Background
As many of us know, the Hyper is not the smoothest bike around town. While it doesn't affect everyone, there are a large number of riders that complain of "lean surging", "stumbling", "sputtering", and other issues, particularly at slow speeds and through traffic. This is an issue that plagues many modern motorcycles as manufacturers try to make them pass emissions regulations by giving less and less fuel. It's not uncommon for a new bike to have complaints of being hard to maintain a steady speed, and having a very sensitive throttle at very small throttle openings.
I hope this is not too basic, but I would like to explain the whole story for those not totally familiar. The acronym "AFR" means Air-Fuel-Ratio, and describes the ratio of air to fuel (duh) in the cylinder during combustion. There are particular ratios that work best with certain engine configurations, but basic chemistry also plays a role.
Here's an informative graph:
Based on lots of research, I've found that an AFR somewhere in the 13:0-14:0 range is a good balance between fuel economy, engine smoothness, power, and longevity. In order to achieve this, you have a couple options.
-Modify the fuel map in the ECU
-Add a piggyback fuel module to change fuel injector durations
In its most basic form, a fuel map is a grid of fuel injector "on" durations with columns representing the throttle body position and rows representing an RPM. So, for every engine operating condition, the computer knows how much fuel to dump in. There are many other parameters that affect the duration, including air temperature, manifold pressure, engine temperature, etc.
Of course, in order to know how the fuel map should be changed, you need to know how the engine is working! Thus, we use an O2 sensor, which tells us the AFR directly. Our bikes are equipped with what they call a "narrowband" O2 sensor, which is simply an on/off switch used for determining whether the engine is at 14.7 AFR or not (for emissions). But that's all they're good for. So we must use a "wideband" O2 sensor, which can accurately tell us the AFR all the way from 9 to 21 (21 being pure air with no fuel, since air is about 20.9% oxygen at sea level).
So, you have two main ways of collecting this AFR data from the engine...
-On a dyno
-On the street/track
The dyno is a very controlled, steady state machine. This is very good for most things. However, dyno sessions cost $, and you must go to a special shop to get your bike tuned.
And now, the point of this thread.
The second option is to use a Data Logger to collect AFR data while you ride on the street or track. This way, you get all the real-world engine behavior with all the air-cooling and dynamic effects you see while riding! It also gives you a lot of insight into how you ride too. It's pretty eye-opening, to me at least.
I installed a Zeitronix ZT-2 data logger on my Hyper last year and only recently logged some data from a couple rides. I am logging the following basic parameters:
-AFR
-RPM
-Throttle Body Position (TPS)
-Throttle Grip Position
Here's my setup:
Front cylinder with O2 sensor
Rear cylinder O2 sensor port
The next step was crunching the data. After about an hour of riding, I had over 150,000 rows of data
So with the power of Excel and some thorough data filtering, I was able to look exclusively at the useful parts of the ride - steady state and acceleration.
The goal here was to create a correction "map", which tells me where to add or subtract fuel duration percentage. Quite simple really. Here's what I found!
Just looking at the front cylinder log...
This graph shows me where I spend the most time riding. As you can see, MOST of the riding takes place at 2 and 5 percent throttle, between 2800 and 4800RPM. I was blown away by how little throttle opening it takes to get most places. The throttle is rarely open 100% - in fact it only opens to 100% by about 7500RPM, even if you open the throttle all the way.
*Note, the 2% TPS column includes all data from 2 to 5%. The 5% column includes all data from 5 to 10%, etc.
Next, the measured AFR can be seen in this chart. Notice something interesting...? Those same areas that I spend most of the time riding, are also some of the most lean. Huh.
Finally, when factoring in the data sample quantity and all the filters, I arrive at the correction map.
and for the rear cylinder.
My conclusions....
1. Many people focus on high RPM, high throttle opening riding conditions. The truth is that during street riding, you spend a LOT of time at low throttle openings, and just going from one place to another. This ride wasn't exactly lazy, so I was surprised to see this.
2. The front and rear cylinders behave very differently. The rear cylinder runs richer than the front, both to provide extra cooling for the cylinder, but also because it runs hotter as it's not exposed directly to the cool rushing air.
3. The factory RapidBike map my bike was supplied with, as well as the "auto tune" corrections, were going in the wrong direction, often removing up to 10% or more fuel at the high RPM. I am not sure why this is. Every motorcycle is different. Every environment is different. There's just so much that goes into it. Here is the included RB map, for comparison: http://i.imgur.com/91SseLE.jpg
*Notice also how the map is fully populated for example, in the 95% TPS column, from 2500 to 7300RPM. How can that be, when the throttle body physically does not open to 95%+ until 7500RPM? Again, they must have their reasons, but I don't know them. The Power Commander map is also populated from 5750 to 7500RPM. Any ideas?
4. Another thing about the RB map. The starting correction TPS is 5. But as you can see from my log, a huge percentage of the riding occurs between 2 and <5 TPS. I believe the reason they do this is to account for different TPS voltage ranges on different bikes, and to avoid adding fuel at closed throttle conditions. With proper calibration, and a 2% TPS starting column, it should really change the way the bike rides.
Phew... I hope this was interesting, and informative! I have always wanted to learn how to do this, and the hyper seemed like a perfect candidate. It turned into a good learning experience. An entirely different, and powerful aspect of engine tuning is ignition timing. Unfortunately I don't yet have the knowledge to start changing this, so it's an entire subject I didn't touch on. Feel free to ask questions or provide input.
Oh, I still have yet to actually ride it with the new map. I will get to that this weekend. I know my data is good, but it's possible my Excel filters could use work.
