Please get it officially verified BEFORE you create a thread about it.

I have seen 4 or 5 threads in the last couple of months made by owners posting about their 60-130 runs, only to find out later that the runs did not pass verification, usually due to not meeting the 3.0% maximum decline limit. One of the owners got so upset that his run didn't pass that he hasn't posted on the forum since.

Please, if you run a time...wait until the run has been verified before you make a thread baout it. I will normally verify runs that are sent to me within 48 hours. Thanks.

 

Assuming whoever posted is interested to be in the rankings I assume!

The 3% is a good accepted threshold for your rankings but does not make a 4% run invalid (I hope at least!). As an aside the slope calculation is based on starting and ending altitude rather than weighted average over the duration of the run. You might be disqualifying a run due to a 3.5% downward slope while in fact it was uphill for 90% of the run..but dropped sharply in the last 100feet only..

 

Interestingly enough, I have yet to find a person that has sent me run that was NOT interested in having it placed on the ranking list. If they weren't, they would simply verify it themselves.

For the official 60-130 list on this forum, it definitely does.

It's an average over the entire course of the run. And yes, I also look closely at the height lines. But thank you for the information, Jean. I never realized what my calculations were measuring until now.

If the person in your example above had a steep enough drop the last 100 feet of the run to cause a previously 90% uphill run to all of the sudden exceed a 3.0% decline, then I woud say that last 100 feet helped the car accelerate much quicker than it did beforehand...thus causing the run to be invalid when comparing it to the 38 existing runs I have on the list.

I think I'll stick with doing it the same way it's been done for everyone else on the list. Thanks,though.

 

Scott,

I take that Peter never sent you the 6.17 I ran that day we had the crappy weather and 30 mph headwind? He posted the graphs in the thread about the event, but did those graphs contain the necessary slope info? We ran at Lonestar Motorsport Ranch, the same place we always run.

 

Sean, calm down tiger! I have an understanding with Scott on the 60-130 graphs and only post those files I have verified. There has NEVER been a time Scott has thrown out a file I verified. I'm sure he is in the process of updating the list.
Peter

 

Scott

I am sure that all the runs that were sent to you are meant to be part of the ranking, but your original post did not make a distinction between those who want to be in the ranking and those who are simply sharing.

As to the slope, the way you are measuring slope disregards all that happens between the starting and ending points, throughout the length of the run, and this is inaccurate.

Calculating slope the way you do is ok as long as the there is no change in slope throughout the run, which is what most textbooks and the internet will teach, but when you have an object moving in variable slope from point A to point B, you need to do a weighted average or else you are in error.

To put it in simple terms, you can easily see one second difference between two runs that show, per your calculations, 3% slope just because what goes on throughout the run is not being taken into consideration by your formula.

This is when disqualifying a run showing 3.5% slope according to this calculation can be as inaccurate as accepting a 2% slope run.

Pleasure sharing my views, this is what the forum is about.

BTW you must have understood me wrong, I am not suggesting you change anything in your validation process.

 

Just curious because I would like to do a few 60-130 times, but is the VBox the only thing I need to get a 60-130 time? Where is the best place to purchase one?

 

vboxusa.com
look under "products" for Performance Box or Drift Box
Most use the P-Box.

 

Jean is obviously correct. I think the AX-22 type device will give you the info he is talking about (I had and sold an AX-22 because I could not figure out how to use all
of the fancy functions)
Unfortunately I do not know my PBox well enough to even know if a run I do is valid.
I guess I need to keep practicing next year and playing around with it. I have run faster runs than the one on the list but need to get another one verified.

 

Pietro,

We ran 3 weeks ago...doesn't look like it will be updated.

 

Hi Marty,

Not really, it does not have to do with the tool. Both of them (GPS tools) provide the data. It has to do with the way one calculates the slope. When you take the height at the beginning of the run and at the end of the run and divide by the distance covered, you get the average of both points only.

For example if you have a 10% steep downhill slope for the first 200 feet throughout your run, you will be going from 60 to 80mph in say 2 seconds, and then if from 80 to 130mph you have an upward slope of 1% for a duration of 5 seconds at the higher speed, you will still end with a negative slope that would disqualify you, whereas your times have been penalized in reality by a mostly upward slope.

So if you find a short steep uphill slope for the first couple of hundred feet that turns to a very long downhill for the balance of the run, you can benefit of maybe a second or more for your run while still being within the limits of the 3%. This is when a 5% downward slope can be more legit than a 3% upward slope!

Worth keeping in mind when analyzing your own runs at least.

 

What I do is take the lowest point of the run and subtract it from the highest point of the run, then divide that number by the total length of the run to come up with a percentage. While there may be more complex and accurate ways of accomplishing it, it works perfectly fine for my purposes.

Thanks for the information, though.

 

Sean,

He did. But in a seperate email you and I discussed whether or not you wanted that run posted. I told you I would post it you wanted, but I was confident you'd hit 5's soon so you might as well wait. I guess I mistakenly assumed you wanted to wait.

No biggie. Just a slight misunderstanding. It's on the list now.

 

Thanks Scott, haven't gotten any suitable weather for another try so might as well have the 6.17 for now. Hopefully next week.

 

Scott,

Thanks for the clarification, certainly for simplicity purposes using the average between two points is fine and makes perfect sense, just trying to highlight that within the 3%, two runs can be impacted very differently by the slope across the run.

For the slope percentage calculation to be right and consistent per your methodology (highest and lowest point), the delta in altitude has to be divided by the delta of the distance between the two points and not the total length of the run, or else you would not be consistent in the calculation between runs, you might want to look into it.

Did not mean to hijack your post with slope discussions. If nothing else, maybe it is of interest to some of the guys who assume that their 2% uphill slope as calculated in these runs, means they were disadvantaged vs a 3% downward slope, this obviously is not right and might even be the other way around depending on the shape of the altitude curve.

Cheers