Octane Ethanol Question
Thread Starter
Intermediate
Joined: Dec 2017
Posts: 38
Likes: 26
From: Lakeland FL
Octane Ethanol Question
I've been running 93 Octane with ethanol (Chevron or Mobil) since I got my Z06. The Mobil station started carrying 90 octane which is ethanol free. Should I consider converting to the 90 ethanol free or keep the 93 with ethanol?
Drifting
Joined: Sep 2019
Posts: 1,913
Likes: 1,957
From: Colo Spgs, CO
In your situation, I'd stick with blended 93 octane.
Safety Car
Joined: Nov 2011
Posts: 3,715
Likes: 343
From: Norman OK
I would always run 93 + E10 before I ran 90 or 91.
In Texas you can get 93 E10, in some states the 93 is made using 91 that has Ethanol blended with it to reach the octane rating of 93. Either way my data logs show that these engines need at least 93 octane, 95 octane would be even better but really doesnt exist without some special blending. When I do run 91 or 93 I always add a couple of gallons of E85 to the gas to up the octane rating.
In Texas you can get 93 E10, in some states the 93 is made using 91 that has Ethanol blended with it to reach the octane rating of 93. Either way my data logs show that these engines need at least 93 octane, 95 octane would be even better but really doesnt exist without some special blending. When I do run 91 or 93 I always add a couple of gallons of E85 to the gas to up the octane rating.
Safety Car
Joined: Mar 2004
Posts: 4,048
Likes: 1,478
From: South Florida
Higher octane fuel is always better for the C7. The only downside of Ethanol is lower fuel mileage but you actually don't see any drop off in mileage on modern cars until about E25-E30 and even then it is insignificant. Once you get to E40 the fuel mileage becomes very noticeable and just gets worse. 85% ethanol fuel will have a 30% drop off in fuel mileage.
Team Owner
Joined: Aug 2011
Posts: 21,590
Likes: 1,615
From: GREER SC
Z06
Higher octane fuel is always better for the C7. The only downside of Ethanol is lower fuel mileage but you actually don't see any drop off in mileage on modern cars until about E25-E30 and even then it is insignificant. Once you get to E40 the fuel mileage becomes very noticeable and just gets worse. 85% ethanol fuel will have a 30% drop off in fuel mileage.
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