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Tuner Resources

"Technology for Tuners" Newsletter #4

This is Innovate Motorsports' "Technology for Tuners" Newsletter, Issue #4. These updates are intended to keep you informed of LM-1 tuning tips, firmware updates, application notes, new product releases, company news, and other useful information. In this issue:

1) AuxBox Released to Production!
2) XD-1 (Digital Display) Product Update
3) LM-1 gets good press
4) Tuning Tip: When to Perform a Heater Calibration
5) Application Note: You CAN be too Rich

The AuxBox is released to production!

The LMA-3, also known as the AuxBox, is released from engineering. This device attaches to the auxiliary input of the LM-1 and allows a user to log and analyze 5 critical engine metrics in addition to the air/fuel ratio native on the LM-1. The AuxBox makes the LM-1 into a complete tuning kit, allowing the user to capture, view, and analyze data on all 6 channels that the LM-1 can log internally. Correlating AFR, RPM, MAP, and CHT, for example, is essential when tuning piggy-back fuel controllers, ECU programmers, aftermarket ECUs, or racing carburetors.

The 5 internal sensors are intended for capturing Manifold Air Pressure (MAP or Boost), Cylinder Head Temperature (CHT) or Exhaust Gas Temperature (EGT), RPM conversion (from a tach signal or inductive clamp), Acceleration, and Injector Duty Cycle (or Dwell). The internal MAP sensor is a 3-bar absolute pressure sensor, providing accurate data up to 44.1 PSIA. The temperature measurement circuit features a K-type thermocouple. The internal accelerometer features 2 axis measurements for a variety of mounting options.

Another key application of the AuxBox is road testing. Even a dyno doesn’t provide as much real data as road testing. Factors like air flow, side force, and load vary significantly on a real road. With an AuxBox, a user can log 6 channels, in multiple sessions, for up to 44 minutes. Then, back at the garage, simply connect the LM-1 to you PC and view all of you log data. Use LogWorks to view fuel mapping, perform statistical analysis, overlay graphs, and playback a log on the virtual gauges. You can also view realtime data on LogWorks’ gauges if you want to take your laptop on the road.

The AuxBox also includes 5 external inputs for connecting external sensors in lieu of the internal sensors. This allows users to log data from external sensors like TPS or suspension data. Each input can also be configured with additional thermocouples, allowing multiple EGT channels.

The AuxBox ships with mounting hardware, a 6’ thermocouple wire, the LM-1 connecting cable, and the user manual.

SPECIAL OFFER: For existing LM-1 owners, we are offerring a limited-time offer. Enter coupon code "LM1VIP" (as in, LM-1 V.I.P. ) to get special pricing of $229. (This offer will end as soon as we've shipped the first production run of 500 units, or on Sept. 30, whichever comes first. This newsletter goes to more than 4000 existing LM-1 customers who've signed up on the mailing list, so get yours now if you want in on the special offer. After the introduction, the AuxBox will be $249.) Click here to buy now.


Digital Display Product Update

The Innovate XD-1 dash-mountable Digital Display is in the final stages of testing, and will be released this quarter. The entire gauge will be a mere .550” thick, so it will be possible to mount even in surface mount configurations. The display will feature a 3 character LED display, "Record" button, and a programmable digital needle. The body is a billet aluminum bezel. It will be available in a variety of color combinations, and is targeted to retail for $189, pending final product release.

LM-1 in Modified Magazine, Chevy Rumble, Muscle Machines, and more

The LM-1 has been receiving quite a bit of positive press recently. This year to date a partial list of magazines featuring the LM-1 includes Car Craft, Modified, Chevy Rumble, Circle Track, Import Tuner, Hemmings’ Muscle Machines, Muscle Car Enthusiast, Performance Business, Performance Racing Industry, High Performance Pontiac, and Family and Performance Boating. Check the site in a few weeks for links to, or reprints of, most of these informative technical articles:

Tuning Tip: When to Perform a Heater Calibration

The LM-1 has two calibrations- one for the sensor heater and one for free air. In general, it’s only necessary to calibrate the sensor heater the first time you use a new sensor, while the free air calibration is required more frequently. Free air calibration will correct for: 1) A change in atmospheric pressure (i.e. going from sea level to 6,000 ft. above for a race); or 2) Sensor wear (i.e. regular use for hundreds of hours).

Heater calibration detects and stores the impedance characteristics of a new sensor. Generally these characteristics don’t change with wear, however some forms of carbonization can impact the impedance of the sensor. The most common problematic carbonization comes from the use of leaded gas. If you see an error #4 (Pump cell circuit open) after using the LM-1 with leaded gas, you probably need to perform a heater recalibration. If you use LM-1 regularly with race gas, we recommend keeping a backup sensor in your tool box, and performing heater recalibrations more frequently.

