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j.reed

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I got in the 12's tonight please update my time. Thanks.

 

Magowin / 12.894 @ 106.90 / 1.898 60' / ATCO, NJ / 5MT / GT ltd sedan / Crucial UP, PLTek DP, K&N Typhoon, Cobb Pulley, Borla Catback, Custom Tune / 25F Humidity 82% Baro 29.57.

 

R/T ..... .488

60' ..... 1.898

330 ..... 5.378

1/8 ..... 8.254

MPH ..... 85.65

990 ..... 10.704

1/4 ..... 12.894

MPH ..... 106.90

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P.S. I went to weather underground for the parameters. Magowin are you reading those weather stats off the slip? If you are they are a joke like most tracks. Your barometer was alot better than that. Your DA was better than minus 2300ft!!!!! To give you an idea the night we ran at E-Town it was minus 1600 so at worst you had another 700ft simply awesome!!!! Probably without question the best weather anyone on this board has ever had the chance to race in.
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P.S. I went to weather underground for the parameters. Magowin are you reading those weather stats off the slip? If you are they are a joke like most tracks. Your barometer was alot better than that. Your DA was better than minus 2300ft!!!!! To give you an idea the night we ran at E-Town it was minus 1600 so at worst you had another 700ft simply awesome!!!! Probably without question the best weather anyone on this board has ever had the chance to race in.

 

I have to agree on the barometer. As I understand, E-town is at-near sea level. We are at 850-900' above sea level, and if we ever have a 29.57 barometer (it's only occasionally in the middle of the winter, the summer would never get that low), we would be in the middle of a hellacious storm!! Our normal baro is around 30.00, so I would have to suspect that a normal baro at sea level would have to be 30.10-30.20 or so with spikes up to better than 30.50-30.60 (a 30.50 day here is quite rare).

Ron
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P.S. I went to weather underground for the parameters. Magowin are you reading those weather stats off the slip? If you are they are a joke like most tracks. Your barometer was alot better than that. Your DA was better than minus 2300ft!!!!! To give you an idea the night we ran at E-Town it was minus 1600 so at worst you had another 700ft simply awesome!!!! Probably without question the best weather anyone on this board has ever had the chance to race in.

 

Yeah thats what was on the time slip I have no idea what it means but figured I'd include it anyway.

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Dont get me wrong we can see 29.XX barometer days here at sea level. As stated it's in stormy weather though. The weather stations at most tracks are always FUBAR. weatherunderground.com is a great site to get all the weather hour by hour anywhere in the US. I also have a DA calculater site to plug the numbers into. NICE JOB!!!!!
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Keep in mind that reported barometer readings are at sea-level equivalent altitude: the reading is adjusted for altitude so that we can compare pressures at different altitudes in terms of weather patterns (low or high pressure). Which is why the baro reading in denver is currently 29.5, although the pressure is much lower (around 24). This may be why track baro readings are "off" -- they would use absolute pressure.
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Keep in mind that reported barometer readings are at sea-level equivalent altitude: the reading is adjusted for altitude so that we can compare pressures at different altitudes in terms of weather patterns (low or high pressure). Which is why the baro reading in denver is currently 29.5, although the pressure is much lower (around 24). This may be why track baro readings are "off" -- they would use absolute pressure.

 

Not sure that I understand your post. Yes, baro readings are "adjusted" (so to speak) to sea level (the weight of a 1 square inch column of air), but baro readings at sea level will directly correspond to a reading up in the mountains on a given day & time.

 

By this I mean that, assuming there is a common weather pattern that covers much of the USA, sea level could have a 30.50 reading, and a 3,000' level may have a 29.50 reading (purely an example pulled out of my you-know-where).

 

IMHO, this is where the NHRA alttude correction factors can be invalid. If you have a high baro day at a high altitude like a 30.00, and a low baro day at sea level at the same 30.00 (disregarding temp and humidity for this hypothetical example), you are basically running under the "same" conditions, and the correction factors don't come into play.

 

I agree that the Density Altitude (DA) calcs can correct some of this, but there seems to even be some discrepancis in DA calcs.

 

For myself, after tracking many runs on various cars that I have owned and run at the strip, I still basically go be the temperature as my primary determinate.

 

FWIW, here is one (of many) explanations that Google will produce:

 

http://www.coscosci.com/barometric/barometer.htm

Ron
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I use a barometer (in my case, a backpacking weather station thingy) to determine uncorrected barometric pressure. Combine this with temperature in the following formula:

 

Relative Air Density = (uncorr. bar. pressure x 1754)/(temp F + 460)

 

This will give you a percentage related to the standard (100%) sea level conditions of 59 deg F and 29.92 uncorrected barometric pressure. If you use this method to figure out your AD, and use that to determine the relative altitude you're operating at, you can use the NHRA correction factors, and come up with relatively accurate estimates. Remember that turbos use a different correction than NA cars.

 

The important thing is to use UNCORRECTED barometer numbers. This is what most tracks should be giving you, but no guarantees...

