[ilovexdrive]

my 2009 e92 335i has 57k miles, and i did replace the lpfp around 40k miles, but it’s not a stage 2 lpfp. just wondering if i could run e50 with it or if i should get a stage 2 lpfp.

[dmckmc]

E50+ was the limit for my stock fuel system. No trouble keeping pressure in the E40 range. E50 and high pressure could not keep up causing misfires under WOT. High and low fuel pressure also easily monitored via MHD or other if you want to try to see your engines limit on stock fueling.

[lookalikehuuh]

My car strugged with any E85 mix tunes on the stock pump. I hear if you have a newer or strong pump then you might be ok with E30 but mine definitely was not ok with E30, I would drop to below 30PSI.

I ended up going with Walbro 450 and have run E50 tune for years now with no issues whatsoever.

***Warning, if you upgrade your LPFP ensure you install cooling on the EKPM because it WILL overheat and trigger codes, plus potentially leave you stranded.***

[oVeRdOsE.]

not sure if we can answer that without any details on the setup.

assuming the car is stock turbos, no, you technically not need a lpfp stage 2.

if you run a E50 mix, you probably have a tuning device that can log.

Low pressure log value typically ranges from 55-70psi. If dropping below 50psi it indicates a problem with your low fuel pressure pump. (be careful , if you have JB4 , some firmware read 10psi lower than actual...)

some says the low limit is around 40psi.
So test it before changing.

Personnaly I was fine with stock LPFP on my ST setup, however the pump was 170k miles, so Ive decided to updrade for a DIY 450 keeping the bucket. Its a fairly cheap upgrade.
EKP cooling mod was 0$ for me, using old PC part laying around

[ilovexdrive]

Originally Posted by oVeRdOsE.

not sure if we can answer that without any details on the setup.

assuming the car is stock turbos, no, you technically not need a lpfp stage 2.

if you run a E50 mix, you probably have a tuning device that can log.

Low pressure log value typically ranges from 55-70psi. If dropping below 50psi it indicates a problem with your low fuel pressure pump.

some says the low limit is around 40psi.
So test it before changing.

Personnaly I was fine with stock LPFP on my ST setup, however the pump was 170k miles, so Ive decided to updrade for a DIY 450 keeping the bucket. Its a fairly cheap upgrade.
EKP cooling mod was 0$ for me, using old PC part laying around

currently i’m just running mhd stage 1+ (fmic and a tune) but there’s also an option for e50 which will take it from 390hp to abt 410 i believe so i wanted to give that a go

[oVeRdOsE.]

Originally Posted by ilovexdrive

currently i’m just running mhd stage 1+ (fmic and a tune) but there’s also an option for e50 which will take it from 390hp to abt 410 i believe so i wanted to give that a go

your best bet will do logs, under few scenarios and temperatures.


There's not a ton of people running E50. Either pump fuel or E85-ish.

MHD log will give you this info, and the reading is precise, so give a shot and post your results here on datazap.

[ilovexdrive]

Originally Posted by oVeRdOsE.

your best bet will do logs, under few scenarios and temperatures.


There's not a ton of people running E50. Either pump fuel of E85-ish.

MHD log will give you this info, and the reading is precise, so give a shot and post your results here on datazap.

is there any chance of me doing this and ruining my car lmao, i’m new to using different fuel other than 93

[oVeRdOsE.]

Originally Posted by ilovexdrive

is there any chance of me doing this and ruining my car lmao, i’m new to using different fuel other than 93

for sure , there's always a risk, but for few pull like this only to log, I really doubt. MHD got safety built in to avoid super lean scenarios.

do 2 or 3 log in 3rd gear to 2kto 6krpm, dont hit the rev limiter, come back home cruising, post logs.

before changing the map, do logs on 93, see air fuel ratio, ignition timing on all 6 cyl should be very similar, check fuel pressure.

then if all good, flash map e50

[turducken54]

Highly unlikely you can run an aggressive e50 map on a stock pump. Most tuners recommend an upgrade even for aggressive custom pump fuel tunes.

[oVeRdOsE.]

Originally Posted by turducken54

Highly unlikely you can run an aggressive e50 map on a stock pump. Most tuners recommend an upgrade even for aggressive custom pump fuel tunes.

mhd is not agressive.

log will tell.

Anyway, the upgrade on DIY is cheap enough that might be not even a question.