inline fuel pump

ttbullet · 11-18-2013, 06:56 PM

I am planning on getting a inline walbro 255 pump. my question is How do they flow more fuel when the weakest link in the flow is still there (stock lpfp)? Do they overwork the stock pump? Wouldn't the stock pump still flow the same? Please explian. Trying to go to higher octane (E85 mix)

Dmacc · 11-18-2013, 07:31 PM

It's my understanding that running pumps in series helps draw flow through the lpfp allowing it not to overwork itself.

RoyalFlush · 11-19-2013, 07:58 PM

Quote:

Originally Posted by ttbullet

I am planning on getting a inline walbro 255 pump. my question is How do they flow more fuel when the weakest link in the flow is still there (stock lpfp)? Do they overwork the stock pump? Wouldn't the stock pump still flow the same? Please explian. Trying to go to higher octane (E85 mix)

What E85 mix are you trying to go for? There's been quite a few people that have ran E20/E30 without any LPFP upgrades. I have a friend that runs E50 on his stock LPFP. Depending on what mixture you're trying to go for, you can probably fill it up (little by little) and do some logs to see how your car's liking the certain percentage.

The inline pump supplements the stock LPFP and increases flow by 20%. (Someone will correct me if I'm wrong and chime in with the technicalities)

FWIW, I installed this LPFP upgrade on my car with a friend and I'm running E50.

PS Whatever route you take, I highly suggest testing the E85 and calculating the exact mixture before filling up.

ttbullet · 11-19-2013, 10:52 PM

I actually plan on running e50 and higher. I ran e30 and took some logs. My LPFP is sitiing at 50 psi during WOT. So seems like it is struggling.

Quote:

Originally Posted by RoyalFlush

What E85 mix are you trying to go for? There's been quite a few people that have ran E20/E30 without any LPFP upgrades. I have a friend that runs E50 on his stock LPFP. Depending on what mixture you're trying to go for, you can probably fill it up (little by little) and do some logs to see how your car's liking the certain percentage.

The inline pump supplements the stock LPFP and increases flow by 20%. (Someone will correct me if I'm wrong and chime in with the technicalities)

FWIW, I installed this LPFP upgrade on my car with a friend and I'm running E50.

PS Whatever route you take, I highly suggest testing the E85 and calculating the exact mixture before filling up.

AK 335i · 11-19-2013, 11:54 PM

if your low pressure fp is at 50 at idle.. your gonna have a bad time even with the inline. You should replace it when you do the inline with a new oem or 450

akotten · 11-20-2013, 12:30 AM

Flowing 450 L/hr of fuel at 72psi requires a specific amount of work energy, which in this case is done by a pump. Running two pumps in series divides the total work between the two pumps. Each pump is capable of doing so much work, so depending on that, the total work required will be split as a percentage to each pump.

The factory pump alone is capable of pushing x-amount of fuel at 72psi. Exceed that and you will have a pressure drop.

An aftermarket pump can also flow x-amount of fuel at 72psi. Exceed the maximum capable work energy of the pump, at say 12V, and you again get a pressure drop.

Join the two and you get a larger amount of total pumping work potential, (at the expense of higher current draw on the electrical system).

When you are below the maximum work potential of the pump, the extra "energy" is recycled by the fuel pressure regulator, back to the tank. At full potential, the fuel pressure regulator will return no fuel.

Hope that clears things up a bit.

I also may have opened up a can of worms and made things worse lol

3000GT MR · 11-20-2013, 12:55 AM

Quote:

Originally Posted by akotten

Flowing 450 L/hr of fuel at 72psi requires a specific amount of work energy, which in this case is done by a pump. Running two pumps in series divides the total work between the two pumps. Each pump is capable of doing so much work, so depending on that, the total work required will be split as a percentage to each pump.

The factory pump alone is capable of pushing x-amount of fuel at 72psi. Exceed that and you will have a pressure drop.

An aftermarket pump can also flow x-amount of fuel at 72psi. Exceed the maximum capable work energy of the pump, at say 12V, and you again get a pressure drop.

Join the two and you get a larger amount of total pumping work potential, (at the expense of higher current draw on the electrical system).

When you are below the maximum work potential of the pump, the extra "energy" is recycled by the fuel pressure regulator, back to the tank. At full potential, the fuel pressure regulator will return no fuel.

Hope that clears things up a bit.

I also may have opened up a can of worms and made things worse lol

Engineers be getting all scientific and shit....

RoyalFlush · 11-20-2013, 07:43 AM

Quote:

Originally Posted by AK 335i

if your low pressure fp is at 50 at idle.. your gonna have a bad time even with the inline. You should replace it when you do the inline with a new oem or 450

This, 50 is strugs.

Quote:

Originally Posted by 3000GT MR

Engineers be getting all scientific and shit....

I love when they get scientific and shit.

Jim9 · 11-20-2013, 10:31 PM

Would you guys perfer inline or the e85 pump itself? I'm debating on ordering something for e85 next year.

enrita · 11-21-2013, 01:12 AM

Inline gives less headaches

HP Autosport · 11-21-2013, 01:33 AM

Quote:

Originally Posted by enrita

Inline gives less headaches

+1. Plus, as I have mentioned before, the walboro sometimes drops fuel pressure randomly. It is also better, in my opinion, to use the stock LPFP ramp up values that the ECU can effectively manage. Use the in-line pump to just draw the fuel faster and more of it.

