RACING IN HOT WEATHER VS. COLD WEATHER -- PERFORMANCE DIFFERENCE????!?!?!

[MannyC]

Question:

Is there a mathematical formula to be used to determine drop in horsepower from running in a particular temperature vs another? For example, racing your car in 70 degree weather vs. running it in 100 degree weather? Is there a noticeable difference?

What about running NOS on hot weather vs cold weather?

[Viperfreak2]

The power is different, but so is the traction. High temp = lower horsepower, high traction. Low temp = high HP, spin all day. I think it's more critical for a Viper to get a good launch. My times are worse when the weather is cold.

[GTS Dean]

Just keep this in mind - everyone racing against you has the same ambient conditions to deal with as you.

[MannyC]

I was in Vegas where it was so hot that my radar detector case got warped -- no joke! Still works, but it looks like a microwaved it for a couple of minutes. That and the fact that I was several thousand feet higher than here in San Diego was causing my Gen I to run... wierd. The car is naturally lopey due to being stroked, but on several occasions it nearly died -- actually I think it did die for a second or so, then it jumped back to life -- very odd. By the end of the day it seemed to be running fine, so I assume the computer adjusted itself? I dunno.

Another thing that happened was that my car totally bottomed out over a big long flat speed bump heading into the MGM Grand. I went over it nice and slow since my front Fascia is so low to the ground -- no problem. But as soon as the front wheel went over the bump, we heard a loud BANG and the bottom of my car sat on the speed bump. I had gave it a quick gas and it scraped/rolled over the bump. Both my friend and I yelled out, "OH FAWK!" or something like that as it happened. Me thinks my car is just too low.

[MannyC]

The power is different, but so is the traction. High temp = lower horsepower, high traction. Low temp = high HP, spin all day. I think it's more critical for a Viper to get a good launch. My times are worse when the weather is cold.

Strange, as I thought the car was way more squirely than normal. Leaving gas stations and getting onto on ramps, the car slithered up to the freeway in 2nd and 3rd gear accelerations, like the tires were melting. I suppose it could be from all the gunk on the road (more melted tires on the road than normal.) Temperature was about 105 to 110 degrees in Vegas the whole weekend.

Superbar, try living here

[1TONY1]

10% air charge temp = 1% horsepower

NO2 can be tuned to make up some of the difference.

[Vreracing]

I think I live in one of the few places where you can have 5F degree weather with no snow.

No question to me there's a big difference in power.

I looked up the formula for calculating it. You have to figure in humidity and altitude as well. Its not a pretty formula. Looking at 1Tony1's picture tells me he's probably a pilot. I would trust him.

[BigCarrot]

http://www.prestage.com/Car+Math/ET+...s/default.aspx

There are several handy calculators on this site!

[96 GTS]

Good info Big Carrot! Thanks.