[95blkmax]

Hey guys, just wanted to get some clarification on this subject (wanted to consolidate the information from multiple threads). I'd like to share with you guys what I understand about it all, and please correct me if I am wrong

So for people looking to run full E85, this Walbro 450LPH (PN -267) pump upgrade... I see that:

- people on stock turbo and the Continental HPFP are running the Walbro -267 with no issues
- People on PS2 turbo and the Continental (OR the FXxxx HPFP) with the Walbro -267 are at times having issues with the EKP module (this being attributed to the higher voltage needed for the LPFP to keep up and thus burning out the stock EKP at that point). For example, I saw Slowspeed on Youtube (435i with a Big Boost turbo kit and a Hellcat/ Walbro 525LPH pump) ran this issue.

Someone with experience in this please chime in . But it SEEMS TO ME that you have the potential of issues with the stock fuel pump module when you have higher than stock turbo fuel demands. Is this correct? I know it's not an all inclusive thing that "all folks with larger turbo upgrades WILL have this issue" kind of situation. Just trying to narrow down the area where one can expect to reach the limits of the stock EKP. TIA!

[ziekxq]

I have been running lpfp walboro 450 with 3 gallons of e85... Car haven't gone into limp mode due to overheat, but I get an error code that power of fuel pump is too high for actual pressure for 1 and half year now. I got that error even when I was running 93 octane only. From what I heard issues start happening when you go e50 mix though I have yet to experience this issue. There is an aftermarket module that can fix this issue. Also, this issue doesn't exist if you running stock lpfp even with PS2. Last thing to mention is that you cannot run full e85 without upgrading hpfp or get Helix OD depending on what year your car is.

[slw535]

What if you setup a hobbs switch to active a relay to hotwire the + side of the connector going to the pump. That should eliminate the EKP module from having to deal with the stress of providing that much voltage.

Has anyone done this?

[BimmerHausPerformance]

Originally Posted by slw535

What if you setup a hobbs switch to active a relay to hotwire the + side of the connector going to the pump. That should eliminate the EKP module from having to deal with the stress of providing that much voltage.

Has anyone done this?

Interesting idea but then you are 'losing' control from the dme controlling what is going on.

Walboro 450 can pull more than 12 amps if your tune demands it which will toast the stock module in no time.

[slw535]

Originally Posted by BrowBMW

Interesting idea but then you are 'losing' control from the dme controlling what is going on.

Walboro 450 can pull more than 12 amps if your tune demands it which will toast the stock module in no time.

hmm I was more or less thinking that the DME will just continue providing X amps (whatever that is) and the hotwire/relay will open and allow a power wire (from the battery to pump) to give whatever juice the pump can handle.

If you tap the power wire going straight into the pump, the DME or fuel pump module will ("should") never know the pump is receiving more than what the Fuel pump module is sending it..... OR will it?

So perhaps in the tune set the power draw to just be X amps and have faith that the hob switch opens the relay and the pump is getting all the juice it can via the hotwire.

[95blkmax]

Originally Posted by slw535

hmm I was more or less thinking that the DME will just continue providing X amps (whatever that is) and the hotwire/relay will open and allow a power wire (from the battery to pump) to give whatever juice the pump can handle.

If you tap the power wire going straight into the pump, the DME or fuel pump module will ("should") never know the pump is receiving more than what the Fuel pump module is sending it..... OR will it?

So perhaps in the tune set the power draw to just be X amps and have faith that the hob switch opens the relay and the pump is getting all the juice it can via the hotwire.

I get what you're saying. I used to do something similar to boost the pumps on built Nissans back in the day. On older/ simpler systems, this method works great.

I too have not seen this done on F10s (or any E/F/G BMW for that matter), but it may be for a reason.

For the sake of example from my experience:
Nissan ECU would sent voltage to the pump. This voltage was not constant. Typically high 12V, as high as 14V, as low as 12.1V, depending on load. I'd take the power of the ECU to make a trigger to a new relay, and this would in turn supply a constant 14V to the pump through a new circuit. Made tuning much easier with a FP that was stable across the board.

On my PWG F10 (that does not have a low pressure sensor so all psi info is derived from the sensor on the high side at the end of the fuel rail), DME interprets HPFP target pressure Vs actual pressure, as well as load, and many other parameters, to tell the EKPS (low pressure fuel pump control module) if it needs "normal fuel" or "more fuel" to the HPFP. The EKPS takes these DME requests and operates the LPFP. This is what supplies the "variable voltage" to the LPFP. So in this setup, if we were to do what you're asking about (or what I used to do to old Nissans), we'd get a drivetrain malfunction on the first pull. Because the DME would see that it's getting more fuel than requested, it will attempt to bypass more pressure at the HPFP and request "normal fuel" to the EKPS and when that pressure doesn't drop as it wants, it will think that the HPFP is not functioning and that will be your first code, plus a few more Im sure.

