Quote:
Originally Posted by LotusBMW
from here http://www.n54tech.com/forums/showthread.php?t=10605
Not sure how well this translates across the pond given our different fuel qualities. Probably makes the below conservative
Can I use E85 ethanol fuel with the JB4? If so what mixture should I use?
1) Generally speaking you can run 30-40% E85 without the need for logging or worrying about fuel trims, fuel pressure, etc. Just mix E85 in and select map 5. Done.
2) For those wanting to run higher mixtures (and more power) then you need to datalog. You'll want to first look at your low fuel pressure in the JB4 logs. If that is dropping below 50 then you're maxing out the low fuel pressure and should either reduce the E85 mixture or add fuel pump upgrade.
3) Next up look at fuel trims. If they are exceeding 50 in the JB4 logs & open loop is already at 90-100, or if you get 29F2 codes from having too high of an open loop, then you need to add the BMS back end flash for E85 fuels to extend the fueling range. The E85 flash also features VANOS changes, higher than factory timing advance, and some other stuff designed to help make more power on E85.
4) Finally after the flash and low pressure pump, you need to keep an eye on the high pressure pump. If it drops below 9 @ wide open throttle then you're maxing out the high pressure pump and need to lower the E85 mixture or lower the boost in the areas where it's dropping below 10. Right now there is no viable high pressure pump update. The only known solution that works is to add meth at this point. This is why BMS suggests 60-70% E85 and not 100% E85. The 100% E85 works the fuel system harder with no power benefit over say 70%.
5) Most cars will need an inline fuel pump upgrade OR meth to run more than 50% E85. We suggest this inexpensive inline option.
6) Using map 7 requires 50-60% E85, the back end flash, AND the fuel pump upgrade. |
OMG how do you know all this stuff
