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About ashesman

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    Past Link Engineer

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  1. Hi Andy, Thanks for taking the time to look into that. I managed to reproduce the same thing and was very surprised to find that result! I have added an item to the firmware issues list but can not give any answer as to exactly when this issue will be resolved and tested. Sorry for the inconvenience.
  2. Hi Andy, Final ignition interpolation is to 0.1 degrees. While some tables may only allow entry of 0.5 degree steps, they are interpolated between cells to 0.1 degree internal numbers that are used for final ignition calculation. If you know of any tables that are not interpolated correctly then please let us know.
  3. ashesman

    MAF usage

    As previously mentioned, MAF support is limited. The reason for this is that while MAF is a very good indication of engine air flow and hence fuel required, it requires its own complex modelling, often engine and intake system specific. The MAF reading is accurate at steady state but less accurate under transient due to manifold and intake track volumes. It is possible to get a very accurate and repeatable tune without using a MAF sensor. Many modern vehicles do not use MAF sensors any more and almost no aftermarket installations do. My opinion is that you will get a better tune from a MAP based install than a MAF install on our ECUs and most other aftermarket brands. While they may support MAF sensor just as we do, check they offer all the correct modelling and compensations to get a reasonable tune first before buying other wise you may end up switching to MAP in the long run. The use of a permanently fitted oxygen sensor will be required to get a good tune for minor variations whether using MAF or MAP so ultimately the engine will probably end up running the same AFR but at least with MAP there is good transient performance. Good injector characterisation is essential especially if you plan to use large aftermarket injectors, this can make or break having a big injector engine that can also idle and cruise nicely.
  4. OK. Here are some answers to some of the issues raised on these posts: Injection timing can be set to use a single number for all RPM/load or a 3D table. If you want to use a 2D table, then using the axis setup form (press X while on the injection timing table), set the Y axis to None. 1 - Cal Tables 7-10. According to our testing logs these work correctly but I have added your comments to have them checked again. 2 - Short PW adder table axis is set to match the pulse width numbers provided with most injector characteristics (GM style). They have reasonably high resolution so should be adequate for most application. I have added a feature request for configurable axis. 3 - The Injector deadtime table can be either a 2D table or 3D table. Select under Fuel->Fuel Setup->Injector Setup->Injector Setup 4 - Can you please give examples so we can reproduce and find this problem. 5 - I will have the help guys look into this and see what is going on. 7 - Good suggestion, added to the feature request list. 8 - You can switch between modelled and modelled-multi fuel modes at will. We recommend tuning on just modelled mode first (just fuel table 1), then switching multi fuel on to enable both tables. 9 - Unfortunately for now there is no intention to add these buttons, in fact they are to be removed from Link software as well soon in favour of more screen space. I will note that you would prefer to keep these buttons. Regards Ashley
  5. The idea of the air temperature sensor is to help determine the temperature (and hence density) of the air charge entering the engine. So, if the manifold is heat soaked then the air entering the cylinder will be significantly heated by the manifold itself and so much less dense. The sensor does not get "heat soaked". It is the manifold that gets hot and heats the air inside it. It is entirely up to you where you place the sensor. If you do not want compensation when the manifold is heating the air temperature above that before the throttle plate, then place the sensor before the throttle plate. You will however notice that all OEM installs place the sensor in the manifold. The fuel equation (both modelled and traditional with charge temp estimation turned on) adjusts the air density exactly as per the ideal gas law. There is nothing stopping you carrying on with doing things exactly as you have in the past. The traditional fuel mode can be used to tune as per older firmware. In traditional mode charge temp estimation can be turned off and the IAT table is applied as a simple percentage correction.
  6. Generally it is considered desirable to have a constant manifold pressure. A constant manifold gauge pressure would suggest less cylinder filling pressure at higher altitudes. Whereas a constant absolute pressure implies there is a constant cylinder filling pressure as altitude increases. If boost target was based on MGP: If you have 200 kPa gauge pressure boost, then at low altitude (100kPa baro) you would have 300kPa cylinder filling pressure. If you had the same boost at 70 kPa baro then you would only have 270kPa cylinder filling pressure. This is overly simplistic and ignores all other dynamic effect, but in general would cause significantly reduced power at high altitude.
  7. Here are a few things: - The CAN Id is correct 1000 (0x3E8) - The CAN Id is NOT extended - The data is sent in frames of 8 bytes. - The first byte (byte 0) indicates what data is in the frames. Â This is what is referred to as the compound Id. Â When byte 0 is zero then it indicates the frame contains RPM, MAP, MGP. Â When byte 0 is 1 the frame contains BAP, TP, Injector Duty Cycle - The multiplexer field specifies the compound Id. Â While technically it is 1 byte long, how you have it set up should be OK as byte 1 is always zero. Â Besides the extended box being checked, everything looks correct to me in your picture. - Some CAN setups change the byte numbering when you go from little to big endian. Â Eg a two byte variable at byte 0 in big endian would start at byte 1 when little endian. Are you able to receive anything? Â Or is the data just erratic?
