Road to Speed Week 2014 Part 1: The AEM Infinity 8 EMS and AQ-1 Data Logger
by Chuck Johnson
If this past year’s Speed Week taught us anything, it was that Project 240SX LSR’s electrical system needed a complete overhaul. Our previous harness had been built in haste during the few days leading up to Speed Week 2012 (read about our Hail Mary story here). At the same time, we also knew that if we were going to top the land speed record we set last year, we needed traction control, data logging, and the ability to control any parameter of the engine whether we were on the dyno or on the dry lake beds of EL Mirage or Bonneville. We found the answer to our needs in the form of AEM‘s AQ-1 data logger and Infinity 8 stand alone programmable EMS.
Along with an install of the AEM Infinity 8 EMS, the plan is to have 5523 Motorsports build a race spec wiring harness to compliment our complete electrical system revamp. During the off season, the entire interior of Project 240SX LSR was stripped out including the old electronics board and wiring harness.
The plan is to make a true motorsports grade harness complete with MIL spec and aerospace grade connectors. Unlike the factory harness, each wire will be completely free of any interruptions or random solders and aging crimps. In other words, each wire will be continuous from point to point.
5523 Motorsports plans to construct the harness completely from high quality, light weight Tefzel wire. Tefzel is constructed from fine, high strand count, silver tinned copper strands and is jacketed with tough Teflon, abrasion resistant and self-extinguishing liner. It’s used in applications where absolute reliability is an absolute must, such as airplanes.
5523 Motorsports’ masterpiece will then be wrapped in DR-25 Raychem heat shrink tubing. Raychem DR-25 was produced specifically as a jacketing for military and motorsports applications by Tyco Electronics. Raychem DR-25 is has long term resistance to high heat as well as caustic diesel, aircraft, and race fuel.
Before 5523 Motorsports could begin laying out the new harness or install the AEM Infinity 8 EMS, we had to address another issue first. It was painfully obvious that the corrosive salt of Bonneville had begun to make lunch of Project 240SX LSR’s chassis.
After days of grinding, sanding, wiping and painting, Project 240SX LSR had a fresh coat of Rustoleom’s light machine grey applied. This time though, a marine paint was applied as a base coat to the entire floor board.
With the interior freshly painted, 5523 Motorsports began focusing on laying out a new electronics board to house the AEM AQ-1 and Infinity 8 EMS.
A series of MIL Spec relays and breakers, which were originally destined for a war machine of some sort, now accompany the Infinity 8 EMS on the aluminum electronics board along with an AQ-1 data logger. 
With the layout of the board pretty much complete, 5523 Motorsports temporarily fastened the board to the main hoop of Project 240SX LSR’s roll cage. Later on, Specialty Cars Fab will attach the electronics board to the roll cage via dzus fasteners. Now, onto the details of our new AEM Infinity 8 EMS. 
The AEM Infinity 8 EMS is a 100% user programmable, total control solution. What does this mean? In a standard road car, you’ll most likely have a combination of different control units: engine, transmission, and ABS for example to make the drive train collectively work together. The Infinity 8 EMS simplifies this down to one system, integrating the ability to tune fuel mixture and ignition timing to develop bespoke knock, launch, boost control, and engine protection strategies. Short of getting your wife to cook and clean on command, the Infinity EMS will give you the ability to control it. 
The AEM Infinity 8 EMS does so through a 32 bit 200 Mhz processor which is capable of 400 MIPS. What exactly is 400 MIPS? It means 400 million instructions per second, precisely half of the commands regarding lawn care that your wife can bark at you on a Sunday afternoon. In other words, it’s pretty damn impressive.
From the outside, the Infinity 8 EMS features a sealed aluminum body with water and dust proof communication ports. In addition, the harness and connectors are fully sealed and of motorsports grade. This is exactly what the doctor ordered since salt seems to find its way into everything at Bonneville… including the nether regions of my trousers. In fact the packaging is so robust, the Infinity EMS is often found on boats where it’s exposed to uber-corrosive environments.
In most any other case, AEM’s Infinity 6 EMS could easily handle the requirements of powering an SR20DET, KA24DE, or any other four cylinder engine. So why’d we go with the Infinity 8?
Put simply, we’ve been scheming up a twin turbo system and/or V8 swap that would allow us to attack another set of land speed records. We’re not prepared to divulge the specific combination yet. Just understand that with its dual wide band capabilities, the Infinity 8 EMS allows us to run one wide band sensor off each turbo outlet and/or different banks of a V6 or V8.
The four individual cam phase controllers along with the eight injector and coil drivers of the AEM Infinity 8 EMS provide us with the flexibility needed to switch power trains and pursue a multitude of other land speed records. You name the engine combination up to 8 cylinders and we can run it now. LS7, 2JZ, VK56, or even a twin turbo four cylinder! Point blank, we’ve got big plans and AEM’s Infinity 8 EMS provides us with the versatility needed to make them all happen. 
