Fuel System Limitations

mithiral67 · 11-02-2011, 06:31 PM

How does a tuner know when they have hit a fuel system limitations. Can it be determined from logs by being unable to hit afr targets and running lean? Is it a performance aspect that indicates issues?

Ilma · 11-02-2011, 06:40 PM

I would think that if your logs showed fuel trims constantly maxed out at 34 with full open loop assistance, and you still don't hit the intended AF target......then you have a fueling limitation.

But that's just an educated guess.

plague · 11-02-2011, 06:56 PM

Quote:

Originally Posted by Ilma

I would think that if your logs showed fuel trims constantly maxed out at 34 with full open loop assistance, and you still don't hit the intended AF target......then you have a fueling limitation.

But that's just an educated guess.

thats right. have exhibited this on on my own vehicle last night so i now need to adjust OL fueling which is now an adjustable parameter on v5.31.

mithiral67 · 11-02-2011, 07:03 PM

What if you dont have access to log fuel trims? Fall back on not hitting afr targets?

JamesM3M5 · 11-02-2011, 07:19 PM

If you're talking about a standalone (Motec, AEM, etc) you know because your fuel table will have maxxed out the duty cycle on your injectors. If you don't have access into the ECU, you can log AFRs and see you're not hitting your target. Basically, you must be able to log to effectively tune.

What exactly are you trying to do? Tune the N54? Something else? With what?

Jeff@TopGearSolutions · 11-02-2011, 07:24 PM

Maxing out fuel trims, injector duty cycle, or not hitting AFR targets.

mithiral67 · 11-02-2011, 07:28 PM

Quote:

Originally Posted by JamesM3M5

What exactly are you trying to do? Tune the N54? Something else? With what?

I was just looking at a log of a 3-4 gear pull on what I believe is the fastest non-nitrous 60-130mph (7.8 seconds) on upped turbos. I would think if anything was pushing the limit of the fuel system, it would be this set up. But the logs look fine to me. So I was curious if there was something else.

mithiral67 · 11-03-2011, 02:11 PM

Heard from Rob at cobb today, he said from all their testing, they havent found any limitation yet. They did have one car show lean up top, but it was corrected with updates to the HPFP tables.

vasillalov · 11-03-2011, 02:52 PM

Interesting!

I've always had the suspicion that the vast majority of the people here are simply reciting hearsay when it comes to fueling limitations of the N54 and N55. A few vendors have attempted to come up with an aftermarket fueling "solution", but all we've really seen is some guys playing with oscilloscopes and plastic gas tanks.

...food for thought...

Q4P · 11-03-2011, 03:29 PM

Quote:

Originally Posted by vasillalov

Interesting!

I've always had the suspicion that the vast majority of the people here are simply reciting hearsay when it comes to fueling limitations of the N54 and N55. A few vendors have attempted to come up with an aftermarket fueling "solution", but all we've really seen is some guys playing with oscilloscopes and plastic gas tanks.

...food for thought...

That's the thing; there is so much conflicting info on that topic that it's difficult to figure out what's up.

jpsimon · 11-03-2011, 03:33 PM

I think the consensus is that there isn't that much of a fuel limitation with the current stockish-housing upgraded turbos. Shiv mentioned that part of the reason for doing a single turbo was to really test the upper limits of the system

vasillalov · 11-03-2011, 03:58 PM

Do we even know the technical specifications of the OEM injectors? More specifically the max injector duty cycle?

Also, I vaguely recall that Delphi (the maker of our injectors) actually has higher output injectors but they were expensive.

vasillalov · 11-03-2011, 04:02 PM

As a side topic: I am really curious to get more details about the upgraded HPFP that BMW has come up. It is rumored to be able to handle higher fuel demands and solve the HPFP failures...

jpsimon · 11-03-2011, 04:06 PM

Quote:

Originally Posted by vasillalov

As a side topic: I am really curious to get more details about the upgraded HPFP that BMW has come up. It is rumored to be able to handle higher fuel demands and solve the HPFP failures...

What's the part number? I just got a new HPFP put in last week while my car was in for other stuff.

