (18)

Look it up 99+ vettes have a built in regulator in the fuel filter. That is how I regulate the correct fuel pressure from an in tank 255 mustang pump to the ls1 motor in my mustang. Amazingly the wix fuel filter with built in regulator is only 35 bucks.