Dyno Tuning

By: Michael Rauscher

Dyno testing is only useful if the data obtained is accurate. The saying goes “Garbage in, garbage out”. To have value the attention to detail is critical. The same applies to engine design and building. Power gains are incremental, small changes adding up to large power gains.

The fact that power increases are small mandates that all phases of testing are controlled and repeatable.

Dyno testing and tuning is a very cost effective method of capitalizing on the small incremental changes that lead to large power improvements.

The ultimate goal of dyno tuning is to optimize engine output from the initial engine design.

Dyno Types

Water Brake
Eddy Current Brake
Inertia Wheel

Data Acquisition

Speed
Accuracy
Resolution

Data Manipulation

Corrects Output From:

Sensors
Transducers
Turbines
Load Cell

Corrects For Weather Conditions:

Barometer
Temperature
Vapor Pressure

Calculates Output Using Corrected Data For:

Standard Horsepower
Corrected Horsepower
SAE Horsepower

Presents Output In A Format That Is Usable By The Engine Designer

Can't Do:

Interpret Data
Most Cannot Simulate Drivability
Some Are Able To Perform Acceleration
Operator and Analyzer

Can Do:

Obtain Torque
Acquire Data - Torque, Temps, Pressures, Flow, Etc.
Fuel Regulators

Set Safeties

RPM Limit
Oil Pressure, Maximum and Minimum
Fuel Pressure

Check

Fuel Pressure
Fuel Leaks
Throttle Opening
Cooling Tower

Monitor

Water Temperature
Oil Temperature
Exhaust Temperature
Air To Fuel Ratio

Set Timing
Set Load On Engine
Set Appropriate Throttle Setting
Run Until Temps Stabilize
Shutdown

Inspect For Oil Or Coolant Leaks
Check And Set Valve Lash
Verify Fluid Levels
Rough In Ignition Timing and Air/Fuel Ratio

Calibrate Dyno

Repeatability
Carburetor Air Temperature
Water Temperature In And Out
Oil Temperature
Weather Factors
Fuel Totalizers
Airflow Turbines
Load Cell
Exhaust Gas Temperature

Verify Safety Limits
Set Torque Absorber Capacity
Set Upper Test Speed Limits
Set Up Test Program
Conduct Initial Pulls
Observe For Any Changes Or Fluctuations
Monitor Data For Stability

Identify Consumption Efficiencies

Present Good And Bad Examples
BSAC, good 5.00
BSFC, good 0.50

Plan Examples

Rocker Change
Carb Change
Carb Mods (Air Bleeds, Jets, Power Valve)
Cam Timing Change

Examples

Fuel Map
Ignition Timing
Valve Events
Spark Plugs
Use Modeling Programs

Detonation must be avoided at all costs. The ability to recognize detonation is a skill that must be obtained by the operator and engine designer.

Detonation is the most destructive phenomenon in the combustion process.

Detonation has to be under control!

Spark Plug Reading Is Mandatory
Ignition Timing
Spark Plug Selection
Fuel Metering

Dyno Tuning

Summary

Dyno Testing Myths And Misconceptions

Dyno Setup

Prestart

Initial Start Up

Break In

Post Break In

Controls & Parameters For Testing

Testing

Formulate Plan

Execute Plan

Analyze And Develop Plan To Address Inefficiencies

Detonation

Final Operations In Vehicle