vasillalov · 11-03-2011, 04:11 PM

13517616170

Exchange High Pressure Fuel Pump

Relevant link: http://www.e90post.com/forums/showthread.php?t=588323

jpsimon · 11-03-2011, 10:34 PM

hmm, it says my "exchange high-press" part number is 13517616446

11-02-2011, 06:31 PM	#1
mithiral67 That guy 117 Rep 5,740 Posts Drives: 2015 Cayman GTS Join Date: Jun 2008 Location: Chicago Burbs iTrader: (4) Garage List 2015 Porsche Cayman ... [0.00]	Fuel System Limitations How does a tuner know when they have hit a fuel system limitations. Can it be determined from logs by being unable to hit afr targets and running lean? Is it a performance aspect that indicates issues?
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11-02-2011, 06:40 PM	#2
Ilma Colonel 184 Rep 2,841 Posts Drives: 2008 135i Join Date: Nov 2008 Location: Mississauga iTrader: (0)	I would think that if your logs showed fuel trims constantly maxed out at 34 with full open loop assistance, and you still don't hit the intended AF target......then you have a fueling limitation. But that's just an educated guess.
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11-02-2011, 07:03 PM	#4
mithiral67 That guy 117 Rep 5,740 Posts Drives: 2015 Cayman GTS Join Date: Jun 2008 Location: Chicago Burbs iTrader: (4) Garage List 2015 Porsche Cayman ... [0.00]	What if you dont have access to log fuel trims? Fall back on not hitting afr targets?
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11-02-2011, 07:19 PM	#5
JamesM3M5 Some dude 91 Rep 1,780 Posts Drives: E92 335i Join Date: Sep 2011 Location: Northern VA iTrader: (0)	If you're talking about a standalone (Motec, AEM, etc) you know because your fuel table will have maxxed out the duty cycle on your injectors. If you don't have access into the ECU, you can log AFRs and see you're not hitting your target. Basically, you must be able to log to effectively tune. What exactly are you trying to do? Tune the N54? Something else? With what? __________________ RRT E92 335i/6MT with stuff and things
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11-02-2011, 07:24 PM	#6
Jeff@TopGearSolutions 3441 Rep 79,211 Posts Drives: C6 Z06, 09 335i, 10 335xi Join Date: Dec 2008 Location: www.TopGearSolutions.com iTrader: (37)	Maxing out fuel trims, injector duty cycle, or not hitting AFR targets.
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11-03-2011, 02:11 PM	#8
mithiral67 That guy 117 Rep 5,740 Posts Drives: 2015 Cayman GTS Join Date: Jun 2008 Location: Chicago Burbs iTrader: (4) Garage List 2015 Porsche Cayman ... [0.00]	Heard from Rob at cobb today, he said from all their testing, they havent found any limitation yet. They did have one car show lean up top, but it was corrected with updates to the HPFP tables.
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11-03-2011, 02:52 PM	#9
vasillalov Mad Linux Guru On The Loose 1121 Rep 5,396 Posts Drives: 2008 335i Sedan, 2023 M3 Join Date: Aug 2009 Location: Chicago, IL iTrader: (5) Garage List 2023 BMW M3 [0.00] 2008 335i E90 [8.00]	Interesting! I've always had the suspicion that the vast majority of the people here are simply reciting hearsay when it comes to fueling limitations of the N54 and N55. A few vendors have attempted to come up with an aftermarket fueling "solution", but all we've really seen is some guys playing with oscilloscopes and plastic gas tanks. ...food for thought... __________________ 6MT \| COBB \| AR \| AE \| Forge DV \| HPF \| P3 Gauge \| Hybrid Intake \| O.S.Giken TCD \| All M3 bits \| TCKLine \| StopTech \| UUC \| ER \| SPEC
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11-03-2011, 03:33 PM	#11
jpsimon Team Zissou 3065 Rep 10,197 Posts Drives: 2022 AWD M3 Comp - SMB Join Date: Dec 2006 Location: CT iTrader: (7)	I think the consensus is that there isn't that much of a fuel limitation with the current stockish-housing upgraded turbos. Shiv mentioned that part of the reason for doing a single turbo was to really test the upper limits of the system
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11-03-2011, 03:58 PM	#12
vasillalov Mad Linux Guru On The Loose 1121 Rep 5,396 Posts Drives: 2008 335i Sedan, 2023 M3 Join Date: Aug 2009 Location: Chicago, IL iTrader: (5) Garage List 2023 BMW M3 [0.00] 2008 335i E90 [8.00]	Do we even know the technical specifications of the OEM injectors? More specifically the max injector duty cycle? Also, I vaguely recall that Delphi (the maker of our injectors) actually has higher output injectors but they were expensive. __________________ 6MT \| COBB \| AR \| AE \| Forge DV \| HPF \| P3 Gauge \| Hybrid Intake \| O.S.Giken TCD \| All M3 bits \| TCKLine \| StopTech \| UUC \| ER \| SPEC
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11-03-2011, 04:02 PM	#13
vasillalov Mad Linux Guru On The Loose 1121 Rep 5,396 Posts Drives: 2008 335i Sedan, 2023 M3 Join Date: Aug 2009 Location: Chicago, IL iTrader: (5) Garage List 2023 BMW M3 [0.00] 2008 335i E90 [8.00]	As a side topic: I am really curious to get more details about the upgraded HPFP that BMW has come up. It is rumored to be able to handle higher fuel demands and solve the HPFP failures... __________________ 6MT \| COBB \| AR \| AE \| Forge DV \| HPF \| P3 Gauge \| Hybrid Intake \| O.S.Giken TCD \| All M3 bits \| TCKLine \| StopTech \| UUC \| ER \| SPEC
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11-03-2011, 04:11 PM	#15
vasillalov Mad Linux Guru On The Loose 1121 Rep 5,396 Posts Drives: 2008 335i Sedan, 2023 M3 Join Date: Aug 2009 Location: Chicago, IL iTrader: (5) Garage List 2023 BMW M3 [0.00] 2008 335i E90 [8.00]	13517616170 Exchange High Pressure Fuel Pump Relevant link: http://www.e90post.com/forums/showthread.php?t=588323 __________________ 6MT \| COBB \| AR \| AE \| Forge DV \| HPF \| P3 Gauge \| Hybrid Intake \| O.S.Giken TCD \| All M3 bits \| TCKLine \| StopTech \| UUC \| ER \| SPEC
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11-03-2011, 10:34 PM	#16
jpsimon Team Zissou 3065 Rep 10,197 Posts Drives: 2022 AWD M3 Comp - SMB Join Date: Dec 2006 Location: CT iTrader: (7)	hmm, it says my "exchange high-press" part number is 13517616446
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