question on upgrading fuel lines - difficult to remove stock lines?
Dec 4, 2011, 09:49 PM
#18
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For kicks, I did a few pressure drop calculations using different ID fuel lines and flow rates (http://www.pressure-drop.com)
**Inputs**
- Fuel line length - 10 ft (approx distance from the tank to the fuel rail)
- Assume straight pipe
- Fluid - pure ethanol (0.789 gr/cm3, coefficient of viscosity = 0.001095 Ns/m2)
**Pressure Drop Results**
*Scenario 1* --- Flow rate: 4.4 l/min (Four 1100 cc/min injectors maxed out)
Factory hardline (~0.25" ID) - 4.5 psi pressure drop
- 6 AN hose (~0.38" ID) - 0.6 psi pressure drop
- 8 AN hose (~0.50" ID) - 0.2 psi pressure drop
*Scenario 2* --- Flow rate: 6.7 l/min (~800 whp on E85)
Factory hardline (~0.25" ID) - 9.3 psi pressure drop
- 6 AN hose (~0.38" ID) - 1.3 psi pressure drop
- 8 AN hose (~0.50" ID) - 0.4 psi pressure drop
Scenario 1 approximates my setup. For a Walbro 255, a ~4 psi pressure drop reduces fuel flow by about 12 L/hr or reduces max power potential for a given AFR by about 25 whp (due to the reduced flow).
**Inputs**
- Fuel line length - 10 ft (approx distance from the tank to the fuel rail)
- Assume straight pipe
- Fluid - pure ethanol (0.789 gr/cm3, coefficient of viscosity = 0.001095 Ns/m2)
**Pressure Drop Results**
*Scenario 1* --- Flow rate: 4.4 l/min (Four 1100 cc/min injectors maxed out)
Factory hardline (~0.25" ID) - 4.5 psi pressure drop
- 6 AN hose (~0.38" ID) - 0.6 psi pressure drop
- 8 AN hose (~0.50" ID) - 0.2 psi pressure drop
*Scenario 2* --- Flow rate: 6.7 l/min (~800 whp on E85)
Factory hardline (~0.25" ID) - 9.3 psi pressure drop
- 6 AN hose (~0.38" ID) - 1.3 psi pressure drop
- 8 AN hose (~0.50" ID) - 0.4 psi pressure drop
Scenario 1 approximates my setup. For a Walbro 255, a ~4 psi pressure drop reduces fuel flow by about 12 L/hr or reduces max power potential for a given AFR by about 25 whp (due to the reduced flow).
Dec 4, 2011, 09:52 PM
#19
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So I did a bit of research on ethanol compatible hose. Aeroquip socketless looks fine, but its not obvious to me that there is something about it that makes it stand above the rest. Goodridge 811 or 910 PTFE lined smooth bore hose looks good to me, and attaching the AN fittings doesn't look difficult.
I've not had time to get a look under the car - is there a fitting, e.g. at the transition from flex to hardline, where I can easily switch over to hose?
I've not had time to get a look under the car - is there a fitting, e.g. at the transition from flex to hardline, where I can easily switch over to hose?
In my case, I just hook up my -6 line directly to the outlet on the filter of the Buschur Double Pumper. I'm going to a different filter next season to get away from the barb/clamp setup that Buschur supplies, but same concept, just with AN fittings connections.
Dec 5, 2011, 08:13 AM
#20
It's not better than the hoses you mentioned, it's just readily available from Jegs/Summit.
In my case, I just hook up my -6 line directly to the outlet on the filter of the Buschur Double Pumper. I'm going to a different filter next season to get away from the barb/clamp setup that Buschur supplies, but same concept, just with AN fittings connections.
In my case, I just hook up my -6 line directly to the outlet on the filter of the Buschur Double Pumper. I'm going to a different filter next season to get away from the barb/clamp setup that Buschur supplies, but same concept, just with AN fittings connections.
Dec 5, 2011, 09:59 AM
#21
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Pusloc/socketless/etc style fittings are designed to be ran with no clamp and hold pressures up to 250+ psi. Used them for years with no issue. Aeroquip Socketless is a far, far safer setup than the barb/clamp setup that a lot of people use. Once you assemble one, you'll see why it'll never come off unless it's cut. In fact, it'd be physically impossible to pull off without damaging the hose. If hooked to a truck, it'd rip the hose first. You get the point.
Dec 5, 2011, 02:05 PM
#23
No, the SIZE of the factory hardline comparatively restricts the flow.
Factory hardline = 1/4" diameter = .025" diameter = .049" area
-6AN replacement = 3/8" = .0375 diameter = 0.11 area (more than 2x stock fuel line)
-8AN replacement = 1/2" = .196" area (nearly 4x stock fuel line)
Going from a stock to a -6 more than doubles the area. Going from a -6 to a -8 nearly doubles the area again.
Factory hardline = 1/4" diameter = .025" diameter = .049" area
-6AN replacement = 3/8" = .0375 diameter = 0.11 area (more than 2x stock fuel line)
-8AN replacement = 1/2" = .196" area (nearly 4x stock fuel line)
Going from a stock to a -6 more than doubles the area. Going from a -6 to a -8 nearly doubles the area again.
Dec 5, 2011, 02:45 PM
#25
No, the SIZE of the factory hardline comparatively restricts the flow.
Factory hardline = 1/4" diameter = .025" diameter = .049" area
-6AN replacement = 3/8" = .0375 diameter = 0.11 area (more than 2x stock fuel line)
-8AN replacement = 1/2" = .196" area (nearly 4x stock fuel line)
Going from a stock to a -6 more than doubles the area. Going from a -6 to a -8 nearly doubles the area again.
Factory hardline = 1/4" diameter = .025" diameter = .049" area
-6AN replacement = 3/8" = .0375 diameter = 0.11 area (more than 2x stock fuel line)
-8AN replacement = 1/2" = .196" area (nearly 4x stock fuel line)
Going from a stock to a -6 more than doubles the area. Going from a -6 to a -8 nearly doubles the area again.
Dec 6, 2011, 06:48 PM
#27
Installing a hose also made a lot easier to install a fuel pressure sensor for a Defi Gauge.
Using the stock hard line looks a lot clear, tho.
Dec 6, 2011, 07:05 PM
#28
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YES
I'm making 790 WHP on E85 with Buschur DP (modded 255's) -6 feed, stock return line, stock fuel pressure regulator. Zero issues.
Dec 6, 2011, 07:11 PM
#30
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fuel rail
I'm going to ask for my own fuel system sticky soon...
1) There is NO reason to use ANYTHING bigger than a -6 feed line. Period. I'm currently making 790WHP on E85 with -6 Feed line, stock regulator, stock return line. Buschur DP W/modded 255's supplies it. I started to see the stock fuel feed line becoming a restriction at around 700whp, and the -6 feed line TOTALLY solved that.
2)Use Aeroquip pushloc. It's the most readily available Ethanol compatable fuel line. Most of your braided line is not, and even if you can find it compatible, it's more expensive, heavier, and a PITA to cut/terminate.
1) There is NO reason to use ANYTHING bigger than a -6 feed line. Period. I'm currently making 790WHP on E85 with -6 Feed line, stock regulator, stock return line. Buschur DP W/modded 255's supplies it. I started to see the stock fuel feed line becoming a restriction at around 700whp, and the -6 feed line TOTALLY solved that.
2)Use Aeroquip pushloc. It's the most readily available Ethanol compatable fuel line. Most of your braided line is not, and even if you can find it compatible, it's more expensive, heavier, and a PITA to cut/terminate.