Your guide into E85 fuel conversions!

To be able to run E85 you need to increase flow rate to reach the same mixture and air fuel ratio as for Gasoline.
The best way of doing this is by changing the injectors to bigger sized injectors.

Which injectors is to be used

Stock injectors is normally too small to be able to deliver enough fuel for an ethanol converted engine.
The flowrate has to be increased by 38% to show the same mixture values as for Gasoline. Use injectors which is as close as possible to 38% bigger than your stock injectors. There is no benefits in using bigger injectors than needed.

For example if you are running ~200 cc stock injectors you will need about 276 cc injectors for E85. The injectors has'nt to be exacly 38% bigger since the finetuning is made in the software at step 2. You need injectors which has the same impedance as your stock injectors. High or low impedance. High is about 12-16 Ohm and Low is about 2-4 Ohm.

Characteristics of E85 Fuel

E85 fuel has a stoichiometric value at 9,7:1 air fuel ratio, "AFR", compared to Gasoline which has 14,7:1. Which means a mixture of 9,7 times of air for each amount of fuel. This stoichiometric point is where exactly all oxygen is consumed and all fuel burned. "Complete combustion". But the point for maximum power output is lower, more rich mixture of air fuel ratio. This is tuned in the software, at step 2.

As long as the stock fuel pipelines and fuel pump is in good condition there is no need to change them even though its good knowing that E85 fuel is more aggressive to the pipelines.

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The software of the engine management system has to be remapped for E85. Fuelmaps is optimized based on the characteristics of E85 and the size of injectors you are using. The ignition timing is also optimized with a more aggressive timing to increase power and drivability.

How to change software to E85 fuel optimized software

In cars buildt around ~1995 or earlier there is stand alone chips/eproms where the software is located in the engine management system controller unit. Then you only need to replace the stock chip with our E85 tuned chip.

In cars buildt later than ~1995 the ECU (Electronic Controller Unit) has to be reprogrammed for E85 fuel. Then you have to send the ECU for reprogramming.

This is what's done in the reprogramming

• Finetuning of all the fuelcontroller maps. Idle control, partload and full throttle maps.
  This settings is tuned unique due to which injectors you are using.
• Optimizing the Ignition timings for E85 fuel to increase the power of the engine. Comparing to Gasoline the E85 fuel has a correlative octane level at 104. When ignition timing is opimized, this will also save some fuel.
• Cold start fix. The coldstart control maps is remapped for E85 fuel so that the car will start normally also when the engine is cold.

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