which fuel pump?

[Ttype6]

You twisting our statements, deriving inaccurate conclusions and quoting us as saying things we have not!

I know what you said. I did not say that my conclusion was correct. I was asking you if it was.

We have NEVER had one of our Hobbs switches fail. These are only used to stage pumps in our DP system (using a relay) and have nothing to do with 87_we4's purchase /this thread.

I was simply asking you if your concern about bypassing the hotwire as a means of reducing pump output was based on a complicated circuit and therefor creating a better chance of failure. I see that this was not your concern.

3. Normal vehicle voltage is OK (nominal = 13.5V). We never said 'adding more voltage would damage the pump' and more is a relative term.

The hotwire adds voltage to the pump. I offered a suggestion that the extra voltage could be added to the circuit at a certain boost level,when the motor would be using more fuel. You said
"We do not recommend bypassing our hotwire kit as a means to reduce pump flow. Doing so greatly increases the possibility of system failure and voids your warranty".
I assumed your statement was in response to mine and was asking what it was about bypassing the hotwire that causes damage to the pump. I concluded that your term of "system failure" meant pump failure.

I didn't accuse you of saying added voltage would hurt the pump. I assumed you were against adding voltage at a certain boost level. Perhaps the part you didn't like was running the pump with the stock wiring during no boost conditions. Whatever the case,I'd like to know what it is about bypassing the hotwire that would harm the pump.

 

[87_we4]

I drilled all the fittings on the return line and can only get down to 44psi at idle. So I guess its time to run bigger return line

 

[87_we4]

I drilled all the fittings on the return line and can only get down to 44psi at idle. So I guess its time to run bigger return line

 

[Ttype6]

I drilled all the fittings on the return line and can only get down to 44psi at idle. So I guess its time to run bigger return line

When this pump is used,high fuel pressure at an idle isn't a possibility,high fuel pressure at an idle is a mathematical certainty. Another car gets modified unnecessarily.

 

[Nick Micale]

If you,re referring to the Aeromotive 340 that they sell,it will be enough. Keep in mind,if you install a pump that has an output higher than 255 LPH,you will likely have to replace or modify the fuel return line as it will not be able to return enough fuel to the tank during low speed operation. This will result in high fuel pressure at low engine demands....................................................

We continually test different GN's on the street and dyno to verify that their fuel system is adequate for various performance levels, and have found all the street cars we have done lately are perfectly fine with stock supply and return line.

In an extensive dyno test last week on a street car running e-85 we developed 519 HP at the rear wheels at 22 PSI with a 45A turbo and 120# injectors.

The engine is a 3.8 with iron heads and I was personally watching the fuel pressure gauge which was ~70 psi at 5600 RPM. The 2 in-tank Walbro pumps provided ample fuel as the duty cycle was never over 70%. This car has run 10.2 at 127 MPH on gas with the same fuel system.

This is the highest HP e-85 turbo car we have done using completely stock lines with no mods at all.

When the dyno session was over, we drove the car home with the AC on, and it idled and ran just fine.

My point is that most modified street cars with e-85 or gas will perform ok using stock fuel lines.

 

[87_we4]

When this pump is used,high fuel pressure at an idle isn't a possibility,high fuel pressure at an idle is a mathematical certainty. Another car gets modified unnecessarily.

I knew from the get go that I would most likely have to run bigger fuel line. I wanted to drill the fittings out and try it just to see what it would do.

 

[3.8L V-8 eater]

Getting ready to install the RXP-340M...Going to try this with the stock return line have heard a few say they can get it down to 45 or just below....My chip is suppose to be 45 as a base setting so I'm thinking that if my tune requires 45 or above I can get away with the stock lines!!

 

[Ttype6]

Getting ready to install the RXP-340M...Going to try this with the stock return line have heard a few say they can get it down to 45 or just below....My chip is suppose to be 45 as a base setting so I'm thinking that if my tune requires 45 or above I can get away with the stock lines!!

The fuel pressure is set to 45 (line off). When the line is re-connected,the engine vacuum will attempt to lower the pressure 5 or 6 psi. If you can't get it down to 39 or 40,you will still be too high.

