[kern417]

I made a video to explain why most tunes are E30-E40 and how you can plan out the best ethanol mix for your custom tune. Hope this helps.

[vektorprime]

Kern you ever thought about going WMI? It's nice not to have to worry about finding an E85 station.

[mike@x-ph.com]

[G.Newt]

Originally Posted by vektorprime

Kern you ever thought about going WMI? It's nice not to have to worry about finding an E85 station.

To do it properly, would probably need to be done via port injection, which introduces its own set of additional costs and failure points. For additional cooling, I think CPI with water would work great to bring IATs down.

[kern417]

Originally Posted by vektorprime

Kern you ever thought about going WMI? It's nice not to have to worry about finding an E85 station.

nope. i have multiple e85 stations close by.

Originally Posted by G.Newt

To do it properly, would probably need to be done via port injection, which introduces its own set of additional costs and failure points. For additional cooling, I think CPI with water would work great to bring IATs down.

also this. not interested in the added complication. if i can't find e85 when i'm traveling, i just flash my 93 map until i get home.

[eluded]

i'd tune it for a 50-50 mix. That way it's easy to calculate when you fill up. Half and half.

[johnung]

Originally Posted by eluded

i'd tune it for a 50-50 mix. That way it's easy to calculate when you fill up. Half and half.

Your suggestion sounds logical but it won't work because neither the gasoline or the ethanol is 100%. They are both mixes themselves.

The gasoline in my state (NJ) and many states is already 10% ethanol. So in the calculation gasoline is considered E10.

The E85 is 85% ethanol, BUT federal law actually allows them to have as little as 49% ethanol and still label the pump E85. My local E85 station actually has 85% ethanol but that tidbit is important to know if you are traveling.

If your tune is setup for a specific percentage of ethanol and you add "E85" that is really less, then that's like flashing a 93 octane tune and putting 89 or 91 in the tank. Bad things can happen to your engine.

If your tank was completely empty, and your gasoline is E10, and your E85 is really 85% ethanol, then to end up with an E50 mix you would need:

8.43 gallons of E85
7.37 gallons of E10

Tip: The sensitivity of gas pumps varies quite a bit. Don't make the mistake of assuming that when the pump shuts off your tank will be full. Most BMWs that we discuss hold 60 liters of fuel which is 15.85 gallons.

So don't calculate how much E85 to put in the tank and then say to just fill up the rest of the tank with E85. You are unlikely to get the exact percentage of ethanol that you want in the tank.

You are better off calculating as if your tank holds less, say 15.5 gallons. Then add very specific amounts of both E85 and 93 octane to your tank. Your tank won't be perfectly full but your ethanol content will be much closer to being correct.

If you are trying to calculate amounts of E85 and 93 to add but you already have some percentage of ethanol in your tank, you will need to estimate the amount currently in your tank. The tick marks on your gas gauge are each worth 5% of a tank. So if you are one tick mark over half of a tank then you have 55% of your tank full.

I have used several ethanol calculators. The best one so far is an app called e85Cal

The gas pumps near me don't allow you to tell them how many gallons to pump in. You have to type in dollars and cents. It's a pain to multiply the gallons from e85Cal by the cost per gallon. I've already written the app asking to calculate both gallons and dollar amount. Others may want to write to ask them for that change too.

Hope this helps!

[eluded]

Originally Posted by johnung

The E85 is 85% ethanol, BUT federal law actually allows them to have as little as 49% ethanol and still label the pump E85.

Agree. I am fortunate to always have 85% and I test all my fuels before hand. I don't use the app to figure out how many gallons to add but rather have a Excel spreadsheet that I use when I'm at the pump. So for me I'd target 46 or so e.

My pumps consistently test 85% ethanol and 5% and the 91 mix. 91 octane here isn't really 91

[johnung]

Originally Posted by eluded

Agree. I am fortunate to always have 85% and I test all my fuels before hand. I don't use the app to figure out how many gallons to add but rather have a Excel spreadsheet that I use when I'm at the pump. So for me I'd target 46 or so e.

My pumps consistently test 85% ethanol and 5% and the 91 mix. 91 octane here isn't really 91

Sounds like you are all over it. I used to calculate my own but recently found the e85Cal phone app that's designed exactly as I would have done it.

I'm on a Bootmod3 FlexFuel MultiMap tune which is perfect considering the lack of consistent E85 in my local area and the states where I travel.

I was explaining it to my wife since it's our daily driver. She was amazed that in a pinch we can fill up with whatever the best gas that's available whether it's 91 or E85. It's like having the DeLorean at the end of Back to the Future. Can give that Flux Capacitor anything for fuel and it will go!

[kern417]

Originally Posted by johnung

Your suggestion sounds logical but it won't work because neither the gasoline or the ethanol is 100%. They are both mixes themselves.

I'm guessing you didn't watch the video but He said 50/50 mix because that's what I commented on at the 9:00 mark. It's not E50. In my case it's around E42. If you have a station with consistent ethanol content it's extremely convenient.

One of the main ones was 1stockF30 because when people asked his ethanol mix, he'd just send a screenshot of his ethanol analyzer app. because he never calculated it during tuning, he just did a 50/50 mix. So it was always around E42-E44.

[johnung]

Originally Posted by kern417

I'm guessing you didn't watch the video but He said 50/50 mix because that's what I commented on at the 9:00 mark. It's not E50. In my case it's around E42. If you have a station with consistent ethanol content it's extremely convenient.

One of the main ones was 1stockF30 because when people asked his ethanol mix, he'd just send a screenshot of his ethanol analyzer app. because he never calculated it during tuning, he just did a 50/50 mix. So it was always around E42-E44.

Great idea to get a mix in a good range to run a Stage2+ tune with an upgraded HPFP.

You are correct. I put your video aside to watch later because I was sneaking a reply in while I was stuck in a doctors office. Reading BMW stuff on my phone is much better than those old office magazines! 😀