| mazdamaniac |
07-15-2008 02:42 PM |
Installation Video:
AccessPORT Installation Video
Basic information on the Cobb AccessPORT can be read here: Cobb AccessPORT for the RX-8
The Cobb sub-forum for the AccessPORT for the RX-8 is here: CobbTuning RX-8 Forum
The "Quick Start" guide can be downloaded here: AccessPORT Getting Started
Some information culled from the older thread:
Quote:
The OE PCM uses a combination of MAF, BARO, IAT, ECT and APP/TDC to come up with a numerical value that represents the load on the engine at any given moment.
This number is then used as an axis on all the fueling and ignition tables, referenced against RPM. (Different subsets of tables are selected as a reference to vehicle speed as well.)
There is a pre-programmed limit on this number that the PCM expects to see. If you exceed this limit, a default value is locked in.
All of the OE tables run out at the pre-programmed limit.
In an FI application, we can expect to see significantly more of this "calculated load" than in an NA setup. Therefore, we extend the limits, lengthen the tables and come up with appropriate A/F targets for these new load limits.
Then, everything is rescaled to utilize this new load range in such a way that it is incorporated seamlessly into the regular load range.
Of course, as you can probably imagine, the relationship between load and manifold pressure isn't linear - or even regular - so deciding what is and isn't boost is a bit of a trick since the target A/Fs for these two "ranges" are significantly different.
Then there are the complications of accommodating the variety of intakes (which FUBAR the MAF), injector sizes (which change the scaling) and the little detail of altitude.
In a normally aspirated setup, the OE PCM does some interesting things with the BARO. In a boosted application, this has to be handled a bit differently.
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Quote:
Short Term Fuel Trim - STFT - is instantaneous correction value determined from wide-band oxygen sensor readings compared to the mass airflow sensor (MAF). Under closed-loop conditions it should cycle fairly rapidly around the 0 percent correction value and is only functional during closed loop operation. When the STFT exceeds plus or minus 10 percent for too long, the Long Term Fuel Trim - LTFT - begins shifting, changing the injector duration to bring the STFT back within the plus or minus 10 percent range. Short term trim can vary as much as plus or minus 20 percent, but the above correction mechanism works to keep it within plus or minus 10 percent.
Long Term Fuel Trim - LTFT - is a learned value over time which changes gradually in response to conditions such as fuel oxygen content, engine wear, air leaks, variation in fuel pressure, altitude and net STFT. LTFT data is stored in the PCM and is not erased even when the engine is shut down. This LTFT information is used under all engine operating conditions.
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All MazdaManiac calibrations for the AccessPORT include the following characteristics:
- Increased idle speed (830 RPM typical - up to 1100 for the Pettit S/C)
- Increased OMP output in all load ranges
- Lower cooling fan turn on points
- Improved low-gear throttle response
- Lean fuel targets for light throttle and cruise conditions
- Removal/cancellation of all or any emissions-related CELs
Further customization can be realized by way of increased engine redline, altered S-DAIS operation and a variety of "novelty" calibrations such as "valet" mode, "anti-theft" mode and other such single-purpose adjustments.
Performance gains are realized through "levels" of fuel and ignition recalibration, allowing for leaner naturally aspirated A/F targets with more aggressive ignition timing or increased torque limits, increased fueling and reduced ignition timing for forced induction applications.
List of CELs masked by the MazdaManiac calibrations for the AccessPORT:
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- P0030 Front HO2S heater control circuit problem
- P0031 Front HO2S heater control circuit low
- P0032 Front HO2S heater control circuit high
- P0037 Rear HO2S heater control circuit low
- P0038 Rear HO2S heater control circuit high
- P0133 Front HO2S circuit slow response
- P0138 Rear HO2S circuit high voltage
- P0139 Rear HO2S circuit slow response
- P0171 System too lean
- P0172 System too rich
- P0300 Random misfire detected
- P0301 Front rotor misfire detected
- P0302 Rear rotor misfire detected
- P0410 AIR system problem
- P0420 Catalyst system efficiency below threshold
- P0441 EVAP system incorrect purge flow
- P0442 EVAP system leak detected (small leak)
- P0443 Purge solenoid valve circuit problem
- P0446 EVAP system vent control circuit problem
- P0455 EVAP system leak detected (large leak)
- P0456 EVAP system leak detected (very small leak)
- P2096 Target A/F feedback system too lean
- P2097 Target A/F feedback system too rich
- P2195 Front HO2S signal stuck lean
- P2196 Front HO2S signal stuck rich
- P2257 AIR pump relay control circuit low
- P2258 AIR pump relay control circuit high
- P2259 AIR solenoid valve control circuit low
- P2260 AIR solenoid valve control circuit high
- P2270 Rear HO2S signal stuck lean
- P2271 Rear HO2S signal stuck rich
- P2401 EVAP system leak detection pump control circuit low
- P2402 EVAP system leak detection pump control circuit high
- P2404 EVAP system leak detection pump sense circuit range/performance problem
- P2405 EVAP system leak detection pump sense circuit low
- P2406 EVAP system leak detection pump sense circuit high
- P2407 EVAP system leak detection pump sense circuit intermittent/erratic problem
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