PRI 2025: Sunoco EPX Promises More Power Than Your Typical E85

We’ve come a long way as a hobby to start embracing ethanol as a cost-effective way to make more power. Seriously, I’m proud of us. The narrative has thankfully changed from “that stuff the government puts in the fuel that ruins my carburetor” to “cheap race gas” and nearly standard in any high-powered, boosted Coyote street car. That has lead fuel companies like Sunoco to make a variety of boutique versions of ethanol-based fuels for racing. Sunoco EPX is the latest generation of ethanol-based race fuel that helps racers push the limits.

We caught up with Sunoco at the 2025 PRI Show in Indianapolis. Sunoco is not only a maker of regular pump gas with stations all over the nation, but also the official supplier of race fuel for NASCAR. Sunoco also manufactures all of its fuel and distills ethanol in Pennsylvania – they are not simply blending fuel from other sources. That helps control the consistency in things like the blend or ratio of ethanol to gasoline as well as the quality of the gasoline and ethanol used.

One of the biggest drawbacks of running pump E85 is that the ratio of ethanol to gasoline can be wildly off from pump to pump and season to season. A lower ratio of ethanol helps with cold start during the winter, for example. That sounds great for a daily driver with a Flex Fuel sensor like an F-150, but what about your late model Mustang or classic that sees track time? That’s where E85-R comes in. At around $86 for a 5-gallon pail, you get something dead consistent with 99-octane and the latent heat of vaporization to cool the charged air in your boosted ride. For the same octane, it’s about $10 more for a comparable unleaded race fuel without the cooling effect.

Just last year, Sunoco came out with E30-R for those that couldn’t keep up with the fuel demands of 85% ethanol, but upped the ante with oxygenation, a hint of methanol, and MMT. At 30% ethanol but the same 99-octane, E-30R was a potent option and we started seeing it being used on S650s before tuning and fuel system upgrades allowed for higher ethanol content.

This year, Sunoco dropped EPX, which is yet another evolution from E85-R, which goes beyond 85% ethanol and adds oxygenation (now 34%, up from 30%). The stoichiometric air-fuel ratio goes from 9.8 to 9.4:1. Just like with methanol there is no octane rating on EPX because of its high oxygenation, but it’s made for over 30psi of boost so it’s definitely higher than the 99-octane that E85-R is rated for. PA-based Evolution Performance has been using EPX since early this year in its 2020 GT500 and other development vehicles.