Proper E85 mix Ratio

[Frank M3 NJ]

Hi after doing some research on the forum I haven't quite found the answer i am looking for.

What is the proper ratio of E85 i can put in my M3 with JB4 on map 2? I currently use 93 octane fuel but would like to add e85 to up the ante. I do have other mods done to the car as well.

Also can i run full e85 or 60/40 (E85) mix with out doing anything else to my car except put it on map 2? will my cars fuel system and computer automatically adjust or is there something else i have to do to my CPU or fuel pump and lines to run full E85 or mix?

Thank you for any input.

[quattr0]

El google comes up w this

http://f80.bimmerpost.com/forums/sho....php?t=1121557

[CaryTheLabelGuy]

Originally Posted by Huxtable87

Hi after doing some research on the forum I haven't quite found the answer i am looking for.

What is the proper ratio of E85 i can put in my M3 with JB4 on map 2? I currently use 93 octane fuel but would like to add e85 to up the ante. I do have other mods done to the car as well.

Also can i run full e85 or 60/40 (E85) mix with out doing anything else to my car except put it on map 2? will my cars fuel system and computer automatically adjust or is there something else i have to do to my CPU or fuel pump and lines to run full E85 or mix?

Thank you for any input.

This question has been answered ad neasuem.

The stock fuel tuning can't handle much more than 10% ethanol. However, if you are running a JB4 and have the fuel pressure sensor connected, you should be able to run just over E30-ish.

Do you have the connect kit or the ability to connect your laptop to datalog? If so, start with 3 gals of E85 and slowly work your way up until your trims start rising to the point that AFRs (Air/Fuel ratios) start to dip into the low 11:1 range during WOT pulls. Set the JB4 up with a Fuel Open Loop setting of "70" before you start testing. If you go slow, you should be able to get to 4-5 gals of E85, depending on the actual ethanol content in your region.

ProTip: When I say go slow, I mean go slow. Start with 3 gals of E85 and run the whole tank down to almost zero. Then, if trims look good and AFr's aren't too rich, move to 3.5 gals of E85 and run the whole tank down. If all looks good, move to 4 gals. Once you get to 4 gals of E85, go in increments of .10 (4.2, 4.3, 4.4....etc.) until you max your trims out to the point that AFRs are in the low 11:1 range. The reason you go slow, is to allow the LTFT (Long Term Fuel Trim) time to adjust to the added ethanol content. The STFT (Short Term Fuel Trim) is based off the LTFT and the STFT is what you're datalogging using the JB4.

The reason AFRs go rich is because if the DME sees fuel trims go too lean, the DME will start to slowly richen AFRs up to protect the engine as the trims go leaner and leaner (this is a protection protocol for trims that are starting to max-out lean). The fuel system has plenty of overhead, but the DME's trims are the limiting factor. The key here is to find the happy spot where trims aren't too lean and AFRs aren't too rich. When AFRs start to get into the low 11:1 range and richer (10:1-11:1), it will cause the engine to misfire due to the S55 being a DI (Direct Injection) engine and the S55 can't tolerate such rich AFRs with that much ethanol. The JB4, when using the Fuel Pressure Sensor connector, is able to raise fuel pressure by faking low fuel pressure to the DME, effectively causing the DME to raise fuel pressure, which allows more trim headroom. This is what the FOL setting is in the JB4. I wouldn't recommend going beyond "70" as if you move that number up too far, the DME will eventually throw a DTC for low fuel pressure. I've been able to run about "72" before running into this issue.

[Frank M3 NJ]

Originally Posted by quattr0

El google comes up w this

http://f80.bimmerpost.com/forums/sho....php?t=1121557

read every post in that thread.... at first they said no then towards the end they said yes. One question is i need a fuel connector? in order to run E85????

[CaryTheLabelGuy]

Originally Posted by Huxtable87

read every post in that thread.... at first they said no then towards the end they said yes. One question is i need a fuel connector? in order to run E85????

Screw that thread. Read my post above yours.

