Anyone use E85 gasoline (i hear its about 105 octane) on their S4? If 105, no need for race fuel?
01-13-2009, 10:30 PM
#4
AudiWorld Super User
Join Date: Dec 2005
Posts: 2,616
Likes: 0
Received 0 Likes
on
0 Posts
I would discuss this with whatever software provider you are running. There are multiple...
things to take into account before you just put e85 in the tank.
First off, if the fuel system is not designed for the E85 it could be damaged by the corrosive properties of the fuel (alcohol).
Second, E85 has a higher octane rating than regular pump fuel, however it has significantly less energy per volume (~30%+/-). Therefore it takes a much larger volume (probably about 25-30% more) of the fuel to have the equivalent combustion to that of pump fuel. Gasoline should have complete combustion with a 14.7 AFR whereas the alcohol based fuel will be somewhere under a 10 AFR.
Because of this need for higher volumes of fuel you may also need bigger injectors, a higher capacity fuel pump, etc. depending on your current hardware.
You will need to customize the tune that you are running to take all of the above into account. Since the ECU is set up to run on gasoline and not E85 it will not be correct- it will not even be close without the corresponding changes.
First off, if the fuel system is not designed for the E85 it could be damaged by the corrosive properties of the fuel (alcohol).
Second, E85 has a higher octane rating than regular pump fuel, however it has significantly less energy per volume (~30%+/-). Therefore it takes a much larger volume (probably about 25-30% more) of the fuel to have the equivalent combustion to that of pump fuel. Gasoline should have complete combustion with a 14.7 AFR whereas the alcohol based fuel will be somewhere under a 10 AFR.
Because of this need for higher volumes of fuel you may also need bigger injectors, a higher capacity fuel pump, etc. depending on your current hardware.
You will need to customize the tune that you are running to take all of the above into account. Since the ECU is set up to run on gasoline and not E85 it will not be correct- it will not even be close without the corresponding changes.
