N54 Next step with my E89 Z4 - fuel supply

Paarma78

New Member
Oct 15, 2023
24
12
0
Finland
Hi,

I'm new here (from Finland), have read a lot of discussion especially on the fuel supply as I think I have issues on that area. The car is Z4 E89 2009 with DCT. Mod list:

Engine (N54)
AMP44 forged pistons
FCP H beam rods
ACL Race bearings (conrod & main)
Fin-Turbo Stage 2 turbos with new housings (up to 600hp crank).
VRSF inlets
VRSF outlets
VRSF chargepipe
VRSF downpipes
Modified original exhaust system
Burger Motorsports DCI intake
RB N54 PCV valve
7.5" FMIC
Oil catch can
Additional oil cooler
B58 OEM coils & DIY support
NGK 97506 2-step colder sparkplugs
Valvoline VR1 RACING 5W-50 oil

Fueling
New OEM HPFP
LPFP Walbro 450 in original bucket
LPFP pressure sensor retrofit (Z4 does not have this from the factory)

I'm on E45 mix (50:50 98oct and E85). With 25psi boost I see rail pressures to drop almost to 1000psi. I won't get codes but can feel a bit stuttering with 4th gear, seems like missfires. Walbro 450 is fairly new, HPFP is brand new (OEM). Currently have mixture of injectors from index 4 to 9, these have just been checked and leak tested. Estimation is that this tune has ~550hp (crank), no dyno yet.

I also have a different track map, max 20psi with smoothened torgue curve. Rail pressure stays 1900psi and no misfires/stuttering.

Datalogs here
4th gear e45 25psi
3rd gear e45 track map max 20psi

Questions to first understand how I am limited
1. Based on LP readings, there should be enough fuel available from LPFP? Or is single 450 on the limit with such boost and E mix (but not visible in the LP pressure)?
2. Rail pressure drops with 25psi. Not sure what is considered as "minimum", but this could cause stuttering/misfires. HPFP is new OEM unit. Is the HPFP on limit with such setup? Or could this be due to LPFP or other way round...
3. Both above?

Target
- To get rid of stuttering/misfires with this E45 mix tune (25psi) & solid performance.

What I already have for upgrades that should at least help (not installed yet)
- 5x index 12 and 1x index 11 injectors with low mileage
- Spool Helix 3x overdrive unit.

Considering
- LPFP upgrade (does Helix need this anyway?). Note that I'm doing track, so a bit reluctant on 2 pump setup and I'm having lower tune for the track (20psi) where all seems to be OK with current setup (450 pump). Easy option should be to change 450 to 535 (but I will get long cranks). Other option to add another 450 pump (or 535 for primary and switch 450 to secondary with hobbs).
- Possibly flex fuel up to full E85. But this is not priority, might add this later. Would 535 be enough?

Sorry the long starting post, but it is (almost) all there. :) Let's start with this...

 
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wheela

Lieutenant
Jun 4, 2021
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Twin Cities, MN
Ride
2015 e84 X1 35i Msport
I'm not super familiar with the n54 style hpfp because I'm n55 with the newer style hpfp, but if you're running 25psi on e45, I think you're out of the capability of the oem hpfp unless you're running an overdrive. Looks like you have a helix 3x planned, did you buy it yet? PFS POD is an option to look into if you haven't purchased yet.

I not as familiar with lpfp needs, so I'm not sure if you're 450 is also a factor at the level you're at.
 

