Landracing Forum Home

Bonneville Salt Flats Discussion => World Finals 2016 => Topic started by: Eric_CA on September 19, 2016, 10:05:26 PM



Title: What is the difference between Speed Week and the World Finals?
Post by: Eric_CA on September 19, 2016, 10:05:26 PM
I am new to all this and was thinking about attending the World Finals...
thanks!!!


Title: Re: What is the difference between Speed Week and the World Finals?
Post by: Stainless1 on September 19, 2016, 10:06:25 PM
usually about 400 entries


Title: Re: What is the difference between Speed Week and the World Finals?
Post by: Eric_CA on September 19, 2016, 10:12:29 PM
is it worth the trip or should I wait until next year?


Title: Re: What is the difference between Speed Week and the World Finals?
Post by: Milwaukee Midget on September 19, 2016, 10:26:57 PM
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.


Title: Re: What is the difference between Speed Week and the World Finals?
Post by: SPARKY on September 20, 2016, 12:42:41 AM
sometimes ist about 60-80 degs. less in temperature


Title: Re: What is the difference between Speed Week and the World Finals?
Post by: Eric_CA on September 20, 2016, 12:12:22 PM
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?


Title: Re: What is the difference between Speed Week and the World Finals?
Post by: trimmers on September 20, 2016, 12:55:10 PM
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!


Title: Re: What is the difference between Speed Week and the World Finals?
Post by: nrhs sales on September 20, 2016, 03:48:53 PM
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! :-D


Title: Re: What is the difference between Speed Week and the World Finals?
Post by: desotoman on September 20, 2016, 04:13:12 PM
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%.



Title: Re: What is the difference between Speed Week and the World Finals?
Post by: Milwaukee Midget on September 20, 2016, 06:25:59 PM
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 -

(http://i361.photobucket.com/albums/oo58/milwaukeemidget/Bonneville%202013/graph2_zps788378e7.jpg) (http://s361.photobucket.com/user/milwaukeemidget/media/Bonneville%202013/graph2_zps788378e7.jpg.html)

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 . . .


Title: Re: What is the difference between Speed Week and the World Finals?
Post by: NathanStewart on September 20, 2016, 07:12:47 PM
If you're going for vacation and to spectate, Speed Week is better. If you're going to race, World Finals is better.


Title: Re: What is the difference between Speed Week and the World Finals?
Post by: manta22 on September 20, 2016, 07:18:26 PM
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


Title: Re: What is the difference between Speed Week and the World Finals?
Post by: rouse on September 21, 2016, 11:17:02 AM
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


Title: Re: What is the difference between Speed Week and the World Finals?
Post by: Milwaukee Midget on September 21, 2016, 11:31:47 PM
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.


Title: Re: What is the difference between Speed Week and the World Finals?
Post by: rouse on September 22, 2016, 07:54:06 AM
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


Title: Re: What is the difference between Speed Week and the World Finals?
Post by: Seldom Seen Slim on September 22, 2016, 08:05:30 AM
Johnnie said:  "...Blown motors change the whole ball game."

They sure do.  Ask SteveM or Fireman Jim.  :evil:

Oh - you didn't mean "blown", you meant "blown".  Now I got it.  Sorry, Johnnie -- it must've your brogue.



Title: Re: What is the difference between Speed Week and the World Finals?
Post by: Stainless1 on September 22, 2016, 08:06:46 AM
Well I would have to say if you maintain the same A/F ratio that you would go faster in denser air with your NA engine.  Midget, do you have AFR to go with your chart?  
Our experience with the lakester, Pork Pie driving, was 199.6 in the high Density Altitude of speedweek at 13:1 and 205 at the same AFR with 3500 feet lower DA.  More air means you can burn more fuel and get more power.
As always your mileage may vary, but we always do better with NA engines in October.


Title: Re: What is the difference between Speed Week and the World Finals?
Post by: rouse on September 22, 2016, 08:59:44 AM
Johnnie said:  "...Blown motors change the whole ball game."

They sure do.  Ask SteveM or Fireman Jim.  :evil:

Oh - you didn't mean "blown", you meant "blown".  Now I got it.  Sorry, Johnnie -- it must've your brogue.



Jon, AKA SSS,

Sounds to me like your anxious for the first cold front to hit your area.

Rouse


Title: Re: What is the difference between Speed Week and the World Finals?
Post by: Seldom Seen Slim on September 22, 2016, 09:09:23 AM
Johnnie, I could read that wrong and say "NAH - Nancy wears warm sweaters" in response, but somehow I don't think that's the line of thought you were following. :roll:


Title: Re: What is the difference between Speed Week and the World Finals?
Post by: Milwaukee Midget on September 22, 2016, 09:12:27 AM
Well I would have to say if you maintain the same A/F ratio that you would go faster in denser air with your NA engine.  Midget, do you have AFR to go with your chart?  
Our experience with the lakester, Pork Pie driving, was 199.6 in the high Density Altitude of speedweek at 13:1 and 205 at the same AFR with 3500 feet lower DA.  More air means you can burn more fuel and get more power.
As always your mileage may vary, but we always do better with NA engines in October.

As slick as the Boxcar is, that doesn't surprise.  

Bob, I think in your case, the lines between aero drag and power output with respect to air density cross at a somewhat higher point on the Graf . . . er, ehh, graph.

We were running a DCOE Weber, and my oxygen sensor gauge was nothing more than a flashing disco light, with readings I did not trust and will not quote.  Plugs read clean, despite 3 jet changes during the runs.


Title: Re: What is the difference between Speed Week and the World Finals?
Post by: Stan Back on September 22, 2016, 12:42:46 PM
I don't even know how you get in that itty-bitty thing -- let alone change jets during the runs.


