[dfv2]

Preface, this issue may well be entirely isolated to my car and hardware. However I find the issue potentially dangerous enough to share just in case it's not isolated to my car.

I sought advice on BB since most of the most knowledgeable members have been banned from e90, and I have also been in contact with Josh@Cobb. In all likelihood the following issue will be resolved by either a hardware/tuning fix on my end, or a new understanding of what the fuel system can and cannot do.

FBO (no meth) 2008 135i , latest HPFP and new injectors, consistently ran ~30% STFT on a 40% mix of E85. Like a kid in a candy shop I got my hands on the new fuel scalable ATR and whipped up a map for 100% E85. With a scalar of 1.4 LTFTs learned themselves at 20+% @ idle so I added more fuel scalar. I finished with a scalar of 1.55 which looked pretty good on idle and cruise. I went out to do a WOT pull and this happened:



Next is a log taken a day later, complete with throttle closures, massive timing corrections (not for knock, looks like a torque/load limit was triggered?) and then lean condition. I tried to bail as soon as I saw the STFT jump so forgive the short logs:



This is simply a cautionary tale for those of you full of piss and vinegar that might fill with straight E85 and slap a 1.4 fuel scalar on without logging. You may be surprised to hit this lean condition with LPFP taking a dive and STFT pegging the hard 34% cap. I never popped a CEL, no codes were ever stored over days of logging and tweaking, and perhaps ironically no timing corrections were seen even at 14+ equiv AFR on 18-15 psi and 12+ degrees timing.

I'll relay whatever I conclude to you gents soon enough.

I'm now on a 50:50 mix and a 1.24 scalar that seem to be working nicely.

[benzy89]

Yikes, short version: N54 is not ready for 100% E85

[ErvGotti]

Whoa those timing corrections were pretty massive, thanks for sharing this I'm planing to go 50/50 tonight and was eventually gonna work my way up to 100% but it looks like it's not ready for it.

[dfv2]

Originally Posted by benzy89

Yikes, short version: N54 is not ready for 100% E85

Perhaps, I know my N54 doesn't agree with it on the map I was using.

[dfv2]

Originally Posted by ErvGotti

Whoa those timing corrections were pretty massive, thanks for sharing this I'm planing to go 50/50 tonight and was eventually gonna work my way up to 100% but it looks like it's not ready for it.

That was most likely related to a larger limit event, maybe some ceiling I didn't raise.

I was running 100% to say I did it. I don't need the octane for the boost and timing I am running, a 50% mix will support some damn aggressive timing on stock turbos.

[Carl Morris]

Glad nothing broke. I had a similar experience with my Mitsu where the "sock" on the fuel pump intake started collapsing after a while of running E85. The bad news is I went lean at full boost several times trying to figure out what was going on. The good news is that it never knocked while doing that. E85 is amazing stuff. Based on that experience I feel fairly confident (crossed fingers) that nobody will lose a motor while running into issues like you just did. I'm assuming that on stock turbos at high elevation I'm not going to hit whatever limit you just hit. But I'm starting at 50/50 today rather than going all the way to 100% right away just in case. My tank of 20% finally ran out.

[ar design II]

props to you for giving 100% e85 a shot.. Still happy you tried?

[dfv2]

Originally Posted by Kai @ AR Design

props to you for giving 100% e85 a shot.. Still happy you tried?

Hell yea, someone's gotta stick their neck out and share some results good bad or otherwise. Easy to say since nothing let go of course - I've melted a handful of pistons in my day.

It's well proven that the N54 will take all kinds of abuse and negligent tuning before catastrophic failure occurs. DI and E85 are a heavenly match, hopefully some upped turbo cars tune for high boost high E85 soon and iron out the kinks for us.

[SuPerNeT]

Hopfully COBB chimes in on this, i'm running a little more then the norm at 65% e85 and 35% 91oct with a scaler of 1..280 then had to trim out my bank 1 a little higher to compensate for my 2 seprate LTFT's (1.285). So far the car is staying under 18% at WOT and idles around 3%. I have been itching to go full retard on this corn but will hold back till we can figure this out. I may try steping it up like 75% and see what happens..

[cloud_connected]

I wonder if you are having LPFP issues. The LPFP is WAY off target and that's almost certainly the cause of the HPFP being under target. Its weird you triggered no codes though...