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I use a barometer (in my case, a backpacking weather station thingy) to determine uncorrected barometric pressure. Combine this with temperature in the following formula:

 

Relative Air Density = (uncorr. bar. pressure x 1754)/(temp F + 460)

 

This will give you a percentage related to the standard (100%) sea level conditions of 59 deg F and 29.92 uncorrected barometric pressure. If you use this method to figure out your AD, and use that to determine the relative altitude you're operating at, you can use the NHRA correction factors, and come up with relatively accurate estimates. Remember that turbos use a different correction than NA cars.

 

The important thing is to use UNCORRECTED barometer numbers. This is what most tracks should be giving you, but no guarantees...

 

I beleve that this is the key thing. People keep piling "correction factors" on top of "correction factors' and the numbers get way off. I would rather deal with uncorrected barometer numbers. Personally, I don't ever want to hear anything about NHRA correction factors, I have the same opinion of them as folks who try and pass off G-Tech numbers as reality.

 

I suggest that we use uncorrected barometer readings, as well as temps, humidity, sea level altitudes, wind factors above 10 mph, and let folks draw their own conclusions.

 

As an example, I haven't sat down with a buddy of mine to reconcile our DA numbers, which never seem to match, and see what we each use for input. His always come in way more optimistic than mine, but IMHO our ETs/trap speeds always seem more consistent with my calcs.

Ron
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Not sure that I understand your post. Yes, baro readings are "adjusted" (so to speak) to sea level (the weight of a 1 square inch column of air), but baro readings at sea level will directly correspond to a reading up in the mountains on a given day & time.

 

By this I mean that, assuming there is a common weather pattern that covers much of the USA, sea level could have a 30.50 reading, and a 3,000' level may have a 29.50 reading (purely an example pulled out of my you-know-where).

 

What I'm saying is that the baro reading reported by the weather man will be adjusted for altitude. So if the true (as in the actual inches of Hg) baro is 29.50 at 3000' ft, then the weather man will say that the barometeric pressure is 32.7 inHg (which is impossibly high).

 

I'm also suggesting that the track will likely report unadjusted baro readings for two reasons: 1) it might be easier and 2) it is more useful.

 

As far as correction factors being unimportant, I agree somewhat (esp with turbos) but it is nice to know the density of oxygen when comparing dyno readings and track times. And the density of oxygen can be calculated directly from absolute barometer, humidity and temperature readings; or equivalently, altitude, adjusted barometer, humidity and temperature readings.

 

I am just beginning to understand how density and temperature affects turbos, but it seems very complicated: you need to account for intercooler efficiency, compressor maps and turbine maps, in addition all of the problems of MAF and MAP sensors, intake air temp, octane, timing, AFR, etc. needed to understand NA engines.

 

So either these tuners are super-pimp bad-asses or they are persistant as hell with really big balls.

 

Da resident playa,

gringo

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Great time! Damn 1.75! what RPM are you launching at? What tires are you Atco guys using? I can't believe the 60' is that much better over what I can get at Cecil (1.86 best)... sheeshhh... When does Atco close for the season?

2012 Forester XT. Stage 2+

Retired from Racing. I used to build FMIC and more.

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Great time! Damn 1.75! what RPM are you launching at? What tires are you Atco guys using? I can't believe the 60' is that much better over what I can get at Cecil (1.86 best)... sheeshhh... When does Atco close for the season?

 

I am launching at ~5000RPM and running on the stock tires. That was the hand of god pushing me because my sixties are typically 1.81-1.84. I am gonna break something soon probably. 12-4-05 is the last day for Atco, closing early because they want to grind and refinish the track.

 

What are you launching at and any weight reduction?

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  • 1 month later...

A TDC 5EAT ROAD tune ran 13.2 today with a passenger

more details soon

 

Hope to have a 5eat in the 12's today !

 

 

weather there:

51°F

Feels Like

51°F

Updated Jan 15 11:00 a.m. ET UV Index: http://image.weather.com/web/blank.gif 3 Moderate Wind: http://image.weather.com/web/blank.gif From NNE at 3 mph Humidity: http://image.weather.com/web/blank.gif 33% Pressure: http://image.weather.com/web/blank.gif 30.16 in. http://image.weather.com/web/blank.gifhttp://image.weather.com/web/common/icons/down_pressure.gif Dew Point: http://image.weather.com/web/blank.gif 23°F Visibility: http://image.weather.com/web/blank.gif 10.0 miles

TDC Tunings LGT Forum

Cobb, Perrin, APS, Invidia, Megan racing and MORE!!

Your #1 source For Subaru / Legacy GT performance parts!

 

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Just got back from the track - best results;

1.732 60ft

8.26 1/8 mile

13.01 1/4 mile

103 trap speed

 

103.5 was my fastest trap speed

 

64 degrees and had over a half of tank of gas 100 octane (with stock top mount)

 

(theory - if I would of had less than a qtr of a tank - I think I would have been in the 12's)

 

Best time with atlanta protuner

1.809

8.69 1/8

13.69 1/4

98.11 trap

 

Also running 100 oct with about two gallons of gas (gas light was on for three previous runs) temp 67 degrees?

 

This TDC is so much more torque than than my last tune.

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