What are the limits of the stock fuel system on a E85 mix?

Mightbaal

Specialist
Apr 22, 2018
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2008 335xi E90
Just kind of wondering this I am not sure what awhp I am at but I am on 100% stock fuel system minus the $99 full bucket eBay Chinese lpfp (it was originally going to be a core but the damn thing handles E60 with 70 psi somehow the past 2 years I put it in for fun as the stock oem wouldn't handle E40). I run E55-60 gas 22-24 psi midrange on stockers 17-18 redline (maxed). FBO+ inlets. Problem is my hpfp which is about 2 years old is sitting around 10 in logs (I think that's 1000 psi) which is alittle low. If I go bigger turbos maybe less E85 what is realistic performance gains I could get on stock fuel system? I am trying to figure out how much of a gain upgraded turbos would be and if it's worth it cuz I'm starting to get into the port injection area with controller lpfp upgrade etc and that will all add up real quick.
 

langsbr

Captain
Apr 5, 2017
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There have been at least a few people hit 600whp on an Emix with just a stage 2 pump (Omar's bucketless) and no PI. I'd say norm is probably closer to 550 -575.
 
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Mightbaal

Specialist
Apr 22, 2018
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2008 335xi E90
There have been at least a few people hit 600whp on an Emix with just a stage 2 pump (Omar's bucketless) and no PI. I'd say norm is probably closer to 550 -575.

I would have to lower my E85 mixture a bit tho for more HP tho right? I am thinking maybe on E85 running my turbos maxed out I'm pushing ehh 440 awhp? That's E60 gas with hpfp barely keeping up with fuel demand.
 

langsbr

Captain
Apr 5, 2017
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That seems low HP wise, but I'm thinking you are likely spiking your torque which may be where your HPFP is hurting, or are you having the HPFP struggle in the top end? I would think mid 500s with E40 - E50 would be possible with no PI or shotgun.
 

Mightbaal

Specialist
Apr 22, 2018
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2008 335xi E90
That seems low HP wise, but I'm thinking you are likely spiking your torque which may be where your HPFP is hurting, or are you having the HPFP struggle in the top end? I would think mid 500s with E40 - E50 would be possible with no PI or shotgun.

"I don't see the fuel system shutting down in that last log but it does appear that you are pushing the limits of your HPFP."

http://www.n54tech.com/forums/showthread.php?t=49760
 

dyezak

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May 4, 2017
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500 is the average tipping point

I would say this is the absolute max. You don't find many people hitting 500, and certainly very few that manage to go above it. I'm on one of the newest N54's produced (2011 335is) just now eclipsing 50,000mi, and with the factory HPFP and index 11 injectors I'm draining the rail at about 420hp. If you have a fresh HPFP and index 12 injectors 500 is achievable.

But don't mistake max capability with average. The VAST majority of N54's out there are closing in on 100k miles and on old injectors and HPFP's.
 

Aaron

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Nov 3, 2016
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Silver 2013 335is 6MT
I've got a 2013 N54, also 50,000 miles, and mine is holding at 470whp and full e85. My HPFP crashes a little on the low end, 2,000-3,000rpm, but past that it picks back up and holds fine. But I'm definitely maxxed .
 

Rcboosted2007

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Jan 28, 2018
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07 335i
I think your Chinese pump will give you some extra space. I have a 07 with 190k miles on it. Fuel it lpfp add on from way back when. Running 30psi on a twisted tune mmp stage 3.turn that baby up and let her eat!
 

langsbr

Captain
Apr 5, 2017
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With all the variance in HP on "full E85", wouldn't the more likely scenario be that the E85 coming out of the pump isn't really E85, but E50, 60, 70 or some lower variation? Does everyone already have an ECA and a gauge?
 

KevinC39

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Jun 27, 2017
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I was wondering about that as well. I do have an ECA and from what I can tell, the station I go to is actually E70 year round and not really E85.
 

dyezak

Major
May 4, 2017
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Are index 12 injectors a higher flowing injector?

No. But they are universally newer and have less problems so you get more consistency out of them.

With all the variance in HP on "full E85", wouldn't the more likely scenario be that the E85 coming out of the pump isn't really E85, but E50, 60, 70 or some lower variation? Does everyone already have an ECA and a gauge?

Possibly, if you were flex fuel (which is nobody yet). But if you are static tuned for E85 and fill up with E60 you aren't going to see drastic differences in fueling just based on O2 sensor values and fuel trims. You are static tuned for E85 you are at that level all the time (unless you reflash).

Someone correct me if I'm wrong, but I think they have a better spray pattern?

Filippo

No, there is a newer fluid (oil) inside the injector that makes them quieter, newer seal compound, and an upgraded filter. I'm pretty sure that the newer filter inside the filter is where you are seeing the benefit. But flow rates are generally the same.
 

Erichale77

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Nov 14, 2016
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07 E92 coupe
I have an ECA and gauge and fill up with E-85 at the pump but it usually reads between E77-E79. I fill only at Thorntons though, haven't tried any other station yet.