Excel Engineering Headquarters | Diagonal, Iowa

Our Diagonal, Iowa headquarters is a fully equipped, ISO 17025-accredited engine and emissions testing lab built to meet the highest industry and regulatory standards. We support a wide range of engine types—from small handheld engines to large non-road and heavy-duty applications—with expert testing services tailored to your needs.

Our capabilities include:

• Performance testing for evaluating engine output, efficiency, and reliability, for ALL FUELS, including Hydrogen
• Durability and endurance testing to simulate real-world operating conditions over time
• Emissions certification in compliance with EPA and CARB regulations
• EPA 40 CFR Part 1065-compliant testing for engines up to 5500 HP
• Altitude Simulation
• Service accumulation programs to prepare products for certification or real-world use
• Evaporative emissions testing for tanks and fuel systems, and portable containers
• Combustion analysis to support development and diagnostics
• Axle efficiency testing to meet GHG compliance standards under 40 CFR §1037.565
• Fuel Cell and FC component development
• Powertrain development support including calibration, validation, and OBD diagnostics
• Full vehicle chassis dyno development, testing and CFR 1066 certification, up to class 6
• EPA primary confirmatory lab for Part 86 small vehicle certification (Motorcycles, ATV, SxS, NEV, Snowmobiles, etc.)
• Electric and Hybrid Vehicle testing, including MPGe (EPA), and Battery SOH / SOC (CARB)
• Marine engine development and certification

Whether you need regulatory certification, prototype validation, or custom test development, our experienced Iowa-based team delivers high-quality, cost-effective results—on time and on spec.

At our Diagonal, Iowa headquarters, Excel Engineering operates a fully equipped, ISO 17025-accredited engine dynamometer emissions test lab. Our facility is engineered to handle a wide range of engine platforms and testing protocols, providing precise, reliable data for certification, development, and validation programs.

Key testing equipment and capabilities include:

• 28 – engine test cells (7hp – 5500hp)
• 9 – EPA 1065-compliant emissions test cells
• 4 – test cells up to 200kW
• 22 – test cells up to 600kW
• 2 – large engine test cells up to 4100kW
• 2 – Altitude simulation test cells
• Powertrain test capability
• Transmission and axle testing
• Off-level tilt, cold room, and thermal cycle testing
• Cooling package evaluation
• Motorcycle and ATV emissions testing
• SHED evaporative testing
• Portable fuel container testing