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JSG1901

2015 GTS Rules are now available

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JSG1901

The 2015 GTS Rules, along with the new minimum weight calculator, can be found at nasagts.com under Rules/Forms.

 

My apologies for not having this wrapped up on December 15 as originally promised, but it was the decision of the series directors and myself that it was more important to get this as right as possible than it was to hold ourselves to an arbitrary deadline. While I recognize that this has caused unnecessary angst among some of our drivers (particularly those who will be racing early in the year) you may be comforted to know that no GTS cars will be required to add weight from where they would have been with the 2014 rules. Having said that, many cars will have the option to reduce weight to some extent.

 

The calculator, available at Rules/Forms > 2015 GTS Calculator on nasagts.com, includes the final computations that will be used for 2015, with the proviso that we reserve the right to make corrections if any bugs are uncovered in the course of use. The current version of the calculator is free-standing (meaning you can calculate your weight but not save the results), but we plan to replace it as quickly as possible with a version which allows you to upload your dyno sheets and/or dyno data files for a more permanent record. We are investigating the idea of also making the calculator available as a mobile application.

 

The final minimum-weight computation is much better as a result of the lengthy and passionate discussion held in this forum. While it is not zero change, as some here would like to see, neither is it as far-reaching as others might prefer. The final algorithm uses the average of the highest 20% of the powerband, then averages that with the maximum horsepower number. This has the effect of both flattening the averages of the peakiest cars somewhat, while also tempering the results of intentionally radical power curves. The resulting value is then multiplied by the various class ratios as used in 2014 and the past. In other words, GTS3 cars on DOT tires will be multiplied by 11.0, GTS2 on DOTs will use 14.5, and so on.

 

Here's to wishing everyone a great year on the track.

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flink

So the difference was split. It's halfway between "peak hp" and "average hp". Perhaps in 2016 we'll fully switch to average hp?

 

My S52 has a pretty flat power band (sheet: http://i240.photobucket.com/albums/ff67/flink-gto/e36/engine/dyno_zpsab29bc0e.jpg). With the 2014 rules I was losing 6hp relative to a flat power band. With the 2015 rules I'll be losing 4hp.

 

 

I ran the numbers for the peaky cup car (http://i240.photobucket.com/albums/ff67/flink-gto/e36/engine/cupcar-out2_zpsf583451c.jpeg) and it came in at

 

Minimum weight: 3,141 lbs

Average power: 355.4 hp. Class multiplier: 8.5

 

Where 3,141/8.5 = 371hp. The 20% powerband is correct for this car. He's getting a 16hp (136lb) disadvantage due to this taking the average of the peak and the average.

 

 

A minor suggestion for the web page: it displays minimum weight and average power and class multiplier, but the minimum weight is not equal to (average-power * class-multiplier). It's a bit confusing. I suggest changing it to:

 

Minimum weight: 3,141 lbs

Average power: 355.4 hp. Peak power: 383.7 hp. Classing power: 369.6 hp. Class multiplier: 8.5

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JSG1901

Andrew,

 

Thanks for pointing that out. We've been through a lot of iterations. I'll take a look at the code as soon as Santa clears the room.

 

Cheers,

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hamflex

Still seems to be a few pounds off, min weight on the calculator shows it being 33lbs over multiplying my avg by my class multiplier.

 

Funny thing it was spot on earlier! Just a heads up.

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UKRBMW

Cool - I lost about 40 pounds. Nothing overly huge here. Probably will retune to pick up a little bit of power and keep the same weight.

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flink
Still seems to be a few pounds off, min weight on the calculator shows it being 33lbs over multiplying my avg by my class multiplier.

 

That's because your classing hp isn't "average-hp * class-multiplier". It is "((average-hp + peak-hp) / 2) * class-multiplier". Calculate that equation and you'll find it's dead-on.

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gjkasten
That's because your classing hp isn't "average-hp * class-multiplier". It is "((average-hp + peak-hp) / 2) * class-multiplier". Calculate that equation and you'll find it's dead-on.

 

It may be worth showing what the classing hp is. I thought the calculator was off as well.

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J Smith

Overall, this looks much better than the first version that a few of us had our regional directors run numbers for us (where detunes were being penalized excessively IMO).

 

A few concerns though:

 

I see this:

...The calculator, available at Rules/Forms > 2015 GTS Calculator on nasagts.com, includes the final computations that will be used for 2015

and this:

The final minimum-weight computation is much better as a result

but then this:

...with the proviso that we reserve the right to make corrections if any bugs are uncovered in the course of use

The calculator should be released when you're confident it is ready, not rushed/pushed into the rules just because time ran out. If you're not sure it's ready and feel you may need to make changes to it, or work some bugs out, probably would be best to do that before it's officially a rule.

 

And how does this work now with the previous 4hp forgiveness rule for dyno compliance testing? Maybe I'm over thinking it, but I it seems like this needs to be addressed with the new calculator?

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hamflex
Still seems to be a few pounds off, min weight on the calculator shows it being 33lbs over multiplying my avg by my class multiplier.

 

That's because your classing hp isn't "average-hp * class-multiplier". It is "((average-hp + peak-hp) / 2) * class-multiplier". Calculate that equation and you'll find it's dead-on.

 

It says at the top what my avg HP is based on all of the parameters then displays weight. There is no math left for me to do.

 

My weight given to me, divided by 11 is a higher weight.

 

Corrected if I'm wrong, but the idea of the calculator is to do all the calculations not 2/3 of it?