Dumaurier7

Lieutenant
May 19, 2020
517
198
0
Hi,

I'm new here (from Finland), have read a lot of discussion especially on the fuel supply as I think I have issues on that area. The car is Z4 E89 2009 with DCT. Mod list:

Engine (N54)
AMP44 forged pistons
FCP H beam rods
ACL Race bearings (conrod & main)
Fin-Turbo Stage 2 turbos with new housings (up to 600hp crank).
VRSF inlets
VRSF outlets
VRSF chargepipe
VRSF downpipes
Modified original exhaust system
Burger Motorsports DCI intake
RB N54 PCV valve
7.5" FMIC
Oil catch can
Additional oil cooler
B58 OEM coils & DIY support
NGK 97506 2-step colder sparkplugs
Valvoline VR1 RACING 5W-50 oil

Fueling
New OEM HPFP
LPFP Walbro 450 in original bucket
LPFP pressure sensor retrofit (Z4 does not have this from the factory)

I'm on E45 mix (50:50 98oct and E85). With 25psi boost I see rail pressures to drop almost to 1000psi. I won't get codes but can feel a bit stuttering with 4th gear, seems like missfires. Walbro 450 is fairly new, HPFP is brand new (OEM). Currently have mixture of injectors from index 4 to 9, these have just been checked and leak tested. Estimation is that this tune has ~550hp (crank), no dyno yet.

I also have a different track map, max 20psi with smoothened torgue curve. Rail pressure stays 1900psi and no misfires/stuttering.

Datalogs here
4th gear e45 25psi
3rd gear e45 track map max 20psi

Questions to first understand how I am limited
1. Based on LP readings, there should be enough fuel available from LPFP? Or is single 450 on the limit with such boost and E mix (but not visible in the LP pressure)?
2. Rail pressure drops with 25psi. Not sure what is considered as "minimum", but this could cause stuttering/misfires. HPFP is new OEM unit. Is the HPFP on limit with such setup? Or could this be due to LPFP or other way round...
3. Both above?

Target
- To get rid of stuttering/misfires with this E45 mix tune (25psi) & solid performance.

What I already have for upgrades that should at least help (not installed yet)
- 5x index 12 and 1x index 11 injectors with low mileage
- Spool Helix 3x overdrive unit.

Considering
- LPFP upgrade (does Helix need this anyway?). Note that I'm doing track, so a bit reluctant on 2 pump setup and I'm having lower tune for the track (20psi) where all seems to be OK with current setup (450 pump). Easy option should be to change 450 to 535 (but I will get long cranks). Other option to add another 450 pump (or 535 for primary and switch 450 to secondary with hobbs).
- Possibly flex fuel up to full E85. But this is not priority, might add this later. Would 535 be enough?

Sorry the long starting post, but it is (almost) all there. :) Let's start with this...

PFS POD with Spool mounting flange.
 

Paarma78

New Member
Oct 15, 2023
24
12
0
Finland
PFS POD with Spool mounting flange.
Not an option, will be Helix. Maybe option in the US, but not here.

How about LPFP (450 Walbro) with Helix 3x and the tune mentioned in the original post? I believe with E45 mix and max 600hp (crank) it should work. But if 100% E85...
 

Dumaurier7

Lieutenant
May 19, 2020
517
198
0
Okaaay I guess since they do the same thing the Spool should work too...... why the 450 walbro though? why not just go with the 535? can't comment on your tune but to be safe I would have it retuned. I am in the middle of modding my Z too, I did all the VRSF bolt on upgrades, Pace setter exhaust upgrade (in progress) for the upgraded twins and for fuel I went with a POD overdrive, PR 535 LPFP and soon an EOS intake manifold to allow for port injection when I eventually make it flex fuel.
 
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Paarma78

New Member
Oct 15, 2023
24
12
0
Finland
450 because it is already in the car by previous owner (mentioned in the original post). If this is sufficient, I don't want to change it to 535 or a double as it is quite a bit of work with Z4.
 

