The average Australian motorist hasn’t embraced E85 and few of them probably ever use anything other than commonly available fuels. 

However, the limited interest doesn’t seem to have stopped the conversions that claim to enable conventional engines to operate on E85. What are the pros and cons of converting?

While E85 is relatively new to Australian motorists, high percentage ethanol fuels aren’t new in global terms and vehicle makers well understand the technology needed to run them.
  • Flex-fuel vehicles can run on straight petrol, or petrol / ethanol blends up to E85.  
  • Downsides are that it’s available from only a small number of outlets and its use increases fuel consumption by around 30 percent. 
  • But E85 is attractive to certain groups as it has a higher octane rating than normal fuels.  
  • This means engines can be modified to produce more power, and for this group high fuel consumption probably isn’t much of a consideration.   
Many changes to the fuel and engine management systems are required to ensure proper performance and durability with E85. But most importantly, as the concentration of ethanol in the tank is variable, the engine management system must be able to identify and deal with this.

 Aftermarket E85 conversions

  • Conversion kits claim to enable conventional engines to run on fuel blends containing up to 85 percent ethanol.
  • In simple terms they enrichen the fuel / air mixture to compensate for the leaning produced by the ethanol. For E85, about 30 percent more fuel must be delivered.
  • This is achieved automatically in flex-fuel vehicles, but many conversions have a manual enrichment adjustment that relies on guesswork to determine the setting. 
We are sceptical that such unsophisticated conversions will provide satisfactory operation. Nor do they address all the other issues the car makers attend to.
Vehicle owners have a legal obligation to maintain their vehicle’s emission compliance. If considering such conversion products always get a written guarantee that the product is legal for use in Australia. 

Like any modification, such conversions may put your new car warranty at risk if it can be shown that the device has caused or contributed to a fault.