JB4 and e85 - N55 Quick Review from a Layman

[Matticus91]

I'm not a pro tuner and most of us on here aren't, after getting a couple questions and PM's I figured I'd do a quick review and share my thoughts as an average enthusiast on running e85 through the N55 1er with just a JB4 and some basic mods.

First off, my specific setup:

• 2013 N55 135i 70,XXX miles
• Tune - JB4 only, no MHD or other flash tunes
• Exhaust - Stock with a cutout/dump after the mids
• Intake - Upgraded Charge Pipe, no intercooler or others
• Fuel system & everything else stock

Note that this specific setup and review are N55 specific - N54's are a bit different.

If you have the JB4 with a newer harness and firmware, you can run UP TO 50% e85 mixed with 93RM gasoline. Keep in mind that most fuels in the US also contain up to 10% ethanol. You MUST HAVE THE FLEX FUEL HARNESS CONNECTED. This is part of newer JB4's, also recommended that you use the latest JB4 firmware.

The Burger Tuning crew suggests that you should start with a 30% mix of e85 with 93 and move up from there. I put in 5 gallons of 93 octane and 2 gallons of e85 to start, ending up with a little less than a 30% mix since I had a tiny bit of fuel left in the tank.

Getting going: I let the car sit for a minute to allow the fuels to mix in the tank and then started it up, nothing different there. With my laptop connected and running logs through the JB4 I then pulled out and drove pretty gingerly for about 20 minutes, again letting everything mix and letting the tune/ecu figure things out, again everything seemed the same. Once I was fairly confident that things were feeling good I rolled into it in second gear from around 2k RPM - immediately I noticed more low-end power and the power felt more "snappy". It wasn't a huge increase in power but very likely the 30whp that I expected doing some math off of this graph. I continued to mess around and ran through the whole tank of fuel in about a day. The next day I filled up with a 40% mix (3gal e85 + 4gal 93 octane) and felt another little bump in power.

What's different & Final thoughts: Butt Dyno estimates an extra 25-35 whp with the e40 mix - the car has much more pull in the mid range, while there is not much change in the top end. I expected that with a stock turbo, I think upgraded turbo + e85 at 40-50% would be a MASSIVE power difference. The stock turbo is just too small. Overall there's a nice feel to it and while the power is welcome, there are some drawbacks. Whether it's the JB4/ECU's ability to keep up, or my diverter valve getting ready to take a dump, there are some serious peaks and spikes to the power delivery with an e85 mix. When I ran the tank of e40 out and went back to 93 I quickly noticed how much smoother things were. I still have the typical spikes and "wobbles" to the powerband that are characteristic of the JB4, but they were way more pronounced with the corn mixed in. With this being the case, plus the extra wear and tear (see FAQ below) on the car, I'll be sticking to 93 octane unless I have a need/thirst for the bump in power.

I may try it again in the future and see if I can work on the settings within the JB4 interface to smooth things out.

FAQs and TL;DR:

• Q: Can I run e85 in my stock 135i?
  A: If you have an up-to-date JB4 with Flex Fuel cables connected, yes.
  
• Q: Will e85 degrade my car's fuel system?
  A: In short, yes. However running a lower mixture, such as 30-40%, will take a very long time to have any noticeable negative impact on your car's fuel system. Keep in mind almost all fuels have up to 10% ethanol content as it is, so modern cars are designed with this in mind.
  
• Q: Do I need to run a certain octane with e85?
  A: You should run 93RM Octane or better with e85.
  
• Q: What JB4 Map(s) should I use?
  A: Start in Map 5, but you may also use Map 2. For advanced users you can run Map 7 with proper fuel, mods, and settings (race gas map)
  
• Q: Can I blow my motor/turbo running e85?
  A: Yes, modifying your car past what the manufacturer built it for is always a risk. Proceed with caution and don't fool yourself into thinking everything will be fine. Motors are expensive
  
• Q: What the hell is e85/corn anyway?????
  A: e85, also known as "corn" or ethanol, is a fuel derived from, you guessed it - corn, as well as other sugar producers. It's more corrosive than gasoline but has a higher resistance to premature detonation, allowing cars to avoid detonation or "knock" and make more power. It has the essential properties of race gas (higher octane rating, typically around 105 depending on mix) at a much lower cost and with higher accessibility. In addition to all this, it also runs cooler than gasoline, again enabling the car to put down bigger numbers. In addition to being more corrosive than gasoline, it also has a lower "energy content" than gas, which generally translates to less MPG's than regular fuel (typically 20% less efficiency) - but who care's about that, because racecar, right?

[Dylanize]

E85 isn't exactly close to me, so it's a every now and then roadtrip/fun time.

I just did 50/50 mix on map 5. Very noticeable bump in power and the car seemed to really like it.

I don't see you mention the 3rd/4th gear pulls on map 5 to adapt? Did you not do that?

[Matticus91]

Originally Posted by Dylanize

E85 isn't exactly close to me, so it's a every now and then roadtrip/fun time.

I just did 50/50 mix on map 5. Very noticeable bump in power and the car seemed to really like it.

I don't see you mention the 3rd/4th gear pulls on map 5 to adapt? Did you not do that?

I hadn't seen anything about that, do you have a link or something about this?

[1N4ttro]

Thanks for sharing. I plan on running e85 next spring/summer from time to time.

[ShocknAwe]

Very important FYI, this post is N55 specific.

[Matticus91]

Originally Posted by ShocknAwe

Very important FYI, this post is N55 specific.

Good point I'll include that elsewhere

[Dylanize]

Originally Posted by Matticus91

I hadn't seen anything about that, do you have a link or something about this?

It's been years since I read it, can't seem to find it it.

But from my experience a couple 3rd/4th pulls to redline after filling up with E85/93 mix made a significant difference over just running map 2.

Car is an absolute beast, and that's just with intake and Jb4.

[Matticus91]

Originally Posted by Dylanize

It's been years since I read it, can't seem to find it it.

But from my experience a couple 3rd/4th pulls to redline after filling up with E85/93 mix made a significant difference over just running map 2.

Car is an absolute beast, and that's just with intake and Jb4.

Ok I'll have to try that next time, top of 4th is a fun number so I'll need to make plans to hit a highway lol. I'm still not planning to run e85 mix that often since I really am not interested in further decreasing the life of my sparkplugs, I change them every 40k as it is