rec.autos.simulators

by **John Cal** » Wed, 27 Mar 1996 04:00:00

Has anyone noticed that the warmer the air in NASCAR Racing, the
faster the laps? Isn't this BACKWARDS? I thought that cooler and
less humid air produced more horsepower and kept the track and tires
cooler for better traction. Did anyone else pick up on this?

John

by **an..** » Wed, 27 Mar 1996 04:00:00

>Has anyone noticed that the warmer the air in NASCAR Racing, the
>faster the laps? Isn't this BACKWARDS? I thought that cooler and
>less humid air produced more horsepower and kept the track and tires
>cooler for better traction. Did anyone else pick up on this?

Well, I don't have a engineering degree but.....

I have noted over the years in watching NASCAR especially the first
few races of the season so far, that <even Benny and Ned> mentioned it
a few times that the cars DID indeed run faster because of the cooler
air temps. primarily in qualifying it seems.

As far as the Tires, yeah it keeps them cooler alright hehe especially
on restarts. I'm not so quick to agree that colder air temps. privide
better traction tho' minimizes tire wear a little as far as I can
tell. But traction is much better wene the air temp is up. The ideal
air temp for traction vs. wear seems to me to be about 80-85 degrees.

My Two Lugnuts are in the pile now :)

Regards,
Andy

by **David Marti** » Wed, 27 Mar 1996 04:00:00

> Has anyone noticed that the warmer the air in NASCAR Racing, the
> faster the laps? Isn't this BACKWARDS? I thought that cooler and
> less humid air produced more horsepower and kept the track and tires
> cooler for better traction. Did anyone else pick up on this?

> John

Cool air is heavier causing more downforce. I'm not sure how much impact air temperature has
on tire temperature, maybe a few degrees. Tire temperature is mostly effected by the friction
between the tire and the track surface. That's why higher air pressure produces lower tire
temps; there is less contact between the tire and the track.

I'm not sure how air temps effect horsepower.

David Martin
IVL Series Director

by **Steve Gran** » Thu, 28 Mar 1996 04:00:00

>Has anyone noticed that the warmer the air in NASCAR Racing, the
>faster the laps? Isn't this BACKWARDS? I thought that cooler and
>less humid air produced more horsepower and kept the track and tires
>cooler for better traction. Did anyone else pick up on this?

> John

I agree. You hear real NASCAR teams talking about a track getting loose as it gets
warmer. In the sim, the opposite is true (remember Richmond, NASSCAR folks).

Steve Grant

by **an..** » Thu, 28 Mar 1996 04:00:00

Richmond? Ha! I won't soon forget it.....
I made it 3/4's thru that nightmare of a race and
Missed my shift and popped the motor 12 laps to go.
And I thought it was gonna be nicer to me than the 'Rock" was <shaa!>
Boy that was a long night.

Andy

by **Eric T. Busc** » Thu, 28 Mar 1996 04:00:00

> Cool air is heavier causing more downforce. I'm not sure how much impact air temperature has
> on tire temperature, maybe a few degrees. Tire temperature is mostly effected by the friction
> between the tire and the track surface. That's why higher air pressure produces lower tire
> temps; there is less contact between the tire and the track.

> I'm not sure how air temps effect horsepower.

Your logic on the downforce and temp would seem correct, but the actual difference in
downforce would not account for much in the way of tire temps difference. I believe that
the air temperature (which also indirectly effects the track surface temperature) has
much more of an impact. On a 100 degree hot summer day the track surface temp could
easily reach 140 degrees (if not hotter). This should cause tire wear to increase when
compared to a cool 60 degree day (hotter day=more tire wear). The problem with NASCAR
Racing is not this, but it is the horsepower difference.

The way the temperature changes should effect horsepower is due to the density of air.
Cooler air is more dense (that's why hot air balloons rise) and thus have more oxygen per
unit of volume than does warmer air. Although the engine is taking in the same volume of
air it is getting more oxygen allowing for more complete combustion producing more
horsepower.

Therefore as air temps increase, the horsepower of the engines should decrease slightly,
and tire temps should increase.

--
Eric T. Busch

Emory University

by **Neil Yeatma** » Thu, 28 Mar 1996 04:00:00

> Has anyone noticed that the warmer the air in NASCAR Racing, the
> faster the laps? Isn't this BACKWARDS? I thought that cooler and
> less humid air produced more horsepower and kept the track and tires
> cooler for better traction. Did anyone else pick up on this?

> John

Well, from what I know...cooler air is more dense = more downforce.
Also, because of the higher density, more oxygen/sq.in., therefore
higher horsepower. Also, the warmer the track the more slippery
it gets, and tires run hotter...as do brakes, water temp, etc.

Overall, yup...NASCAR Racing has it backasswards...

by **P. Campbe** » Fri, 29 Mar 1996 04:00:00

>Cool air is heavier causing more downforce. I'm not sure how much impact air temperature has
>on tire temperature, maybe a few degrees. Tire temperature is mostly effected by the friction
>between the tire and the track surface. That's why higher air pressure produces lower tire
>temps; there is less contact between the tire and the track.

>I'm not sure how air temps effect horsepower.

I'm not sure about the downforce thing, but there are two reasons for reduced
speeds in hot weather. One is reduced HP. Hot air is less dense than cool
air, which causes a reduction in HP.

Also, when track temperatures go up, the asphalt becomes slicker. In July at
Daytona, the drivers are always fighting a loose condition due to a much
slicker track. While cool weather makes for reduced tire temps (which also
cause a decrease in grip) once the tires get warm, they adhere very well.

These are the reasons that all the speed records ever set at Daytona and
Talladega were set in February and April, not in July.

Pat

-----------------------------------------------------------------------------
Pat Campbell 6,94,88,16,4,25
Lexington, AL The Chevy Monte Carlo

War Eagle!!!
-----------------------------------------------------------------------------

by **Mike Donnel** » Fri, 29 Mar 1996 04:00:00

says...

Lower air temps produce more horsepower as the air is denser and a richer
air/fuel mixture is used. One byproduct is that fuel economy decreases as
the amount of fuel used increases.

Mike

--
_
___/ \___ Speed Bump Motorsports... The name says it all.
NRL95 #110 Hershey's Kiss Chevrolet Monte Carlo
PRO95 #53 Hershey's Kiss Penske PC23/Ilmor D
SIMCAR96 #45 Hershey's Kiss Pontiac Grand Prix
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rec.autos.simulators

NASCAR Racing Air Temp. Effects -- Backwards?

NASCAR Racing Air Temp. Effects -- Backwards?

NASCAR Racing Air Temp. Effects -- Backwards?

NASCAR Racing Air Temp. Effects -- Backwards?

NASCAR Racing Air Temp. Effects -- Backwards?

NASCAR Racing Air Temp. Effects -- Backwards?

NASCAR Racing Air Temp. Effects -- Backwards?

NASCAR Racing Air Temp. Effects -- Backwards?

NASCAR Racing Air Temp. Effects -- Backwards?

NASCAR Racing Air Temp. Effects -- Backwards?