  8. Ethrottle Signal 1 is the PWM control Ethrottle Signal 2 is the Direction control These signals together form a PWM control for an external H bridge driver. Â When Direction is low, PWM is pulsed high with short duty cycle to open the throttle a little and high duty cycle to open it further. Â When Direction is high, PWM is pulsed low for short duty cycle to close the throttle a little and high duty cycle to close it further. Â The Link ethrottle module provides the high power H bridge required to drive the motor. Â The ECUs control signals directly control this driver. Â The module also includes a power switch to disconnect power to the driver in case of faults. Â This is controlled by the ECUs ethrottle relay signal. An external driver module could be used if it can work with these signals. Â However, this is not supported or recommended and may compromise the safety systems. Regards Ashley
  9. Hi Steve, I have added an item to our todo list to change all 5 Bar calibrations to 7 Bar. The reason they say 5 Bar as that the original sensor they matched up with was sold as 5 Bar even though it could measure up to 7 Bar. I have also got someone to look into the Aux 9/10 supply warning. Someone will be in touch soon regarding testing once the FW is ready to go. Cheers Ashley
  10. Hi Steve, We are currently in the internal testing phase of firmware version 5.1.0. The next phase, due to start in the coming weeks is external testing. The release date is not set yet. This is not a "full re-write", just an update with many bug fixes and some new features. If there is a particular issue you are interested in seeing if is resolved then let us know and we can confirm if it is in this update. If you would like to help in the external testing program, then contact tech@vi-pec.com and put your name down. As for the analog inputs having their own calibration each, this is on the feature request list but definitely not part of the next release. I thought we had cleared up that 5/7 bar thing. If you could let us know where it is still a problem then we will tidy it up. Regards Ashley
  11. Hi Jeremy, While this sounds like a useful suggestion, there is a slight technicality for most users: Do you know the actual delay from the exhaust port to the sensor plus the response time of the sensor and controller, plus the filtering of the analog input signal? Â Without this exact information, you would be risking making your tuning information less accurate by entering in an incorrect delay. Â Furthermore, this response time varies depending on the average exhaust velocity (ie engine RPM/load) and also on the rate of change of AFR. On a high quality wideband controller located close to the exhaust under high flow conditions, it is usually considered to have a response time that nears the typical sample rates used for AFR measurement (eg 20 to 50 Hz). Regards Ashley
  12. The problem here is that you are sending (in very quick succession) two frames with the same CAN ID. So the dash receives one with the light on, then one with it off, but the other light on etc... You need to put everything you wish to transmit on one particular CAN ID into a single frame so that the dash periodically receives only one CAN frame containing the state of all of its inputs. When trying to replicate OEM can modes, you will never (actually very rarely) have a stream with more than one frame in it. Multi-frame streams are only used by aftermarket devices such as loggers.
  13. The exact fuel equation in full detail is proprietary. However, it is not overly complex and is based on the ideal gas law http://en.wikipedia.org/wiki/Ideal_gas_law. Nearly all aftermarket ECUs use the same or a very similar fuel equation. It takes into consideration all of the measurements available to the ECU in the absence of a Mass Air Flow meter. No after market ECUs fully model the engine as OEM ECUs do as this process is extremely complex and not practical from a tuners point of view. OEMs spend millions characterising one engine exactly and mathematically (and empirically) model it in their ECUs. A good understanding of the exact maths f injector pulse width calculation is not critical for a tuner but a firm understanding of the requirements to change fuel delivered with the changes in measured variables is extremely useful. A good understanding of injector characterisation and the effects of incorrect injector information is also very important. Andre's course would be very valuable if you have not been exposed to the ideal gas law and exactly how injector pulse width can be estimated from it taking all the factors into consideration. Andre offers two courses, one on basic tuning and one on using PCLink software. The tuning one is what you want.
  14. For a fully scychronised (sequential injected) engine, the injectors are fired once per two crank revolutions (ie once per intake stroke). Â So the frequency is RPM dependent. Â Injector Frequency (Hz) = RPM / 120. The injector pulse width and duty cycle is determined by the size of the injector you use and the amount of fuel required. I would recommend using a GP PWM function on an aux output for your aquamist or looking into the ECUs Auxiliary Injection function.
  15. The ViPEC ECU uses a full speed density calculation with the exception of intake temperature. The master fuel setting takes into consideration the factors for engine displacement, injector size, equations constants and so on. The fuel table is the VE number in the equation. MAP is the pressure used in the equation. The open loop AFR target table is used as the lambda element in the equation. If you do the maths you will find that it is not necessary to completely calculate and display the calculated air mass to determine the injector pulse width exactly. The same result can be achieved. However, the next release of firmware for iXX ECUs will include a charge temperature correction option to also consider an estimated port temperature in the fuel equation. A full non linear injector characterisation will aso be included in this firmware. If you are having trouble getting stable AFR on a day to day basis, the problem may be your setup or tune and may be able to be resolved easily.
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