testo 350 - Engine Kit (for Compliance testing & tuning and combustion maintenance)

Order-Nr.  400563 3513

  • For EPA Emissions Compliance testing – EPA test methods OTM 39, OTM 38, 7E, CTM-030, CTM-034, ASTM D6522, SCAQMD 1110.2, SCAQMD 1146.  Its also used for state, local and company testing.

  • For combustion tuning IC engines (spark-Ignited rich and lean burn and compression-ignited diesel engines)

  • Measures O2, CO, NO, NO2 (NOx) on EPA dry basis for Compliance and Pre-compliance testing, establish emission baselines and confirm combustion / emissions permit status and combustion maintenance

  • Used to confirm catalyst performance, optimizing combustion dynamics and confirm proper fuel delivery & set-up, and preventative maintenance

  • Used to confirm Engine O2 sensor and AFR output

  • Find inbound air (O2) leakage in gaskets, between catalysts and pollution control devices, etc

  • Identify engine or emission problems to avert future failures

This kit is configured specifically for Compliance testing and ideal for tuning and pre-testing applications. Special components make it the perfect portable Emission analyzer for testing spark or compression ignited RICE in gas compression, oil or refining, power generation, water pumping, and more.
Testo 350s are sold through our Authorized Emissions Distributors network.  Please contact Testo to find your local distributor.


Product Description

The testo 350 Engine Kit is a rugged emissions and combustion analyzer that is configured specifically for testing engine exhaust.  It has specialized components for testing engines for compliance (under EPA’s Quad Z and Quad J requirements and other state testing for NOx or CO) or for combustion and emission tuning, commissioning and maintenance.

AND NOW... Compliance testing using EPA New protocols and the testo 350 is faster and less costly than ever before.   

EPA’s new testing protocol, combined with the testo 350, is shaking up the compliance testing world by saving testers time and money.  It’s been known for decades that testing protocols for Electrochemical (EC) based analyzers did not utilize the benefits of the sensing technology.  A better test method was needed, and now it’s here.  The performance test method OTM 39 can be downloaded from EPA website (https://www.epa.gov/sites/production/files/2020-08/documents/otm-39_performance_method_using_portable_gas_analyzers_08_24_2020.pdf)

For More information on the periodic monitoring OTM 38, go the main page here - https://www.epa.gov/emc/emc-other-test-methods#Other%20Test%20Methods

Measurement accuracy of the testo 350 was proven long ago, but the bureaucracy did not allow the benefits of Testo’s sensors to be utilized. Testers were saddled with calibration procedures that did little to assure accuracy and consumed large quantities of expensive calibration gas.  It all changed with the issuance of the New Protocols (OTM 39 for performance testing, OTM 38 for Emission checks.  

Using the testo 350, along with the TECsoft compliance software will make you testing faster, less costly, and more successful.
The Control Unit controls the analyzer box and displays the measurements in a high definition graphic display. View the separate values or the trending graphs. Select the “Rich Burn” or Lean Burn” engine icon and the analyzer will activate the proper settings and guide you through the measurement.  Save each reading or let the automatic program data log the test.

One test run or three?  You define it or use one of the default programs (i.e. EPA CTM-034).  Bluetooth connectivity to over 330 feet keeps your informed of the readings.  The Control Unit’s magnets allow you to dock next to the AFR cabinet which makes for easier combustion adjustments.  You can also connect via USB to stream data seamlessly.
The Analyzer Box (contains the sensors, pumps, power, etc.) The 300-foot Bluetooth connection allows the analyzer to be closer to the stack, and you in a better location.  The closer location results in sensor response times faster than any other portable analyzer in the market.  The 350 uses a patented sample gas path and advanced Peltier sample conditioning system.  The chiller is temperature monitored and controlled and continuously removes moisture from the gas path. It starts with a powerful pump that pulls a high velocity sample through a Teflon sample line all the while monitoring flow rate and automatically adjusting to maintain a constant flow.  Perfect for compliance testing.   It’s the most advanced and most powerful sample preparation system in the market. It not only satisfies EPA compliance for a dry sample, it also protects the sensors for longer life.
Testo’s sensors are unique.  We pioneered and have developed our own designs which result in extraordinary stability, life span, and accuracy. Connected circuit boards allow for plug & play sensor swapping.  The circuitry monitors individual sensor temperature, signal output, and other data input, resulting in highly accurate measurements.  The sensors deliver linear results from the high ranges of many thousands of ppms down to single digits.  This especially important to comply with EPA ZZZZ, quad J or quad O or ASTM D6522 protocols.
Communications & Software
Connectivity is abundant with either easyEmission software (0554-3334) for everyday testing and data logging or TECsoft software (400563 3511) for compliance testing.  Other digital options include an analog output box, and an SDK (toolbox).  The testo 350 can also connect to each other for simultaneous sampling at multiple sample locations.  Connect two (2) analyzers together via cable to see side-by-side comparisons of NOx and CO for catalyst performance or use the CAN BUS to connect 16 analyzer boxes in a SCR to see the complete NOx profile at once.  See the Applications tab for more information on multi-analyzer testing.

