E85 vs. Gasoline: What Project Farm's Dyno Test Really Showed

Alright, gearheads, let's talk about E85. Everyone’s chasing that extra horsepower, and the lure of ethanol-blended fuel is strong. But is it all it’s cracked up to be? Project Farm recently put E85 to the test in a 2003 Chevrolet Suburban – a flex-fuel vehicle – and the results are worth digging into. Forget the hype; let’s see what the dyno *actually* said.

This isn't some armchair debate; Project Farm strapped a Suburban to a dyno and ran the numbers. They even went the extra mile to verify the actual ethanol content of the E85 at the pump – turns out, it wasn’t quite 85% as advertised. That’s a detail a lot of folks miss; variation in blend percentage can really throw off your expectations.

The initial dyno results showed a slight bump in horsepower and torque when running E85 compared to regular gasoline. At 3,500 RPM, we’re talking about a 17-horsepower gain and 8 ft-lb of torque. That sounds pretty good, right? But the gains tapered off significantly at higher RPMs. By 5,000 RPM, the horsepower difference was down to just 5, and the torque difference was only 8 ft-lb. Keep in mind, the dyno test was performed in second gear due to the Suburban's limited RPM range, so those numbers are artificially inflated, but the *difference* between the fuels should still be comparable.

Now, here's where things get interesting. Running E85 requires significantly more fuel. That's because it contains roughly 30% less energy per gallon than gasoline. Project Farm noted that the engine was running very lean on E85, which isn't a surprise given it wasn't designed for it and the carburetor wasn’t adjustable. To compensate, they had to swap out the original carburetor for a Tillotson mechanically injected system – a classic example of needing to adapt to work with a different fuel source.

The Tillotson setup allowed for adjustments to the fuel delivery rate, which is a lesson for any of us considering switching to E85. It's not just about dropping in a different fuel; you might need to modify your fuel system to ensure proper operation. And as Project Farm discovered, ethanol can be corrosive, leading to issues like fuel leaks.

Fuel Efficiency – The Real Cost

While the horsepower bump might seem appealing, the fuel efficiency hit is a major consideration. The Suburban's MPG took a noticeable dip when running on E85. That extra horsepower comes at a price, and in this case, it’s a hit to your wallet.

Lessons Learned for the Garage

This isn't just a video for those who've got a Suburban and are curious about E85. It’s a lesson in understanding the nuances of fuel chemistry and engine tuning. It’s a reminder that chasing horsepower isn’t always the smartest move, especially when it impacts fuel economy. And it highlights the importance of proper parts and maintenance, like a reliable carburetor (or a Tillotson replacement!).

This kind of testing is what separates the casual observer from a true gearhead – understanding the “why” behind the numbers. It’s the kind of knowledge you pick up wrenching in the garage, diagnosing problems, and tinkering with engines. If you’re looking for more content like this, hit up Project Farm’s channel; Jim does a solid job breaking down complex topics.

If you're struggling with fuel system issues on your own project, don't spin your wheels. Find a Master Mechanic near you, or list your project car here. Need parts? Check out CrownRunners to get those parts delivered, especially if you're facing supply chain headaches.