Weather stations
 

I have a question for experienced sportsman racers and bracket racers. In your experience, how well does your weather station predict your performance?

Re: Weather stations
 

I have an old TAG hand held that hits mind very close unless it is very humid. Doesn't allow enough for high humidity.

Re: Weather stations
 

I do not claim to be very experienced, but I use crew chief pro software and a Altronics PC weather station. For example, the last race I attended we had a cross wind and tail wind. The prediction was dead on what the car ran.

Sean

Re: Weather stations
 

There are some that work pretty well and I surely can't imagine going to the track without one, particularly if you make a change to your car.

Re: Weather stations
 

I have an older performaire. I have a 25 run data base programmed in it. I do not add or subtract runs. I track +- on the prediction. Then base my dial in against the prediction. Its like any other tool in your tool box. It takes some practice to get used to using it. Wind and crazy swings in weather can make it difficult to come up with a good prediction.

Re: Weather stations
 

It also depends on which way you are tuned for AFR.

Re: Weather stations
 

Cad, please elaborate on what you mean by "Tuned for AFR"!

Re: Weather stations
 

I don't mean to intrude, but I imagine that he's referring to the fact that if you run your car on the "rich" side, that you would tend to pick up a bit more in very good conditions and fall-off a bit more when the air is real bad. On the other hand, if you run on the "lean" side, your car won't vary as much.

Re: Weather stations
 

What he said...

Re: Weather stations
 

That is the way I read it but I just wanted to make sure. This highlights the need to find the A/F ratio that YOUR engine runs best at, not what your buddy or what the forum said is the best! If you find that optimum A/F ratio for your engine, and you do whatever you have to maintain that A/F ratio as conditions change, your performance should only move with the changes in air density, which should make your weather station a more reliable predictor of performance.
Interestingly enough, the factors that the weather stations use as far as air density are the exact same factors (and the same math) that a true speed density EFI system uses.