SETUP

VEHICLE (optional — auto-fills tank size)

TANK SIZE US gallons

FUEL CURRENTLY IN TANK 25% (4.0 gal)

ETHANOL % OF FUEL IN TANK what's already in there

FILL MODE

GALLONS TO ADD

PUMP GAS TYPE

PUMP ETHANOL %

E85 PUMP ACTUAL ETHANOL E85

“E85” at the pump legally ranges E51–E83 by season — test it if you can.

TARGET BLEND E30

TEST YOUR FUEL tube-tester helper

Fill the tube with water to a line, top up with fuel, cap and shake, then let it settle. Ethanol bonds to the water and raises the separation line — enter the three readings and skip the printed scale.

WATER LINE ml

FUEL FILLED TO ml

LINE AFTER SHAKE ml

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Approximate — ignores the small volume shrink when water and ethanol mix, same as most testers' printed scales.

No tester yet? Grab a tube tester on Amazon — a few bucks, lives in the glovebox.

THE MIX

E30 RESULTING BLEND

ADD E85 0.00 gal

ADD PUMP GAS 0.00 gal

IN TANK E85 PUMP GAS

Blend after fill: E30 across 16.0 gal in the tank. Estimates only — always verify your fuel system, tune, and ethanol content before running high blends.

CAN IT RUN E85?

Factory flex-fuel lookup, engine by engine — live from EPA fuel-economy data covering every US-market vehicle since 1984.