[BMW GENIUS]

I see here on the forums all the time where someone runs about 3.5 or 4 gallons of E85 mixed with pump 93 or 91 octane. What's the most amount of E85 that you put in your tank? Everyone seems afraid of high amounts of E85. Why?

[daisy16905]

It all comes down to fuel system abilities, our fuel pumps and injectors can't handle the volume required to run e85. Factory system maxed our around e40ish. Look at all the GTR's running e85, they have upgraded fuel pumps / injectors ..... something that is not as common with BMW's.

[BMW GENIUS]

Originally Posted by daisy16905

It all comes down to fuel system abilities, our fuel pumps and injectors can't handle the volume required to run e85. Factory system maxed our around e40ish. Look at all the GTR's running e85, they have upgraded fuel pumps / injectors ..... something that is not as common with BMW's.

Oh okay. I know a lot of people seem to be a bit tentative using E85 thinking that its detrimental to the car and I can understand needing to upgrade the fuel pump, but I got my car dyno'd again recently using Map 2, DP, intake, and used 9.5 gallons of E85 and it made some stupid numbers and ran really smoothly!

[daisy16905]

9.5 gal of e85 mixed with???? 3 gal of 91. With you running that much octane you should try either map 5 (Auto tune) or map 7 (race map w/max boost of 18.5).

Either of those maps are compared w map 2.

Originally Posted by BMW GENIUS

Oh okay. I know a lot of people seem to be a bit tentative using E85 thinking that its detrimental to the car and I can understand needing to upgrade the fuel pump, but I got my car dyno'd again recently using Map 2, DP, intake, and used 9.5 gallons of E85 and it made some stupid numbers and ran really smoothly!

[BMW GENIUS]

Originally Posted by daisy16905

9.5 gal of e85 mixed with???? 3 gal of 91. With you running that much octane you should try either map 5 (Auto tune) or map 7 (race map w/max boost of 18.5).

Either of those maps are compared w map 2.

I think I may try it today but I'm just scared of the OEM Charge Pipes cracking! How long have you been running Map 7 on the OEM charge pipes?

[JibHonk]

I tend to mix 6 gallons ethanol to 7 of 93. Play around with the FOL until it looks happy then run map5

[harkes]

Methanol has roughly half the amount of energy/volume as gasoline so that explains why the fuel system cannot keep up increasing the content.

[daisy16905]

For the past year or so, with no issues.

Originally Posted by BMW GENIUS

I think I may try it today but I'm just scared of the OEM Charge Pipes cracking! How long have you been running Map 7 on the OEM charge pipes?

[Pparana]

Our cars with the ewg (15 my maybe late 14). Are not super happy on enthonal above 35 percent or so. If pure power is what you want just get methonal injection.

[Pparana]

Originally Posted by daisy16905

For the past year or so, with no issues.

Not to thread Jack but what offset are you running to. Fit the rs3 under your front. Do. You run camber? I am getting some rubbing on 245s with over 3 degrees of camber and the fenders rolled.

[JibHonk]

I also run straight methanol injection. It's not the same. E85 has the cooling benefits

[Pparana]

Originally Posted by JibHonk

I also run straight methanol injection. It's not the same. E85 has the cooling benefits

I think your backwards on this.

Meth/water injection is rated as 116 - 108 octane

ethanol is rated as 105 - 100 Octane



in the combustion chamber both meth injection (methanol and water) and ethanol achieve a similar result.

Ethanol: burns cooler than gasoline and since you need to spray 30-40% more of it doubles down on the cooling effect resulting in a high octane rating

Methanol: Burns even cooler then ethanol, water undergoes a phase change (liquid to gas) absorbing heat from the combustion chamber + steam cleans your intake values, and before being injected it cools the IAT so the starting point of the gasses being combusted is lower.

Water resists knock well, to split water molecules you need 5500F which will melt any usable metal alloy (ex: titanium melting point is 3200F)

Tune for Ethanol:, spray as much as you can without misfire (DME needs to be adjusted)

Tune for meth injection up the boost until you get timing retard then decrease the amount of boost ( easy w jb4)

[mike@x-ph.com]

Originally Posted by BMW GENIUS

I see here on the forums all the time where someone runs about 3.5 or 4 gallons of E85 mixed with pump 93 or 91 octane. What's the most amount of E85 that you put in your tank? Everyone seems afraid of high amounts of E85. Why?

You cannot run very high E85 mix for 2 reasons.

1- Without a proper flash you are risking going lean
2- you need to upgrade your fuel pump so it can keep up

For best results start with 3.5 gallons, log and slowly increase the mix until you reach the max mix for your car

[Jasond13]

I started out at about 4 Gals. and worked my way up to 6.5 Gals of E85 and the rest 93 over the past year. I log regularly & see there's room for more but I have to slowly increase and test. The problem is if you're going to do this you have to know your car & have some tuning knowledge or have a tuner help you because you have to adjust certain settings in the JB4. I have a custom map 6 because I found Map 5 to be too inconsistent, even Map 7 was not working consistent with the E85 because it's based on Race Gas. A properly set up map 6 custom for your car by a "TUNER" will be very consistent but your E85 mixture has to be on the money every time and you should log and always make sure your running safe. I will say this again don't mess with any settings if you don't know what you're doing. You're responsible if you F*** your ride up. Ask for help from someone who knows how to tune. send your logs to burger if you don't know what your looking at they are very informative and helpful. Do your research there is so much info out there.

[JibHonk]

If I'm running 6.5 gallons of e85 to an assumed 7 gallons of 93, that gives me roughly 99 octane fuel. I've found that is good enough to run map 7. Usually I have to set FOL to around 70-80 to keep trims in order.

[bkx-U85]

Originally Posted by BMW GENIUS

I see here on the forums all the time where someone runs about 3.5 or 4 gallons of E85 mixed with pump 93 or 91 octane. What's the most amount of E85 that you put in your tank? Everyone seems afraid of high amounts of E85. Why?

EWG models do not react good to more than 40%(e40) e85 but bms recomends not exceeding 30% e85 (e30). Personally i have not exceeded those limits and wont, due to the lack of tolerance the electronic waste gates have towards high ethanol content.

[JibHonk]

That is a very broad statement and does not apply to all cars. All you can do is test and find out. A lot of guys don't like to tinker either which is why their cars don't tolerate it well.

[Racer's Edge]

Ethanol = Sugars
Now ask me if I want to put this in my car