Feb 21, 2017 update to the Ford Mustang GT project car

Project Mustang: An Effort to Standalone

One of our big projects involving we’re tackling on this Mustang is the installation of a standalone engine management system, namely the AEM Infinity. While AEM does a lot of work to get you up and running quickly and efficiently, we’re learning that replacing the powerful OEM ECU of a modern car is not as easy as it looks. However, we were in good company for the installation at the well-equipped headquarters of Very Cool Parts.

The AEM Infinity specifically designed for a Coyote Mustang comes with a “lay over” harness—literally a supplemental wiring harness that lays over the factory wiring and plugs into many of the Ford connectors. A minimal amount of wiring splices need to be made, and only a few sensors (fuel pressure and oxygen) need to be changed out to work with the AEM system.

The tricky part comes when we try to retain the “street” functions of our street-legal Mustang. Though AEM fully admits that this system is recommended for competition use only and makes no claims of suitability or legality for street use, we figured we were smart enough to make it work. The jury is still out on that one.

See, while the AEM Infinity is an exceptional engine management computer, the Ford ECU is a whole car integration system. It runs stuff like the dash gauges, the cruise control, the climate control and the anti-theft system. While we could probably live without some of those things, like anti-theft and cruise, the rest we deemed rather necessary to keep the car streetable.

The physical installation was straight forward, but somewhat time consuming. We had to install a different set of fuel rails with additional ports for pressure sensors, so we went with a set from Radium. The Radium bits are of exceptional quality and fit, and provide lots of options for mounting additional bits of hardware.

A few wire splices need to be made to ensure the fans run correctly, the fuel pump operates, and the starter engages properly—the OEM starter signal is controlled by the stock ECU as well. Aside from those, getting the engine running is mostly a matter of plugging in connectors and installing the “base” map into the AEM computer.

And that’s where we’ve left off at this point. Our AEM Infinity runs and operates the engine, and we’ve researched what needs to be done to restore some of the additional systems like a/c. The next step is actual tuning and exploration of the abilities of the Infinity. One of our favorite features is the ability to switch between preset maps on the fly, without rebooting the ECU. Rain starts to hit your windshield in grid? Just flip to the “rain” map before your next run and you’re good to go.

Stay tuned for full reports on the install and tuning of our new electronic brain.

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View comments on the GRM forums
Sky_Render SuperDork
2/21/17 2:13 p.m.

So what problem are you trying to fix with the AEM Infinity, since the stock PCM can be nearly infinitely tuned and is still emissions compliant? The only real advantages I can see to using the AEM Infinity are the switch-on-the-fly maps and the ability to datalog on one device, while having a lot of disadvantages that all come from using a "race-only" (and expensive) ECU.

Or is your intent to make your Project Mustang race-only?

Robbie UltraDork
2/21/17 2:39 p.m.

In reply to Sky_Render:

I was going to ask a similar question - what is the advantage of going full-standalone?

Brett_Murphy PowerDork
2/21/17 2:53 p.m.

They are showcasing an advertiser's product, most likely. However, unlike some other rags, it sounds like they are also answering a big question a lot of potential buyers will have at the same time instead of just showing the optimal configuration.

JG Pasterjak
JG Pasterjak Production/Art Director
2/21/17 3:05 p.m.

Those are actually all valid answers. In some cases with project cars, we're not always "solving problems" but rather "exploring options." The answer we come up with is that it may not be the ideal setup for a "street" car that has to retain a lot of functionality in ancillary systems, but for a dedicated track car the switchable maps and faster i/o speeds are a great combo. I was building an engine swap car, or a kit car with Coyote power, I know one would be at the top of my list.

In some ways, we're asking the system to perform beyond its design intent, and that's where we've been running into hurdles.

mazdeuce UltimaDork
2/21/17 3:22 p.m.

Does it have the ability to control some creature comforts in a 'regular' car? Say I want to drop a Coyote in an F-150, is there an easy way to retain AC, or are those sorts of things a standalone from the standalone?

STM317 Dork
2/21/17 5:13 p.m.

In reply to mazdeuce:

Wouldn't any F-150 that's new enough to have the ECU tied into HVAC stuff have a factory Coyote option?

HapDL New Reader
2/22/17 9:07 a.m.

Seems like a lot of time, money and trouble to be able to change "maps" on the fly. But I'm old school from the days when the "map" was in the driver's right foot, and when it rained the foot map took care of the rain issue.

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