Ideal Features for Engine Testing

The testo 350 engine kit is configured specifically for the requirements of engine testing:
  • Sensors include: O2 (0-25%), CO (0 -10,000ppm with dilution to 400,000 ppm), NO (0-4000 ppm) and NO2 (0-500 ppm) for a “True NOx” reading.  Hardware protections make the sensors last up to 5 years making cost of ownership the best in market. Sensors are plug & play allowing you to change in field to a LOW NOx 0.1 ppm measurement.
  • The “RICH burn” mode activates the CO dilution to the 50,000 ppm (5X) range. Switch to a 10X when commissioning for even better sensor protection.  Switch to “overall-dilution” to double the range on CO, NO, and NO2. The analyzer will automatically calculate and display the corrected values.  User defined setpoints means you can extend sensor life and maintain accurate measurements. Switch to “LEAN burn” mode to deactivate.
  • Dilution system allows for more accurate CO measurement throughout the testing range.  See our white paper on our Hydrogen compensated CO sensors.  It provides the technical reasons the testo 350 has superior accuracy.
  • Important displayed values. See the raw NO and NO2 (and NOx) values along with the NOx corrected value to 15% O2 (or other user-defined percentage). This way you can immediately see if you are below, or above your permit limit.
  • Calculates and displays grams per brake horsepower hour (g/bhphr.)  Just input the fuel consumption and BTU value, horsepower and f-Factor, and the analyzer will calculate the “grams.”  It doesn’t get any easier than this.
  • Automatic data logging programs – Set up one run or three. Set the time interval and sampling rate. During the run, check the calculated averages NOx and CO reading against your permit limits.  Yes, you can watch the status real time. This saves valuable time and allows you to stop a test and adjust the engine instead of wasting time on a failed test.
  • Convenient “fresh air” button purges sensors. Press the button to purge instead of climbing ladders to remove the probe. The “purge” increases sensor life, establishes better sensor equilibrium, and virtually eliminate measurement drift.
  • Onboard diagnostics helps you before the emissions test!  Push the i (information) button to see: sensor, battery, error code, and leak check status.
  • On-Site Calibration – Even with the best sensors in the market, calibrations are a protocol necessity.  Here the testo 350 shines in its simple procedures and intelligent feedback to let you know if you’re having problems.  It shows the gas flow rate and even detects and informs you if the concentrations are not correct. The 350 has instrument intelligence that at the highest level.
  • The Engine Probe utilized high temperature stainless steel, heat deflector shield and cone allow it to be used on hot engine applications. A 13-foot Teflon lined hose and an extra filter/condensate trap protects the analyse from moisture especially when sampling from a drop hose.


Other Useful Options for Engine Testing:

  • For Diesel testing – use the sintered filter probe to keep high soot levels from entering probe and analyzer. The welded-on filter withstands high vibration and provided better engine security.
  • Hose extensions - 9-foot quick connect extensions means you can extend the hose to 25 feet. Disconnect them for easier, less bulky transport.
  • TECsoft (Testing & Emission Compliance Software) – for real time data logging (or downloading from instrument memory) directly into excel report templates. Eliminates the copy and paste hassles.  Pull together the Pre- and Post-calibration gas data for comprehensive reports.  Highly flexible and easily customized Excel report templates.