Dumaurier7

Lieutenant
May 19, 2020
517
198
0
Heard many stories of subsystem ECUs being trashed by low batteries…you’ve had it bad…interesting anecdotal evidence on how bad it can get with failing to register / code the battrry…

Well done on your journey..is it Ohlins time yet ?😳🙈👌

I'm on E45 mix (50:50 98oct and E85). With 25psi boost I see rail pressures to drop almost to 1000psi. I won't get codes but can feel a bit stuttering with 4th gear, seems like missfires. Walbro 450 is fairly new, HPFP is brand new (OEM). Currently have mixture of injectors from index 4 to 9, these have just been checked and leak tested. Estimation is that this tune has ~550hp (crank), no dyno yet.
Your rail pressure should not drop, this is a clear sign that you need to upgrade your pumping capacity.
I also have a different track map, max 20psi with smoothened torgue curve. Rail pressure stays 1900psi and no misfires/stuttering.
Which clearly indicates that fuel pressure is your issue.
Questions to first understand how I am limited
1. Based on LP readings, there should be enough fuel available from LPFP? Or is single 450 on the limit with such boost and E mix (but not visible in the LP pressure)?
I have twin 450's and an upgraded HPFP on my single turbo F22 and my LPF stays rock solid at 100psi!
2. Rail pressure drops with 25psi. Not sure what is considered as "minimum", but this could cause stuttering/misfires. HPFP is new OEM unit. Is the HPFP on limit with such setup? Or could this be due to LPFP or other way round...
I saw LPF drop off to 60psi on my F22 which made it throw a code, not sure what the N54 will do but I don't want to find out.
Target
- To get rid of stuttering/misfires with this E45 mix tune (25psi) & solid performance.

What I already have for upgrades that should at least help (not installed yet)
- 5x index 12 and 1x index 11 injectors with low mileage
- Spool Helix 3x overdrive unit.
Install your upgrades then tune, don't want to melt a piston, or do you?
Considering
- LPFP upgrade (does Helix need this anyway?). Note that I'm doing track, so a bit reluctant on 2 pump setup and I'm having lower tune for the track (20psi) where all seems to be OK with current setup (450 pump). Easy option should be to change 450 to 535 (but I will get long cranks). Other option to add another 450 pump (or 535 for primary and switch 450 to secondary with hobbs).
Once the Helix is installed the HPFP will be able to hold a higher static rail pressure but will require more fuel make up once the injectors are opened up more during higher boost in order to maintain rail pressure and the required A/F ratios.
- Possibly flex fuel up to full E85. But this is not priority, might add this later. Would 535 be enough?
I believe you may need a second LPFP and port injection.
Sorry the long starting post, but it is (almost) all there. :) Let's start with this...
No problem.
 
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Dumaurier7

Lieutenant
May 19, 2020
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450 because it is already in the car by previous owner (mentioned in the original post). If this is sufficient, I don't want to change it to 535 or a double as it is quite a bit of work with Z4.
Having to pull the motor for a rebuild will be more !;)
 

Paarma78

New Member
Oct 15, 2023
24
12
0
Finland
Thanks for the very clear feedback!

Does 600hp crank with 100% E85 really need PI? Sounds like the best would be to stay E45 with my power levels.
Just recently discovered, that here (Finland) is one N54 making 654hp (crank) with single Walbro 450 and 35% ethanol without issues (it is MHD flex fuel, has bigger turbos than mine) and without PI. He might be on the limit though (injectors and LPFP)... :sweatsmile:

When I install Helix 3x + updated tune for it, I can still monitor LPFP as I have the pressure sensor retrofit done. So basically with the same setup, it increases requirements for LPFP, thanks for confirming (this was what I assumed). As I'm doing track, I'm reluctant on 2 pumps so then if upgrade needed I think the only option is 535 (with additional valve as I don't want long cranks).

And I don't want to destroy my motor, that is why I'm confirming plans that all make sense but don't want to put unnecessary effort or money as I have other hobbies and a family too. :blush: I have always tried to assure that I have a bit of headroom to mitigate severe issues, this is my first petrol turbo engine (been tuning diesels earlier).