-Mike

135Pats · 11-21-2013, 08:59 AM

Quote:

Originally Posted by HP Autosport

+1. Plus, as I have mentioned before, the walboro sometimes drops fuel pressure randomly. It is also better, in my opinion, to use the stock LPFP ramp up values that the ECU can effectively manage. Use the in-line pump to just draw the fuel faster and more of it.

-Mike

+2 and if god forbid the inline series pump were to suddenly fail, you wouldn’t risk a catastrophic lean out since the stock pump and bucket would still be functional.

HP Autosport · 11-21-2013, 01:20 PM

Quote:

Originally Posted by 135Pats

+2 and if god forbid the inline series pump were to suddenly fail, you wouldn’t risk a catastrophic lean out since the stock pump and bucket would still be functional.

I learned that the hard way.

-Mike

Jim9 · 11-24-2013, 11:49 PM

Wish list added. Thanks guys

WedgePerformance · 11-25-2013, 12:23 AM

I just put a new stock bucket/pump in. I know a lot of people say that doing the Walbro drop in is ok, but I didn't want to take any chances with plumbing. I also run the FFTEC/Vishnu 455 inline. Although expensive, this is by far the best and most reliable combination. I have a friend with the Walbro 255 inline also and it seems to work fine as well as long as you have a strong stock pump.

11-18-2013, 06:56 PM	#1
ttbullet Second Lieutenant 29 Rep 243 Posts Drives: 2009 135i Join Date: Oct 2008 Location: 949 area code iTrader: (0)	inline fuel pump I am planning on getting a inline walbro 255 pump. my question is How do they flow more fuel when the weakest link in the flow is still there (stock lpfp)? Do they overwork the stock pump? Wouldn't the stock pump still flow the same? Please explian. Trying to go to higher octane (E85 mix)
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11-18-2013, 07:31 PM	#2
Dmacc Colonel 200 Rep 2,799 Posts Drives: 2011 BMW 1M Join Date: Mar 2010 Location: So Cal iTrader: (1)	It's my understanding that running pumps in series helps draw flow through the lpfp allowing it not to overwork itself. __________________ thanks to MGallop
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11-19-2013, 11:54 PM	#5
AK 335i Major 48 Rep 1,290 Posts Drives: black 335i E90 Join Date: Sep 2012 Location: boynton beach iTrader: (0)	if your low pressure fp is at 50 at idle.. your gonna have a bad time even with the inline. You should replace it when you do the inline with a new oem or 450 __________________ - Proven Power Tampa Built 6466 ST N54 6AT WR 711whp 637wtq -
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11-20-2013, 12:30 AM	#6
akotten Major 38 Rep 1,079 Posts Drives: 2004 M3 Join Date: Mar 2011 Location: Wichita, KS iTrader: (2)	Flowing 450 L/hr of fuel at 72psi requires a specific amount of work energy, which in this case is done by a pump. Running two pumps in series divides the total work between the two pumps. Each pump is capable of doing so much work, so depending on that, the total work required will be split as a percentage to each pump. The factory pump alone is capable of pushing x-amount of fuel at 72psi. Exceed that and you will have a pressure drop. An aftermarket pump can also flow x-amount of fuel at 72psi. Exceed the maximum capable work energy of the pump, at say 12V, and you again get a pressure drop. Join the two and you get a larger amount of total pumping work potential, (at the expense of higher current draw on the electrical system). When you are below the maximum work potential of the pump, the extra "energy" is recycled by the fuel pressure regulator, back to the tank. At full potential, the fuel pressure regulator will return no fuel. Hope that clears things up a bit. I also may have opened up a can of worms and made things worse lol __________________ 2004 E46 M3 \| Imola Red on Cinnamon \| Slicktop \| Manual Seats \| 6spd MT \| Last edited by akotten; 11-20-2013 at 12:37 AM..
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11-20-2013, 10:31 PM	#9
Jim9 Enlisted Member 0 Rep 35 Posts Drives: 335i Alpine Join Date: Jun 2013 Location: Minnesota iTrader: (0)	Would you guys perfer inline or the e85 pump itself? I'm debating on ordering something for e85 next year.
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11-21-2013, 01:12 AM	#10
enrita Major General 161 Rep 7,377 Posts Drives: 335i - Big turbos Join Date: Sep 2008 Location: Italian in Sweden iTrader: (0)	Inline gives less headaches
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11-24-2013, 11:49 PM	#14
Jim9 Enlisted Member 0 Rep 35 Posts Drives: 335i Alpine Join Date: Jun 2013 Location: Minnesota iTrader: (0)	Wish list added. Thanks guys
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11-25-2013, 12:23 AM	#15
WedgePerformance BimmerPost Supporting Vendor 1334 Rep 1,701 Posts Drives: Slot Machines.. Keep Taking $ Join Date: Oct 2013 Location: Portland, OR iTrader: (0) Garage List 2007 BMW 335i Sport [9.67]	I just put a new stock bucket/pump in. I know a lot of people say that doing the Walbro drop in is ok, but I didn't want to take any chances with plumbing. I also run the FFTEC/Vishnu 455 inline. Although expensive, this is by far the best and most reliable combination. I have a friend with the Walbro 255 inline also and it seems to work fine as well as long as you have a strong stock pump.
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