This was the most startling pass we made all year. Just after shifting into second gear Alex felt all of the power disappear. She assumed the supercharger belt broke. But it hadn’t. This AEMdata software screen shows the manifold pressure suddenly turning from boost into vacuum (yellow trace pointed out by red arrow). Did the supercharger break? No. Further analysis of the AQ-1 logs revealed that the voltage had dropped severely during the run. The ultimate problem was a failing alternator; the low voltage caused a glitch in our drive-by-wire throttle car’s engine controller. Problem found and solved.

Yet one more example of data helping us to improve our race car’s consistency and performance was how it helped us devise a solution to a problem we’ve had all year long breaking belts. Late Model Mopars have a very long serpentine belt. This belt gets even longer when it has to turn a supercharger. We’d already documented that the belt suffered severe “whiplash” at the shifts. This was caused by the different loads that the belt was seeing. Under load at redline the engine was at almost 7,000 RPM and the supercharger was at 15,000 RPM. With our non-clutch torque converter, at the moment of the shift the load was reduced on the engine and the engine and supercharger had differing amounts of inertia. We filmed the belt going through a violent whipping action at the shift. We thought we’d cured that problem because we stopped breaking belts after the burnout. But looking at the data, we weren’t breaking the belts at the shift; they were breaking under maximum load in third gear near the 1,000-foot line. With help from the folks at Magnuson Supercharger our car was changed to a two belt system with a significantly shorter supercharger belt, reducing belt stretching at maximum load. And the folks at American Racing Solutions provided us with their outstanding heavy duty billet HEMI belt tensioner which is not only super strong in structure but has a higher spring rate than a factory tensioner. Together, these things solved our belt problem and we never looked back.

We have only scratched the surface on what we can do with our AEM AQ-1 data logger. We love how fast it is to pull data; it takes only seconds which allows us to start analyzing the data almost instantly. When minutes and seconds count between rounds, this is really helpful. As is the ease with which we record logs, Alex flips a toggle switch on to start logging, and then flips the switch off to stop logging.

We’ve used our trusty Diablosport Trinity for four years now and can recommend it as a handheld programmer to all late model HEMI fans. It’s useful enough that even with our 4,000-pound car running in the 9.8 second range in the quarter mile, we still use the factory PCM and our Trinity.

We’ve only used the AEM AQ-1 for this season, but our love of the unit deepens with each new discovery we make of a useful new way to use its data. We’re building a database on how supercharger case temperature correlates to power loss on hot days. We notice that when the supercharger case gets hotter than a certain temperature, boost falls off a little The hotter it gets from there the more boost falls off. This data will help us make better predictions for our dial-ins next year.

Our transmission has a provision for an input speed sensor, which we will be adding in the future. If you log input speed along with driveshaft speed, your transmission and torque converter builders can read the resulting slip data as easily as you are reading this article. With the AQ-1s daisy-chaining ability the number of channels and types of data that we log are limited only by our needs and imagination.

Data logging used to be difficult and expensive. But the AEM is affordable with the data logger priced at $374.82. We got the long, 96” flying lead harness which runs another $261.82. You can use any sensors you wish, but we opted for AEM sensors because the AQ-1 configuration includes the calibration for their own sensors, making it as easy as choosing from a drop down menu when setting up the unit. How much you spend on sensors depends on what you want to log, check out the AEM website for more information. Overall, given how valuable high quality data is, it’s remarkable that you can get this much capability for this small of an investment. And given that good data can not only make you a better racer, but detect small problems before they become big and expensive problems, the AQ-1 can quickly return your investment with more round wins and maybe save you a lot more than the unit costs if you catch a potentially catastrophic issue early enough.


AEM Electronics


Phone: 310-484-2322

2205 W 126th Street, Unit A

Hawthorne CA 90250



Phone: 561-908-0040

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