Better gas choice? 91 no ethanol or 93 with ethanol
Better gas choice? 91 no ethanol or 93 with ethanol
Hi guys,
What would be a better choice, 91 octane no ethanol or 93 octane with 10% ethanol?
My car has cams and all bolt- ons.
Tune is maxed out for my injectors and I'm boosting 25lbs on larger hot side evo8 turbo.
Afrs aren't higher than 11.5 at max boost.
Thanks,
Damon
What would be a better choice, 91 octane no ethanol or 93 octane with 10% ethanol?
My car has cams and all bolt- ons.
Tune is maxed out for my injectors and I'm boosting 25lbs on larger hot side evo8 turbo.
Afrs aren't higher than 11.5 at max boost.
Thanks,
Damon
Well around my area it 92 w/o ethanol and 93 with. But I run non ethanol just herad it's better on motors. W/o ethanol you get better mileage so kinda don't know. People have lots of opinions on fuel anymore.
Evolved Member
Joined: Jun 2006
Posts: 591
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From: Mesa, Az
I was tuned for 91 octane in AZ, and when I moved to FL I got tuned on 93 octane and picked up nearly 30 hp, the octane being the only change. The car was noticably faster on 93. I moved back to AZ and got retuned for 91 octane again and lost about 27 hp. All dynos were mustang dynos. The moral of the story is get 93 if it's available!
Last edited by RoMeIX; Jul 17, 2012 at 08:43 PM.
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Ethanol makes more power than gasoline. So more ethanol would make more power. Although with only 10% added the gains would be minimal.
I know that my lawn mower doesn't like ethanol...
I know that my lawn mower doesn't like ethanol...
I was tuned for 91 octane in AZ, and when I moved to FL I got tuned on 93 octane and picked up nearly 30 hp, the octane being the only change. The car was noticably faster on 93. I moved back to AZ and got retuned for 91 octane again and lost about 27 hp. All dynos were mustang dynos. The moral of the story is get 93 if it's available!
You also have the altitude air density difference betwen AZ to FL to account for. I gained HP in my move from Scottsdale to Florida on the same octane
I would run the higher octane even with the ethenol for the knock protection.
Newbie
Joined: Apr 2012
Posts: 40
Likes: 0
From: DFW
Ethanol is actually good for your engine. It Burns much cleaner and cooler extending engine life. A lot of the negative things said about it applied 20-30 years ago. Boaters don't like it because it absorbs water which can rust the fuel tank.
Ummm, 93 octane is 93 octane.
If a fuel blend if rated to 93 octane the percentage of ethanol is irrelevant the fuel is 93 octane. The supplier can use slightly lower octane fuel and blend with higher octane ethanol to develop a 93 octane "blend". (M+R)/2=Octane rating
Typical E85 has a true octane rating of 94-96.
A minimum octane for E85 is not specified. FFV’s
can tolerate the lower octane of gasoline i.e. 87 (R+M)/2.
There is no requirement to post octane on an E85 dispenser.
If a retailer chooses to post octane, they should be aware that
the often cited 105 octane is incorrect. This number was
derived by using ethanol’s blending octane value in gasoline.
This is not the proper way to calculate the octane of E85.
Ethanol’s true octane value should be used to calculate E85’s
octane value. This results in an octane range of 94-96 (R+M)/
2. These calculations have been confirmed by actual octane
engine tests.
can tolerate the lower octane of gasoline i.e. 87 (R+M)/2.
There is no requirement to post octane on an E85 dispenser.
If a retailer chooses to post octane, they should be aware that
the often cited 105 octane is incorrect. This number was
derived by using ethanol’s blending octane value in gasoline.
This is not the proper way to calculate the octane of E85.
Ethanol’s true octane value should be used to calculate E85’s
octane value. This results in an octane range of 94-96 (R+M)/
2. These calculations have been confirmed by actual octane
engine tests.
Evolved Member
Joined: May 2011
Posts: 964
Likes: 0
From: New Zealand
(That is a question).
What is your question?
E85 makes more power than gasoline due to the characteristics of the fuel. E85 has a lower heat value (LHV) and resists detonation better, that is why you can make more power with E85.
Octane is not a rating of a fuels energy, it is more like an overall rating of the fuels characteristics.
The wiki page actually has a pretty good overview.
http://en.wikipedia.org/wiki/Octane_rating