New Track Times

kooldawg6 said:

Just corrected my times(using my quickest run with coresponding MPH, not best of each). Uncorrected it was 13.345@104.11. Corrected that is 13.17@105.45.
The day is wrong It was on a Sunday(22nd), the 23rd was a Monday. Somebody in the tower got out of bed on the wrong side
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Well, at least they got your car number right. On one of my runs one time, they got my car # wrong by one number, thank god it was a slip that didn't have anything noteworthy on it.

I noticed your 60 foot time was 2.032. My previous best with a Superchips 91 octane performance tune was 2.157. I did a 2.052 60 foot time last week in my first outing using a Bamachips 91 octane race tune. I would have to say that Doug's tunes are the best for an automatic.

I've been tempted on getting a tune from Doug for that reason...perhaps next year.

kooldawg6 said:

I've been tempted on getting a tune from Doug for that reason...perhaps next year.

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For $400, it would be worth it. I have driven my car with stock setting, Superchips 91 Octane performance tune setting and Doug's 91 Octane Race tune all in the same day. With stock setting, it has sluggish throttle response and doesn't skreech the tires shifting into gears. With Superchips 91 tune, it has better throttle response and skreeches the tires hard shifting into second. With Doug's race tune, it has very noticeably better throttle response in low gears and skreeches the tires shifting into second AND third. I will never drive my car with stock tune ever again. It is boring and sluggish.

They say for every tenth of a second you drop off your 60 foot time, it translates into two tenths of a second on your final 1/4 mile time. My best 1/4 mile time the day I had the 2.052 60 foot time using Doug's new race tune was 13.835 and the density altitude was 2300-2400 the time of that run. It baffles me why it still corrects to a 13.4, not much better than what I density altitude correct to using a Superchips 91 Octane tune. But I imagine when I get good weather, I will see a bigger difference in 1/4 mile time. I am thinking that I should be able to produce some runs that density altitude correct to 13.3s because Doug claims his race tunes are .2-.3 seconds better than base SCT tune.

onebad95 said:

r/t .237

60' 2.019
330 5.658
1/8 8.647
mph 82.30
1000 11.212
1/4 13.395
mph 102.88

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13.395 looks a lot more like 13.4 than 13.3, to me, anyway.

onebad95 said:

I was thinking the same thing. I went out and did the 4.10's on sunday and the car definately accelerates quicker now. I will be going back to the track this week.

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I'd like to see those numbers for comparison....

LB

Just out of curiosity, what was the other car you ran? (In referance to post 14)

Five Oh Brian said:

For a little more grunt off the line (60'), and through the 330' and 1/8 mile, may I suggest 4.10 gears and/or a bigger stall converter. My '07 GT AT is "all stock" on the outside, but I have 4.10's, 3800 rpm stall converter, and DiabloSport "firm shifting" tune. No airflow mods of any kind. 60' times are in the 1.83-1.89 range (consistently with drag radials), 330' times are in the 5.4 - 5.5 range, 1/8 mile times in the 8.4 - 8.5 range, and 1/4 mile in the 13.3 - 13.4 range with a best ET run of 13.280 @ 101.92 (best mph was 102.92).

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Since several of you are noting Density Altitude corrections, I feel obligated to share DA corrections for my runs. My home track is Pacific Raceways (formerly known as Seattle Int'l Raceway). 250 ft above sea level, but with high temps and humidity this summer, many of my runs were in air equivalent to 2000-2500 ft above sea level.

So, the best run I've had (13.28 @ 101.92, uncorrected and printed on the timeslip) was run when the DA was 1345 ft above sea level. Corrected, this would have been a 13.09 @ 103.40. I don't have a scanner, so here's the whole timeslip typed out (uncorrected)....

R/T = 0.076
60' = 1.833
330' = 5.424

1/8 mi ET = 8.444
1/8 mi mph = 81.15

1000' = 11.066

1/4 mi ET = 13.280
1/4 mi ET = 101.92

This is with an automatic, drag radials, 4.10 gears, 3800 rpm stall converter, and Predator tuner with a canned tune for "firm shifting" as purchased from www.rpmoutlet.com. No intake or exhaust mods of any kind! Weight with me in the car was 3,620 lbs (1/4 tank of gas).

The best I've run on the factory tires, but all other mods noted above, was 13.319 @ 102.13. I didn't have weather info to make any DA corrections, so that is just as it was printed on the timeslip. It was 75 degrees and sunny, and the air "seemed" decent. The whole timeslip looked like this (uncorrected)....

