So the title basically says it all but there's one more caveat, and that is, my engine was tuned on 93 w/10% ethanol @18psi. So would switching to 91 (e-free) have any adverse affects or negative ramifications? Or would I need to have the car re-tuned? Thanks in advance for any/all input.

 

bump

 

No reason to switch to ethanol free. If your car was tuned with 93 it's best to stick with it regardless if it has ethanol or not.

 

x2 to the guy above. but 93 with ethanol will have a little higher ignition requirements than 93 without ethanol. not by a lot, but enough it could make a difference

 

Good to know... thank you gentlemen.