 

[3.8L V-8 eater]

The fuel pressure is set to 45 (line off). When the line is re-connected,the engine vacuum will attempt to lower the pressure 5 or 6 psi. If you can't get it down to 39 or 40,you will still be too high.

Did you run the return line as 1 piece straight to where it hooks up to the sender?? Or did you run the bigger return line to the small section of hard lines that go to the sender??

 

[Ttype6]

Did you run the return line as 1 piece straight to where it hooks up to the sender?? Or did you run the bigger return line to the small section of hard lines that go to the sender??

I run a Red's double pump set-up,so I have no need to replace or modify my lines. I try to warn people of this problem. It's common for many to think they might not have a problem,based on what they read on this sight. I commend Eric at Turbo Tweak for giving a disclaimer to his costumers who consider buying his 340 lph pump.

The stock line that connects to the regulator,is the biggest restriction in the return line. Actually it contains one of the two biggest restrictions,the Saginaw fitting that houses the O-ring where that line connects to the regulator. The other,and more restrictive,Saginaw fitting is in the return line that this line connects to. The best you can hope for is that drilling these two areas to a larger ID will remove enough restriction to get your idle pressure down. The regulator is another area of restriction,but I don't know if it is more or less than the line. I know that the Red Armstrong regulator is less restrictive than stock and some aftermarket regulators. I don't know which aftermarket regulators are restrictive and I'm not sure if Red's is still available.

 

[3.8L V-8 eater]

I will likely just bite the bullet and run the -6 braided line from the regulator all the way to the tank...Might go E-85 someday anyways just not practical no stations close in the area...Just wondering if I do run -6 if it should go from the regulator straight to the sender or to the first set of rubber hoses behind the shield...

 

[Ttype6]

I will likely just bite the bullet and run the -6 braided line from the regulator all the way to the tank...Might go E-85 someday anyways just not practical no stations close in the area...Just wondering if I do run -6 if it should go from the regulator straight to the sender or to the first set of rubber hoses behind the shield...

I think it would be smart to go all the way. It's too bad you don't have E85,as the extra fuel consumed by the motor can sometimes get your pressure where it needs to be. What regulator do you have.

 

[87_we4]

I will likely just bite the bullet and run the -6 braided line from the regulator all the way to the tank...Might go E-85 someday anyways just not practical no stations close in the area...Just wondering if I do run -6 if it should go from the regulator straight to the sender or to the first set of rubber hoses behind the shield...

I ran -6 from the fuel regulator all the way to the tank.

Posted from the TurboBuick.Com mobile app

 

[3.8L V-8 eater]

I ran -6 from the fuel regulator all the way to the tank.

Posted from the TurboBuick.Com mobile app

Did you add a nipple to the -6 line to be able to seperate the line in the same fashion as the stock lines??? Or did you just leave enough extra line to drop the tank far enough to disconnect from the sender unit??

 

[3.8L V-8 eater]

I think it would be smart to go all the way. It's too bad you don't have E85,as the extra fuel consumed by the motor can sometimes get your pressure where it needs to be. What regulator do you have.

If E-85 was more readily available I would go that route...Using an accufab regulator....

 

[87_we4]

Did you add a nipple to the -6 line to be able to seperate the line in the same fashion as the stock lines??? Or did you just leave enough extra line to drop the tank far enough to disconnect from the sender unit??

I just left just enough hose to drop the tank

Posted from the TurboBuick.Com mobile app

 

[Nick Micale]

I did forget to mention that on the dyno test in my post above, the base fuel pressure was set at over 60 PSI base pressure, and at max HP was 70 PSI.

We have found when tuning with e-85 and an XFI, the higher fuel pressure is works better in mid-range and at higher RPM.

On the street build e-85 cars we have done, they seem like 50 PSI or more base fuel pressure.

A local e-85 11 sec. GN which went on an 800 mile trip at 65-75 MPH cruise across the desert was able to get 18-19 MPG, a gas GN on the same trip was 25-26 MPG, so we must be doing something right!