Need Fuel Pump Recommendation

DiscoJax · 12-02-2023, 03:33 PM

I have a 2005 Z4 3.0L that is supercharged. My tuner is telling me to upgrade the fuel pump to a 255lph unit. I am looking at the Walbro and the Deatschwerks. Anyone have a recommendation based on what they did?

Steeler · 12-03-2023, 05:41 PM

Quote:

Originally Posted by DiscoJax

I have a 2005 Z4 3.0L that is supercharged. My tuner is telling me to upgrade the fuel pump to a 255lph unit. I am looking at the Walbro and the Deatschwerks. Anyone have a recommendation based on what they did?

Good discussion here on the subject.
Interested in your tuners reason(s) for recommending a different pump.

https://www.zpost.com/forums/showthread.php?t=1408727

DiscoJax · 12-04-2023, 06:26 PM

Yeah I saw that post. In the link you provided, some people seemed to be talking about the Z4M fuel pump being able to handle the volume. I have the lowly Z4.

Also my OEM fuel pump assembly was replaced when the original fuel pump started failing. So not sure how much this new pump from Delphi can handle.

My tuner stated "Although my concern is we seem to be running out of fuel. It leans out significantly above 5800rpm under full throttle and we are exceeding 100% injector duty cycle (I can't add anymore fuel)."

So I am thinking the Delphi pump may not be able to keep up?

dre99gsx · 12-04-2023, 10:48 PM

I'm the author of that thread. I'm making well over 600whp with the stock Z4 fuel pump (3.0si/Z4M are identical), part number is 16117198099. I run OEM fuel pressure 68psi at boost and am at roughly 65% duty cycle on RC 1200cc injectors at 8000rpm. I track this thing often and have no fuel delivery issues, and I run it rich.

The OEM pump can definitely flow what you need.

I'm not sure if the 3.0i have the same pump but the part numbers are different.

You can try and source an aftermarket pump and swap it in, but due to the returnless system, it may be more hassle that you want to deal with.

If " It leans out significantly above 5800rpm under full throttle and we are exceeding 100% injector duty cycle" on a supercharged 3.0i, you must be running serious power or your injectors are not able to flow enough fuel / fuel pump voltage isn't increased to get full pressure at boost.

I tried swapping to a Walbro 255 and to stick with the OEM unit because it just plain works.

Good luck!

12-02-2023, 03:33 PM	#1
DiscoJax Enlisted Member 8 Rep 40 Posts Drives: 2005 BMW Z4 3.0i Join Date: Jun 2022 Location: Jacksonville iTrader: (0)	Need Fuel Pump Recommendation I have a 2005 Z4 3.0L that is supercharged. My tuner is telling me to upgrade the fuel pump to a 255lph unit. I am looking at the Walbro and the Deatschwerks. Anyone have a recommendation based on what they did?
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12-04-2023, 06:26 PM	#3
DiscoJax Enlisted Member 8 Rep 40 Posts Drives: 2005 BMW Z4 3.0i Join Date: Jun 2022 Location: Jacksonville iTrader: (0)	Yeah I saw that post. In the link you provided, some people seemed to be talking about the Z4M fuel pump being able to handle the volume. I have the lowly Z4. Also my OEM fuel pump assembly was replaced when the original fuel pump started failing. So not sure how much this new pump from Delphi can handle. My tuner stated "Although my concern is we seem to be running out of fuel. It leans out significantly above 5800rpm under full throttle and we are exceeding 100% injector duty cycle (I can't add anymore fuel)." So I am thinking the Delphi pump may not be able to keep up?
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12-04-2023, 10:48 PM	#4
dre99gsx Captain 510 Rep 911 Posts Drives: 1994 Toyota Supra Join Date: Aug 2011 Location: NJ iTrader: (2)	I'm the author of that thread. I'm making well over 600whp with the stock Z4 fuel pump (3.0si/Z4M are identical), part number is 16117198099. I run OEM fuel pressure 68psi at boost and am at roughly 65% duty cycle on RC 1200cc injectors at 8000rpm. I track this thing often and have no fuel delivery issues, and I run it rich. The OEM pump can definitely flow what you need. I'm not sure if the 3.0i have the same pump but the part numbers are different. You can try and source an aftermarket pump and swap it in, but due to the returnless system, it may be more hassle that you want to deal with. If " It leans out significantly above 5800rpm under full throttle and we are exceeding 100% injector duty cycle" on a supercharged 3.0i, you must be running serious power or your injectors are not able to flow enough fuel / fuel pump voltage isn't increased to get full pressure at boost. I tried swapping to a Walbro 255 and to stick with the OEM unit because it just plain works. Good luck! __________________ Andre - 2J into a Z4 Coupe!
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