When we swapped a V6 into our 1996 Miata a few years ago, we threw away some wiring in the process. We removed the front half of the Miata’s OEM wiring harness and its OEM fusebox, replacing it with $6000 worth of Racepak electronics, including a solid-state Power Distribution Module (PDM) and the company’s IQ3 Logger Dash.
To run the engine, we used V8 Roadsters’ self-contained swap harness and fusebox, essentially creating a Miata/Racepak/V8R wiring turducken with some parts handled by OEM circuits, some parts handled by the PDM, and some parts handled by the swap harness. We figured that after a race or two of testing, we’d streamline the wiring and move everything to the PDM.
But while the Racepak system worked most of the time, we never liked it well enough to recommend it. We went as far as writing this diss track of a review–and we certainly weren’t willing to move more circuits into its care. We became even saltier after the dash mysteriously wasn’t logging data when we blew an engine at NCM. We never did fully explain that failure.
But while our electronics weren’t perfect, they weren’t our biggest problem. For years we’ve had lower-hanging fruit to pick and bigger problems to solve. But we’ve solved most of them, and this sort of “good enough” philosophy keeps costing us track time, so it’s time to finally fix our car’s electronics.
Our wish list was simple: a bigger, more readable, more customizable dash. Warning messages that weren’t arbitrarily limited to a few characters. Logging that worked reliably, with powerful, user-friendly analysis software back in the pits. Easy installation and programming. Support from actual racers who understood what we needed. And, above all else, rock-solid reliability that would keep our endurance racing car racing.
In other words, we wanted a system from AiM. It’s long been the industry standard in dashes and data analysis, and we’ve used the brand’s products for decades and knew its reputation for just. Plain. Working. When AiM announced its new line of PDMs, we knew we had to try one in the Miata.
Sounds crazy expensive, right? Actually … no. By the time we connected it to our ECU and a few sensors, the Racepak hardware in our Miata totaled $6039. No, that’s not a typo. That sum bought us a very basic two-color dash and PDM and connected them to our car.
We’d be replacing the system with AiM’s PDM32 Power Module and Logger with 10-inch Race Display, which is fairly self-explanatory: It’s a 32-channel PDM with logging built right in and a giant, bright, full-color, 10-inch dash for the driver.
It also includes an external GPS antenna. Retail price is $2800 at vendors like BimmerWorld, and rather than adding thousands of dollars of dongles, we added only a $77 four-way data hub and two $299 keypads. In other words, all this stuff was orders of magnitude less expensive than the system we were removing. Plus, it’s widely compatible with other sensors and CAN networks, so you’re not locked into one brand going forward.
Parts acquired, it was time to install them. We again leaned heavily on Wayne Presley, owner of Very Cool Parts, to do the bulk of our wiring, as he’s the only one on earth who could still keep track of our V6 Miata’s wiring mixtape.
Most of the car’s circuits already ran through the old PDM, so Wayne spent the bulk of his time cleaning up connections and eliminating the last few fuses in the car, which were still running the V8 Roadsters swap harness. Now, finally, every single circuit runs through the PDM.
Oh, right, we never really explained why that’s a benefit. PDMs are awesome–especially for race cars–for a few reasons. First, because they’re solid-state, there are no moving parts or relays to fail. They’re roughly as durable as a GoPro, meaning fewer failure points for endurance racing.
Second, they eliminate all fuses. Because a computer is constantly monitoring current draw, it can automatically shut off circuits when they draw too much power–and log its actions the whole time. That’s a cool trick that can save money on fuses.
But, more importantly, this also means the computer can turn the circuit back on later, without the driver unbelting or doing anything. This means an intermittent short that puts a normal car on a flatbed can instead mean a few seconds of coasting before a reset–and that the dash and driver can tell the team what’s wrong before pitting.
And there’s one more big benefit of PDMs: That computer can string together actions that would take a bunch of relays and timers to do manually, meaning controlling fans, parking wipers, or even automating whole groups of circuits is as easy as toggling a few boxes during programming.
In summary, a PDM is basically as close as you can get to having R2-D2 flying along in your race car with you, managing circuits and keeping tabs on everything so you can focus on racing. That’s why we’re now on our second attempt at properly integrating one into our Miata.
Fair warning: This still isn’t a job for the faint of heart, and it basically requires completely rewiring any car you install it in.
Even with Wayne’s help, we traded plenty of emails with AiM’s tech team and either received a dud (or accidentally fried) unit for our first GPS module. After a few months of downtime, though, our Miata was finally running again.
And wow, what a difference. In short, our AiM system just plain works. The dash is extremely bright and fully customizable. It was a breeze to set up gauges, warnings, logging, predictive lap timing, headlights, wipers and more. Every gripe we had with the old electronics package is now solved, and our Miata is the most user-friendly race car in the fleet.
And once it’s off track, we use AiM’s Race Studio 3 to review our data. It’s not the prettiest piece of software ever written, but it’s immensely powerful, fairly user-friendly and an industry-standard tool at this point.
Finally, our car has an electronics package we can fall in love with. We’ll get back to that low-hanging fruit in the next update.
More like this
Comments
I'm assuming from the comments that AiM has rewritten their software to be considerably more user friendly! I've set up a few MXL and MXL2s along with their SmartyCam and it's not what I'd call intuitive. Doesn't sound like the documentation has improved. Solidly built hardware, though.
Your PDM sounds a lot like the factory EDM in the ND Miata. It seems like extra complication when you start - why do the reverse lights have go through multiple modules instead of being a light and a switch? - but it allows the rest of the system to use that information, such as displaying the R on the dash or adjusting how the top works depending on if you're in reverse or not.
Keith Tanner said:
Your PDM sounds a lot like the factory EDM in the ND Miata. It seems like extra complication when you start - why do the reverse lights have go through multiple modules instead of being a light and a switch? - but it allows the rest of the system to use that information, such as displaying the R on the dash or adjusting how the top works depending on if you're in reverse or not.
Yeah, PDMs and CAN bus let you do cool stuff in race cars pretty easily. Hit the "pit" button on the streering wheel and it not only tells the ECU to apply the pit lane speed limiter, but also turns off the super bright endurance headlights.
Displaying 1-2 of 2 commentsView all comments on the GRM forums
You'll need to log in to post.
