Disclaimer: This article is a note after studying Hondata turbo pressure control and some related knowledge. As a non-vehicle engineering related person, some of the article content may be incorrect and are for reference only.
The turbo brush program to improve power is nothing more than a few adjustment points: increase the turbo pressure, optimize (such as enriching) the air-fuel ratio and change the ignition advance angle (to make the advance angle more radical). The failure situations of the three adjustments are: turbo burnout ( or engine scuffing), cylinder flooding, and detonation leading to blown cylinders.
> Image source: https://club.autohome.com.cn/bbs/thread/d31338b49d4a8da5/94001521-1.html
The general turbo pressure is the focus of many people’s adjustment, because as long as it is adjusted within a relatively safe range, it is relatively controllable, and different turbo pressure curves can make the vehicle have completely different power generation methods, that is, it can be achieved. A sentence on the front page of “Nova Kwok’s Civic FK7 Car Modification Notes”: “It is definitely more meaningful to grow up with the car than to spend money without brains to follow the trend.” By adjusting the ECU, you can make the car look like you like more Drive in style.
On Hondata’s Calibrations page, we can see a lot of basic programs such as +3psi, +6psi high octane to choose from, here is what people call “+3 and +6 public version programs”.
Through the Compare function provided by Hondata software, we can find that for the original factory, +3, +6 and +9 programs, the air-fuel ratio and ignition advance angle do not change at all. The only variable here is actually the turbo pressure curve, which is accurate For example, there is only “TC maximum pressure ratio” (please ignore the other diffs except for the first two lines, this seems to be a bug of Hondata, although there is a difference in the display, but the actual opening is the same)
In the Hondata program, the control of the turbo is under Boost Control, and there are the following 6 tables that can be adjusted, namely:
- TC maximum pressure ratio (actual request turbine pressure gauge)
- TC max boost(IAT) (IAT based turbo pressure limitation)
- TC max boost(PA) (turbo pressure limitation based on atmospheric pressure)
- TC boost command (temporarily unknown)
- Boost by gear limit (Turbo pressure limit based on gear)
- Knock air limit (turbo pressure limit based on intake air volume)
Only the first one is the control of the actual turbine pressure that is expected to be achieved. The following max boost (IAT) and the like are used to limit the turbine not to exceed a limit pressure (to prevent damage to the turbine) in some cases. Boost by gear limit can be defined to limit the maximum turbo pressure in different gears, for example, the 1st gear at start can limit a certain turbo pressure to reduce slipping.
Here we focus on TC maximum pressure ratio, which is the turbo pressure in many people’s ears. What are the so-called “Civic constant pressure 1.0Bar, instantaneous pressure 1.1Bar”?
TC maximum pressure ratio
In this TC maximum pressure ratio table, we need to interpret the data in this way, for example, the original turbine pressure curve is as follows:
We can see that the abscissa is PA (atmospheric pressure), and the ordinate is RPM (engine speed). In the area I selected, since the top PA is 1.0, the numbers in each column are exactly the same (I don’t understand why here Hondata makes so many columns for the same PA).
From this table, we can know that for program calibration, if you are in a coastal city, then your PA will be 1, and your set turbo pressure will be executed in the columns on the right where PA is 1. If you are in some Cities with higher altitudes, then your turbo pressure will be in some columns on the left, the higher the altitude, the lower your overall turbo pressure will be.
Assuming you are in Shanghai, then your original factory program turbo pressure calibration is:
| TC maximum pressure ratio |
|---|
| 1.118 |
| 1.164 |
| … |
| 2.02 |
| 2.122 |
| 1.968 |
| 1.843 |
| 1.712 |
It can be seen that the peak pressure is 2.122 Bar at 5500RPM, and after subtracting one atmospheric pressure, it is 1.122 Bar (maybe it is the “instantaneous pressure 1.1Bar” posted on the Internet (then what is “constant pressure 1.0Bar”?)
Ok, now that you have understood what the turbo pressure curve is, let’s take a look at the original factory, +6psi and +9psi turbo pressure curves~
Original turbo pressure curve:
+6psi Turbo Pressure Curve:
+9psi Turbo Pressure Curve:
Do you feel the contrast is very clear? We can see that the original factory curve starts from around 1500 RPM, and the turbo quickly starts to pressurize, and then increases steadily all the way to 5500 RPM, reaching the highest pressure of 1.12Bar, which is also in line with the original Civic’s smooth driving experience despite showing full pressure .
At the same time, refer to the rated power on the manual: 130kW@5500RPM, can you understand it at once?
When it comes to +6psi, it can be found that there is a plateau between 1550 RPM and 2550 RPM, the pressure remains at 0.4Bar, and then it surges to 1.1Bar, and reaches a peak of 1.375Bar at 5550 RPM.
For +9psi, there is a platform similar to +6psi, with a maximum pressure of 1.686Bar, but here the maximum pressure is reached at 5000RPM, and then the pressure begins to drop.
turbo pressure control
Now that we know the above table, we need to understand how the turbo pressure is controlled, we can see the following picture:
> Image source: https://www.researchgate.net/figure/A-schematic-of-a-turbocharging-system_fig8_260878177
There is a thing called Wastegate on the exhaust side of the engine (the Chinese name may be wastegate valve, commonly known as “la pot”). The opening and closing of the bypass valve and the degree of opening can be determined by the computer. How much of the exhaust gas is used to blow the turbine, and how much of the exhaust gas is directly exhausted.