To clear the heater calibration data, simply connect the LM-1 to 12V and power it on for 10 seconds without the sensor connected. Then turn it off, connect the sensor and power up again. The LM-1 detects the sensor as new and performs a full heater calibration. Of course don’t calibrate the heater with the sensor in very hot exhaust or in an overheated state.

Application Note: You CAN be too Rich
By Klaus Allmendinger, VP of Engineering, Innovate Motorsports

Many people with turbochargers believe that they need to run at very rich mixtures. The theory is that the excess fuel cools the intake charge and therefore reduces the probability of knock. It does work in reducing knock, but not because of charge cooling. The following little article shows why.

First let’s look at the science. Specific heat is the amount of energy required to raise 1 kg of material by one degree K (Kelvin, same as Celsius but with 0 point at absolute zero). Different materials have different specific heats. The energy is measured in kJ or kilojoules:

Air ~ 1 kJ/( kg * deg K)
Gasoline 2.02 kJ/( kg * deg K)
Water 4.18 kJ/( kg * deg K)
Ethanol 2.43 kJ/( kg * deg K)
Methanol 2.51 kJ/( kg * deg K)

Fuel and other liquids also have what's called latent heat. This is the heat energy required to vaporize 1 kg of the liquid. The fuel in an internal combustion engine has to be vaporized and mixed thoroughly with the incoming air to produce power. Liquid gasoline does not burn. The energy to vaporize the fuel comes partially from the incoming air, cooling it. The latent heat energy required is actually much larger than the specific heat. That the energy comes from the incoming air can be easily seen on older carbureted cars, where frost can actually form on the intake manifold from the cooling of the charge.

The latent heat values of different liquids are shown here:

Gasoline 350 kJ/kg
Water 2256 kJ/kg
Ethanol 904 kJ/kg
Methanol 1109 kJ/kg
Most engines produce maximum power (with optimized ignition timing) at an air-fuel-ratio between 12 and 13. Let's assume the optimum is in the middle at 12.5. This means that for every kg of air, 0.08 kg of fuel is mixed in and vaporized. The vaporization of the fuel extracts 28 kJ of energy from the air charge. If the mixture has an air-fuel-ratio of 11 instead, the vaporization extracts 31.8 kJ instead. A difference of 3.8 kJ. Because air has a specific heat of about 1 kJ/kg*deg K, the air charge is only 3.8 C (or K) degrees cooler for the rich mixture compared to the optimum power mixture. This small difference has very little effect on knock or power output.

If instead of the richer mixture about 10% (by mass) of water would be injected in the intake charge (0.008 kg Water/kg air), the high latent heat of the water would cool the charge by 18 degrees, about 4 times the cooling effect of the richer mixture. The added fuel for the rich mixture can't burn because there is just not enough oxygen available. So it does not matter if fuel or water is added.

So where does the knock suppression of richer mixtures come from?

If the mixture gets ignited by the spark, a flame front spreads out from the spark plug. This burning mixture increases the pressure and temperature in the cylinder. At some time in the process the pressures and temperatures peak. The speed of the flame front is dependent on mixture density and AFR. A richer or leaner AFR than about 12-13 AFR burns slower. A denser mixture burns faster.

So with a turbo under boost the mixture density raises and results in a faster burning mixture. The closer the peak pressure is to TDC, the higher that peak pressure is, resulting in a high knock probability. Also there is less leverage on the crankshaft for the pressure to produce torque, and, therefore, less power.

Richening up the mixture results in a slower burn, moving the pressure peak later where there is more leverage, hence more torque. Also the pressure peak is lower at a later crank angle and the knock probability is reduced. The same effect can be achieved with an optimum power mixture and more ignition retard.

Optimum mix with “later” ignition can produce more power because more energy is released from the combustion of gasoline. Here’s why: When hydrocarbons like gasoline combust, the burn process actually happens in multiple stages. First the gasoline molecules are broken up into hydrogen and carbon. The hydrogen combines with oxygen from the air to form H2O (water) and the carbon molecules form CO. This process happens very fast at the front edge of the flame front. The second stage converts CO to CO2. This process is relatively slow and requires water molecules (from the first stage) for completion. If there is no more oxygen available (most of it consumed in the first stage), the second stage can't happen. But about 2/3 of the energy released from the burning of the carbon is released in the second stage. Therefore a richer mixture releases less energy, lowering peak pressures and temperatures, and produces less power. A secondary side effect is of course also a lowering of knock probability. It's like closing the throttle a little. A typical engine does not knock when running on part throttle because less energy and therefore lower pressures and temperatures are in the cylinder.

This is why running overly-rich mixtures can not only increase fuel consumption, but also cost power.

Until next time... Keep On Tuning!

-Innovate Motorsports

 

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