verbs

Well, I don't think you can do this 100% accuracy, but I've always wondered what my car would run in optimal track conditions. I'm up at 1500ft elevation, and always running in high heat and low barometers.

Based on weather calculations from the time of day you run your car, you can supposedly figure out "Density Altitude."

Air density is affected by the air pressure, temperature and humidity. The density of the air is reduced by decreased air pressure, increased temperatures and increased moisture. A reduction in air density reduces the engine's horsepower.

Go to this site to figure out your density altitude.

http://rshelq.home.sprynet.com/calc_da.htm

Use weather information from your timeslip, or www.weather.com to figure out weather conditions if they aren't on your timeslip.

Once you figure out what the density altitude was at the time of one of your runs, then go here to figure out what you would have run in optimal conditions at sea level.
http://www.smokemup.com/tech/NHRA_co...on_factors.cfm

This correction website tells you how to adjust your times based on altitude (not sure if you can use density altitude). You multiply your ET and mph by the adjustment factors listed. Although you maybe be at 1000ft altitude for example, hot temperatures and low barometers can make the air equal to a place with 4000 ft elevation.

For example, my best run a while back (before all my new mods) was 12.5@112.6mph. This was done at 1500ft elevation, temperature was 99 degrees fahrenheit, dewpoint was 38 degrees, and the altimeter(barometer) was at 29.59 in.

That gave me a density altitude of 4811 ft.

Now, I use the altitude correction factors to get the following:

12.5*.9406= approximaely an 11.76 ET

112.6*1.0633= approximately a 119.7 mph

So in theory at sea level in cool weather my car would have run a 11.76 @ 119.7 <img border="0" title="" alt="[Roll Eyes]" src="images/icons/rolleyes.gif" />

Now, I don't know about you guys, but that seems a bit high to me. In fact that seems way too high for me.

My car weighed 3600lbs. with me in it, I had 357rwhp and 366rwtq even with 4.10 gears. I was on drag radials and cut a 1.9 60ft.

I don't think I would have run those times at sea level, period.

Just using elevation (w/o weather conditions) as the only variable when trying to come up with a corrected ET and MPH, I would get:

12.5*.9835= 12.29 ET

112.6*1.0171= 114.5mph

So just using elevation only to correct my ET/mph, my car would have run a 12.29@114.5 at sea level in identical weather conditions. Being that it was basically 100 degrees with poor barometers, I would think that 11's would have been possible at sea level, especially come winter time. Hi 11's for a bolt-on car with no weight reduction and just drag radials rocks IMO, but I think I'm getting hyped up over nothing.

So given the situation listed above, what "could" my car have run at sea level in optimal weather conditions??? Any takers??

I guess I have to drive to Houston to find out <img border="0" title="" alt="[Sad]" src="gr_sad.gif" />

Tim98TA

iTrader: (7)

You RUN what the timeslip says you run.
Correction factors are for bench/timeslip racers.

Tim

verbs

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Tim98TA:
<strong>You RUN what the timeslip says you run.
Correction factors are for bench/timeslip racers.

Tim</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">No **** I run what the timeslip runs. <img border="0" title="" alt="[Roll Eyes]" src="images/icons/rolleyes.gif" /> But running at elevation in bad weather makes for bad comparisons with the majority of cars on this board. I even get people that tell me I'm a dyno queen because I dyno high but don't back it up with good track numbers.

Everyone says well, dyno's aren't ****, so go to the track. Well I do go to the track, and my times aren't overly impressive.

I'd like to know if my car is running what it should run at the track.

Why go to a dyno if they aren't going to correct it?? So you know what your car really does put out. I'd like to have some sort of comparison so I can compare dyno figures vs. track times to see if something isn't working right. I can't compare my times to most people on this board, so I'm looking for other ways to do so.

I'd like to know what my car is capable of given the weather most of you see in the midwest/east coast.

<small>[ May 14, 2002, 10:16 PM: Message edited by: verbs ]</small>

jfm

iTrader: (4)

This will get you close,for every 1000' subtract a tenth.

Plus 4800'= 4.8tenth reduction.That will get you to 0 or sea level.

My bench racing estimate on your 12.5 would be 12.02,high 11s at sea level.

kent

Can you drive to another track at a lower sea level? Do it at another track with good weather to boot. I love to drag race and the math does not enter my mind. I have only run at the local track only and I know within a hundred miles or so there are much better tracks, but I have never driven to another track to race. Mayble one day I will. Just my humble opinion. Hope you run a faster time. A year or so ago I didn't know the first thing about drag racing <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> , can't tune or work the computer for adjustments, but I have ran a 11.72 and I am planning on running 11.50 with suspension tunning. I hope you run some new times.

verbs

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by kent:
<strong>Can you drive to another track at a lower sea level? I hope you run some new times.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Unfortunately, the next closest tracks (with lower elevation) are about 500 miles away on the coasts of California. Phoenix has the lowest elevation tracks in Arizona, and unfortunately, the weather here is never track friendly, nor are the tracks ever prepped.

Barometers are usally 29.60-29.75 which leads to horrible density altitudes. There is a small window in the fall and winter where it will be cooler, but the barometer will still never be good.

The best density altitude I ever ran in (in Arizona) was 2100ft or so. <img border="0" title="" alt="[Sad]" src="gr_sad.gif" /> Kind of frustrating when I see a bunch of tracks in the south, east, and midwest with negative density altitudes. <img border="0" alt="[hail]" title="" src="graemlins/gr_hail.gif" />

Today for example, at the opening of the track (6pm), density altitudes will be between 4500 and 5000 ft....absolultely horrible <img border="0" title="" alt="[Sad]" src="gr_sad.gif" /> ...they won't get any better than 4000 by track closing at 11pm. <img border="0" title="" alt="[Sad]" src="gr_sad.gif" />

If I run low 12's tonite, I'll be extatic, knowing that no bolt on LS1 will come within half a second of me. I guess that is going to have to be good enough for now <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

verbs

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by jfm:
<strong>This will get you close,for every 1000' subtract a tenth.

Plus 4800'= 4.8tenth reduction.That will get you to 0 or sea level.

My bench racing estimate on your 12.5 would be 12.02,high 11s at sea level.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">That seems to be a more conservative method than the supposed "Official NHRA Correction Factors"

Have you actually tested your theory?