Title: Re: What is the difference between Speed Week and the World Finals?
Post by: 4-barrel Mike on September 22, 2016, 01:57:13 PM
I don't even know how you get in that itty-bitty thing -- let alone change jets during the runs.

He has a tiny riding mechanic?

(http://i233.photobucket.com/albums/ee171/4-BarrelMike/Bonneville%202014/Midget02_zpsc2f16dcd.jpg)

Mike


Title: Re: What is the difference between Speed Week and the World Finals?
Post by: Interested Observer on September 22, 2016, 04:20:51 PM
Well, I may have to take issue with Chrisí graph in reply #9.  As presented it seems to show an uncanny correlation between the speed and density altitude.  However, when you look at the numbers and make a more valid graphical comparison, the correlation seems much less emphatic (see worksheet below).  Plus, there were apparently jet changes involved, morning/afternoon changes in the salt surface, wind, etc. etc.  And, does anybody know just how the density altitude printed on the time slips is arrived at?  Does SCTA calculate that on their own as a site specific value, and if so how do they do it.  Or do they just repeat a value obtained on-line, like Wendover airport or Weather bureau numbers.  Some of the simpler calculation methods (incorrectly) do not include the effect of humidity e.g. Weather Bureau. 
So, with only about a 3% variation in velocity for a 20% variation in an ill-defined DA, and a number of other unsubstantiated variables, concluding that there is a speed/DA correlation of some sort would seem to be unjustified on the basis of this data set or any other such loosely supported numbers.


Title: Re: What is the difference between Speed Week and the World Finals?
Post by: tortoise on September 22, 2016, 04:29:11 PM
. . . concluding that there is a speed/DA correlation of some sort would seem to be unjustified on the basis of this data set or any other such loosely supported numbers.

What he said. Furthermore, the other unaddressed issue is gearing. Unless you regear the vehicle, or use a CVT, either the high density or low density situation will be geared more suitably.


Title: Re: What is the difference between Speed Week and the World Finals?
Post by: Stan Back on September 22, 2016, 05:27:47 PM
Ya know, the correlation might depend a whole lot on the configuration of the vehicle.  What's shown on a brick would not apply to Costella.  That alone could be the most relative factor.

Get the slide rules out -- or just change pills.


Title: Re: What is the difference between Speed Week and the World Finals?
Post by: turborick on September 22, 2016, 06:32:13 PM
Ya know, the correlation might depend a whole lot on the configuration of the vehicle.  What's shown on a brick would not apply to Costella.  That alone could be the most relative factor.

Get the slide rules out -- or just change pills.

I agree Stan
On nebulous theorem 2 with a turbo we would always go faster when the DA was high. Record return runs were always slower unless I tuned it up


Title: Re: What is the difference between Speed Week and the World Finals?
Post by: Milwaukee Midget on September 22, 2016, 06:40:02 PM
Well, I may have to take issue with Chrisí graph in reply #9.  As presented it seems to show an uncanny correlation between the speed and density altitude.  However, when you look at the numbers and make a more valid graphical comparison, the correlation seems much less emphatic (see worksheet below).  Plus, there were apparently jet changes involved, morning/afternoon changes in the salt surface, wind, etc. etc.  And, does anybody know just how the density altitude printed on the time slips is arrived at?  Does SCTA calculate that on their own as a site specific value, and if so how do they do it.  Or do they just repeat a value obtained on-line, like Wendover airport or Weather bureau numbers.  Some of the simpler calculation methods (incorrectly) do not include the effect of humidity e.g. Weather Bureau. 
So, with only about a 3% variation in velocity for a 20% variation in an ill-defined DA, and a number of other unsubstantiated variables, concluding that there is a speed/DA correlation of some sort would seem to be unjustified on the basis of this data set or any other such loosely supported numbers.


A fair and valid critique.  My understanding is that the DA is calculated at the timing shack in real time - likely 3 1/2 miles from the end of the run, and collected at the time the run was made.  I'm also assuming it's accurate - it may not be.

Track conditions, wind speed, driver error, engine temp, jet sizes, tire pressure - none of this is taken into consideration.

I'm thinking I'd like to check out some other timing slips from multiple runs of naturally aspirated, aerodynamically challenged cars.  If we compare only the speed to DA in a larger pool of data, we may well spot a trend or a coincidence, and STILL walk away not completely sure!   

 


Title: Re: What is the difference between Speed Week and the World Finals?
Post by: Interested Observer on September 22, 2016, 10:23:03 PM
Quote
If we compare only the speed to DA in a larger pool of data, we may well spot a trend or a coincidence, and STILL walk away not completely sure!   

Yep.


Title: Re: What is the difference between Speed Week and the World Finals?
Post by: Eric_CA on September 23, 2016, 07:01:43 AM
Not sure if anyone noticed yesterday.  World Finals has been cancelled.
See you guys in 2017.
Thanks for the great info/feedback!


Title: Re: What is the difference between Speed Week and the World Finals?
Post by: Seldom Seen Slim on September 23, 2016, 07:25:03 AM
Eric, with all due respect - you're not experienced in the way the land speed racers hang together -- yeah, we noticed that WF had been cancelled.

I got emails and phone calls from all over the country in a 15-30 minute period yesterday telling me/asking me about the cancellation.  People on the road got calls, people in Wendover sent emails and photos, and so on.

I suppose other forms of fun have their inner networks -- but boyoboy, the LSR folks sure do.

Yep, we noticed that the event had been cancelled.  Thanks for your interest and questions and please hang around here.  Thanks.


Title: Re: What is the difference between Speed Week and the World Finals?
Post by: Turbo Dog on September 28, 2017, 03:41:57 PM
A blower will not make as much boost at altitude as it can at sea level...less density.