Air and E.T.'s

This is well known to most who race, but I thought I'd bring it up anyway.

I read a lot of posts about e.t. improvements after changing the combo.

As most do, only one modification at time can be evaluated.

Here's what I'd like to point out (to those who may not have considered it): That one change you make must be tested several times (different days) because of the difference temperature, humidity and barometric pressure can make. A weather station makes this easier, but you have to race a lot to become familiar with how to evaluate the info it gives.
This is mostly for small changes. Several small improvements make for a well sorted combo that runs "right".

My own personal experience comes from a Stock Eliminator car that varied roughly .25 of a second, just based on the weather.
I also bracket raced a completely stock '72 340 Demon that ran between 14.75 and 15.25 the one full season I raced it. I made zero changes to it. The weather ranged from cool, dry, high pressure spring time air to 95* plus temps, high humidity summer air.

-Just wanted to provide some food for thought.