fuel line size upgrade lesson learned

[NY_GN]

So, what I have found out the hard way is...if you upgrade your fuel pump to a 340 and try to use factory feed & return lines; you can't lower fuel pressure. FP is at 100 psi. New regulator and modified middle saginaw fitting on sending unit and no change. I've heard people say, they upgraded and had no issue, I wasn't that lucky.

stock return line is too restrictive.

I have the new line, -6 steel braided, gonna run it tomorrow. I'll post results after

I received a warning beforehand, but didn't listen.

 

[Jerryl]

. . .
I received a warning beforehand, but didn't listen.

Well, unless you tried it, you would have never known how it would work on your car.

100psi sounds excessive though, which tells me the return circuit is more than likely completely blocked off. (?)

 

[salvageV6]

I'd check the joint underneath the power steering pump first for blockage.

 

[NY_GN]

Also, I ran new stock return line already, no change.

 

[cruzn57]

been using a 340, with stock lines for 10+ yrs, can set line press at anything I choose,
you must have a blockage somewhere!

 

[pacecarta]

are you referring to a walbro 340 (255lph) or 340lph pump, two completely different pumps when it comes to stock return line

and there is no saginaw on the hanger , theres a bulbed end on the necked down tube but not a saginaw

 

[V6sleeper]

Subscribed, .. wanna hear the results..

 

[ZNix]

100psi is way off. Running stock lines with 46psi. Didn't effect my blms too much. You have something else wayyy wrong.

Posted from the TurboBuick.Com mobile app

 

[NY_GN]

Pacecarta, it's a deatschwerks 340 lph and Ya I cut the bulbed end.

 

[ZNix]

100psi might be enough to rupture the diaphragm in the regulator. Clear the return line of restrictions and try again.

Posted from the TurboBuick.Com mobile app

 

[NY_GN]

Regulator is said to be rated at 300 psi (ACUFAB). The return line from regulator to tank is new, but it's stock size.

 

[jpwalt1987]

I have run two Deatschwerks 301 pumps at the same time and had a base pressure of 55 psi. You have something else wrong.

 

[pacecarta]

i have two 340lph pumps (rtx purple turbine pump) feeding stock rail with a -08 using an accufab stock style regulator and a -06 return line returning to the tank through the stock line at the hanger (with the bulbed end) . there is very little FP change when running both pumps at same time
before i went AN lines i ran stock lines twin 255lph walbro 340s and with both pumps id see around 55 psi , i agree with the post above .. your 100 psi seems like theres more going on

the 340lph is too much pump for a stock return line dont know who would have told you that you would be fine on a 1/4 return line ,

ive seen issues with new 255lph pump hotwired on stock lines and by issue i dont mean it ran at 45 psi but issue in that i was not able to get the idle reference down below 40 which should drop around 9psi from base on a motor that pulls 18 in/hg of vaccum (1/2 psi per in/hg of vac)

 

[pacecarta]

Regulator is said to be rated at 300 psi (ACUFAB). The return line from regulator to tank is new, but it's stock size.

300 psi is a measure a pressure not volume, you have a 340lph pump and a 1/4 line with several restricting connections in it ,,you are going to see high base pressure . shouldn't be 100 but it will be higher than desired base

what are you using to say the pressure is at 100 ....

 

[5280GN]

I put a dw300 on my car with stock lines and I was able to get the pressure down to 45 psi. I am running e85 so that might have something to do with it too, I'm taking more fuel off the rail at idle.

 

[NY_GN]

300 psi is a measure a pressure not volume, you have a 340lph pump and a 1/4 line with several restricting connections in it ,,you are going to see high base pressure . shouldn't be 100 but it will be higher than desired base

what are you using to say the pressure is at 100 ....

Fuel pressure gauge and I checked it at the rail as well.

 

[coach]

All stock lines, Canton racing filter, and a Red's double pumper...I can set my pressure anywhere. When we first hooked up everything...I had to raise pressure from 35 to 43.
You have a major issue and do not need a new line...you need to find your problem and fix it.

 

[bison]

With an old xp double I can't get below 42psi using one pump with non drilled fittings. It goes to about 65psi with both on at idle. I've flow tested another old one that came off a 153mph car and it was almost identical to what I experienced. There is definitely variances from car to car though


BPE2013@hotmail.com

 

[Mike T]

This is strange why it works for some and not others. I have the Aeromotive Stealth 340 with completely stock lines and have never had a problem. The information below came from Aeromotive and it states that their 340 puts out over 340 lps while in most cases retaining stock lines.


What sets the 340 Stealth Pump apart is its superior flow throughout a wide pressure range. Compared to other popular aftermarket pumps, at 40 psi the 340 boasts more than 340 lph. That's over 30% more flow. This pump is ideal for applications requiring more flow while retaining the factory lines and mounting provisions available in the Original Equipment (O.E.) configuration. The 340 is also perfect for use as a universal replacement for applications that require more flow to support forced air power adders such as turbo and supercharged applications. - See more at: http://aeromotiveinc.com/products-p...-fuel-pump-offset-inlet/#sthash.54YyFsPQ.dpuf

 

[pacecarta]

i tested an aero 340 on a double pump setup and found that it wasnt delivering 340lph and fell much shorter than expected at operating pressure with only 1/2 gallon per minute at 70psi which is only about 120lph and that was on AN lines .. so much for their claims . with that output you wont have issues with idle fuel pressure on stock lines but you wont be running high hp on it either
changed to twin reds pumps and saw 1 gallon per minute per pump or around 240lph at 70psi