fuel compensation tables

In the EFI fundamentals you say over and over how standard temp is 15C or 59F... here you say it's 20C or 68F ?? which is it??

what temp are you referring to?

(edit) no answer? - ok - lemme expand on that:

air intake temp at the sensor, in the engine bay or ambient or on a turbo - pre or post intercooler?

when your tuning your car - you should aim to do the tuning when the air temp your measuring has stabalised

its not worth trying to start tuning when your air temp is "cool" and gains more heat while your tuning as your map will be well screwed when your done

when someone says "standard temp" what they actually mean is - for the thing your tuning, what is the stable temp you have normally when the engine and engine bay and intake are fully up to normal operating temps.

some cars have efficient cold air intakes - and the "standard temp" would be closer to ambient than say something that has a pod filter under a bonnet and has much higher ambient temps in the engine bay available to draw air from.

once you have tuned your car at that stable temp - then you can fill in your air temp correction table to keep the target you have tuned to no matter what the air intake temp ends up being.

Hi Kevin,

There are a couple of different Standard Conditions that are used depending on the reference conditions and the standards being used, here is some information on the most commonly used ones.

https://en.wikipedia.org/wiki/Standard_sea-level_conditions

https://en.wikipedia.org/wiki/Standard_temperature_and_pressure

https://en.wikipedia.org/wiki/Standard_state

I bow before the superior knowledge from Stephen :) Thank you! now I understand more as well - cheers! (adds to reading list)

Back to you Kevin - with the comments from Stephen above - I hope your able to find out what you were asking about and those temps you were asking about make more sense now :)

Hi Lawrence,

I cheated a bit, I used to work here in the physical metrology lab where temperature management was critical to getting the correct measurements, so I had to be aware of all of the different standards being used.