[Lariat4x485]

Can someone tell me the difference between E85 and Gasoline??? I currently have a custom tune for 89 Performances. Is it better to get a custom tune for E85??? Thanks in advance....

[cleatus12r]

You HAVE to get a custom tune for E85. Running E85 in a vehicle that cannot compensate for the MANDATORY decrease in air/fuel ratio will cause codes (P0171/P0174), lack of power (more than you'll lose just going to E85 with dedicated tuning), and driveability concerns.

E85 has a stoichiometric ratio of around 9.6:1. Gasoline's stoich ratio is 14.7:1. The engine control module is only able to compensate so much for a perceived lean condition.

It takes A LOT more E85 per unit of air to maintain happy operation than with gasoline parameters.

Is there any particular reason that you are wanting to run E85?

[Lariat4x485]

Thanks, there is no particular reason i was just wondering what was the difference.