Apexi AVCR tuning
Posted 06 June 2006 - 08:10 PM
In this guide, i will show you how to set up all the different parameters of the AVCR. From the initial boost setting through to the final start duty trimming of the boost maps.
Start up check;
Before we go into the setting up mode there is a couple of things which we must check to make sure the unit is set up correctly for the manual adjustment mode we are about to use. First off I would advise we go now and turn OFF the self learn mode for each gear. The AVCR uses a unique fuzzy logic self learning mode that can adjust the boost to prevent spikes etc. but i have found that it is very inconsistent and actually makes the car ramp up boost a LOT slower than what we can achieve by manually setting the controller.
Go into the the main menu:
Select setting A first then once we have done A go on to setting B.
Now move down the menu until we highlight the Learn-Gear mode and press the next button. Now we can go along and make sure each gear is marked with an X, it should look like the following screen shot;
This will disable the self learn for all the gears and allow us to fully customize the adjustments to achieve the fastest ramp up and most stable boost control the unit can offer.
Secondly we need to make sure that when the boost controller was installed that the purple wire from the AVCR unit was connected to the RPM signal wire from the cars main ECU. This is a must if we are going to use the RPM specific adjustments and to get an accurate measure on how the boost is sitting at certain RPM points in the monitor mode.
How to check the boost level after adjustments are made;
Now i will show you how to check your boost setting the correct way. Any adjustments made to the AVCR should be checked by using this method. This method gives you an accurate true reading of your full boost under full load. Boost should not be checked any other way in my opinion. If you have access to a dyno i would recommend this is done on the dyno but it can be done on the drag strip or another closed road.
Once you have the boost and duty set ( we will learn how to do this later in the guide ) get the car into 4th gear ( 5th gear in a 6 speed box ) at around 60km/h at a cruising pace, then go full throttle and hold it full until around redline. Monitor the boost on the AVCR or a boost gauge and see what the boost reached. If you have a passenger that can watch it more closely to check if there are any spikes etc. at a certain rpm point. This is very important when setting the start duty and RPM specific boost levels later in the guide.
I like to use the following monitor mode so i can keep an eye on boost at certain rpm points.
Each time you make an adjustment to the AVCR i would recommend checking the boost with the above method. This way you can make sure that you have made the correct adjustment and not have the car overboost later on if left unchecked.
Setting the basics up;
The initial set up requires you to go into the ETC. menu on the main menu screen. In here we can adjust the Car select, Screen brightness etc. I will leave this menu and setting up to Apexi themselves as they have covered it very well in the AVCR manual. If you do not have a copy of the manual check it out in PDF format here: 21.pdf 1.23MB 3316 downloads
Setting the initial boost setting;
Once we have the car specific settings sorted out we can start to adjust the boost nice and accurate. We will start off with the initial setting.
In this menu select either setting A or setting B to adjust either of the 2 boost maps. Setting OFF means the car will run on standard wastegate spring pressure boost. Which on a turbo such as a T28 is 7-10psi ( 0.5-0.7 bar )
Once you have selected the map you would like to adjust press the next button and we will move onto the Map A or B setting screen. Select Boost/duty #1 in the menu and press the next button. Now we can adjust the initial boost/duty level.
Highlight the Boost or Duty setting and press > to highlight the setting. Pressing the up or down button we can adjust the boost and duty cycle level accordingly. Every different engine and turbo combination will have a different duty cycle setting required to achieve the desired boost level. I would recommend starting with a setting of around 30% duty for boost levels of 0.7 bar and then going and checking the boost with the method at the start of the guide. If the boost is to low then raise the duty cycle a couple of % at a time and repeat the checking procedure. If the boost is to high and it overshoots the desired boost level then lower the duty a couple of % at a time accordingly. This may take some time to get accurate but it is a must to achieve stable boost.
Once we have this set and the boost is relatively stable we can move on to the RPM specific boost levels.
