This is my first winter on ethanol and I finally decided to look at my tune for e70 since I ran it a few times.

As far as the different between e85 and e70 what changes with timing and fueling?

Does e70 like a richer then 12:1 target or the same?

Can I leave timing about the same or should that also be reduced?

 

I didn't really notice much difference between e85/70. Most noticeable are my fuel trims but thats about it (changed by a few %).

 

Unless your shooting for like 600+whp I wouldn't worry about it and even then I am not sure of the limits of E70. I know I can run 530whp no problem on it. You might need to adjust your fuel map a little to keep your af ratios the same, but other than that, it shouldn't be a problem. My AF ratios vary between 11.5 and 12.5 WOT depending on the tank of gas I get. I think the fuel might just be a bit inconsistent.

 

I use the same tune for E70-E85. Same power across this ethanol content range, no knock.

 

The only reason you would need to change timing going from e85 to e70 would be if you started getting knock. In which case you would just drop it a hair until your knock free again. You will most likely be slightly richer going to e70 as well, I wouldn't change it unless it was drastic. Im a big believer in one map year round and that is what I run.