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UKRBMW

John, Chris, Ed - as ex or current Porsche owners I would highly encourage you to help spread this change with Porsche racers. I posted a thread on renn list and it seems most were not aware or do not fully understand it based on responses and pms I got. It would be a huge waste to do all this work and ruffle all the feathers if we don't end up getting any new participants.

 

Thanks

Alex

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cstreit911

Thanks Alex... Can you please PM me a link to the thread?

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UKRBMW

Chris - looks like you already found it. Thanks for posting there. All the emotion aside I would love to see this change bring out more folks.

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911.racer

Agreed,

 

Thanks

 

Ed

 

John, Chris, Ed - as ex or current Porsche owners I would highly encourage you to help spread this change with Porsche racers. I posted a thread on renn list and it seems most were not aware or do not fully understand it based on responses and pms I got. It would be a huge waste to do all this work and ruffle all the feathers if we don't end up getting any new participants.

 

Thanks

Alex

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Surfbum

How do we get the "Raw Data" from dyne runs taken after Jan 2015?

Do we submit a thumb drive?

Do we need new software to be able to read the data?

 

I am a techno idiot so please excuse my questions if the answer is obvious.

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7VO-VOM

The new rule is far better than what was initially posted. It can still be gamed and is unfair in all the ways mentioned before, however to a lesser degree. The way it was pushed on the series without any reason other than to penalize people with completely legal cars is irresponsible, dishonest, and detrimental to the series.

 

The rules do not state how average hp is calculated. I see that it is posted above, but the forum is not the rules. The rules should have the exact method of calculation stated. In fact, the algorithm should be stated in the rules. The calculator needs a version and date so people know if/when any changes are made.

...with the proviso that we reserve the right to make corrections if any bugs are uncovered in the course of use

The calculator should be released when you're confident it is ready, not rushed/pushed into the rules just because time ran out. If you're not sure it's ready and feel you may need to make changes to it, or work some bugs out, probably would be best to do that before it's officially a rule.

After January 1, 2015, the calculator should not be changed until January 1, 2016. If you are not confident in the calculator, it should not be used in 2015.

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mikew968

I'm amazed at how hard people fight for something that they say is not any advantage. In addition what is the issue with averaging HP at the peak 20% of the power band? The averaging effect is really only measuring 600-800 RPM of peak power. The flatter the HP curve the less change that will occur.

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fbirch

I’d like to thank the GTS directors for their efforts to balance inputs from a very ornery and opinionated bunch of participants. I understand the motivation for tweaking the rules and agree with it. The rule changes could have gone further IMO, but it’s a step in the right direction. Thanks again for putting up with some less-than-civil discourse on behalf of the sport we all love.

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JSG1901
How do we get the "Raw Data" from dyno runs taken after Jan 2015?

Do we submit a thumb drive?

Do we need new software to be able to read the data?

 

I am a techno idiot so please excuse my questions if the answer is obvious.

First, that's not the least bit idiotic, and those are great questions.

 

The dyno operator should be able to give you electronic copies of your dyno runs. If you take a thumb drive along with you, I'm sure they would be happy to copy them onto it, or you could probably have them emailed to you if that's simpler. You can either get the raw DynoJet data (which can be read by software described below), or as a "CSV" (comma-separated values) file, which can be read directly into most spreadsheets.

 

We will (but do not yet) have a place on the NASA GTS site where you will be able to upload your CSV file(s) and have them automatically read into the system, preventing you from having to enter your dyno number manually. Until the upload is available, you will still have to enter your data manually but rather than estimating the values (as you would have to do when entering from a typical dyno graph), you should use the actual numbers.

 

For those with Windows systems and a little technical ability, you can download the free WinPEP software from DynoJet to get the dyno output numbers from your files:

 

http://www.dynojet.com/Downloads/Software-and-manuals.aspx

 

While WinPEP reads the actual dyno files, it can export to CSV, also.

 

For those who can't or don't want to do it that way, ask the dyno operator to print out the data sheet and to export to a CSV file. You will get what is essentially a spreadsheet of values showing your horsepower at various RPMs. Be sure to let the operator know you care about RPM and not about MPH values.

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doclouns

Scott-

Which of the three software downloads do we need?

Thanks

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Eric W.

RunFileX.drf

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CARVAL Motorsports

Crap, I don't know how I can lose any more weight

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Michael G.

Low carb diet > Sorry couldn't resist.

 

Michael G.

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Zach H.

Carl,

 

do you run an s2 intake? if not you should!! worth a nice power bump over the 2.5s intake mani.

 

also you could buy my cams!

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Greg Smith

FB discussion:

"Maybe I'm blind, but for 2015 how many dyno runs are we required to do and which run do we use for the official number?"

 

Scott Good's response:

"It's the same as always. Three runs, use the one with the highest peak horsepower number."

 

New question:

When plugging in "maximum horsepower", do I use the data from the export file, or what the screen shows? There's a small difference, it has to do with the peak horsepower not falling on a 100rpm interval. With that said, there's also a difference for maximum horsepower when choosing 100rpm or 500rpm intervals for the export file.

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Zach H.
FB discussion:

"Maybe I'm blind, but for 2015 how many dyno runs are we required to do and which run do we use for the official number?"

 

Scott Good's response:

"It's the same as always. Three runs, use the one with the highest peak horsepower number."

 

New question:

When plugging in "maximum horsepower", do I use the data from the export file, or what the screen shows? There's a small difference, it has to do with the peak horsepower not falling on a 100rpm interval. With that said, there's also a difference for maximum horsepower when choosing 100rpm or 500rpm intervals for the export file.

 

I would assume the maximum hp number for the run will be what you are judged on vs the max on the export file.

 

can you post a picture of the differences in numbers please

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