What is the difference between Speed Week and the World Finals?

[Eric_CA]

I am new to all this and was thinking about attending the World Finals...
thanks!!!

[Stainless1]

usually about 400 entries

[Eric_CA]

is it worth the trip or should I wait until next year?

[Milwaukee Midget]

Your hotel bill will be about 25% of what you'd spend at Speedweek.

World Finals will give you a nice sampler, if it's something you're just wondering about.

A lot of folks who waited until "next year" wound up waiting two.

[SPARKY]

sometimes ist about 60-80 degs. less in temperature

[Eric_CA]

So, with lower air temperatures you get more dense air and  as a result, higher power. 
How come more don't come to Bonneville when its cooler (and more enjoyable)?
Does the aero friction/drag caused by higher density air have more effect on speed than more engine power?

[trimmers]

In the past, World Finals has been rained out frequently.  I guess that's at least part of the reason they decided to move it up one week!

[nrhs sales]

In the past, World Finals has been rained out frequently.  I guess that's at least part of the reason they decided to move it up one week!

Exactly!

[desotoman]

And we hope this does not hit the racetrack.

Tom G.

Wednesday 09/21 40% / 0.1 in
Partly cloudy early. Scattered thunderstorms developing in the afternoon. High around 80F. Winds SE at 10 to 20 mph. Chance of rain 40%.

Wednesday Night 09/21 80% / 0.44 in
Thunderstorms in the evening, then cloudy with rain likely overnight. Low 54F. W winds shifting to ESE at 10 to 20 mph. Chance of rain 80%.

Thursday 09/22 90% / 0.36 in
Thunderstorms. High 59F. E winds shifting to NNW at 10 to 20 mph. Chance of rain 90%.

Thursday Night 09/22 80% / 0.21 in
Windy with rain showers in the evening becoming steadier overnight. Low around 45F. Winds WNW at 20 to 30 mph. Chance of rain 80%. Rainfall near a quarter of an inch. Winds could occasionally gust over 40 mph.

Friday 09/23 80% / 0.14 in
Overcast with rain showers at times. High 57F. Winds WNW at 10 to 20 mph. Chance of rain 80%.

[Milwaukee Midget]

So, with lower air temperatures you get more dense air and  as a result, higher power. 
How come more don't come to Bonneville when its cooler (and more enjoyable)?
Does the aero friction/drag caused by higher density air have more effect on speed than more engine power?

That's a good question - and it depends.

If you have a car with really good aero and you're power challenged - say a normally aspirated streamliner with a small engine - the additional air density can create enough extra hp to push you faster.

But if you're running a little brick, the air density can kill you.  That was my experience in the Midget - adjusted altitude chart which roughly correlates with air density vs. speeds -



The MG - bad aero and low power - liked the thinner air, and my slowest runs were always in the heavy, cool air.  By the time it was so hot and thin you couldn't stand it, that's when I made speed.  Your results may vary . . .

[NathanStewart]

If you're going for vacation and to spectate, Speed Week is better. If you're going to race, World Finals is better.

[manta22]

Chris;

I am surprised at the excellent correlation between the density altitude and top speed that you show in your chart. Good use of data!

Regards, Neil  Tucson, AZ

[rouse]

Chris,
Glad you put that chart together, it makes good sense and goes along with what I have told folks in the past.

As the air get thinner you lose HP and lose aero drag. I have found that you lose aero drag slightly more than HP, and your chart shows that.

Rouse

[Milwaukee Midget]

Thanks - it held true for me, but I suspect with a blown motor using modern engine management, the thinner air might tip the scale even further.  It all depends on the combination, I suppose.

Either way, Eric, personally, I'd sample the smaller event first.  That way, when you do attend the big gig, you'll have a point of reference and won't be overwhelmed by Speedweek's magnitude.

[rouse]

Blown motors change the whole ball game.

The higher you go the faster you will go, as long as the boost remains constant. In other words, you have the same HP and lower drag, what more could you ask for.

NA engines are the ones I was referring to, as the altitude split being in favor of more speed, but just slightly.

Rouse