My car got slower

[65sohc]

A couple days ago I was entering the freeway during rush hour, a situation I don't find myself in often. I wanted to quickly cross over three lanes so I did a WOT second gear acceleration from about 30-70. I made the move OK but the car didn't seem to pull like I expected. I filed this in the back of my brain under "maybe headers afterall?" and drove on to my meeting. The next morning my low fuel light popped on and then it dawned on me. The last time I went to fuel up the Valero station was out of e85 so I was forced to fill up with 91. Yesterday I topped off with 11 gal. of corn juice, bringing me up to e58 on my Nguage, 100 octane in my tank, and about 30 more horsepower at my wheels. I guess I had forgotten how much difference the flex tune makes with e85.

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[HizliBullet]

its a "91 octane only" car

 

[mattlqx]

its a "91 octane only" car

You're obviously having a hard time reading the parts of his post and signature that state he has the flex tune.

 

[mattlqx]

A couple days ago I was entering the freeway during rush hour, a situation I don't find myself in often. I wanted to quickly cross over three lanes so I did a WOT second gear acceleration from about 30-70. I made the move OK but the car didn't seem to pull like I expected. I filed this in the back of my brain under "maybe headers afterall?" and drove on to my meeting. The next morning my low fuel light popped on and then it dawned on me. The last time I went to fuel up the Valero station was out of e85 so I was forced to fill up with 91. Yesterday I topped off with 11 gal. of corn juice, bringing me up to e58 on my Nguage, 100 octane in my tank, and about 30 more horsepower at my wheels. I guess I had forgotten how much difference the flex tune makes with e85.

Glad you're still getting some difference in pep from E58, you may be getting more of that in the future. The latest revision of the ASTM D5798 spec rebrands E85 to "ethanol flex fuel" and changes the blend range to 51 to 83 percent ethanol, which blenders will vary by season. Rather a bit of a bummer. Word is pumps around here are already down to the E60 range. Your pumps may already be or will soon be significantly lower as well.

I'm happy that tune does such a great job adjusting to the alcohol content though! I had great luck with it when I gave it a shot during my track days last week and had to shift back to 91 when I ran out on the third day.

 

[fuhrius]

even the difference between straight 91 and a 91/100 mix that brings it to an effective 93 made a noticeable difference in my car. (says the but dyno)
I did the same in the FoRS and I'm logging data with a Cobb AP, and the peak torque goes up by ~25.

 

[Helmet]

its a "91 octane only" car

Actually 91 octane is the minimum recommended fuel.

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