Best 49 foot to Best 42 foot time/speed conversion

[HAB]

Our BSA district race was run on a 49 foot best track. The time with a all BSA kit car was 3.660 - 135.06 mph. The track could use a little TLC. I would like to try to get a rough idea on what the car would run on a 42' Best track since that is what most league's seem to be running but not sure how to work the math on it.

I took the time 3.660 and divided it by 526" (Best Track 49' actual length) and then multiplied it by 442" (Best Track actual 42' track length) and came up with a time of 3.0755 however that doesn't take into account of the loss of speed/deceleration that happens over the last 7' of track. Any suggestions on how I can get a rough idea of what his speed would be on the 42' track.

My son's Council race is coming up soon and I realize that each track runs differently. I am trying to gauge where we are related to time/speed and evaluate if the tire/axle prep work we are doing is heading in the right direction or if we need to scrap what we have and start over.

 

[B_Regal Racing]

There is a mathematical formula in which this can be calculated and you have obviously did some research since you pointed out you do not have the deceleration numbers. And you already know every track is different and probably know the parts/craftsman greatly contribute to the speed of a car. BUT - I believe you are over-thinking this. If you have built the fastest car possible, just go and kick some butt. At Nationals, on a 42' Besttrack, the top racers were running 2.93x and the bottom racers were running 2.96x. I don't see how this helps, but I offer it up there as information.

 

[HAB]

Thanks for the comments B Regal. I have done some research on the 42' times from here and from the Mid America past races. My son's car set a new track record at the district race on a 49' track, but without having a reference time to compare to the 42' foot tracks and its much larger sampling of competitive times it is hard to know where he stands. My thinking was that if I could get a conversion rough time estimate I would have a better feel for the quality of prep work we are doing and could adjust before loosing at the Council rather than after. I built a car that I was able to run once against his just for fun in between races at the district event and mine beat his by almost a car length, unfortunately the timer wasn't set so I don't have numbers for it . The axle prep work was the same (or at least followed the same prep process), he had a better set of wheels, but the difference I think was aero dynamics and more importantly weight placement (his was built before we discovered this awesome site). It would be neat to have a reference for my car ahead of sending it in to race as well.

The bug has bitten me, I suppose I will start saving my pennies for a one or two lane 42' Best track and timer. If there is anyone in West TN that has one for sale I would be interested!

 

[ZZRacing]

The problem with trying to compare times between tracks is setup. You may have the hill set at 29 degrees and I may have the hill set at 27.1 degrees. Same length tracks but different slope gives different times. To many variables to get a accurate time. Best way to see where you stand is send it in and run it against the best racers. When I first started racing in the league races in 2011 I took my sons scout car ( which won our state championship race ) to a league race to see where it would finish and I was amazed at how much faster pro cars were running.