Anyone run an E85 mix? Like 2 gallons?
Will it mess up our fuel pump?
I hear lots of people do it on other cars but I haven't heard it on a mini.
Anyone done it? Thoughts?

 

What's the objective?

Using any E85 with E10 will raise your ethanol percentage above 10% which is the limit allowed by Mini. Even 2 gallons of E85 in a full tank of E10 would result in nearly 25% ethanol. It might (or might not) work fine for a period, but long-term, I can't see anything but serious risk of major/expensive fuel system problems. It would definitely void the warranty and I've heard Mini is doing fuel analysis to deny warranty coverage where they suspect ethanol is the culprit.

Do the math and you could put 1.5 gallons of E85 in a tank of pure gas and be at the 10% ethanol limit of E10. I still wouldn't do it, but theoretically this would be Okay from an ethanol mix standpoint.

There are, of course, flex-fuel engines which are designed for E85, but the modifications are extensive.

- Mark

 

What do u mean 10% limit? Is the limit on paper or on the ECU?
And people mix E85 for a lot better cooling on turbo applications and higher octane. I was just curious since so many people say "WOW" when they do the mixture on their turbo cars. I feel left out

 

10% ethanol content is the limit Mini says is safe for the fuel system. It's in the OM. E10 is what is currently being sold in most of the USA with a few exceptions of stations selling "pure gas".

The engine tuning does need to change with increasing ethanol percentage as the energy content of ethanol is only about 2/3'rds of gas. Engines designed to run high ethanol mixes, in addition to changes to the fuel system to tolerate the ethanol, need to have different fuel maps, larger injectors, etc. to deliver the larger volumes of fuel with a lower energy content. If nothing is compensated for, an engine makes lower power on E10 than on pure gas (by about 3%). And it would make even less as you increase the ethanol beyond E10.

I doubt our Minis sense the percentage of ethanol and adjust engine tuning to compensate. So they just live with the small tuning variance between pure gas and E10, and make slightly less power (and less fuel mileage) when running on E10 vs. pure gas.

This is one of those things, like higher octane fuel, where if you build/modify an engine to take advantage of the higher octane of ethanol and the cooler operation of the turbo, you can perhaps add more boost and make more power. But this has little bearing on what is going to happen when you take your stock engine, designed to run on E10, and start throwing more ethanol into the gas mix. Unless the tuning is changed to take advantage of the ethanol, it will make less power, not more. And likely trash your fuel system and void your warranty. Such a deal.

- Mark

 

Wow. Thanks Mark.
You sound like a very intelligent man. I just didnt want to cause damage to any part of the fuel system or freak out any of the computers on board. I do have the JB+ from Burger Motorsports and had an idea of running a small mixture of E85 to 91 octane so I can turn up the boost on a track day. Boosting 16-18psi now, I hear heat soak and IAT going up tremendously. I am turning the boost down but I was wondering if E85 would help cool and be safe to run.

 

Well, you do have some capability to modify your engine's tune and if the extra ethanol does increase your detonation margins allowing you to run higher boost, it might be helpful. How much octane is raised by mixing a little E85 with 91-octane fuel, I don't know. You could try a small amount and see what happens. But you are skating on thin ice with respect to how your fuel system will tolerate the extra ethanol.

If you do decide to experiment with E85, I'd find a station near you selling 91-octane pure gas. (pure-gas.org has a directory of stations selling pure gas.) If your base fuel is pure gas, then you can mix some E85 into it and keep the ethanol within the 10% limit. Someone may want to check my math, but I think up to 12% of the fuel mix can be E85 and be under the 10% ethanol limit. For example, if you are filling a 13-gallon tank, put in 1.5 gals of E85 and then top it off with pure gas and you're be right at 10% ethanol which is, according to Mini, safe to use. And the octane of this mix should be somewhat higher than 91.

You could, of course, use race fuel. Some folks mix 100LL aviation fuel into the tank although it is technically illegal and airport fuel dealers are not supposed to sell it for cars. It does contain a lot of lead though, so if you have a cat, it will poison it.

By far the safest option is to use the stock approved fuel and run whatever boost gives you acceptable detonation margins.

- Mark

 

We've been using E85 for a couple years with the BMWs and recently the last couple of months with our MINI N18. The car loves it but there are some tuning considerations. You can't just run straight E85 without changes to the tuning and fuel pump capacity. But we've found zero data to validate any claims of corrosion or other negative effects of E85. Many countries like Brazil have high ethanol contents mandated by law so most 2006+ vehicles are ethanol resistant from a mechanical perspective.

On the MINI end we'd suggest a 20-30% mix to start. Just keep an eye on the AFR in dash to ensure the car doesn't lean out. You're working against fuel trims here and the JB+ for example can not directly alter the fuel mass calculations so if you exceed the 33% long term fuel trim additive will start to lean out. But you should see higher adaptive timing values and stronger performance even with the smaller mix compared to pump gas alone.