Setting the RPM specific boost levels;
First we need to set the NE points ( specific RPM points that the duty cycle can be adjusted ) I would recommend the settings as follows for use on an SR20DET engine;
For different engines you can try different settings, for the SR20DET using a T28 turbo these settings provide the most adjustment where the main boost ramp up takes place.
Once we have the NE points set we need to take the car out and do a boost level check. Making sure we monitor the boost all the way through the RPM`s to see if there is any certain point at which the boost drops off or overshoots. Take note of these points if there are any and we can move on to the setting mode, which is located in the Boost/duty setting menu by highlighting the duty cycle and pressing the next button.
Now we can go along the graph using the arrow buttons and raise or lower the boost at any points that had a spike or a dip.
Now the boost level should be very stable if not perfect across the entire RPM range. Only trouble is, this is all good but it is only for 4th gear. The car will have varying boost in every gear so this is where we come to adjusting the Start Duty.
Adjusting the start duty for each gear;
This is more of a fine tuning tool but is an important one at that. Before we go on make sure that the gear judge in the ETC menu has been set up correctly for the AVCR to determine which gear the car is in. Refer to the manual link below for the correct procedure of setting this up.
21.pdf 1.23MB 3316 downloads
First off we have to go and check the boost for each gear. We will have to do this differently now as we have 4th gear set pretty good at this stage.
I like to start off doing 1st gear and then going up through the gears as i get each one set correctly. Start off at low RPM`s ( around 1500-2000 ) in each gear and go to full throttle up to about 6000 rpm and monitor the boost closely the whole time watching for spikes or drop offs. If you find it spikes or drops off in a particular gear, simply raise or lower the duty cycle accordingly until you can smash through the gears at wide open throttle and the boost stays consistent throughout the rev range.
If the car has wheelspin trouble in 1st gear we can lower the duty cycle down for this particular gear until we eliminate wheelspin. If you love the wheelspin then great...enjoy it!!
Setting up the feedback setting;
The feedback setting is one of the last settings we need to use and is only needed if after all the above adjustments are made and boost is still a bit inconsistent and unstable. Basically the higher the feedback setting is for a particular gear, the more the AVCR will correct itself to achieve the boost setting inputted. I would not recommend a setting higher than around 6-7 as any higher than this the car can tend to feel a bit jumpy, as the AVCR will sometimes over correct itself and make itself unstable in the process.
Using the Self Learn mode
If you decide that the manual set up mode is a pain in the ass and you want to use an easier method than the self learn mode works ok, It is far from accurate most of the time but if your target boost pressure is within 5-7psi of the wastegate spring pressure it can be a good one.
To set this you will need to make sure first off that the target boost pressure is very close to the perfect or else the AVCR will not begin self learning as a safety feature. You will need to go into the set up menu for the self learn and make sure it is enabled for the gears you want to use it for.
Make sure you have a "O" in the gears you want it turned ON and an "X" in the gears you want it OFF.
Now go out and set the initial boost like described earlier in this guide, now we have to make sure we are almost spot on with our target boost, as the AVCR will not self learn if it is not within about 0.2 bar of the target boost.
Once you have this you need to do a few runs at above 85% throttle out to redline, if the AVCR see`s that the target boost pressure is close enough for safety it will begin self learning. Self learning can be seen as *** in the following screen beside duty: ( Note: when setting the duty set it at the below screen and DO NOT set any of the individual RPM duty cycle points until it has self learnt, if you do it will bring up the *** beside the duty and you will not be able to determine whether or not the AVCR is actually self learning or not. By setting the duty as a whole number like 40% in the following screen, as soon as the AVCR begins self learning it will replace the 40% with the *** if it does not do this then the boost pressure is either overshooting or not reaching the target boost setting )
Once it begins self learning it will adjust the rpm specific boost levels based on feedback from itself, much the same as we set it in manual setting mode.
That pretty much wraps it up. It is a time consuming process to set this boost controller up but it is well worth it in the end.
Any dramas feel free to shoot me a PM.
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