Testo 350 – Probes and hoses - Options

Do you have a difficult or different sample location? Or have high particulate or extreme temperature.  Or need a heated probe? Testo has you covered:
  • Probe adapters to attached you own sampling hose via Swagelok fittings
  • Heated sample lines (self-regulating), lightweight with small turning radius and with LED features to let you know the heating status
  • Industrial sample probes from 3 feet to 9 feet long. Made from stainless steel, Inconel, or Ceramic covers a wide variety of temperature needs. From 1112⁰F to 3200⁰F

Delivery Scope

Testo 350 engine kit includes:
  • testo 350 Control Unit
  • testo 350 Analyzer Box
  • Sensors in Kit: O2, CO, NO, NO2, Dilution system
  • Thermoelectric sample conditioner with condensate removal pump
  • Delta pressure, temperature
  • On-Board data logging, USB connection
  • Rechargeable batteries and AC power cable
  • Bluetooth 2.0 communication (to 330 feet away)
  • 6' data bus communication cable, BUS connections
  • EasyEmission software
  • 13" Engine probe (1832 °F max) with 13' Teflon-lined hose
  • Extra particle filters
  • Rugged transport case, with manuals, calibration certificate


Temperature probes

$ 165.00
excl. tax

Type K (NiCr-Ni) probes



testo 350 - Turbine Kit

Order Number: 400563 3514

testo 350 - Engine Kit

Order Number: 400563 3513

testo 350 - Boiler and Burner Kit

Order Number: 400563 3512



testo 350 - Kits for Engine Testing

Unleash Your Engine's Horsepower!
Your task is to produce maximum horsepower with the highest efficiency and still maintain the emissions within the permit.  Emission testing for state or federal compliance requires stable, reproducible and accurate measurements. No need to worry, the testo 350 is built for accuracy.  Tuning the engine prior to the test will expose the analyzer to the harshest concentrations. No problem, the 350 measures the highest (and lowest) concentrations.  For any testing and tuning you need an analyzer that is reliable, rugged, and easy to maintain and operate.  The 350 does it again.  And finally, data collection needs to be secure and emission reporting done with ease.  Testo’s software programs deliver the data, as you need it.

Rich Burn, Lean Burn, Diesel Emissions Testing

Rich-burn engine exhaust, when uncontrolled, can have wide concentration ranges and both CO and NOx can fluctuate significantly. The on-board CO dilution system will automatically set-up for optimum engine testing, perfect for a rich burn engine. Lean-burn engines have different exhaust characteristics, but NO2 can make up a significant portion of the total NOx measurement. The 350 measures both NO and NO2 for proper lean-burn engine set-up.

Download Testo's PDF and learn more about proper engine tuning and testing. See what combustion characteristics contribute to detonation problems. See how engine emission develops and how the testo 350 can be used for both tuning and emission testing. Download the PDF to get a better understanding of how proper engine setup can provide better combustion and lower emissions.

EPA Engine Testing Regulations

The federal guidelines for testing stationary Reciprocating Internal Combustion Engines (RICE) have made their way into the field. The National Emission Standards for Hazardous Air Pollutions (NESHAP) 40 CFR subpart ZZZZ (aka "quad Z") addresses one type of engine testing criteria. The New Source Performance Standards (NSPS) subpart JJJJ (aka "quad J") addresses still another set of engines and testing criteria. You can learn more about the standards by reviewing the official EPA Implementation Question and Answer Document.

In both the quad Z and J standards, portable electrochemical (EC) emission analyzers are accepted for testing. Since the late 1990s, Testo's analyzers have demonstrated that both high accuracy and low cost are achievable.

TECsoft Reporting Software

TECsoft Testing & Emissions Compliance Software integrates the Testo 350 and the simplicity of Excel into the fastest and most flexible testing software available

Innovative multi-unit simultaneous testing (Quad Z Testing Solution)

The testo 350 greatly reduces the hardware and software needed and make data logging and review easier. Two analyzers link together to display the catalyst measurements. It's simple and the cost for this system is substantially lower than the traditional trailer mounted testing rigs.

It starts by connecting two probes and analyser boxes to the exhaust stack. Each analyzer is specifically configured for the different gas conditions found in pre- and post-catalyst exhaust gas. Both analyzers are connected to the handheld control unit. The high definition display shows the side-by-side measurements. Communication through Testo’s “BUS” system makes it possible.

easyEmission Software

Data collection and interpretation is much easier when you know the actual pre- and post-catalyst measurement in real time.  The software shows the simultaneous measurement in a variety of formats.  User-define “measurement groups” allow you to select single (or multi) parameters from two up to 16 different analyzer boxes.  Simple, useful displays for  complex measurements make tuning far easier than before.


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