Intake Air temperature compensation.

[JDG Gt4]

Hello All,

 

I'm just wondering what setup you guys use for the intake air temp compensation? do any of you use it? The default file for my car doesn't but I want to implement it.

 

It does however have a default graph that takes out -7 degrees BTDC timing once it reads over 80 degrees C increasing to -12 degrees BTDC at 110 Degrees C and then it is flat from there.

 

Does this setup work for all cars, or is this something that needs to be road or dyno "tunned".

 

cheers

Ben

[ktm]

Each car is different. I am using the intake air temperature modifiers for fuel and timing. I drop timing when IAT's hit 48 *C up to a maximum of -4 degrees at 60 *C. My fuel is modified using a linear relationship; +5% at -64 *C to -10% at 190 *C.

 

It would be difficult to dyno tune IAT compensation since it is typically only experienced at the "extremes".

[JDG Gt4]

Each car is different. I am using the intake air temperature modifiers for fuel and timing. I drop timing when IAT's hit 48 *C up to a maximum of -4 degrees at 60 *C. My fuel is modified using a linear relationship; +5% at -64 *C to -10% at 190 *C.

 

It would be difficult to dyno tune IAT compensation since it is typically only experienced at the "extremes".

 

Your setup is more what I would have been expecting. It seemed strange to an uneducated mind that you would wait till such temps before pulling a large amount of ignition timing.

 

Is there a guide somewhere I could read on how to set this up? or is it more by experience of on road performance? listening for knock, and noting the temp and correspondingly dropping the timing?

 

This is probably a hard question to answer but any help would be appreciated

[HowlerMonkey]

Edited out useless drivel that diverged from the topic.

[ktm]

I picked temperatures that were just on the hot side of normal operating temperatures. IAT's have less of an impact than engine temperature on detonation. I am also modifying fuel and timing based on engine temperature.

 

For instance, I've logged my IAT (before methanol injection) and recorded a faily consistent 40/42 *C during pulls. I start to pull timing at 48 *C. This was with engine temps at the time around 80 *C (normal operating temps). Now, I could have high IATs and high engine temps, and would be modifying my fuel and timing with both. Some supercharged applications run from 65 *C up to 87 *C when heat soaked. I selected a value that was conservatively low, but outside of the normal operating temperature.

 

Once my engine temps get over 90 *C, I start to pull timing. This is because the entire engine is now "hot". The cylinder head is quite hot and the cooling system is working overtime.

[JDG Gt4]

I assume that is with a 80 degress thermostat?

 

I like the methodical thinking with the IAT setup. I suppose it would have been handy to know the IAT when it wasit all dyno tuned, because this wold obviously been the point to start taking timing out once it exceeded that.

 

cheers it all makes a lot of sense.