Definition of Standard Conditions

Hi,

Standard conditions in EFI Tuning Fundamentals were defined to be 15 degrees C with IAT compensation being +/- 3% for every 10 degrees C change in air temperature.

Here it is defined as 20 degrees C with IAT compensation of +/- 2.5% every 10 degrees C.

Which is correct?

Vincent

I've seen many "standard" values to correct to, and I'd suggest you use the one you're happiest working with.

For me, metrology used 20C, and that's what I'd use, but there are very good arguements for using Kelvin, or a close approximation where 20C would be 293K.

The important thing is to be consistent, perhaps using what your 'tuner' uses would be a good start point?

Hi Gord,

Thanks for responding.

My thinking is that "standard" is whatever temp that obtains when the vehicle is tuned and using IAT compensation to adjust for temp variations away from that.

However, on the other hand, if the AFR/Injector Pulse Width is first developed in a spreadsheet then using a fixed temp standard whatever it may be is a good place to start. I just wanted to know what is the accepted standard as the EFI Fundamentals course stated 15 degrees C whereas the Understanding AFR course set it at 20 degrees C.

Vincent

There are multiple standards, and then as Vincent mentioned you can also choose to make conditions present during tuning your standard, then create corrections around that point. I've seen this done with success either way, so it is a matter of preference as long as the values are appropriate.

Similar to Gord, I worked in a government Physical Metrology lab for a while, so 293.15K and 101.325kPa are my standards, this also applies to the calibrations that I do. Most Metrological work is done using these values as the standards as well (it's a lot more comfortable working in 20 degrees C than 15 degrees C!). These is differences in the Standard Condition though, depending on the industry involved.

Standard temperature and pressure