[Frank M3 NJ]

Originally Posted by CaryTheLabelGuy

This question has been answered as neasuem.

The stock fuel tuning can't handle much more than 10% ethanol. However, if you are running a JB4 and have the fuel pressure sensor connected, you should be able to run just over E30-ish.

Do you have the connect kit or the ability to connect your laptop to datalog? If so, start with 3 gals of E85 and slowly work your way up until your trims start rising to the point that AFRs (Air/Fuel ratios) start to dip into the low 11:1 range during WOT pulls. Set the JB4 up with a Fuel Open Loop setting of "70" before you start testing. If you go slow, you should be able to get to 4-5 gals of E85, depending on the actual ethanol content in your region.

ProTip: When I say go slow, I mean go slow. Start with 3 gals of E85 and run the whole tank down to almost zero. Then, if trims look good and AFr's aren't too rich, move to 3.5 gals of E85 and run the whole tank down. If all looks good, move to 4 gals. Once you get to 4 gals of E85, go in increments of .10 (4.2, 4.3, 4.4....etc.) until you max your trims out to the point that AFRs are in the low 11:1 range. The reason you go slow, is to allow the LTFT (Long Term Fuel Trim) time to adjust to the added ethanol content. The STFT (Short Term Fuel Trim) is based off the LTFT and the STFT is what you're datalogging using the JB4.

The reason AFRs go rich is because if the DME sees fuel trims go too lean, the DME will start to slowly richen AFRs up to protect the engine as the trims go leaner and leaner (this is a protection protocol for trims that are starting to max-out lean). The fuel system has plenty of overhead, but the DME's trims are the limiting factor. The key here is to find the happy spot where trims aren't too lean and AFRs aren't too rich. When AFRs start to get into the low 11:1 range and richer (10:1-11:1), it will cause the engine to misfire due to the S55 being a DI (Direct Injection) engine and the S55 can't tolerate such rich AFRs with that much ethanol. The JB4, when using the Fuel Pressure Sensor connector, is able to raise fuel pressure by faking low fuel pressure to the DME, effectively causing the DME to raise fuel pressure, which allows more trim headroom. This is what the FOL setting is in the JB4. I wouldn't recommend going beyond "70" as if you move that number up too far, the DME will eventually throw a DTC for low fuel pressure. I've been able to run about "72" before running into this issue.

thanks this clears things up for me. I need to get a fuel pressure sensor. and ill stick to running maybe 3-4 gallons E85 and mix the rest with 93 octane. Unless i can find race fuel around me.

[CaryTheLabelGuy]

Originally Posted by Huxtable87

thanks this clears things up for me. I need to get a fuel pressure sensor. and ill stick to running maybe 3-4 gallons E85 and mix the rest with 93 octane. Unless i can find race fuel around me.

The fuel pressure sensor connector is on your JB4. Is it connected to the fuel pressure sensor on the engine?

[Frank M3 NJ]

Originally Posted by CaryTheLabelGuy

The fuel pressure sensor connector is on your JB4. Is it connected to the fuel pressure sensor on the engine?

i didnt hook up my JB4 i had a tuner do it. he never mentioned that it wasn't. I asked him if everything was connected right and he said yeah, then i mentioned i wanted to do a mix of 93 octaine and E85 and i honestly forgot the reply he gave me. the sales person pulled him off the floor quickly to chat with me while he was working on another car and I dont know if he was 100% sure of fuel ratios and the programing of the JB4

[Frank M3 NJ]

im thinking about taking my car up to THE SHOP in norwalk to double check my tune and to adjust me for E85 if need be. Thats where my brother took his GTR and hes running straight E85 and the before and after difference is insane.

[CaryTheLabelGuy]

Originally Posted by Huxtable87

im thinking about taking my car up to THE SHOP in norwalk to double check my tune and to adjust me for E85 if need be. Thats where my brother took his GTR and hes running straight E85 and the before and after difference is insane.

As long as everything is hooked up correctly and you know how to datalog, you'll be fine doing this yourself.

