It's not bad in the winter, obviously better than the summer but it's generally not real fast when compared to other tracks as far as atmospheric conditions go.

Track conditions (the drag strip itself) on the other hand is excellent compared to most tracks.

 

Ok, guys, Just read through all of these posts.

1. Someone needs to explain Density Altitude, or DA to me...if you look at my original post I said I was not sure if I got that right b/c using figures from Accuweather.com adn then plugging them into another website gave me the number I came up with. I had never even heard of that crap until I got my Wife a Trailblazer SS which is VERY sensitive to all those factors...it ran a 13.9 back to back bone stock and then got a tune and ran a 14.1 back to back...but it was 20-30 deg warmer and more humid that day...so anyway, I need that broken down for me please.

2. My times and trap speed are NOT corrected and 100% what they were...NE Dragway is like 80 feet above sea level so it's one of the best atmospheric tracks to run at in the Country. NJ has some great tracks too. But yes, I am lucky and I know that.

3. That sounds right about the reaction times...makes good sense too.

 

Density altitude is basically a comparison of what altitude you'd have to be at under "normal" conditions (like 60 degrees and 60% relative humidity, something like that, SAE has a standard for it but I don't know what it is off hand) and the atmospheric conditions that you are experiencing at your observed altitude which in this case is 80 feet.

Basically all it is saying is that on your track, on that day, at that temp, with that dew point, and at that barometric pressure it would be roughly equal to you running at an altitude of roughly -1033ft under normal conditions. Clear as mud?

No one is calling BS on your times or anything, they seem totally possible under those conditions to me. I'm extremely jealous that I don't have a track like that.

 

I should have done this earlier, but according to this site http://wahiduddin.net/calc/calc_hp_dp.htm, the DA for Boss' runs was in the -600' range. His car was making 106.3% of it's available power.

DA is very important and most people don't understand it. My first time out in me a best of a 14.49. The DA was around 1,500'. I went back out in the Fall and the car ran a 14.32 with the DA in the 300' range. No changes to the car and a similiar 60'.

The lack of understanding DA often makes people attribute reductions in ET to a recently added mod like an intake, high flow-cats, etc, when in reality, it was the change in DA that improved the times.

 

Ok, so...I get what it is...but can either of you take my figures that I provided in the first post and using math for dummies just break down what you did to achieve the DA?

I used this site: http://wahiduddin.net/calc/calc_hp_dp.htm

But I was not sure of the Altimeter Setting which is in HG apparently...Accuweather did not give a clear figure for that...so I guessed at what was supposed to be in there...also, the track is 90' above sea level, not 80 fyi.

Lastly...how come no one is replying to my Fastest Coupe Thread??????

 

Roneski,

I didn't think anyone was calling BS so all is good.

Thanks for your follow up as well. vbmenu_register("postmenu_1450730", true);

 

I always use http://www.wunderground.com to get my historical weather data. I checked the weather data for Epping, NH for the evening of 10/6 and the conditions you listed were the same ones found on wunderground, including pressure.

As for your fastest Coupe thread, they're more concerned about stuffing in 22s and how to wire in the Play Station.

 

ROTFLMFAO!!!!

Ok, so do you know what the heck I did wrong to get the incorrect DA?

 

There's a couple of ways to figure it out but the formulas are too complicated to post. The online calculators work fine.

http://en.wikipedia.org/wiki/Density_altitude

 

I think that your DA is actually correct.

 

Roger that, good to know! Thanks for the follow up!

 

what does it mean if you pickup a lot of speed in the 2nd 1/8mi?

lets say there were another car that got there first, trapped higher, but had a lower 2nd 1/8mi speed difference...what would that mean?

 

It means you're running him down. You may catch him by the end or you may not. You had a slower start because of a bad launch, poor gearing, weak low end power, etc, and his car on the other hand was strong at the beginning, but looses steam on the far end. That too can because of poor gearing or lack of upper rpm breathing ability.

I constantly get smoked by WRXs in the first 1/8 because of their superior launch capability, but right around 60-70mph it's clear I'm closing in. As 80mph rolls around, I'm closing in fast and often times I'll pass them about 100-300' short of the finish.

Most cars will gain 18-20mph in the last 1/8 mile. However, the VQ series motors, especially the VQ35 in the G/Z, has strong lowend power and strong upper rpm breathing ability which in term gives the car a very fat powerband. That in term gives the VQ35 some serious legs from a 60mph+. My 5AT typically sees 21.5-22mph in the last 1/8 and my prior modded 5MT Maxima saw 23mph. Lots of 6MT G/Zs typically see 23mph and sometimes even 24mph. Usually anything above 24mph is indicitive of forced induction and anything above 26mph is very fast car. It's also related to the terminal at the first 1/8 vs the last 1/8. Example, an LS7 Z06 is probably seeing 91-92mph in the first 1/8 and 120mph at the end which means the car is gaining 28-29mph. That is some serious power to be cutting the such high speed air resistance in such a short amount of distance. That is major acceleration and is far stronger than a G35 going from 80mph in the 1/8 to 102mph in the 1/4.

 

Most 6mt's I've seen, even the z's, are at 22mph flat. 23mph are few, and 24mph is downright rare.

Though there was that one guy on my350z recently whose bone-stock 03 got something like 24.5mph or so.

 

Yeah, that guy was running at "The Rock" in Rockingham, NC. There is something up with that track because it turns out some seriously amazing times.