89 octane w/10% ethanol VS. 87 w/out ethanol

[Ray McIntireJr]

Just wondering if anyone here has done their own real-world test comparison concerning mpg's of the 89 vs the 87? I have looked at different tests and some say you don't lose any mpg while burning the 89 w 10% ethanol and some say you do. I uasually burn the 89 and wasn't doing bad as far as mpg but when I started using the xcal3 it dropped to about 17.5mpg. Before the xcal I was averaging closer to 18.5-19mpg with the same driving habits.

 

[Tom Schindler]

I uasually burn the 89 and wasn't doing bad as far as mpg but when I started using the xcal3 it dropped to about 17.5mpg. Before the xcal I was averaging closer to 18.5-19mpg with the same driving habits.

You are hot rodding your Trac. That is why your mileage went down. It is so much better to drive with the new programming, it is hard not to.



I use nothing but 87 octane.





Tom

 

[Michael Cacioppo]

If your vehicle can run on 87 without pinging you will get much better mileage with it than with gasohol. 10% alcohol coverts to about 4% less energy per gallon of gasoline if I remember the BTU content of gas verses alcohol correctly. Running E85 will absolutely destroy your mpg. I'd go with the 87 which probably is cheaper also. Alcohol in gasoline = farmer's subsidy.

 

[Keola P]

My mileage improved after using the xcal3. Used the 87 performance tune for a while which was good, but I found that I get the best gas mileage with the 91 performance tune with conservative driving.



Got an updated premium fuel performance tune from torrie...damn! I can now do those burnouts I was so envious of I'll try posting a video one day.



But yeah as far as mileage goes 91 octane with the 91 performance tune suits me best.

 

[Ray McIntireJr]

No Tom I wasn't "hot rodding". Ok, maybe at first, but after I got over the first high I started driving sensibly. Before the xcal, if I tried I could get 20-21 on the 89 w/10% eth. Right now I am trying the 91 with the 91 perf tune. I think I'll email Torrie and try a 87 perf tune for awhile to see if I can improve the mileage and if the mpg do improve, if the improvement is worth the extra 10cents a gallon the 87 is over the 89 w/10% eth. And as far as the subsidy goes, I have alot of freinds that are farmers(small farmers) or grew up on a farm. I don't have a problem with that paying a little less for a gallon of gas if it helps them.

 

[Bob Corning]

As a follow-up question, what would be the advice if both the 87 and 89 octane had 10% ethanol? In our area the vast majority of the gas stations have 10% ethanol in all grades, and most time the 87 and 89 are the same price. I tend to use the 89 when it is not any more expensive. Is it a good idea? My '07 V8 runs fine on 87 octane.

 

[Michael Cacioppo]

Crash use the 89 in lieu of the 87. The ECU will keep a higher advance and provide a little better performance.