Boost Control using Max Wastegate Duty #
#17
Originally Posted by heyzeus11
Has anyone been using these maps to control their boost? Does anyone know when anyone of the specific Max Wastegate Duty maps are used; is it based on load, or what gear your in?
I dont think that is good to set WGDUTY =F( LOAD,RPM) because it is similar to use WGDUTY= F( Manifold Pressure ,RPM) .
In the system with significant lag we cannot controll Pressure watching Pressure - the system will oscillate and will allways overboost cause the overboost is the signal to increase WG and decrease boost. The aftermarket boost controllers like apexi use gear dependent WGDUTY (RPM) table . The drawback of this metod that it works unstable when weather changes- in cold weather it overboosts if the tables made on hot weather.
But i have a huge boost gaudge and somtimes watching it - if its getting cold and i see overboost I reflash the ecu
#18
Arma, you may be able to put FF in the flash, but that doesn't mean that it will give any more duty at the solenoid than C7 if you see what I mean. Having run a known solenoid at C7 it gave so much overboost I am pretty sure it was on 100% actual duty at the solenoid as it hit 32 PSI. Also I don't think it just adds or subtracts based on error as that is proportional control only and would give boost offsets. If it is an integral correction (with a proportional gain as well) then that would fit better with the way most boost control systems work and how this appears to work in practice. But we're all learning!
#20
Originally Posted by jcsbanks
Arma, you may be able to put FF in the flash, but that doesn't mean that it will give any more duty at the solenoid than C7 if you see what I mean. Having run a known solenoid at C7 it gave so much overboost I am pretty sure it was on 100% actual duty at the solenoid as it hit 32 PSI. Also I don't think it just adds or subtracts based on error as that is proportional control only and would give boost offsets. If it is an integral correction (with a proportional gain as well) then that would fit better with the way most boost control systems work and how this appears to work in practice. But we're all learning!
Max value in the wastegate duty map is 127.5 not 100.
Try it.
Last edited by Armagedon; Aug 29, 2006 at 10:28 AM.
#21
Thanks. I will look into the code and experiment some more.
Mine may be different as I have dual solenoids on the JDM/UK model.
If &HFF in the wastegate tables does give a higher duty then we should get ECUflash updated as it shows as wastegate duty.
Mine may be different as I have dual solenoids on the JDM/UK model.
If &HFF in the wastegate tables does give a higher duty then we should get ECUflash updated as it shows as wastegate duty.
#22
You are welcome.
On every evo 8 i tune, i am using a total duty (Duty map + max correction value)
between 105-115 to have about 21-22 psi. Depending of the WGA setting of eatch car. (Without any restrictor pill near the solleno)
On every evo 8 i tune, i am using a total duty (Duty map + max correction value)
between 105-115 to have about 21-22 psi. Depending of the WGA setting of eatch car. (Without any restrictor pill near the solleno)
#23
Armagedon, you have PM re WG duty. A leading Evo Ecutek mapper has told me that it maxes out at 100, but whilst I find references to the equivalent of 100 in the flash, I don't see it limiting it, but there is a lot of code in other places that could limit it.
#24
It's strange for two reasons :
First the max possible duty value in Ecuflash is 127.5 not 100.
Second our turbo error boost (turbo correction map) on euro model has a max correction value of +27.5.
Maybe it's coincidence, maybe not... I ll test it more on my next tune.
Arma.
First the max possible duty value in Ecuflash is 127.5 not 100.
Second our turbo error boost (turbo correction map) on euro model has a max correction value of +27.5.
Maybe it's coincidence, maybe not... I ll test it more on my next tune.
Arma.
#25
The correction map can go to 63.5 unless your scaling is different. The WGduty scaling in ECUflash has a maximum of 100 if you edit the definition, although ECUflash only seems to use the max and min to allow correct display of fonts rather than limit what you can enter. That is only limted by the actual byte or word value and its scaling.
Additionally, the code shows the new wastegate duty being a modification of the old one (from correction map) and limited to maximum. It doesn't show maximum+correction map.
I need to get a voltmeter on the output to the solenoid, but I don't have my car available at present to test.
Additionally, the code shows the new wastegate duty being a modification of the old one (from correction map) and limited to maximum. It doesn't show maximum+correction map.
I need to get a voltmeter on the output to the solenoid, but I don't have my car available at present to test.
Last edited by jcsbanks; Sep 4, 2006 at 09:48 AM.
#28
I have a scope, but the voltmeter will do it as well in DC mode. Just divide the voltage you read by the battery voltage. Since the frequency of the duty cycle is considerably faster than my 3Hz DVM it will be fine. Done it many times before.
#30
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Originally Posted by jcsbanks
I have a scope, but the voltmeter will do it as well in DC mode. Just divide the voltage you read by the battery voltage. Since the frequency of the duty cycle is considerably faster than my 3Hz DVM it will be fine. Done it many times before.