My next fueling mods: sanity check?

[whyzee125]

Hey guys,

This is my first post on here but I've been a lurker for quite a while. I've been on e90post for 10+ years but have been finding this forum much more informative. I'm switching LPFP setups and would like your input if I'm missing something or if I'm going the right direction.

My setup currently is as follows:
- 2009 N54 335i 6AT
- Stock turbos
- Inlets
- Port injection w/ AIC6
- Full e85
- Custom Wedge tune, peaking @ 21psi, tapering to ~15 at redline
- Fuel it stage 3 LPFP (Dual Walbro 450s) triggered by a 15psi Hobbs Switch

Here's the problem. I need more fuel than a single 450 can provide but am really well below what the dual 450s can do. This means that as RPMs increase and boost tapers, sometimes the Hobbs switch will begin to deactivate, which causes the fuel pressure to dip for a second when the secondary pump turns off. I've had this happen just a few times (high RPM, medium load, boost tapers and cuts fuel pressure, causing the car to buck and go lean for a split second). I'd imagine this could cost me an engine if the circumstances were exactly right. The throttle response in the mid range also feels a bit like an on/off switch as you can very much feel when the second fuel pump kicks on. I have an LED light in the cluster to show when it's running too.

Ideally I want a BPM4 but they've been out of production for a while. I could probably get a lower PSI Hobbs switch or adjust mine but I think I'd rather do away with it entirely if possible.

I'm thinking of switching to the following setup:
- Single Walbro 535 (295)
- Arc Terminator upgraded EKP with increased voltage capacity and active cooling

and call it a day. This would not leave me the headroom for upgraded turbos someday but mine are in great shape so I don't have plans to upgrade for some time. This pump was not available when my current LPFP was installed but I think this would provide enough for my current power level and would simplify things a lot.

Any thoughts or suggestions?

Thanks so much!

 

[whyzee125]

datazap.me | whyzee125 | Back on e85

datazap.me

Here is a log showing what happens when the second pump kicks off. The LED when off and I felt it too.

 

[wheela]

Welcome to spoolstreet, nice to see you over here!

535 was what came to my mind, though I'm not sure of it's exact limits. Have you looked into et3 designs for ekp control? People seem to be having pretty good luck with them:

ET3design

UFO Detector UAP Detector designed for the study of the UAP phenomena. People that want to learn more about the UAP phenomena now have tool to help.

et3design.com

 

[ShocknAwe]

535. Get a EOS BPM4 to control your setup instead of a Hobbs.

 

[whyzee125]

Welcome to spoolstreet, nice to see you over here!

535 was what came to my mind, though I'm not sure of it's exact limits. Have you looked into et3 designs for ekp control? People seem to be having pretty good luck with them:

ET3design

UFO Detector UAP Detector designed for the study of the UAP phenomena. People that want to learn more about the UAP phenomena now have tool to help.

et3design.com

Thank you! That's actually the one I've looked the least into but will research further. My ideal solution would be the BPM4 and just leave my twin 450s but can't get one. The speedsty controller can control 2 pumps more reliably than a Hobbs switch but it runs each pump at all or nothing, so that's what lead me to just doing the arc terminator unit which would be very good at running a single 535.

535. Get a EOS BPM4 to control your setup instead of a Hobbs.

Thank you for the reply! I would get a BPM4 if I could and just leave the twin pumps but if I go 535 it will be a single pump. Just hoping that's enough for my power level with a little headroom.

 

[Maroon_e90]

Ive seen this from precisionraceworks they seem to have done a lot of testing. Maybe it would be worth a shot to try out?

"with either of our engine bay mounted regulator options the flow increases by 100%, that means a single 450 pump is capable of flowing the same as what traditional setups running twin 450's on the stock filter/regulator were capable of!"

Quote from their website

 

[whyzee125]

Holy cow, I've seen that piece but never read that in the description. This is awesome to know!

I actually ordered their stage 2.5 LPFP on black friday too even though I hadn't 100% decided to go this route. Maybe single 535 with their regulator on the arcterminator or et3 EKP will be the ticket. Thank you very much!

 

[ShocknAwe]

IIRC I would have needed another pump or PI/meth etc if I went above 650. Single 535 with increased flow limit via the BPM4 was fine

 

[whyzee125]

I didn't realize BPM4 increased the output of a given pump too. Great to know! I wish I could get my hands on one.

 

[ShocknAwe]

You can do it in the flash. The BPM4 just makes the EKP safe and removes fluctuations with their own PID control.

 

[Cruizinmax]

There are LS swap guys going to a 335d fuel hat on the drivers side which moves the fuel tank jet pump to the return side of the fuel system. It also gets rid of the filter restriction and has a built in return for running a return fuel system. I think that's going to be my next move when I outgrow the single 450 and stock arrangement.

I pieced together the lines, regulator, fittings on racetronix site for a couple hundred. The fuel hat is a hundred on FCPeuro. Just need to add an external filter.

 

[ShocknAwe]

There are LS swap guys going to a 335d fuel hat on the drivers side which moves the fuel tank jet pump to the return side of the fuel system. It also gets rid of the filter restriction and has a built in return for running a return fuel system. I think that's going to be my next move when I outgrow the single 450 and stock arrangement.

I pieced together the lines, regulator, fittings on racetronix site for a couple hundred. The fuel hat is a hundred on FCPeuro. Just need to add an external filter.

Why? That's needlessly complicated. If you're trying to get rid of the return/regulator restriction Id just buy the PR regulator.

Seriously, a 535 significantly outflows an old 450.

 

[whyzee125]

Welp. My 535 pump arrived and then I found out I can still get a BPM4. I think I'm going to return/sell the 535 and keep the dual 450's on a BPM4 because that's more future proof and really probably the most cohesive solution. Agree/disagree?

 

[Silver]

I just receive my BMP4 from Torqbyte for my Z4. The sell Them. 950$ plus danish vat & tax . but the only right solution in my world