I have a similar issue. Before I pull the trigger on the Whipple I need more tuning info. I am looking for increased towing ability not trying to break any quarter mile speed records. Didn't mean to piggy back your post just looking for info.

The MPG issue was the reason I stopped using E85 in my 05 GMC, 1500 Sierra. It was costing me additional dollars per mile to run the E85. I live in the Illinois corn belt and want to support the local farmer but E85 is going to have to come down to a reasonable break-even point.

I hate to dredge this up again but... I have the 7193 for my E85 Flex Fuel 05 Sierra with a 5.3. My question is: can I run the 93 Octane tune with straight E85 or do should I run the 87 Octane tune. A search of the forums has left me perplexed. Thanks in advance for clarification,