As many of us know, the Hyper is not the smoothest bike around town. While it doesn't affect everyone, there are a large number of riders that complain of "lean surging", "stumbling", "sputtering", and other issues, particularly at slow speeds and through traffic. This is an issue that plagues many modern motorcycles as manufacturers try to make them pass emissions regulations by giving less and less fuel. It's not uncommon for a new bike to have complaints of being hard to maintain a steady speed, and having a very sensitive throttle at very small throttle openings.
I hope this is not too basic, but I would like to explain the whole story for those not totally familiar. The acronym "AFR" means Air-Fuel-Ratio, and describes the ratio of air to fuel (duh) in the cylinder during combustion. There are particular ratios that work best with certain engine configurations, but basic chemistry also plays a role.
Here's an informative graph:
Based on lots of research, I've found that an AFR somewhere in the 13:0-14:0 range is a good balance between fuel economy, engine smoothness, power, and longevity. In order to achieve this, you have a couple options.
-Modify the fuel map in the ECU
-Add a piggyback fuel module to change fuel injector durations
In its most basic form, a fuel map is a grid of fuel injector "on" durations with columns representing the throttle body position and rows representing an RPM. So, for every engine operating condition, the computer knows how much fuel to dump in. There are many other parameters that affect the duration, including air temperature, manifold pressure, engine temperature, etc.
Of course, in order to know how the fuel map should be changed, you need to know how the engine is working! Thus, we use an O2 sensor, which tells us the AFR directly. Our bikes are equipped with what they call a "narrowband" O2 sensor, which is simply an on/off switch used for determining whether the engine is at 14.7 AFR or not (for emissions). But that's all they're good for. So we must use a "wideband" O2 sensor, which can accurately tell us the AFR all the way from 9 to 21 (21 being pure air with no fuel, since air is about 20.9% oxygen at sea level).
So, you have two main ways of collecting this AFR data from the engine...
-On a dyno
-On the street/track
The dyno is a very controlled, steady state machine. This is very good for most things. However, dyno sessions cost $, and you must go to a special shop to get your bike tuned.
And now, the point of this thread.
The second option is to use a Data Logger to collect AFR data while you ride on the street or track. This way, you get all the real-world engine behavior with all the air-cooling and dynamic effects you see while riding! It also gives you a lot of insight into how you ride too. It's pretty eye-opening, to me at least.
I installed a Zeitronix ZT-2 data logger on my Hyper last year and only recently logged some data from a couple rides. I am logging the following basic parameters:
-AFR
-RPM
-Throttle Body Position (TPS)
-Throttle Grip Position
Here's my setup:
Front cylinder with O2 sensor
Rear cylinder O2 sensor port
The next step was crunching the data. After about an hour of riding, I had over 150,000 rows of data
So with the power of Excel and some thorough data filtering, I was able to look exclusively at the useful parts of the ride - steady state and acceleration.The goal here was to create a correction "map", which tells me where to add or subtract fuel duration percentage. Quite simple really. Here's what I found!
Just looking at the front cylinder log...
This graph shows me where I spend the most time riding. As you can see, MOST of the riding takes place at 2 and 5 percent throttle, between 2800 and 4800RPM. I was blown away by how little throttle opening it takes to get most places. The throttle is rarely open 100% - in fact it only opens to 100% by about 7500RPM, even if you open the throttle all the way.
*Note, the 2% TPS column includes all data from 2 to 5%. The 5% column includes all data from 5 to 10%, etc.
Next, the measured AFR can be seen in this chart. Notice something interesting...? Those same areas that I spend most of the time riding, are also some of the most lean. Huh.
Finally, when factoring in the data sample quantity and all the filters, I arrive at the correction map.
and for the rear cylinder.
My conclusions....
1. Many people focus on high RPM, high throttle opening riding conditions. The truth is that during street riding, you spend a LOT of time at low throttle openings, and just going from one place to another. This ride wasn't exactly lazy, so I was surprised to see this.
2. The front and rear cylinders behave very differently. The rear cylinder runs richer than the front, both to provide extra cooling for the cylinder, but also because it runs hotter as it's not exposed directly to the cool rushing air.
3. The factory RapidBike map my bike was supplied with, as well as the "auto tune" corrections, were going in the wrong direction, often removing up to 10% or more fuel at the high RPM.
I am not sure why this is. Every motorcycle is different. Every environment is different. There's just so much that goes into it. Here is the included RB map, for comparison: http://i.imgur.com/91SseLE.jpg*Notice also how the map is fully populated for example, in the 95% TPS column, from 2500 to 7300RPM. How can that be, when the throttle body physically does not open to 95%+ until 7500RPM?
Again, they must have their reasons, but I don't know them. The Power Commander map is also populated from 5750 to 7500RPM. Any ideas?4. Another thing about the RB map. The starting correction TPS is 5. But as you can see from my log, a huge percentage of the riding occurs between 2 and <5 TPS. I believe the reason they do this is to account for different TPS voltage ranges on different bikes, and to avoid adding fuel at closed throttle conditions. With proper calibration, and a 2% TPS starting column, it should really change the way the bike rides.
Phew... I hope this was interesting, and informative! I have always wanted to learn how to do this, and the hyper seemed like a perfect candidate. It turned into a good learning experience. An entirely different, and powerful aspect of engine tuning is ignition timing. Unfortunately I don't yet have the knowledge to start changing this, so it's an entire subject I didn't touch on. Feel free to ask questions or provide input.
Oh, I still have yet to actually ride it with the new map. I will get to that this weekend. I know my data is good, but it's possible my Excel filters could use work.
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