E50 without a tune
Thread Starter
Melting Slicks
Joined: Oct 2009
Posts: 2,560
Likes: 485
From: Moberly, Mo
Very aware of that, I've been running E65 since 2019 in several of my GM cars which are listed in my signature. I've seen 3 to 4 mpg loss on each of those cars, however E30 and E65 (E85) are much cheaper than 91 or 93.
93/10 Octane is 3.49x18 is 62.82 a tank. 27 mpg at 77 mph 486 miles to a tank in all highway
91/10 Octane is 3.29x18 is 57.42 a tank
E30 2.39x18 is 43.02 a tank 23 to 24 mpg at 77 mph 414 miles to a tank in all highway
E85 (E65 in our area) is 2.19, It pays for me to run E30
The Ethanol is much cleaner to burn, love the smell.
93/10 Octane is 3.49x18 is 62.82 a tank. 27 mpg at 77 mph 486 miles to a tank in all highway
91/10 Octane is 3.29x18 is 57.42 a tank
E30 2.39x18 is 43.02 a tank 23 to 24 mpg at 77 mph 414 miles to a tank in all highway
E85 (E65 in our area) is 2.19, It pays for me to run E30
The Ethanol is much cleaner to burn, love the smell.
Melting Slicks
Joined: Feb 2000
Posts: 3,420
Likes: 565
From: new orleans
I ran straight E85 pump, it threw a check engine after about 1/2 tank of fuel, I filled up the 1/2 with 93, and reset the light, and it never came back. The MIL code was O2 sensor poor performance, out of range. The long-term fuel trims are still adding about 14-16 % fuel. My car is not tuned, but I can look at the fuel trims with HPT.
Instructor
Joined: Oct 2025
Posts: 100
Likes: 53
I ran straight E85 pump, it threw a check engine after about 1/2 tank of fuel, I filled up the 1/2 with 93, and reset the light, and it never came back. The MIL code was O2 sensor poor performance, out of range. The long-term fuel trims are still adding about 14-16 % fuel. My car is not tuned, but I can look at the fuel trims with HPT.
Safety Car
Joined: Nov 2005
Posts: 4,364
Likes: 930
From: Huntsville Alabama
added 5 gallons of e85 to my 93 tank. topped off with 93. So should be close to E30.
Can't really tell a difference still a slow car haha. I did scan it on the way into work and saw 24.5 timing so 1 degree increase... will do a few other pulls like I did before on 93 to get real comparison. but while every little bit helps. 1-3 degree timing in stock car is not going otbe life changing but fun to play with experiment with.
My last E55 C7Z it was 100 hp almost haha very noticable
Can't really tell a difference still a slow car haha. I did scan it on the way into work and saw 24.5 timing so 1 degree increase... will do a few other pulls like I did before on 93 to get real comparison. but while every little bit helps. 1-3 degree timing in stock car is not going otbe life changing but fun to play with experiment with.
My last E55 C7Z it was 100 hp almost haha very noticable