[dfv2]

Originally Posted by cloud_connected

I wonder if you are having LPFP issues. The LPFP is WAY off target and that's almost certainly the cause of the HPFP being under target. Its weird you triggered no codes though...

Yes, this appears to be the root cause.

Can anyone log req/act for HPFP, LPFP, boost, load, lambdas & STFTs for a 50% or higher E85 WOT pull? I'd like to see if/when LPFP dips below design pressure for you guys. It's bound to happen to some, I'm just curious how prevalent this might be. Hell I hope it's just me so I can fix it and keep pushing!

[cloud_connected]

Originally Posted by dfv2

Yes, this appears to be the root cause.

Can anyone log req/act for HPFP, LPFP, boost, load, lambdas & STFTs for a 50% or higher E85 WOT pull? I'd like to see if/when LPFP dips below design pressure for you guys. It's bound to happen to some, I'm just curious how prevalent this might be. Hell I hope it's just me so I can fix it and keep pushing!

If I had access to e85 I would definitely get you a log, unfortunately its nearly a 2 1/2 hour round trip for me to get e85.

What is also odd is how much you're overshooting the requested HP and LP pumps immediately before the pressure loss.

[JamesM3M5]

We replace regular (non-turbo) BMW fuel pumps somewhat often for many racecars, and upgraded FPs for aftermarket turbo BMWs as well. They simply get weak. They will keep up with stock power, but once you have a significant increased demand they may not keep up nearly as long as a stock pump on stock power.

Unfortunately since the fuel pump module (EKP) monitors pump speed and current draw, upgrading the in-tank pump with a different unit can be problematic. Did it on a Grand Am 328i using a Bosch 044 pump, but luckily it only complained about the pump current draw. Not sure what the N54 EKP will complain about, though. I have a feeling that will be one easy upgrade to increase the fuel output for E85, big turbo(s), or whatever the future holds.

[cloud_connected]

Originally Posted by JamesM3M5

We replace regular (non-turbo) BMW fuel pumps somewhat often for many racecars, and upgraded FPs for aftermarket turbo BMWs as well. They simply get weak. They will keep up with stock power, but once you have a significant increased demand they may not keep up nearly as long as a stock pump on stock power.

Unfortunately since the fuel pump module (EKP) monitors pump speed and current draw, upgrading the in-tank pump with a different unit can be problematic. Did it on a Grand Am 328i using a Bosch 044 pump, but luckily it only complained about the pump current draw. Not sure what the N54 EKP will complain about, though. I have a feeling that will be one easy upgrade to increase the fuel output for E85, big turbo(s), or whatever the future holds.

Whenever a new development is made that really puts stress on the fuel system the LPFP always seems to be the hardware at the center of the discussion. I think you're absolutely right about the LPFP.

[ErvGotti]

Originally Posted by dfv2

Yes, this appears to be the root cause.

Can anyone log req/act for HPFP, LPFP, boost, load, lambdas & STFTs for a 50% or higher E85 WOT pull? I'd like to see if/when LPFP dips below design pressure for you guys. It's bound to happen to some, I'm just curious how prevalent this might be. Hell I hope it's just me so I can fix it and keep pushing!

Just did a 3rd and 4th gear run with 50/50 and the lowest my LPFP went to was 62. I didn't have huge variences with requested LPFP and HPFP and what the car was actually running like you did on the 100% run.

[dfv2]

Originally Posted by ErvGotti

Just did a 3rd and 4th gear run with 50/50 and the lowest my LPFP went to was 62. I didn't have huge variences with requested LPFP and HPFP and what the car was actually running like you did on the 100% run.

Thanks for the feedback, much appreciated.

[Dmacc]

BrianMN has been running 100% e85 last I read and has slowly been tweaking the tuning to be able to with no problems, but he's running a procede. Maybe you would like to consult with him to see what he did differently?

http://www.e90post.com/forums/showthread.php?t=719659

[BrianMN]

My car had been on 100% E85 for nearly 2 months...issue free and feeling great. It did take a fair amount of to tuning get things as happy as "normal", but once the tuning was solid, it was rather uneventful. No issues at all.


