got it! Really looking forward to the end result mate. Thanks for the update
Stu
Stu,
Initially when I removed the Slatted - Screen, I believed if the airflow through the Venturi and the remainder of the MAF housing were the same, this would result in a leaner AFR, than the one recorded during my Dyno run.
With the status quo, it is presumed the embedded ECU figure for the airflow through the unmetered section of the MAF represents 75% of the total airflow, the remainder;25%, being through the Venturi. This is a guess-timation, or at the very least, an assumption that the airflow inertia suffered through the Venturi is the same as that through the rest of the MAF body! But it cannot budget for any airflow inertia suffered, through the Venturi, due to the slatted screen's opposition to airflow. A factor which I maintain is non - linear.
With the removal of the slatted screen, the airflow through the Venturi and the rest of the body is much more accurately reflected wrt the embedded figure in the ECU program.
Certainly the Cat seemed to come up to temperature quicker, the idle was quieter and the throttle response sharper still. However, it all seemed a little too "Raw"; crude, is probably more accurate with the lower end being a lot less smooth.
The Petrol Chip I bought seemed; at the time of removing the Slatted - Screen, redundant. However, after more tests, I came to realize that the AFR may well have been leaned - up, but I had not accounted for the possibility of an overall increase in airflow as a result of the removal of the restriction. That seems to make sense to me, but how could I reduce the airflow, whilst maintaining the AFR at the new figure - hypothesis at the moment as this will not be confirmed until the car is back on the dyno.
It seems the Petrol - Chip is a spin off from similar devices for Turbo Diesels and Turbo-ed Petrol vehicles. But it works on the premise that one has more to work with than is actually needed due to the forced induction.
This I believed to be true of my engine, curtesy of the camshafts, the headers and the exhaust system. But it seemed insufficient other than fine - trimming, meaning I was not seeing the kind of increased control I expected. However, it is a helpful tool.
However, after the removal of the Slatted - Screen, the airflow across the MAF sensor appears to have increased, sufficiently to substantially increased its output signal at tick - over as well as across the rpm range. This increase appears to be sufficient to create a greater range over which the Chip - Tune has control of the MAF Sensor Amplifier/Bridge.
It is going to be a few more weeks of trial and error before any real conclusions can be drawn and I can return for another Dyno run. However, in my conversation with Supersprint, they stated, a car fitted with their system should not be overly noisy. Until now, the level to me did not seem particularly noisy. However, the degree of adjustment the Petrol - Chip appears to have created, seems to have reduced the sound track even further. Perhaps nearer to what Supersprint were suggesting it ought to be !!!!
The way the Petrol - Chip works is, it alters the voltage across the Temperature sensitive Wheatstone Bridge, whilst at the same time maintaining the Operational Amplifiers "Null Point/Operating Threshold".
The voltage applied to the Wheatstone Bridge is a notional 5 volts, but should be more accurately described as a "Fuel Map Derived Voltage". So, it is not a fixed value of 5 volts. It is determined by the authors of the ECU software, when they are Mapping the ECU, chosen to produce a specific AFR across the entire range of the engine and is conditional upon the factors, sensors around the engine are indicating to the ECU.
Under ideal conditions, it is suggested by the manufacturers of the Petrol - Chip, it allows for fine tuning of the engine maps, without expensive and intrusive software editing of the ECU. It can be quickly removed and the original ECU program remains in tact.