R/T = - 0.062 (red light!)
60' = 1.862
330' = 5.472

1/8 mi ET = 8.492
1/8 mi mph = 81.55

1000' = 11.109

1/4 mi ET = 13.319
1/4 mi ET = 102.13

I had to really cook the factory tires (3rd gear burnout) to get them hot enough to pull such good short times! Probably took 500 miles worth of tread off the tires to make this good of a pass on the factory skins! Drag radials sure make launching super easy and more consistent, but the factory tires can hook if heated (tortured) properly.

I've noticed that many people struggle to get 60' times under 2.000. My 07 GT never launched better than 2.006 with the factory stall converter (and averaged around 2.1), so the 3,800 rpm stall converter has really helped in this respect. Average 60' times have improved two to three tenths with the stall converter. Now, I need to work on getting the new converter to lock-up sooner in 4th gear to get the mph back up (it's lower than it was with the stock converter as it slips more). A little tuning should fix that, though.

This density altitude crap is confusing

anticubicle said:

This density altitude crap is confusing

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I agree Looks good on paper, but they don't use it at the track so why should I

kooldawg6 said:

I agree Looks good on paper, but they don't use it at the track so why should I

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EXACTLY! In all my years of racing I've never seen so much talk about DA corrected times as I have since I'd been lurking in the '05 forums. Sure, it can be useful in tuning and judging your own car over varied conditions, but if you tell any real racer your DA corrected times when asked you'd be laughed at. I know I would!

Exactly why I don't post DA corrected info in my signature!

It is useful to know how DA affects a car's performance, however. I've run a lot of 13.30's @ 102+ mph (uncorrected), so I know my car's normal capabilities.

I'd never even heard of DA corrections until last month after I went to the track on a balmy 93 degree day and ran in the 13.60's @ 99-100 mph - ouch! I was trying to think what I did wrong to the car. Noticed the track's tower had a weather station, so I jotted down all the weather details for each run.

Did a search online when I got home to see how the weather affects performance and found the NHRA DA corrections. The DA for that hot, balmy day was 2600+ ft above sea level, so the corrections were in the 13.30's @ 102-103 mph, just like I know my car runs in normal weather.

Knowing the DA corrections allows me to make tuning changes on the fly at the track and know if they help - regardless of the weather as it can be corrected.

However, when it's time to post or talk about best ET's at the track, I will always post uncorrected info.

kooldawg6 said:

I agree Looks good on paper, but they don't use it at the track so why should I

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Well, they don't use it at the track but it is extremely important when comparing 1/4 mile times. The NHRA does use Density Altitude corrections to level the playing field around the country in national classes. See: http://www.hardtail.com/techtips/altitude.html

The reason why it is important is because for every 1000 mile increase in altitude, there is a corresponding reduction in air density of 4.5%. So for a 300 hp GT, for every 1000 foot altitude increase, it robs 13.5 horsepower. Temperature, Dew point (humdity) and barometric pressure all factor into the performance of an engine.

The warmer it is, the less dense the air is, which means poorer engine combustion.

The more humid it is, the less dense the air is because water vapor displaces oxygen so the engine ingests less oxygen.

Barometric pressure has been called "Mother Nature's supercharger" It is the force that pushes air and fuel into the cylinders to fill the low-pressure area created by the downward motion of the pistons. Barometric also affects engine exhaust backpressure. The higher the barometrice pressure, the better an engine will run. Barometric pressure is almost as important as temperature and you hope for 30+ barometric pressures when you drag race. The higher, the better.

Density altitude figures all these factors in to give you an idea of what simulated altitude you were really running at a given time and track.

I have seen firsthand how my times all get better when the density altitude is lower. I can reel off 13.7s like nobody's business when the density altitude is around 1500 or lower. And I have also seen how hard it is breaking into the high 13s when the high density altitude is high at my track (2500+)

I will be going back to the track on Sept 23. Hopefully it will be near ideal weather for running good times. The one and only time I've been was back in the end of April which had good weather. The great thing about our Mustang club is that it has the track between 8 am-noon.

kooldawg6 said:

I will be going back to the track on Sept 23. Hopefully it will be near ideal weather for running good times. The one and only time I've been was back in the end of April which had good weather. The great thing about our Mustang club is that it has the track between 8 am-noon.

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Lucky you, I would get 60-70 degree weather here in the morning quite often. It is hottest between 2-5pm here and racing starts at 6pm and lasts until 10pm.

Yeah, the club rents the track for just us and who we invite along. For $50, it can't be beat. If you so choose, you can realisticly get in at least a dozen or more runs. Last year there was a V6er that made 27 passes!!!!!