Fuel Tips: More Oxygen for More Power?

David S.
By David S. Wallens
Jan 14, 2020 | Fuel Tips | Posted in Features | From the Aug. 2019 issue | Never miss an article

The promise almost sounds too good to be true: Get more horsepower just by using a certain type of fuel. What’s in these magic elixirs? Oxygen. A lot of it. But like most seemingly miraculous solutions, today’s highly oxygenated fuels come with a potential trade-off.

The Promise:

It’s right there in print on the Sunoco Race Fuels website: “Evo 10 produced a 17% HP gain against 93 octane pump gas when tested at our local performance tuning shop.” Evo 10 is an unleaded, highly oxygenated, 105-octane race fuel that’s 10 percent oxygen by weight. Typical pump gas containing 10 percent ethanol by volume contains only 3.7 percent oxygen by weight.

The Proof:

Zachary Santner, technical specialist at Sunoco Race Fuels, sent us a dyno chart produced by a supercharged Ford Coyote V8. Running Evo 10, the Ford produced a max of 879 horsepower. When fed a competitor’s 105-octane unleaded fuel, the engine topped out at 866 horsepower.

The Science:

“A simple way of looking at this is that gasoline has a high energy density–BTU per gallon–when compared to other fuels,” Santner explains. “So, one tank of gas can make you go farther than other fuels. When looking at energy density and air/fuel ratio together, you can see how much energy is produced during combustion. Some fuels release more energy when combusted with 1 gram of air. These fuels will offer higher power output from an engine. The components in Evo 10 allow it to release slightly more energy for the amount of air burned when compared to gasoline.”

The Extreme:

He offers another example: “Nitromethane has only 38 percent the energy density of gasoline. When combusted with 1 gram of air, nitromethane releases over 2.1 times more energy. Nitromethane wouldn’t win the miles-per-gallon comparison, but the energy released in combustion is much higher.”

The Trade-off:

Like Santner noted, that extra performance comes with less fuel efficiency. All fuels are a compromise, he notes. “You can’t argue with chemistry.”

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David S. Wallens
David S. Wallens Editorial Director
1/14/20 10:22 p.m.

Just bumping this up because, darn it, Chris made a nice title card for this. 

Floating Doc
Floating Doc GRM+ Memberand SuperDork
1/14/20 10:28 p.m.
David S. Wallens said:

Just bumping this up because, darn it, Chris made a nice title card for this. 

Well, you know? That he did.

David S. Wallens
David S. Wallens Editorial Director
1/14/20 10:30 p.m.

Thanks. Vu from PCA said the title card looked "young." 

Paul_VR6 Dork
1/15/20 9:28 a.m.

Starts with a little extra O2 in the the VP import or Q16, then you put in E85, then you get addicted to methanol and soon enough you are blowing the crank out of the bottom of the engine with a little too much nitro. By the last bit you are destitute, so it's not a huge deal. I assume that's how most people end up on skid row.

Rodan Dork
1/15/20 10:01 a.m.

I experimented with a VP oxygenated fuel when I was drag racing bikes back ~2001-2002.  It was only 94 oct, and produced a benefit of 4 rwhp on a 170hp bike engine over 91 oct pump.

For what I was doing, the small benefit (2.3%) wasn't worth the fuel cost.  Even the supercharged Coyote example above is only 1.5%.

If you absolutely need every last possible horsepower, it does work.

It also smelled bad... really bad.  I wonder if the new stuff is better?

Knurled. GRM+ Memberand MegaDork
1/15/20 10:32 a.m.

In reply to Rodan :

I wonder if that was the crap a certain rallycrosser was putting in a certain Miata.  Even 50 yards away you would know right away they were refueling.  And due to an incredibly small fuel tank they had to do it often.

Paul_VR6 Dork
1/15/20 1:22 p.m.

It has to smell bad to work.

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