The opening and closing of the valve is controlled by vacuum. The principle is that when the preset air pressure is reached in the intake manifold, the vacuum valve opens the bypass valve on the Turbine side to release pressure, or maintain the manifold pressure. The so-called “boost value” is the instantaneous maximum air pressure (instantaneous pressure) in the intake manifold and the air pressure (constant pressure) at constant work. The so-called turbine intervention speed, from the pressure of the intake manifold, is from The moment the negative pressure turns to positive pressure, it is called “bar”.
——The second thing about the turbo: wastegate valve (Honda)
Let’s take Civic as an example. Let’s first define that the computer-controlled pressure is called BP CMD (Boost Pressure Command), the actual turbo pressure is called BP (Boost Pressure), the bypass valve is WG (Wastegate), and the computer-controlled bypass valve is WGCMD (Wastegate Command), let’s look at a piece of Log data:
This data is a moment when I sprint at full throttle in 3rd gear (TPedal is always at 91%). When the speed reaches the red line, it can be seen that the turbo pressure is gradually increasing as the speed rises. At 5000RPM, BP and BPCMD reached the maximum value of 20psi, and then the turbo pressure began to drop. The reason for the turbo pressure drop is that WGCMD controls WG to become larger, and the bypass valve gradually allows more exhaust gas not to pass through the turbo, so that the turbo can be controlled in the computer. The design pressure is within (not overpressure).
If you want to know more about the turbo, maybe you can look at the third thing about the turbo: about the intake of the turbo system , mainly about the intake pipeline, air filter (style), turbo pressure related knowledge (webpage Mirror: https://archive.ph/EcHuE)
turbo pressure adjustment
With the above knowledge, we may come to a conclusion: I wrote the turbo pressure greatly! Then I can fly!
really.
The guidance here is this:
Second-tier riders who don’t know much about it often ignore this item, thinking that it is better to increase the turbo pressure. But in fact, high turbo pressure means high intake resistance, not high pressure necessarily means high horsepower. To give a simple example, for the TD025 turbine used by the original factory, there may be a difference of 20 horsepower between 1.1bar and 1.3bar, but there may be a difference of 5 horsepower between 1.6bar and 1.8bar, because the turbine flow has reached the bottleneck, continue to increase the pressure and You can’t push more air into the combustion, but because the pressure is too high, the turbine is easy to break. And if you change to an enlarged turbo, you can achieve the same maximum horsepower value with a smaller turbo pressure.
Tenth Generation Civic Pit Avoidance Modification Tutorial! Tier 3 car owner written in blood and tears! (Technical Post) ( https://club.autohome.com.cn/bbs/thread/d31338b49d4a8da5/94001521-1.html)
So my personal adjustment suggestion here is: if you are now a +6psi public program and want to make some additional adjustments, copy the last column of TC maximum pressure ratio of +9psi to the last column of +6psi, so that you can Get an extra curve to use as a reference, like this:
At this time, the purple line on the top is the line of the +9psi public version program, followed by the line of the +6psi public version program. With the top line as a reference, you can properly adjust the curve of the penultimate column, according to Adjust according to personal driving habits and desired full pressure point. Note that the adjusted overall curve style should be similar to the upper and lower lines. After adjustment, just cover all the columns with PA 1 with the adjusted column, and then drive while driving Record the data and see if your set turbo pressure is being reached correctly.
Statement again: This article is a note after studying Hondata turbo pressure control and some related knowledge. As a non-vehicle engineering related person, some of the article content may not be correct and is for reference only.
turbo pressure limit
Finally let’s look at some of the turbo pressure limitations mentioned above
- TC max boost(IAT) (IAT based turbo pressure limitation)
- TC max boost(PA) (turbo pressure limitation based on atmospheric pressure)
- TC boost command (temporarily unknown)
- Boost by gear limit (Turbo pressure limit based on gear)
- Knock air limit (turbo pressure limit based on intake air volume)
Taking the +6psi public version program as an example, these charts are as follows:
TC max boost(IAT) (turbo pressure limitation based on IAT):
TC max boost(PA) (turbo pressure limitation based on atmospheric pressure):
TC boost command (temporarily unknown):
Boost by gear limit (Turbo pressure limit based on gear):
Knock air limit (turbo pressure limit based on intake air volume)
The above tables are mainly some restrictions. For example, for different PA, intake air temperature, etc., it can reduce the turbo overpressure caused by exceeding certain preset limits after TC Max Pressure is reached, but the limits here are generally very high. , will not hit, but it can still be used as a clue for troubleshooting (for example, when a certain turbo pressure is set but it is found that it cannot be reached anyway).
Happy Lunar New Year
This article was written on New Year’s Eve, a night alone, with Hondadata Datalog as a companion.
Happy Chinese New Year 2023 to everyone!
References
- The third thing about the turbo: about the intake of the turbo system , mainly about the intake pipeline, air filter (style), and turbo pressure (webpage mirror: https://archive.ph/EcHuE)
- Tenth Generation Civic Pit Avoidance Modification Tutorial! Tier 3 car owner written in blood and tears! (technical stickers)
This article is transferred from https://nova.moe/hondata-turbo/
This site is only for collection, and the copyright belongs to the original author.