 

For track day, I used to be able to buy 104 unleaded near me. Haven't checked lately. It was for off road use only so the pump wouldn't fit the car directly (too big - the station was next to the highway, not a race track) so we held a portable container and pumped into it as it flowed out the other end into the car :-)

 

Did you think it was a world of a difference using an E85 mixture on the mini?
Did you up the most more since E85 cools or should the JB+ remain on default settings?

 

I've not yet dyno tested the E85 mixture but judging by timing in dash and seat of the pants feel I think the 20% mix is well worth it.

 

Thanks Terry. Will try it in these coming days. Do you think it is safe to run it on every tank? A 20% mix?

 

Sure.

 

Terry, if you were running a mix of E85 and 93 can the JB+ be safely turned up a little bit? If so, how do people live with doing say a 20% mix. This means going and buying fuel and storing it at home, or visiting a gas station twice as often. How do people live like this daily? Even if I saw the value and wanted to do this and getting E85 wasn't a hassle, how does one: go on a road trip, have their spouse drive the car and get fuel, etc? Am I just too lazy or is not that often that people do this kind of mixing, just people looking for every last hp?

 

On my JB4 1M I would fill the tank with a 40/60 e85/93 mix all the time. I would wait until the tank was close to dry and head to my local station to fill it up. Rinse and repeat.

 

Yes but keep an eye on the air/fuel ratio. Higher boost levels also require more fuel.

 

When you guys say your mixtures. Is that including the 10% already in premium gas. Or not including that 10%. Like when you mean 20% mix. Do u mean add 20% more or 10% more.

 

Just run a 20% added mix and see what you think... Prob not going to see a benifit as outside temps are dropping. I personal have not seen timing drops with 91 at 17psi with factory timing. E85 might help some sleep better, especially when it's hot outside.

 

You will risk not having your high pressure fuel pump replaced under warranty if it fails. When my high pressure fuel pump failed on my 2007 MCS, the first thing they checked was the percent of alcohol in the fuel tank. I was using a top tier gasoline (Exxon) and so my alcohol was not higher than the 10% limit. My fuel pump was replaced under warranty without any cost to me. If they found the amount of alcohol was over 10% it would have violated the warranty and I would have paid the total cost.

Morris, 2011 MC, PW/B, 24,000 trouble free miles

 

I would add 30% E85 and that plus the 10% in 93 would get me to the 40/60 mix.

 

Just keep in mind that a 40% ethanol mix means 40% of your fuel has 2/3'rds the power of pure gas. Right off the bat, that's a 15% drop in engine power that has to be compensated for with higher boost just to get back to the power level you'd have with pure gas.

And as already mentioned, your warranty on any fuel-related system problem (pump, filters, injectors, anything touched by fuel) and any major engine issue is toast.

- Mark

 

Mark.. Educate yourself of E85 as it relates to Di engines, cooling effects and octane combined octane rating. You clearly do not understand, further manufactures including BMW since the early 90's have all built their fueling systems to handle alcohol. the lower density if alcohol skews the fuel curve lean and will cause a check engine light if to much alcohol is present. IE Chevy has a denser built in line to monitor real time the density of fuel and automatically comp for this, thus you have a "flex fuel" vehicle that can run 100% E85... Again read up and stop posting mis info.

 

Nothing to do with power output. Running 40% E85 just means just means 15% (using your numbers) more total fuel volume must be injected for a given power output. Which the DME is happy to deliver. If the tuning is setup properly.

 

"Stop posting mis info" right back at you.

We can debate whether tuning can compensate for the lower specific power output of ethanol, but one irrefutable fact is that Mini (and virtually every one car mfg except for flex-fuel vehicles) specifically prohibits use of any fuel in their cars with more than 10% ethanol. No Mini engine is designed to handle more than 10% ethanol - period. It may tolerate it to some degree, but the idea that all engines these days are automatically able to handle higher concentrations is BS.

Let's just agree to disagree without attacking the other's opinion.

- Mark

 

This is correct, but I doubt that little gizmo that guy was using would be able to compensate to this degree and keep anything approaching reasonable A/F ratios.

- Mark

 

Not you character, it's you lack of knowledge of the topic. It's misleading to those who may not have the knowledge of the topic. You default to mini's recomdation of less than 10%.. Yes the owners manual does say this, as Terry and others have stated many times, BMW and mini as well as every manufacture for the past decade have supported eth. I personally have been using a 20% + mix for a little under a year. Instead of spreading info that has zero merit, take a minute and read on the topic. There is a ton of info out there on E85 with DI turbo engines. Suburu's, speed3, 335, as well as Corvettes, turbo Porsches have been running E85 in the last decade. But hey don't take my word, YouTube 335 E85. I highly recommend running a 20% mix in the summer heat on higher boost to guarentee zero knock counts or be the guy that cracks or melts a piston. Take time and learn.