Check our work.

Oak Ridge National Laboratory (ORNL/TM-2012/88)

Controlled immersion testing of metals, elastomers and plastics in CE10a through CE85a. The single best non-commercial source on what ethanol actually does to fuel-system materials. Tests infrastructure (dispenser) materials, not vehicle components specifically — directionally applicable, not a substitute for an OEM spec.

U.S. DOE Alternative Fuels Data Center / U.S. EPA

Defines the three age-based compliance categories for alternative-fuel conversions and the Clean Air Act tampering prohibition. Authoritative on legality.

U.S. EPA

The rule itself, effective 2011-04-08. Cited for the tampering-exemption pathway.

Electronic Code of Federal Regulations

Legal definition of a 'clean alternative fuel conversion', including the good-engineering-judgment requirement.

Performance Racing Industry

Trade-press engineering guidance on injector/pump sizing, filtration and line materials. Written for racing builds, so its margins are more conservative than a street conversion strictly requires.

eFlexFuel Technology

Kit manufacturer. Useful for install time and fuel-property figures; commercially motivated, so compatibility claims are corroborated against ORNL and EPA before being taught as fact.

eFlexFuel Technology

Vendor install sequence: sensor into the fuel line, harness to injectors, ground, control unit in the bay. Basis for the field checklist ordering.

QFS / High Flow Fuel

Electrical spec for the de-facto standard ethanol content sensor: linear 50–150 Hz output, ±5% accuracy, 13.5 bar max fuel pressure, −40 °C to +140 °C ambient.

U.S. NHTSA

Authoritative decode of VIN to make/model/year, fuel type (including factory FFV flag), injection type and displacement. Free, no key. Field coverage is uneven on older and imported vehicles.

U.S. EPA / U.S. DOE — fueleconomy.gov

EPA certification ratings for every vehicle sold in the US. Critically, factory FFV records carry BOTH a gasoline rating (comb08) and an E85 rating (combA08), which yields a measured per-vehicle economy penalty instead of an estimate. 1,538 such records underpin our penalty model: median 26.3%, sd 3.2%. Measured on the EPA test cycle, so a given driver's real-world penalty will vary around it.

U.S. DOE Alternative Fuels Data Center

Quarterly national and regional retail prices for E85 and gasoline. April 2026: E85 $3.31/gal, gasoline $4.09/gal — a 19% nominal spread against a 26% break-even requirement. Regional dispersion is large and is the reason the calculator insists on local prices rather than defaulting to national averages.

ASTM International

The spec that makes 'E85' a range rather than a number — seasonal classes put pump ethanol content anywhere from roughly 51% to 83%.

Renewable Fuels Association

The ethanol industry's own trade association, disavowing the '105 octane' figure that everyone repeats: it comes from misapplying ethanol's BLENDING octane value, and the correct answer confirmed by engine tests is 94-96 (R+M)/2. An industry body arguing against its own product's marketing is unusually strong evidence. Dated 2009, so read the fuel spec itself from ASTM D5798-21.

Oak Ridge National Laboratory

The measurement that decides the performance question honestly. Wide-open-throttle acceleration on four factory FFVs: the two direct-injected gained 2.5-3%, the port-injected van 1.7%, and the port-injected F150 nothing at all. The turbocharged GDI car gained 5% on E15 alone. Establishes that octane only pays where the engine was already knock-limited.

AAA / Automobile Club of Southern California Automotive Research Center

Chassis-dyno test of higher-octane fuel in three naturally-aspirated cars designed for regular, with no tune: -1.51%, -0.19% and +2.36%, which AAA characterised as run-to-run variation. Tests octane without ethanol, so it isolates exactly the variable a no-tune conversion changes on an NA car. Not an E85 test.