Motor was just built by the previous owner, want to keep it running. :laughing:
 
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Dumaurier7

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May 19, 2020
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So, I am currently in the process of getting my Z ready for tuning, so far, I've purchased a PR DIY stage 2.5 (Walbro 535) kit to upgrade the stock LPFP. After the initial tune on pump gas, I will be making the car Flex Fuel capable and setting up port and Meth. injection, which leads me to the question of how to install a second pump without compromising SAFETY due to the unique configuration of the Z's fuel tank with the side mounted access lid/filter assembly. After a bit of searching, I've settled on the PR top hat kit for the A90/Z4 M40i cars, I am hoping that if it doesn't fit exactly, it will lend itself to be easily modified as it is billet aluminum, what are your thoughts? anyone have an E89 filter/lid on hand to take a measurement of the flange outer diameter?

BilletTopHat-Front4.jpeg
BilletTopHat-Under-1.jpg
BilletTopHat-Overview.jpg


This configuration will require an external mounted fuel filter with check valve which I had planned to install because the 535 doesn't have an internal check valve, as well as a 1:1 rising rate regulator which can easily be integrated here as well.
 
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pbondar

Sergeant
May 30, 2020
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Lot of plumbing going on there..good luck…fortunately for me ethanol fuels are not available here so flex fuel is removed as a temptation..

Since I use my car for multi day long car trips I’m not keen on WMI as the tankering to me is an emotional issue.

So I’ll limp on with limited power …but enjoy ..I’m watching…
 

Dumaurier7

Lieutenant
May 19, 2020
517
198
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I always work with the " Over Engineer and Future proof " principles so that I do not have to be constantly re-doing and updating when I can me enjoying the car.
 

Dumaurier7

Lieutenant
May 19, 2020
517
198
0
Does anyone have an OEM fuel tank cover/ filter on hand to measure the diameter please? I wanna know how they compare before I buy.
So, I am currently in the process of getting my Z ready for tuning, so far, I've purchased a PR DIY stage 2.5 (Walbro 535) kit to upgrade the stock LPFP. After the initial tune on pump gas, I will be making the car Flex Fuel capable and setting up port and Meth. injection, which leads me to the question of how to install a second pump without compromising SAFETY due to the unique configuration of the Z's fuel tank with the side mounted access lid/filter assembly. After a bit of searching, I've settled on the PR top hat kit for the A90/Z4 M40i cars, I am hoping that if it doesn't fit exactly, it will lend itself to be easily modified as it is billet aluminum, what are your thoughts? anyone have an E89 filter/lid on hand to take a measurement of the flange outer diameter?

View attachment 89183View attachment 89184View attachment 89185

This configuration will require an external mounted fuel filter with check valve which I had planned to install because the 535 doesn't have an internal check valve, as well as a 1:1 rising rate regulator which can easily be integrated here as well.
Does anyone have an OEM fuel tank cover/ filter assembly on hand ? I need to know its diameter, thanks in advance!
 
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Dumaurier7

Lieutenant
May 19, 2020
517
198
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Does anyone have an OEM fuel tank cover/ filter on hand to measure the diameter please? I wanna know how they compare before I buy.
Does anyone have an OEM fuel tank cover/ filter assembly on hand? I need to know its diameter, thanks in advance.
Sooo , this weekend I did get around to installing the 535, for information the filter/cover is indeed 6" in diameter!
 
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Neg89

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Jul 4, 2021
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Hi. I am also e89 owner. Maybe my car is unique but i had LPFP issues even on pump fuel with new HPFP and even i upgraded to walbro 530.

I have new unused PFS POD in the original box. Imported year or so ago from USA. I am from Latvia. I forgot that i have one. But recently find it and want to sold because i went PI route finally. PM me if you are interested or interested in e89 related things. Also check my thread about manifold explosion.
 
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Dumaurier7

Lieutenant
May 19, 2020
517
198
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Hi. I am also e89 owner. Maybe my car is unique but i had LPFP issues even on pump fuel with new HPFP and even i upgraded to walbro 530.

I have new unused PFS POD in the original box. Imported year or so ago from USA. I am from Latvia. I forgot that i have one. But recently find it and want to sold because i went PI route finally. PM me if you are interested or interested in e89 related things. Also check my thread about manifold explosion.
Thanks, but I already have a POD installed on my car.