AFR Test Results - SharkTuned Shark
03-22-2006, 06:36 PM
#17
Under the Lift
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Lifetime Rennlist
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Good information, Cameron and John. I have had a RRFPR since installing the X-pipe. We had some erratic mixture results on the dyno after the install and never got very good tuning. I think the fuel pressure it too high at idle. I'd rather go back to the 85-6 regulator and tune it as Cameron has done.
12-16-2006, 03:39 PM
#18
Drifting
How do you know if your MAF will still compensate for other ambient air temperatures? I just see your remapping might be off at some other air temperature.
Is this what the SuperMAF is all about? With more air flow per the same engine speed, are you getting outside the MAF's range of air flow?
Is this what the SuperMAF is all about? With more air flow per the same engine speed, are you getting outside the MAF's range of air flow?
12-16-2006, 05:19 PM
#19
Rennlist Member
The airflow range of the MAF isn't the problem. The MAF will continue to give a progressively higher output voltage versus air mass at levels well in excess of any practical boost level.
The problem is that when the output voltage of the MAF is greater than about 5.5v the stock LH ECU reaches its maximum input level and won't register higher values.
However, you can't just fit a resistive attenuator between MAF and LH ECU because the ECU will decide that the lower than standard voilts at idle mean that the MAF is faulty, and the ECU will go into limp home mode.
The SuperMAF gives a stock voltage output at idle load values, but then remaps the upper values so that even at very high boost the voltage into the LH ECU does not exceed its limit.
There are specially modified fuel maps in the Sharktuner that allow you to use the SuperMAF.
Running into MAF input limiting at the top end of boost will mean that changes in air density and/or air temp will not be accurately mapped anymore. In Cameron's case the "compression" of values was minimal.
The problem is that when the output voltage of the MAF is greater than about 5.5v the stock LH ECU reaches its maximum input level and won't register higher values.
However, you can't just fit a resistive attenuator between MAF and LH ECU because the ECU will decide that the lower than standard voilts at idle mean that the MAF is faulty, and the ECU will go into limp home mode.
The SuperMAF gives a stock voltage output at idle load values, but then remaps the upper values so that even at very high boost the voltage into the LH ECU does not exceed its limit.
There are specially modified fuel maps in the Sharktuner that allow you to use the SuperMAF.
Running into MAF input limiting at the top end of boost will mean that changes in air density and/or air temp will not be accurately mapped anymore. In Cameron's case the "compression" of values was minimal.