Another motivation for using the Infinity 8 EMS is its four channels for wheel speed which can be used for traction control. Again, in most any other four cylinder-powered 240SX application, the two wheel speed inputs for traction control of the Infinity 6 EMS would more than do the trick.
Take a moment to review the tank slappers from the in-car video of Project 240SX LSR’s record breaking run at El Mirage last year. Then, you’ll begin to understand why the Infinity 8 EMS’ four wheel speed input for traction control is so enticing to for us. 
In order to take advantage of the traction control capabilities of the AEM Infinity 8 EMS, 5523 Motorsports swapped out the front spindles for ABS spindles which accommodated the wheel speed sensor. In addition, a ABS ring from an S14 was installed on the hub.
Essentially, the infinity 6 EMS is a two channel system taking input from one front wheel and one rear wheel. The Infinity 8 takes input from all four wheels. In our case, we went with a single rear wheel speed sensor since we have a welded differential. However, a four channel system is possible by using a Z32 300ZX diff cover with individual wheel speed sensors.
In both cases, a slip differential can be established by comparing the driven wheel speed and the drive wheel speed. Once the drive wheel (rear) speed exceeds the driven wheel (front) speed, throttle, ignition, fuel or a combination of the three can be progressively cut with the assistance of the Infinity EMS’ built in traction control system.
Our particular traction control strategy will start with the modulation of the throttle plate itself. Instead of relying on my clumsy right foot to perfectly modulate the throttle; instead, we’ll be swapping to a drive by wire throttle body from a Nissan VQ35DE and relying on AEM’s Infinity 8 unit to control the throttle plate position.
It just so happens that the VQ35DE drive by wire throttle body diameter at 71 MM is the same as the SR16VE N1 throttle body we were previously using. Unfortunately though, the flange pattern is different, requiring John Kuchta of Specialty Cars to weld a new flange on to the intake manifold.
In addition, swapping to the drive by wire throttle body required us to also swap to a 350Z gas pedal. Fortunately, 5523 Motorsports had one of these stashed away for a rainy day. The 350Z gas pedal happens to share the same two bolt flange as the S13. However, the pedal needs to be modified to suit the S13 floor pan. Without bending the pedal’s rod or some other type of modification, there is not enough room to sweep the gas pedal through its intended full range of motion.
In addition to enhanced reliability and complete system control, the other major benefit we gained was the AEM Infinity 8’s data logging capability. I can’t tell you how many times I’ve gotten done with a high speed pass grateful that both my body and the car are still intact only to be greeted with a hundred questions on how the car was behaving.
Let me tell you, at 186 MPH the last thing I am really worried about is the how much boost the turbo is making, if the car felt like it was squatting too much, or what peak EGTs were. With up to 100 channels (at 200Hz) of data logging capability at our finger tips, we’ll be data logging all the key engine parameters… and the crew will have all the data they ever wanted.
Paired with the AQ-1, we’ll have enough channels to also log suspension travel through the use of linear transducers (shock pots.) Basically, this will allow the crew to make data-driven decisions during dyno tuning and track testing instead of relying on my butt dyno and borderline senile level memory. 
Using the AEMDATA software, we’ll be able to take the gathered data and overlay them with one another to draw correlations and understand the effects of our changes without the bias of a butt dyno. Here’s a short list of some of the data we’ll be collecting using the AEM Infinity 8 and AQ-1.
| I/C water temp in | Charge air temp after I/C |
| I/C water temp out | Absolute press before I/C |
| Intake air temp | Absolute press after I/C (MAP) |
| Charge air temp before I/C | Oil pressure |
| Cooling system pressure | Suspension movement (all four corners) |
| Wheel speed sensors (drive and driven) | Turbo speed sensor |
| Crankcase pressure | Exhaust back pressure |
| Lambda (air fuel ratio-wide band) | GPS speed |
| Accelerator pedal position | Throttle position |
| Fuel pressure | Dual wastegate positions |
So wait, why are we throwing an AEM AQ-1 data logger in the mix if the Infinity 8 EMS has data logging capabilities? Simple, we’ve done run out of space for any more inputs into the AEM Infinity 8.
The single most important reason for the AQ-1 was to allow us to accurately log speed through our Garmin GPS receiver. Although the Infinity 8 EMS is more than capable of logging speed off the factory sensor, the accuracy of factory sensors at high speeds sucks. The factory speed sensor does not account for aerodynamic drag or wheel scrub. The AQ-1 has an RS-232 port that is capable of taking the input from our ultra sensitive and uber accurate Garmin 18x 5hz receiver.
In our next update, we’ll get into more detail on the AEM Infinity 8 and AQ-1’s data logging capability, the infrastructure needed to support it, and specifically how the data is used to optimize the engine tune. In addition, we’ll pay a visit to the dyno where Nick Hunter and Jen Drach of 5523 Motorsports along with Clark Steppler of Jim Wolf Technology will work their magic to develop a tune for our unique SR15VET 20V.
Written by Chuck Johnson of Moto-IQ. Originally published at Moto-IQ
