88gtman

If I were to get a street tune on a hot summer day when the temp is 96+ would this cause my tune to be way off when the winter rolls around and the temp is down in the 30's. or will the computer compensate for the change in weather to keep the tune spot on?

SSpdDmon

iTrader: (10)

Warmer IAT's tend to lean out the air/fuel mixture whereas richer mixtures come with cooler IAT's. At least, that's what I've observed over the years.

If you're tuned to run in closed loop, it will pull fuel at cruise when winter rolls around. However, it's likely that WOT will be rich. The only way around that is to tune the car so that you have some positive fuel trims (i.e. ~+5%).

NoGo

iTrader: (2)

The tune swings around a bunch anyways - different gears, different loads, sensor deviation, engine temp, etc....

The small drift due to weather is just noise. As long as your IAT is plugged in and not simulated then you should be fine.

ramairJP

iTrader: (3)

I agree with above. A MAF based tune should tolerate the temp swings better, but CLSD still isn't bad. From hot to cold I richen up about .3-.4 points AFR at WOT, but all closed loop cells stay trimmed to stoich. If you run LTFTs (I don't) it would probably be a touch better. I like the response of SD tuning, so I just load a cold, mid, or hot weather tune based on the time of year. One tune will do the job as long as it's not tuned right on the ragged edge, though.

KRAZY K 2000 TA

iTrader: (5)

i have learned never to tune in the morning only in the afterenoon on my drive to and from work. or there is a +-5 to 6 error