U.S. DOE Co-Optima / National Renewable Energy Laboratory

Quantifies what octane is worth: roughly 1% efficiency per 1.6 octane-index points, via a compression-ratio increase. Critically, those gains presuppose REDESIGNING the engine to exploit the fuel — it is a fuel-screening tool for future engines, not a prediction for pouring E85 into an existing one. Also the source for ethanol's 900 kJ/kg heat of vaporisation, and for the caution that charge cooling is largely already captured inside octane sensitivity.

Argonne National Laboratory

The current US government lifecycle model: corn ethanol at 43.8 gCO2e/MJ direct plus 4.99 land-use and indirect, against a 93.1 gCO2e/MJ gasoline baseline. The most favourable credible figure, and not independent of the land-use dispute — its own ILUC term is three to five times lower than EPA's or CARB's. Read alongside LARK_PNAS or not at all.

Lark et al., Proceedings of the National Academy of Sciences 119(9)

The leading peer-reviewed case against corn ethanol: measuring observed cropland expansion rather than modelling a counterfactual, it puts ethanol at 115.7 gCO2e/MJ — at least 24% WORSE than gasoline. 'At least' because it counts domestic land-use change only; international effects would add to it. Contested by USDA_OCE on soil-carbon grounds. Peer-reviewed, open access, never retracted.

U.S. Department of Agriculture, Office of the Chief Economist

The best-argued rebuttal to Lark: argues the implied soil-carbon release of 4.85 t CO2e/acre/yr is an order of magnitude above USDA's DAYCENT figure, and that the total exceeds the upper-bound accumulation on ALL US conservation-reserve grassland. Quantitatively specific and it lands — but USDA is corn ethanol's promoting agency and this is an internal memo, not peer-reviewed.

California Air Resources Board

CARB's regulatory land-use penalty for corn ethanol: 19.8 gCO2e/MJ, sitting between Argonne's ~5 and EPA's ~26-30. Cited to show the disagreement is between governments, not between government and industry. In force for California's LCFS, so it has legal as well as scientific standing.

California Air Resources Board

THE source of truth for whether a conversion is legal in California — not the kit vendor's 'E85 compatible' claim. Every certified system, with its B-series Executive Order, model year, base make and test group / engine family. Checked in full on 2026-08-12 against the list dated 22 May 2026: the strings 'E85' and 'ethanol' appear ZERO times. Certified retrofits are EV, CNG, LPG and LNG only. The 1993-and-older list is CNG and LPG only. There is no California-legal E85 conversion path for any vehicle today.

California Air Resources Board

Why the CARB list is empty, from CARB. Aftermarket rules 'do not preclude the use of E85 conversion kits' and acknowledge their cost-saving potential — the barrier is that almost nobody applies. Since 2019 CARB has received 'only a few applications', and has been working with one company on its application since August 2025. It also asked EPA, and reports that USEPA 'has not received any E85 conversion applications which would apply to any MY2020 or newer vehicles'. That last clause is the single most important sentence for this business: the modern-vehicle gap is federal, not just Californian.

U.S. DOE Alternative Fuels Data Center

DOE's own summary, including the 40% average lifecycle reduction claim and the important regulatory fact that FFVs must meet the same emissions standards on E85 as on gasoline. The 40% traces to a 2021 Argonne conference presentation rather than a refereed paper, and the page carries no date — quote it as DOE's position, not as settled fact.

International Energy Agency AMF

The counterweight to the air-quality story. E85 cuts carbon monoxide and the benzene family, but RAISES acetaldehyde and formaldehyde by two to twenty times, more so in the cold. Acetaldehyde is reasonably anticipated to be a human carcinogen and both are ozone precursors. Much of the underlying vehicle data is Tier 1/Tier 2 era; no comparable Tier 3 dataset exists.

U.S. DOE Alternative Fuels Data Center

Where E85 actually exists: 4,911 stations across public and private, of which more than 4,200 are public in 44 states. Roughly half sit in the Midwest. Backed by a free API at developer.nlr.gov — note the host changed from developer.nrel.gov, which was retired in May 2026. The API carries no fuel prices and never has.