Face it, E85 is an effective race gas with plenty of power potential for high-compression or boosted engines, but it also requires a few hardware and tuning adjustments for maximum output. Holley is taking most of the pain out of setting up an E85 system with its new line of Ultra HP E85 carburetors and E85-compatible fuel system components.
“E85 is a nice, cheap race gas,” says Holley’s Bill Tichenor. “This carb is calibrated for it and the fuel pump is set to deliver more volume.”
While E85 has a high octane rating — which allows more aggressive ignition timing and it can handle boost because it initiates a cooler intake charge — it doesn’t have the same energy content or density as pump gas. That means more fuel is needed to deliver the same horsepower.
“This isn’t the same as an alcohol carb,” adds Tichenor. “It’s designed for E85.”
Two views of the new Holley Ultra HP E85 carburetor.
Five models of the Ultra HP E85 are available: 600, 650, 750, 850 and 950 cfm. All carbs feature 97 percent aluminum construction to save weight yet offer 20 percent more fuel-bowl capacity. The metering blocks are E85 specific and there is a high-flow primary power valve. Other features include .130-inch stainless needle and seat, 50cc secondary accelerator pump and secondary jet extensions are installed.
“The E85 carb has all the upgrades we made to the Ultra HP line,” adds Tichenor, adding the carburetor comes in a Hard Core Gray hard-annodized finish.
The supporting equipment is also compatible with E85. The Earl’s plumbing features hoses impervious to E85, and the filters are CNC machined from 6061-T6 billet aluminum with a customer’s choice in micron rating. Both styles of fuel pump are E85 compatible and can be used with either fuel injection or carbs.
Finally, Holley offers an E85 checker to determine the level of ethanol content in the fuel. Depending on the region and time of year, E85 pump fuel can be diluted.
“This helps the racer stay consistent at the track,” says Tichenor. “They can start a chart and record the fuel content along with jet sizes and conditions.”