| I have seen more than two dozen MINES ECUs and can draw one single conclusion: THEY ARE ONLY INTENDED FOR HIGH-OCTANE 110+ LEADED FUEL USE. These programs were developed during the time when there was no ethanol in the fuel - only MTBE as a percentage additive similar to that of the ethanol they are using today. Most of today's commercially available vehicles can run on blends of E10, a blend of 10 percent ethanol and 80 percent gasoline, or lower. E10 is the most common low concentration blend. Many areas of the country mandate its use as a replacement for MTBE. MTBE is made primarily from natural gas or petroleum products. It has been used in U.S. gasoline at low levels since 1979 to replace lead as an octane enhancer, helping to prevent engine "knocking." Since 1992, MTBE has been used at higher concentrations to fulfill the oxygenate requirements required by the Clean Air Act Amendments of 1990 (CAA). Oxygen helps gasoline burn more completely, reducing harmful tailpipe emissions from motor vehicles. The CAA required regions with poor air quality (nonattainment) to use gasoline reformulated with an oxygenate. Most refiners chose MTBE over other oxygenates for financial reasons and for its blending characteristics. After MTBE was proven to be a carcinogenic groundwater pollutant, many states banned MTBE, which accelerated the use of ethanol as the only economically feasible fuel additive for states with air quality problems. The Energy Policy Act of 2005 further accelerated the demise of MTBE in that gasoline marketers were no longer required to use an oxygenate, but they also did not receive the MTBE liability protection that they had petitioned for. This put refiners at a liability risk if they continued to use MTBE after an oxygenate was no longer required by law. Predictably, the demand for ethanol increased at unprecedented rates as most refiners replaced MTBE with ethanol. Even though refiners were not obligated to use an oxygenate after May 6, 2006, most of them switched from MTBE to ethanol primarily for these reasons: There still exists EPA emissions control requirements. Adding oxygen to gasoline allows for more complete combustion of the fuel, which reduces exhaust emissions of CO (carbon monoxide), which can result in lower levels of toxic, ozone-forming pollutants and greenhouse gases, especially if higher-level ethanol blends are used.
Ethanol has the advantages of MTBE without the same dangers, and it contains 35 percent oxygen by weight, twice the oxygen content of MTBE. Ethanol is the highest-octane fuel in the market. Because it doesn't leave gummy deposits, it helps to keep the vehicle's fuel system clean for optimal performance.
Ethanol extends gasoline supplies. Because its production is encouraged by a federal tax credit of 51 cents per gallon, ethanol is economically attractive. Without this credit, it would not be as competitive. So going directly to the differences, chemically speaking, between MTBE and ethanol enriched fuel, we are already seeing leaner mixtures when using fuels available at the pump today when the engine is run in heavily loaded open-loop conditions (where the ECU is no longer taking air/fuel measurements from the O2 sensors and using such information to more accurately control fuel flow). In short, one aspect of the MINES programs, the fuel delivery parameters while in open loop, will cause the engine to operate with air/fuel mixtures that are catastrophically lean. Going one step further: The ignition timing parameters in the MINES programs will require an octane rating of at least 100 octane as per the more intensive "MON" testing conditions. Adding more to this, there are other variables in the system that play a vital role in determining the the headroom of safety such programming found within the MINES ECUs has to offer. Inadequate intercooling will result in charge air temperatures that exceed the detonation threshold of a given fuel octane. You can get away with lower octane fuel for longer durations of time under a fully loaded engine state when you have ample intercooling in place. With lesser intercooling available, you may be able to push the same limits as the former example in terms of boost, but will not be able to maintain those levels for as long before detonation occurs. Because MINES programming came around a decade ago and was clearly intended for high-octane fuel applications only, I would strongly recommend you against using that product in your Z. Your best bet is to purchase a chip/program that caters specifically to your modifications and available fuel octane to start and then validate the tune using a wideband O2 system. From there, if the cookie-cutter program needs refinement you can either purchase the hardware/software to tune it yourself or find a competent tuner to do it for you.
Enthusiasts soon understand each other. --W. Irving.
Are you an enthusiast? If you are out to describe the truth, leave elegance to the
tailor.
Albert Einstein
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