How important is data-logging?
Data-logging is most valuable if the data is analyzed and understood. Bob spent 5 years as a rocket scientist for General Dynamics Aerospace. There were 10 pounds of data for every pound of manufactured rocket metal. All that data was analyzed to fine tune the finished product. We am seeing the need for a similar trend in data-logging for drag racing.
Fully utilizing on-board data can be very time consuming. It can be a real-world window into the operation of a race. However, to gain the benefits, additional crew labor should be planned just for data-logging. The latest generation of youth are skilled with computers and data management and can do a good job of data-logging collection, analysis, and reporting.
One of the limits to data-logging is that the information is gained after the fact. You have to make a run to gain data to analyze. To ‘extrapolate’ or ‘connect-the-tuning-dots’, sometimes you have to go overboard in an adjustment to measure the effect. In addition, most data-logging sensors should be re-calibrated to make sure subsequent data is in the same baseline scale.
However, with consistent data logging and analysis, a tuner can gain a deeper understanding of the engine and it’s quirks. When it comes down to the wire, knowing your engine can mean the difference between a precision-tuned fuel system and a gamble every time you run.
What tuning “tools” (electronic or other) are used by professionals to optimize engine performance?
With regards to the fuel system:
- Fuel injection or carburetor flow bench tests find leaks or flow restrictions as well as measure and set the fuel flow characteristics of a fuel system. Most of these services do not produce air/fuel ratio numbers for a tune-up.
- Dyno tests measure the performance of the running engine, usually in a stationary environment. Some are equipped with air/fuel ratio measurements and recordings.
- Track testing measures the performance of the finished product. Although track testing is very indicative of the performance of a setup, it is dependent on the condition of the track. Depending on the track, it may not be as good as an NHRA national event surface. Full performance potential may not be achievable on a test track with lesser traction conditions. Additionally, track testing is dependent on the local weather and season. When transferring from a test track to competition tracks, air/fuel ratio management is beneficial.
- On-board sensors such as air/fuel ratio meters can provide valuable tuning data. Oxygen sensors from these meters are connected to the exhaust and are used to measure a combustion species. The meter interprets the species, then converts it to an electrical measurement that displays an air/fuel ratio.
Readings are calibrated for different fuels. Several setups read numbers such as near 12 to 1 regardless of the fuel. However, that is considered the gasoline scale. Suppliers have mathematical conversions for alcohol fuels. Actual air/fuel ratios for normally aspirated ethanol would be near 9 to 1 even though the meter may read 12 to 1. Air/fuel ratios for normally aspirated methanol would be less than 6 to 1, even though the meter may read 12 to 1.
Some OEM oxygen sensors on gasoline fuels can become contaminated from even momentary excess enrichment, such as from excess launch enrichment. Excessive oil burning from bad rings or valve guides can also be a culprit. Subsequent readings may not necessarily be accurate with a contaminated oxygen sensor. It is difficult if an air/fuel ratio meter is not working but it is very serious if it provides a reading that is inaccurate.
- Computer programs such as ProCalc are used by mechanical fuel injection professionals to gauge the weather from one location to another or from one time of day to another in order to ensure consistency is maintained from the shop environment to the test track to the competition tracks.
How important is dyno testing (chassis or engine)?
Dyno testing chassis or engine have become an important step for many when setting up a drag racecar. However, there are advantages and disadvantages. In the end, it can come down to time and money versus the potential knowledge gained for customized engine tuning.
Dyno testing advantages:
- Break-in the engine
- Get through infant mortality including leaks, adjustments to reach engine temperature, fuel mixture adjustment from meter, gauge, and/or spark plug readings
- Make adjustments between multiple dyno runs to optimize performance
- Better prepare before going out to the track the first time when there is the added cost of crew, travel, and racecar expenses
- According to Mike Shriver, SpeedSportS, up-to-date dyno’s can simulate drag racing engine acceleration for better preparation.
Dyno testing also has disadvantages:
- Not nearby in many areas with added cost of shipment or travel to a distant facility
- Added cost & time for dyno testing
- The facility’s environment is only one air density that would not necessarily apply to other air densities without further adjustment. Air/fuel management becomes important when interpreting data from the facility and applying it to the race track environment.
- Only one stage of engine setup or state-of-tune is That often changes once the engine is put into competition.
- The testing environment is stationary and not indicative of the engine installed in a moving drag racecar where the weight of the fuel from acceleration may affect the fuel system. The inlet of air from ram air may otherwise increase through the engine with a fuel enrichment need.
- Cooling system on an engine dyno may be more robust and not indicative of cooling in the drag racecar.
- Facilities with uncalibrated meters and gauges can provide exaggerated readings. We saw differences as high as 100 horsepower between uncalibrated dyno readings and attainable readings. Attainable readings were from brake specific fuel consumption analysis and subsequent racecar acceleration.
According to Mike Shriver, SpeedSportS, dyno results often vary greatly due to the dyno operator or the operator’s shortcuts. This can cause unqualified results.