speed data sheets

[bvillercr]

This is a computer program we have been using for a long time to estimate the potential speeds of our car.  We used the Summers Brothers streamling as an example for the accuracy of the program and it came out very accurate.  The time it takes to run and the acceleration from mile to mile is off.  Our car usually gains 20mph every mile after the 2.  The first spread sheet shows the Summers Brothers streamliner.





Each of the following sheets shows our car with different HP ratings and CD.  The pages show in red ink the differences.

[edweldon]

Lotsa interesting stuff in your spreadsheets nice straightforward layout and data presentation... Pretty self explanatory.
Got a couple of questions after studying the spreadsheets.
1.  How do you make use of the Lift Coefficient in your calculations?
2.  Do you take any account of tire slip in the calculation or are you assuming dry pavement conditions? Is this related to the traction index?
3.  What does the number 11 mean for traction index?
4.  I may have missed this; but what are the assumed conditions (density - altitude or temp/ pressure/RH) of the dyno test data?
5. Do wheelbase or tire width figure in the calculations anyway or are they just there for info.?
   Thanks, Ed Weldon

[jl222]

Hi Ed
hope i can answere your questions.
1. changing the lift from .200 to .300 knocks off 3mph at 313mph. I came up with .200 after reading published reports of lift on passenger cars .300-.400. We have a spoiler and lots of weight on the rear.
2.tire slip. Yes you can input 1-15 1 is dry asphault 5 is best salt 15 is worse salt.
  Narrow tires,low gearing,loose salt,to much power will show up as in the acceleration column.
3.11 means loose salt
4. Density-Altitude -temp can be inputted in the general data section,but they don't want you to change the barometer.
5.You can change the tire width but only down to 7.5" up to 15" "one problem with program" as a lot of cars have less. No input for wheelbase.
 Overall were happy with the program when we went 288 it was amazing how close the speeds were from mile to mile they just happened futher down course. The gear ratio inputs are great being able to see the rpm drop and mph.

           Hopes this helps  JL222


       Wear did those lines come from?

 
 

[SPARKY]

I would LOVE 20 after the 2  LORD I would love 15-- barely getting over 12..

[landracing]

JL22,

Got rid of those pesky lines for you.

Jon

[jl222]

    This program has several courses El Mirage-muroc-bville 5 mile-bville 3 mile-1 mile dry pavement 2 mile dry pavement.
                          JL222

[edweldon]

Looks good.  What's the availability of the program?  Freeware? Shareware? Price and formats available?  Answer me e-mail direct if you need to or prefer to.
Ed Weldon

[jl222]

hi Ed
The program is available at www.Racingsecrets.com. look at top of spreadsheets.
Their are several body types available gas coupe-lakester-motorcycle-roadster-sports and streamliner,just laugh at his inputs and put your own in. The formulas seem to be close,but we never accelerate as fast as predicted. If you know your speed you can work backward to find hp.
  Its been helpfull to us in figuring gearing and tire groth. One year we went 275 out the back door but the tach indicated less rpm to go that speed. by adding diameter to the tire input we were able to get a more correct reading.
  Program comes with cd and booklet,200 bucks last time i looked.

       Good luck  JL222