TXCatfish

I just picked up a Altronics performaire handheld weather station. What do you guys look at to predict your e.t.? It does have an et predictor but if I can learn what to look for I would like to try and predict the weather on my own. I found this on biondo's racing site.

Gas vehicle (1/4 mile)
1. Density altitude +150 (+.01)
2. Barometer +.10 (-.01)
3. Humidity +18-20% (+.01)
4. Water Gains - If this goes up same time humidity goes up, there will be more et loss.
5. Wind - Usually 1-2.


I also read it is more important to watch "corrected altitude" and not density altitude. Not sure how true that is, this handheld does not have corrected altitude.

Taxman20

iTrader: (11)

We have used them for years and they work. You just need to make a pass, enter your ET as quick as you can so the DA is as close as it was to when you ran. Make sure to keep it out of the sun too. Then just go off the ET it gives you. The more you enter your ET the better it gets at its prediction because it learns, sort of. The things you need to look at on your own is wind speed and track temp. But DA is really all you need to worry about. We dialed our dragsters to .005 in the 1/4. So if mine was predicted at a 7.658 I would dial a 7.65 and run it out. If it showed a 7.652 I would either dial the same 7.65 and watch the other lane to maybe drag the brake at the trap or drop to a 7.64 if the wind changed in my favor or the track temp dropped a little for a better 60'.

TXCatfish

That's what I may end up doing but I was wonering if anyone uses a formula to predict there own ET. I'm gonna try what I posted above from Biondo's website and see how close it is.

Just trying to come up with a 2nd prediction other then the handheld but also want to learn on my own just in case I have to go off someone elses weather station.

JL ws-6

iTrader: (50)

Taxman has it right. If you're making no changes to the car or tuneup and you do exactly what he said you will be able to get really close once you have some runs entered into it.

If you can get someone at the opposite end of the track at the booth to grab your slip and put it in as you're pulling off the track, even better. That's what the bracket guys I know do, wife/pitcrew stops golf cart at booth and picks up test slips as they finish the run and input it then go get the car, fwiw.

TXCatfish

Thanks.

Taxman20

iTrader: (11)

Yep, we did that too. Getting the slip asap and entering it. The hard part is when you get the prediction for your dial and then you sit in the staging lanes for 20 minutes, things can change. Was the sun on the track on your last pass and now its clouded up some? Has the wind changed? Lots of things can happen. If you have a buddy with you, take the weather station with you, keep it in the shade and see what it says right before you enter the water box. You then just worry about what you see yourself, wind, sun ect. Also if your parked on the grass, it can make a difference too. At some big races, that's the only place to park, if this happens just keep it at the trailer. It will be hotter I the lanes due to the asphalt, so it might lie to you thinking its gotten hotter.

As for predicting on your own, some guys do it but it takes a ton of time to figure out. The station just makes it easier. You can make it as complicated as you want to though. LOL We just used the station and concentrated on killing the tree.