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Discuss all things tuning in this section. News, products, problems and results.
I believe this is the best source online to as tuning shops and people if they have calibration data. Starting with what and why on my motec m600 id like to enter the values of voltage vs temperature 2d table from the Nissan RB25det Water Temperature Sensor yet nobody has been able to help me not even Motec HQ. Anyone has that info. Kindly pass it along.
And calibration table for the HKS Map sensor 3 bar, if anyone can find for me i don't understand the PIM equation the website www.1jzmerc.com is talking about. Maybe Andre be able to to explain what should I fill in those tables, yes map sensor is from the hks fcon vpro but I will use it on the Motec all wires are already crimped and boy are those terminals ever cheap?
And I have put the dwell time for my nismo high impedence 740cc injectors but there is a wierd thing in motec ecu manager where it asks the injector scalling JPU, i have clearly no idea what that is i didnt touch the value. And there is a thing injector peak current( AMPS) and peak hold ratio (Amps) too. Motec told me to send the injectors to them thru a dealer and I am guessing it will take all the time in the world. Or, should I go through with it?
high impedance injectors = saturated injectors
peak and hold strategy should be used ONLY with low impedance injectors.
I don't know how Motec deal with saturated injectors on their setup.
Maybe you could find some guidance by pressing "F1" .
Injector scaling (IJPU) refer to the "base opening time" of you injectors.
100% VE on the fuel map = IJPU (+ corrections)
If the motec M600 is limited to VE between 0 and 100%, I would start with 10ms
if it can go above 100% VE, I would recommend a value of 4ms
The Mx00 series of ECU's are not VE based, they use a pulse width (ms) fuel map, the IJPU is specifying the maximum time that the injector will be open for, and how that value relates to the Fuel Map, i.e. an IJPU of 10ms, and a value of 50 in the fuel map will have the injector opening for the 5ms, if you increase the IJPU to 15, without changing the fuel map, then the injector opening time will be 7.5ms, once the Injector Battery Comp values have been taken into account. The reason that you cannot just use a random value for the Battery comp is that, especially at low duty cycle values, the ECU will be trying to inject a calculated pulse width of fuel, but if the Battery Comp value is wrong, it may not inject any fuel, or to much.
Saturated injectors are dealt with through the Injector Current settings, if the value is set to 0, then the Mx00 runs the injectors as saturated.
The usual turnaround time for injector calibrations is 2 weeks.
From the Mx00 ECU Manager software help file for IJPU.
The Base Injector Pulse Width is calculated by multiplying the number from
the Fuel Table (as a percentage) by the IJPU setup parameter.
eg. If IJPU = 20 msec and the Fuel Table No = 50 %
then the Base Injector Pulse Width will be 10 msec
for that RPM / Eff Site.
Typical Values : Normally Aspirated : 15 to 20 msec
Turbo Charged : 10 to 15 msec
NOTE : Turbo charged engines require lower IJPU values because the end
injector pulse width is increased due to air density compensation.
i.e. at 200kPa manifold pressure the base injector pulse width will
be doubled due to the increase in air density.
If the maximum value in the Fuel Table falls below 60 then the IJPU setup
parameter should be decreased to increase the Table numbers. This ensures
that the Fuel Table has sufficiently fine resolution.
IJPU may also be used to compensate for changes in injector flow rate due
to a change in injector type or fuel pressure. This allows the Main Fuel
Table to remain unchanged.
Some users may prefer the table values to represent the pulse width in
msec. In this case use an IJPU of 10msec. The table values will then
represent msec x 10, i.e. 100.0 = 10.00 msec.
When IJPU is changed the Fuel MAIN Table may be modified to compensate for
the change in IJPU without effecting the tuning.
To the Question "Interpolate Fuel Table to correspond to change in IJPU ?"
Answer YES - if IJPU was changed to increase or decrease the table numbers
without effecting the tuning.
Answer NO - if IJPU was changed to allow for changes in Injector flow
rate OR IJPU was changed for initial Setup.
The engine being an RB25DET with 740cc/min injectors, on a modern VE ECU like I said earlier you would use 3.8ms as a "base".
(416.5cc/cylinders, to fill it you need 500mg of air/cycle, with a standard ratio of 14.7:1 that's 34mg of fuel, converted in cc that's 0.0466 -> 740cc/min divided by 0.0466 = 1/15880min or 3.78ms)
Now if you use 15.2ms as a "base" instead of 3.8ms, that's 4x more.
If you had 100% on the fuel map ("true" VE), now you would have to use 25%.
Doesn't that sound JUST like the IJPU to you ?
Sure the IJPU doesn't represent the "real" VE of the engine (it work like a "scaled down" version), but it work exactly the same way !
In a true PW type ECU (like Pectel) you DON'T have any ratio, you enter the opening time directly in ms in the fuel map.
I'll add my 2c to the conversation and hopefully remove a little confusion.
@Ludo, a true VE based ECU such as the Motec M1 or Link G4+ using the modelled fuel equation doesn't have an IJPU or base or master injector pulse width. The VE fuel model relies on the ECU knowing what mass of fuel will be delivered for a given pulse width. If it knows this and it knows what mass of air is entering the engine and your desired AFR target it can calculate the required pulse width to achieve the target.
A base or master pulsewidth (IJPU in Motec speak) is an aspect of a millisecond based fuel table such as the Mx00, Link G4/ViPEC using traditional fuel equation and many more.
@Falah the key with selecting the IJPU is to provide adequate resolution in the fuel table. If the IJPU number is too large, you may find your maximum table values only reach perhaps 30-40. What this means is that we lose resolution when we make changes to the table values. For instance when the peak value is say 40 and we make a change of 0.5 then that change represents a 1.25% change in our fuel delivery which is quite large. If on the other hand our peak value in the fuel table was 80, then this same change represents a 0.6% when we make a change in our fuel delivery. This allows us to make finer changes to the air fuel ratio and achieve a more precise tune.
The key here is that with the engine tuned correctly we want to see the maximum numbers in the fuel table reaching somewhere around 80-90% to give us good resolution. Motec make it nice and easy to make changes to the IJPU without affecting the tuning so you can dial in the IJPU to achieve the right resolution as you go. While it was filmed using the Link G4 platform, we did run a webinar on this that you may find beneficial. You can find it here - https://www.hpacademy.com/previous-webinars/fuel-table-resolution/
Duly noted, thanks for the webinar .
One more thing I didnt understand about the ecu manager and it is about the injectors, where the help file says "if you have used cc/min or 0.01 for gallon/ minute or injector flow rate." but i see no menus where these can be changed, are they referring to use the amount in the mathematical model while filling for a item called "Fuel Used Cal"?
Initially I set it to 740 as i was assuming its asking about injector sizes, but after i see they have given a formula i started wondering what kind of setting does this ecu recognize at the moment? and there is no way of checking that kind of data.
here, i am attaching these screenshots just to tell me more, sorry guys hate to suck the life out of you.