[Frank M3 NJ]

i dont know how to data log im a noob im just getting back into cars and i have a little bit of catching up to do. havent been on a car forum since 05!

[CaryTheLabelGuy]

Originally Posted by Huxtable87

i dont know how to data log im a noob im just getting back into cars and i have a little bit of catching up to do. havent been on a car forum since 05!

Sounds like you'll need some help.

I wouldn't recommend running ethanol mixes in your car until you figure out how to do basic JB4 stuff like datalogging and changing settings. Don't get the cart in front of the horse.

I also seriously recommend the JB4 Connect Kit. It allows you to datalog and change settings using your phone as opposed to using a USB cable and laptop.

[Frank M3 NJ]

will do thanks!

[mike@x-ph.com]

Originally Posted by CaryTheLabelGuy

Screw that thread. Read my post above yours.

[Fast4d]

he is running map 2.

does he really need to max out the amount of Ethanol?

I think 4 gallon per fill up (from empty) should be plenty. what do you think?

[CaryTheLabelGuy]

Originally Posted by Fast4d

he is running map 2.

does he really need to max out the amount of Ethanol?

I think 4 gallon per fill up (from empty) should be plenty. what do you think?

If he can run 4 gals of E85. And yes, if you're going to make an effort to run an ethanol mix, you might as well run as much as you can.

Datalogging is key here. Some people report not being able to even get to 4 gals of E85 depending on actual E85 quality and other factors such as ambient conditions.

[DLSJ5]

Originally Posted by CaryTheLabelGuy

If he can run 4 gals of E85. And yes, if you're going to make an effort to run an ethanol mix, you might as well run as much as you can.

Datalogging is key here. Some people report not being able to even get to 4 gals of E85 depending on actual E85 quality and other factors such as ambient conditions.

Cary, have you tested the max amount you can run yet on your ZCP? I was able to go 5.5 E85, the rest 91 with no issues.

[wakeofdeath]

Saw this a few days ago

https://www.instagram.com/p/BI-IBlNB...ken-by=rktunes

86whp 155wtq Gained with our DME tune!!!
Our tune with E60 fuel vs the factory Competition package tune with 93.
Only mod is downpipes. The car still has the factory airbox.
We will soon publicly release Map switching through the obd2 port so you can easily swap between tunes.

[Commanderwiggin]

Proper way to do ethanol would be ... go to E85 pump... fill up car...drive and not care what % because the ECU should be flex fuel :P Hopefully one day BM3 will have full flex blending capabilities.

[CaryTheLabelGuy]

Originally Posted by DLSJ5

Cary, have you tested the max amount you can run yet on your ZCP? I was able to go 5.5 E85, the rest 91 with no issues.

You should test your E85 and see how much ethanol is actually in the blend. I'm betting it's close to the lowest amount possible (51% ethanol) if you're able to run that much of it without issue.

I'm in Florida and my E85 is really close to 85% ethanol and my happy medium is 4.5 gals of E85 and the rest 93 (10% ethanol).

[///F80M3]

Originally Posted by CaryTheLabelGuy

You should test your E85 and see how much ethanol is actually in the blend. I'm betting it's close to the lowest amount possible (51% ethanol) if you're able to run that much of it without issue.

I'm in Florida and my E85 is really close to 85% ethanol and my happy medium is 4.5 gals of E85 and the rest 93 (10% ethanol).

Is changing FOL to 70 necessary when using e85 mix?

[DLSJ5]

Originally Posted by CaryTheLabelGuy

You should test your E85 and see how much ethanol is actually in the blend. I'm betting it's close to the lowest amount possible (51% ethanol) if you're able to run that much of it without issue.

I'm in Florida and my E85 is really close to 85% ethanol and my happy medium is 4.5 gals of E85 and the rest 93 (10% ethanol).

My GTR buddies with flex fuel kits / gauge say it's around E80 at this station, which everyone in our area uses for E85. So that would be around E34, I'll do some logging and see how it looks.