If you power tuned your engine in warm or hot weather, you better recheck your AFRS and knock levels in cold weather.

Cold air increases air density which means even at the same boost level, the engine will injest more air.

If the Air Temp vs Injector table is not setup correctly, your AFRS might lean out.

More air + more fuel = more power and higher combustion pressures. Your optimize summer timing might be too hot for winter.

 

How true. I made the mistake of richening my boost rows when it was cold instead of working with the correction factors for Inj vs Air Temp.
Barry

 

what's the temperature difference we're talking about when u mean it will lean out as temperature drops...

if a day time 34 degrees celcius and night time 25 degrees celcius... does it make any difference based on experience ? i can do a log run.. but wanna get some theory set first.

i've been tuning myself on hot weather... where AIT is around 60 to 70 degrees.

 

I will leave it up to you to search the internet for the affect on air density by temperature. It will vary by humidity, but when you find an average base line to use, go compare that to the values in the Air Temp vs Inj table in the PFC (using the DL).

It does not make too much difference between day and night when the tempertures are seasonal stable. But from a USA summer to winter is more drastic than in Malaysia.

 

I've always wondered about that. Good to know.