So really besides upgrading to a stronger pump, you have two ways of getting more fuel out of the LPFP. A- rigging a way for the EKPS cooler (as some have done here with computer fans and heatsinks) to prevent it from overheating and putting the car in limp mode until it cools down. or B- upgrade the EKPS (and there are a few options available depending on the requirement). The downside of running stronger pumps is that- again, depending on fueling demands- stronger pumps need more amps to feed those higher demands. So at some point the stock EKPS just will not do and you'd need to upgrade.

Hope this answers your question!

[slw535]

Damn I see what your saying now. Because the EKP module couldn't control the lpfp (because relay is open) and thus cant control high side/low side rail pressure, then the DME would freak out and throw codes. Even setting the "high load" rail pressure limits via a tune might not work.

Butttttt.. Lets say high side fuel rail pressure when relay trips (@10psi) and lpfp is hot wired is at 3000PSI, couldn't a tune set the "high load" rail pressure requirement to 3000 thus not requiring the DME to send any adjustment voltage to the EKP.

Damn as I'm typing this I'm slowly realizing that it will never be a static pressure as fuel demands increase during boost/RPM (decreasing high side pressure if lpfp cant keep up), thus causing the dme to eventually need to send adjustments to EKP.

Cant we just tune the EKP out and add a low side FPR with a return back to the tank LOL?

[$howtime456]

you will need an EOS EKPM. Above e40 you will burn out your stock ekpm3 and will leave you stranded. I have used full e85 with and without port injection. With Spool FX150 you will get around 18psi before you start starving for fuel.On FX180 your lucky if you hit 21psi. With port you i have hit 26psi on 750cc injectors. All this is done on a single 525 lpfp. STFT were steady. My new setup now i am running 2 525lp with a Motive Reflex to monitor fuel pressure. Thegood thing about EOS EKPM is that you can control 2 pumps! I have also upgraded my injectors to ID 1050x to leave a little bit more wiggle room.

[$howtime456]

Originally Posted by slw535

Damn I see what your saying now. Because the EKP module couldn't control the lpfp (because relay is open) and thus cant control high side/low side rail pressure, then the DME would freak out and throw codes. Even setting the "high load" rail pressure limits via a tune might not work.

Butttttt.. Lets say high side fuel rail pressure when relay trips (@10psi) and lpfp is hot wired is at 3000PSI, couldn't a tune set the "high load" rail pressure requirement to 3000 thus not requiring the DME to send any adjustment voltage to the EKP.

Damn as I'm typing this I'm slowly realizing that it will never be a static pressure as fuel demands increase during boost/RPM (decreasing high side pressure if lpfp cant keep up), thus causing the dme to eventually need to send adjustments to EKP.

Cant we just tune the EKP out and add a low side FPR with a return back to the tank LOL?

cant run a return on these fuel systems. This is static fuel pressure which runs at 72 base psi.

[BimmerHausPerformance]

So you were only running one 550 walboro to handle your HPFP and PI?

[slw535]

Originally Posted by $howtime456

you will need an EOS EKPM. Above e40 you will burn out your stock ekpm3 and will leave you stranded. I have used full e85 with and without port injection. With Spool FX150 you will get around 18psi before you start starving for fuel.On FX180 your lucky if you hit 21psi. With port you i have hit 26psi on 750cc injectors. All this is done on a single 525 lpfp. STFT were steady. My new setup now i am running 2 525lp with a Motive Reflex to monitor fuel pressure. Thegood thing about EOS EKPM is that you can control 2 pumps! I have also upgraded my injectors to ID 1050x to leave a little bit more wiggle room.

Well that pretty much ends that discussion right there lol. Thanks for chiming in! Looks like I'll be getting the EOS EKPM in the future.

[$howtime456]

Originally Posted by BrowBMW

So you were only running one 550 walboro to handle your HPFP and PI?

1 525lpfp. -10 lines from the fuel hat to the hpfp got rid of the stock lines. (dont know how much of a difference that made.) Shoup recommended 2 pumps for full E85 so it will be less strain on the first pump as boost increases and no pressure drops. Ive also seen Fuel It and all other cars recommend 2 pumps above 600hp

[ziekxq]

I need a two pump kit some how... I will be ordering port injection soon... trying to hit 550-600whp.