I really like to know what the temperature is when I am riding. Not entirely sure why other than it helps me understand how I should dress for different weather conditions on future rides. Maybe I am just weird that way but I expect a lot of others like to know also.
So I was very happy to see the S10 had a build in air temperature display. . . until I found out it just the EFI inlet air temperature.
Why is this bad?
I know from building and tuning my own EFI system on my DR-650 that the inlet air temp is always higher than the ambient temp except when the engine is dead cold. Sometimes by a lot. This is caused by two factors. Obviously the inlet air is heated by the hot engine as it comes in to the air box but this effect is small on a bike. The bigger factor is a well known effect in EFI tuning known as "manifold heat soak". As the engine heats up the manifold gets warm and the sensor is mounted in the manifold. Even though the sensor protrudes into the air stream, some heating through the sensor base is unavoidable. This is a known and understood effect and compensated for by the EFI controller. In my DIY system (Microsquirt Controller) there is a table to tune to correct it.
So how far off is it? I added this separate cheap but accurate sensor to find out. $11 at Autozone and a 20 minute install.
I made this simple bracket from thin aluminum sheet and mounted it with double stick tape.
I mounted the sensor in the right air intake away from any heat source and in the incoming air stream. I had one of these mounted on my V-Strom for over two years and 50K miles or so before it finally died.
At start with a cold engine both readouts are dead on and match the thermometer in my garage. As the engine heat up the error slowly increases. How much and how far depends on the conditions. Slow riding in traffic increases the error and steady cruise brings it back down. Unfortunately the error is all over the map! :'( From as little as 2 degrees to as much as 20 degrees. To me the most important is at steady cruise and that typically runs 5 to 7 degrees high. But i have seen it a low as 2 degrees off and as much as 9.
Still if you are not too concerned about the accuracy, subtract 6 degrees to the reading at cruise and call it good. Just understand it will be much higher if in traffic, sitting in the hot sun, or when restarting a warm motor, and so on.
I installed this cheap gauge thinking I would map out the error in my head and then always know about how much to subtract from the reading to know the actual temperature but I like the result so much I am going to keep it. It is out of the weather but it is not waterproof so it may die some time in a heavy rain but so what, the bike won't stop and for another $11 I can replace it.
::001::
John
So I was very happy to see the S10 had a build in air temperature display. . . until I found out it just the EFI inlet air temperature.
Why is this bad?
I know from building and tuning my own EFI system on my DR-650 that the inlet air temp is always higher than the ambient temp except when the engine is dead cold. Sometimes by a lot. This is caused by two factors. Obviously the inlet air is heated by the hot engine as it comes in to the air box but this effect is small on a bike. The bigger factor is a well known effect in EFI tuning known as "manifold heat soak". As the engine heats up the manifold gets warm and the sensor is mounted in the manifold. Even though the sensor protrudes into the air stream, some heating through the sensor base is unavoidable. This is a known and understood effect and compensated for by the EFI controller. In my DIY system (Microsquirt Controller) there is a table to tune to correct it.
So how far off is it? I added this separate cheap but accurate sensor to find out. $11 at Autozone and a 20 minute install.
I made this simple bracket from thin aluminum sheet and mounted it with double stick tape.
I mounted the sensor in the right air intake away from any heat source and in the incoming air stream. I had one of these mounted on my V-Strom for over two years and 50K miles or so before it finally died.
At start with a cold engine both readouts are dead on and match the thermometer in my garage. As the engine heat up the error slowly increases. How much and how far depends on the conditions. Slow riding in traffic increases the error and steady cruise brings it back down. Unfortunately the error is all over the map! :'( From as little as 2 degrees to as much as 20 degrees. To me the most important is at steady cruise and that typically runs 5 to 7 degrees high. But i have seen it a low as 2 degrees off and as much as 9.
Still if you are not too concerned about the accuracy, subtract 6 degrees to the reading at cruise and call it good. Just understand it will be much higher if in traffic, sitting in the hot sun, or when restarting a warm motor, and so on.
I installed this cheap gauge thinking I would map out the error in my head and then always know about how much to subtract from the reading to know the actual temperature but I like the result so much I am going to keep it. It is out of the weather but it is not waterproof so it may die some time in a heavy rain but so what, the bike won't stop and for another $11 I can replace it.
::001::
John
