[jjjferro]

Ran the car last week and best time was 13.84 @ 100 mph temp was 77* My best time before that was 13.4 @ 102 mph temp was 48*

Did the temp effect me that much? If so anyone know the conversion rate?

[VFAST]

also humidity aka water grains

[tripleblack]

Originally Posted by jjjferro

Ran the car last week and best time was 13.84 @ 100 mph temp was 77* My best time before that was 13.4 @ 102 mph temp was 48*

Did the temp effect me that much? If so anyone know the conversion rate?

Cool air is dense air, and it can definitely make a difference.

Weather conditions in general get involved. Wind (a head wind will slow you down, a tail wind will speed you up). Air Pressure (altitude matters, again because dense air will give the engine a stronger charge of oxygen and help it pump more air - and even a high pressure zone vs a low pressure zone can change things).

There ARE some math formulas, but to really do any good you'd have to run the math for ALL the variables. Track conditions (was it slicker this time because of the combination of stuff that was on there this time vs last time?) vary a great deal, and this too can be affected by temperature (heat softens the layer of oil, rubber and seepage from asphalt, and can make the track slicker).

Its hard to say without being there, but I'd say that at least part of the difference was the higher temps (and probably some other variables you might not have noticed).

Finally, a good indicator is 60 foot times. They will often show a bigger difference than the overall times.

[jjjferro]

13.8 60 ft times was 2.1
13.4 60 ft times was 2.0

First run of the night was 13.9 at 86*, 5pm
Last run was best run of 13.8 at 77*, 10pm, 6th run of the night

I now have MT ET Streets and uca/lca on car that I did not have back in April when I had the 13.4

[tripleblack]

Originally Posted by jjjferro

13.8 60 ft times was 2.1
13.4 60 ft times was 2.0

First run of the night was 13.9 at 86*, 5pm
Last run was best run of 13.8 at 77*, 10pm, 6th run of the night

I now have MT ET Streets and uca/lca on car that I did not have back in April when I had the 13.4

OK, I recently read some interesting data on the www.maximummotorsports.com site about their LCAs. Go there and review what they have to say about some LCA's actually INCREASING Ets and decreasing rear end weight transfer control.

Still, those conditions WOULD seem to make a difference to me. Just not sure how much.

[kenneth]

For Fun Ford Weekend this year it was hotand humid at the track. with my old tune I usually run 13.0 in the cooler months and with the same tune the best I ran was 13.2 running in high 80* temps.
Forensicsteve was losing around .4 tenths from what he usually runs because of the weather.

[UBie]

Many NHRA tracks can tell you the correction factors for both altitude and atmospheric conditions. Bother will affect ET and MPH. For example a mildly modified car will run 1 second slower at Bandimere's, which is at 5800ft. If you factor in air density/atmospheric conditions, the altitude correction factor could be equivalent to running the car a 8,000 ft. So just because you're running a car at sea level the altitude correction factor could be as high as 1500ft or more.

If your track doesn't offer this information, most of the big boys have the equipment that gives them all of the measurements, because they use it to optimize the cars performance based on atmospheric conditions.

[BADASS03SVT]

the 60 changes it too. that one tenth is ususally good for two tenths at the big end.

my car went 10.7s on two trips ot the track back in october....temp was 58-60 degree's. first trip back this year it was 68 with a DA of 1200 and best I could get was a 10.82. temp last week was 80 with a DA of 1400 and best I could get was a 10.86. all same 60's (which indicate track conditions) and I have an auto that runs pretty consitant, usually within .08 every pass. plus its a blower car and temp affects me more.