I'm sure if you were able to spend more time in the ATR tuning it your ca would run a bit better. There is no reason to say "the N54 is not ready for 100% E85"

[dfv2]

Originally Posted by BrianMN

My car had been on 100% E85 for nearly 2 months...issue free and feeling great. It did take a fair amount of to tuning get things as happy as "normal", but once the tuning was solid, it was rather uneventful. No issues at all.


I'm sure if you were able to spend more time in the ATR tuning it your ca would run a bit better. There is no reason to say "the N54 is not ready for 100% E85"

I agree and want to clarify that I have found the flow limit of my LPFP , which may be tired and in need of replacing, using 100% unfettered signals, voltages, pressure targets, etc. Cobb's fuel scalars are very slick and work perfectly.

You are tuning for fuel system trickery with a piggy and I give you even more props for making it work with that hardware. Do you ever get mixture codes? I cannot imagine how you deal with the STFT limits without major skewing of some signals or a base flash, and that is exactly why I prefer ATR.

The intent of my thread is to say to others with the same general setup - please log and keep an eye on STFT, AFR and watch your LPFP, my issues gave ZERO warning or indication (no codes, runs great, etc) and I pretty much got lucky catching the STFT as I had that on the dashboard from my pre-scalar days. If I had limped, popped a CEL, etc I wouldn't have made the thread because I'd be confident that others would have fair warning too.

[BrianMN]

Originally Posted by dfv2

I agree and want to clarify that I have found the flow limit of my LPFP , which may be tired and in need of replacing, using 100% unfettered signals, voltages, pressure targets, etc. Cobb's fuel scalars are very slick and work perfectly.

You are tuning for fuel system trickery with a piggy and I give you even more props for making it work with that hardware. Do you ever get mixture codes? I cannot imagine how you deal with the STFT limits without major skewing of some signals or a base flash, and that is exactly why I prefer ATR.

The intent of my thread is to say to others with the same general setup - please log and keep an eye on STFT, AFR and watch your LPFP, my issues gave ZERO warning or indication (no codes, runs great, etc) and I pretty much got lucky catching the STFT as I had that on the dashboard from my pre-scalar days. If I had limped, popped a CEL, etc I wouldn't have made the thread because I'd be confident that others would have fair warning too.

Thanks...It really isnt' very difficult to get desired results..obviously nobody wants to hear it but it's not like the Procede is just a bunch of resistors doing trickery. The stuff works and for me and a handful local customers it's worked extremely well up to 60% ethanol content. The advice and consultation I've given provided to 10 other members on this forum have also resulted in smooth and desired performance on higher mixtures.

Once you get the new LPFP it shouldn't be too hard to get things to a workable state with the ATR and lots of testing time. As always- tuning is all about the details and you can never stop improving

[dfv2]

Originally Posted by BrianMN

...obviously nobody wants to hear it but it's not like the Procede is just a bunch of resistors doing trickery....

No one said that in this thread! I'm floored with what the procede and jb4 can do and there are many clear benefits compared to a flash tune - namely meth & boost control, gauge hacking, etc.

Again, in this thread, I'm talking stock fuel system, stock fuel DME mapping (aside from scalar). Basically those that want software only straight E85 cannot simply pop a scalar from the cobb help file and go drag racing - which I feel the cobb announcement thread implies to n00bs. For the record I still consider myself a n00b with the N54.

If I save one single soul with a similarly tired LPFP (mine's original at 42kmi and tuned at stg2+ levels for 10kmi) from melting a piston I will sleep well at night.

Down to business Brian. What LPFP do you have (original OEM, replacement OEM, upgraded OEM, different pump)? Did you run into any hardware limitations on your quest for 100% E85? What load do you hit with your most aggressive tune (or what boost at what ambient conditions for the sake of discussion). What is your favorite color? Do you deal with code issues for mixture, lean or plausibility?

[ErvGotti]

Originally Posted by BrianMN

Thanks...It really isnt' very difficult to get desired results..obviously nobody wants to hear it but it's not like the Procede is just a bunch of resistors doing trickery. The stuff works and for me and a handful local customers it's worked extremely well up to 60% ethanol content. The advice and consultation I've given provided to 10 other members on this forum have also resulted in smooth and desired performance on higher mixtures.

Once you get the new LPFP it shouldn't be too hard to get things to a workable state with the ATR and lots of testing time. As always- tuning is all about the details and you can never stop improving

Hey BrianMN if you don't mind me asking how much timing are you running up top on 100%.