Lpfp Advice

[Kdiddy007]

I have a 2012 135i dct fbo and just ordered a pure stage 2. Had a few questions about what low pressure fuel pump you guys recommend. How much e85 can I run with stage 2 vs stage 3 and what are the pros and cons? Does stage 3 run full e85?

Thanks again for any help in advance!

[135 TING]

Read on a couple people having trouble with the stage 2 fuel pumps.
Getting too hot and or shutting down with low fuel due to fuel starvation.
Would like to get updates on how it works for you before I pull the trigger

[dtla1]

Then there's Matticus91 who has gone a totally different route with his build and opted to go for the XDI HPFP.

[iminhell1]

If you're going for more power in the future, future proof your fuel system. It's not fun at all.

Dual 450's (274) will be well enough to meet any power goal you have. The problem is driving them. A single will run at the edge of the factory controllers limits. The second won't be able to be controlled by it; needs a second way to control it, Hobs and relay. Or you could go the BPM4 route.


Full E85 takes a lot of pump. Be ready for it.

[Matticus91]

Originally Posted by Kdiddy007

I have a 2012 135i dct fbo and just ordered a pure stage 2. Had a few questions about what low pressure fuel pump you guys recommend. How much e85 can I run with stage 2 vs stage 3 and what are the pros and cons? Does stage 3 run full e85?

Thanks again for any help in advance!

Originally Posted by 135 TING

Read on a couple people having trouble with the stage 2 fuel pumps.
Getting too hot and or shutting down with low fuel due to fuel starvation.
Would like to get updates on how it works for you before I pull the trigger

Originally Posted by dtla1

Then there's Matticus91 who has gone a totally different route with his build and opted to go for the XDI HPFP.

Originally Posted by iminhell1

If you're going for more power in the future, future proof your fuel system. It's not fun at all.

Dual 450's (274) will be well enough to meet any power goal you have. The problem is driving them. A single will run at the edge of the factory controllers limits. The second won't be able to be controlled by it; needs a second way to control it, Hobs and relay. Or you could go the BPM4 route.


Full E85 takes a lot of pump. Be ready for it.

The pumps are all different. I'm selling a Stage 2 LPFP here that is from a company recommended over Fuel-It by several tuners for anything up to 550-600whp. I've heard people are having a lot of issues with the Walbro pumps lately.

The general consensus (NOT my opinion, based on statements by several tuning companies including MHD, Twisted Tuning, and Tuning Tech FS) you need a Stage 2 or above LPFP if you plan to run any ethanol above e20ish you should upgrade the LPFP.

Additionally, if you are running past 450whp you'll need to upgrade the LPFP.

That said, the less common thought is that the HPFP is barely able to keep up with even 400whp, and attempting to push past that on the stock HPFP is asking for trouble, regardless of octane/e contents.

TTFS/XDI's HPFP's more than solve this issue. Yes, they are expensive, $2k+ if they aren't running a deal. The fact is that the logs back this theory up easily. On the stock HPFP the fuel rail PSI drops below IDLE levels at WOT which is super scary. With the new XDI pump we see 3000PSI at WOT and it's barely turning, the ceiling is miles away and the AFR's were steady and well within spec, at/under 13 at WOT. AFR's prior to the HPFP were at times above 15!!!

The short story is, if you want to do an OTS tune like MHD etc, just upgrade the LPFP and do an e-mix. The car will protect itself from failure. If you're looking to go big power on pump gas, upgrade the HPFP and LPFP, do it right.

You will fry the EKPM unit (EKPM3 in my car, the fuel controller iminhell1 referred to) if you run a bigger pump than stock, and it's a huge pain in the ass.

Port injection is just as expensive, incredibly difficulty to maintain and tune, and just as hard to set up.

[135 TING]

Originally Posted by Matticus91

The pumps are all different. I'm selling a Stage 2 LPFP here that is from a company recommended over Fuel-It by several tuners for anything up to 550-600whp. I've heard people are having a lot of issues with the Walbro pumps lately.

The general consensus (NOT my opinion, based on statements by several tuning companies including MHD, Twisted Tuning, and Tuning Tech FS) you need a Stage 2 or above LPFP if you plan to run any ethanol above e20ish you should upgrade the LPFP.

Additionally, if you are running past 450whp you'll need to upgrade the LPFP.


The short story is, if you want to do an OTS tune like MHD etc, just upgrade the LPFP and do an e-mix. The car will protect itself from failure. If you're looking to go big power on pump gas, upgrade the HPFP and LPFP, do it right.

You will fry the EKPM unit (EKPM3 in my car, the fuel controller iminhell1 referred to) if you run a bigger pump than stock, and it's a huge pain in the ass.

I’m looking into upgrading my fuel pump at the moment wanted to run e85 more often so I figured i’d look around.
Car right now is on PS1,FBO,JB4 and e mix.
The HPFP upgrade is out of question due to the cost.
The more I read on things I see and hear people having issues with the stage 2 fuel pump which lead me to believe it’s not really worth it. Hence why you’re not keeping the stage 2 pump along with your new HPFP.

[Matticus91]

Originally Posted by 135 TING

I’m looking into upgrading my fuel pump at the moment wanted to run e85 more often so I figured i’d look around.
Car right now is on PS1,FBO,JB4 and e mix.
The HPFP upgrade is out of question due to the cost.
The more I read on things I see and hear people having issues with the stage 2 fuel pump which lead me to believe it’s not really worth it. Hence why you’re not keeping the stage 2 pump along with your new HPFP.

For me it doesn't make sense since I upgraded the HPFP and had the car dyno tuned on 93. If you're running a PS1 and Jb4, you're going to need an e mix to see any performance out of that PS1. Trying to squeeze anything out of it on 93 is a big gamble, and the car will pull a ton of timing and be super inconsistent. That's where the LPFP comes in, which will allow you to run as much ethanol as the rest of the car can handle.

[135 TING]

Originally Posted by Matticus91

For me it doesn't make sense since I upgraded the HPFP and had the car dyno tuned on 93. If you're running a PS1 and Jb4, you're going to need an e mix to see any performance out of that PS1. Trying to squeeze anything out of it on 93 is a big gamble, and the car will pull a ton of timing and be super inconsistent. That's where the LPFP comes in, which will allow you to run as much ethanol as the rest of the car can handle.

Makes sense. I usually drive the car on map 1 when I don’t have a mic and when I do have a mix I bump it to map 6.
But I see what you’re getting at.
If you still have the pump towards the end of the month i’d take it off your hands.

[dtla1]

Originally Posted by 135 TING

Makes sense. I usually drive the car on map 1 when I don’t have a mic and when I do have a mix I bump it to map 6.
But I see what you’re getting at.
If you still have the pump towards the end of the month i’d take it off your hands.

Well shit, looks like I have a deadline to decide if I want to grab this before you do lol. I've been thinking of picking it up and telling my mind that it's more of a maintenance item since i'm still on stock LPFP at almost 100k miles.

[Matticus91]

Originally Posted by 135 TING

Makes sense. I usually drive the car on map 1 when I don’t have a mic and when I do have a mix I bump it to map 6.
But I see what you’re getting at.
If you still have the pump towards the end of the month i’d take it off your hands.

Originally Posted by dtla1

Well shit, looks like I have a deadline to decide if I want to grab this before you do lol. I've been thinking of picking it up and telling my mind that it's more of a maintenance item since i'm still on stock LPFP at almost 100k miles.

It's all about upgrade path. If you never expect to spend $2k+ on an HPFP and push past 400whp, or if you're running e-mixes, you'll probably want to do the LPFP lol.