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CLOSED 2016 Rule Change -Limit De-tuning by electronic means

Michael G.

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I also don't have a dog in this hunt as I don't run detuned. My 2 cents anyway...


I thought last year's change had a lot of merit as it did not overcomplicate things IMO. Defining Power:Weight with "power" being area under the curve made more sense to me as that is the true power of the car during a race. The peak HP at max RPM is irrelevant as you are at that point for only a few seconds per lap.


This specific change does seem very complex and I am more concerned with the negative reaction from all that have responded. Any proposed rule changes must take into account the racer community response. If there is an overwhelming opinion -- hopefully we go in whatever direction that is.


I have no facts on cheating frequency or offenders, but if that is the main concern -- I'd prefer to see more efforts to police vs. layering on more complicated rule sets that may drive racers away.

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Simple examples -


BMW S54 - 333 HP (factory),-15% = 283 HP X 11 = 3114 min w for GTS3 (plus additional 10% allowance with restrictor),

BMW S52 - 240 HP (factory) - 15% = 204 HP X 14.5 = 2958 - GTS 2,

BMW S65 - 414 HP (Factory) - 15% = 352 HP X 2991 - GTS 4 (on DOT), etc.


In addition, S54 and S65 will not be able to run in GTS2.

By what you just posted above, an S54 can run in GTS2, and S54 and S65 are penalized vs built engines.


The landscape and perceived cheating?


The entire GTS 3 fields across the country now 90% detuned BMWs with the majority of those being S54s.

What is wrong with the idea of running cars at expected power and above?

What is wrong with enforcing the current rules and telling the people who perceive cheating to learn how to drive or prove it. People who complain about cheating with absolutely no evidence are the problem. My car is not detuned. It's tuned for maximum performance within the incredibly simple and fair rules of GTS. The new rule is neither simple, not fair. I am being penalized for investing in GTS because somebody doesn't have the balls or brains to follow the rules and protest at the track. This will (has) lead to the perception that GTS cars are no longer welcome at NASA events.


15% allowance will still accommodate mild de-tunes, but will stop extremes.
This is absolutely laughable and proves that the person/people who wrote this 'proposal' have absolutely no knowledge of the cars in the series. The 15% accommodates nothing for an S54 or S65, or really most engines from most manufacturers. A stock S54 is rated at 333hp, but you would be lucky to get over 275 on a dynojet. Most are around 265 stock. S65 are in reality 345-355hp stock.


Dyno is not capable of policing the modern electronics and AIM will need at least an RPM feed, as well as become mandatory before it becomes true compliance tool, which will need some time to develop.
Most of us have AiM dashes now and/or some other data logger. We have offered to pull our data and run GTS's math channels. That would give you RPM, throttle position, fuel level for weight changes over the race, and probably some more useful data. I haven't heard of that being used.
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100% against this rule. My first race weekend in GTS was this October in an E36 with an S54 swap. I detuned the car to GTS2 so I could have a shot at having a competitive car since GTS 3 and 4s are pretty much all E46 chassis. Apparently I didn't get the memo that buying this car means I'm immediately suspected of cheating. I also forgot to get anywhere near the race winners, so I struggle to fathom how this rule makes GTS better and more competitive. If this rule goes through that will have been the last GTS race I participate in.

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GTS was supposed to be for those able to build a faster car based on skill and brain power and then execute by driving said car.


This rule change puts me and many of my customers outside of GTS rules and most are already talking about moving on.


I vote NO!, for my own selfish reasons and its bad for GTS as a whole

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I'll weigh in as a Porsche guy with both a 4 and a 5 car, neither of which are detuned or restricted in any way. I thought the compromise rule change on HP calculation made sense last year. As for the current proposal, I think it sways too far from the spirit of GTS and is too restrictive.


There are many reasons to electronically detune a car and run down a class or two, most of which have no foundation in attempting to cheat. I wish the P car could more easily be tuned as it would provide more flexibility in running a class with a larger field etc. if I so chose. I am not so naive as to say noone in a BMW is gaming the system, but I don't support a rule change to punish the masses for an unproven, perceived violation.


I vote NO on this one.

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This is completely bullshit proposed rule. There are hundreds of gts cars build to the current rules.. if you don't like it stay the fuck out of gts...

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If the perceived cheaters cars are datalogged on the dyno and on track you can watch for,


Valve timing at WOT

Throttle position at WOT

Ignition timing at WOT (subjective based on engine temperatute)


If these items dont match for the majority of WOT between dyno and track then it is obvious the engine map is different and you have isolated your "cheater"


Dont destroy the purity of the rules.

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OK, my turn.... I never ran de-tuned. My car was in the middle of the GTS4 range and I spent a lot of money to bring the power/weight ratio closer to GTS5. Then last year, the rules changed, and I was back in the middle of the GTS4 range... I expressed my frustration and the answer I got was "just take another 100lbs out of the car". Ah! Funny... So my choices were to spend a lot more to get, again, closer to GTS5, detune and go down to GTS3, or do nothing, and try to make up the disadvantage by running new tires every race (which is what I did and was also a lot of money). My point is this: many guys spent a lot of effort and money to be competitive in a specific class, and no new rules should render those efforts obsolete. If someone cheats, he will find a way to cheat under any new set of rules you will come up with. GTS has always been about power to weight. Stop changing the definition of "power". Ask all racer to contribute $100/year and spend that money on verifying the disclosed power.


I vote against.

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You data on stock S54 on the dyno is different from others - it is much more than 265 on the dyno.


S54 and S65 running in GTS 2 will be prohibitively heavy and be better fitted in the classes naturally expected in.


NASA CCR prohibits pulling out the performance data, and the fact drivers agreed at VIR - doesn't make it a Rule, and not everyone complied - some channels were disabled.


Michael G.

N\GTS Nat. Dir.

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I vote NO


This goes completely against the rules of the class and it complicates it more than it should be. It just seems that we're back into the he's too fast he most be cheating. Last year changes were made to control this and the same guys were fast and the same guys that were complaining continue complaining. This series continues to grow because of the rules it has, you change that and it will die, racers will go to a different class like ST while GTS dies out.


I said it before and I will say it again. Fast guys don't rely on power they spend a tremendous amount of time and money making their cars work with the rules we have, they spend a lot of time on suspension, brakes and aero aside from becoming better drivers. The rest spends their time and effort pointing the finger, this is gonna happen no matter what rule changes you guys make! Stop trying to Taylor the series to them or the guys that might come if the rules change!


So what's gonna happen if this rule change happens and the fast GTS3 guys move to GTS4 and continue to win in that class? You gonna change the rules again? Most of them are already faster than the GTS4 cars. All this is gonna do is make people spend more money on building engines just to keep up with the rule changes..... don't try to fix something that doesn't need fixing... It has been working for all this years!

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Using hp at the flywheel is ridiculous when we're classed based on whp


Careful John, with statements like these your post probably will get deleted.

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That is why 15% loss is factored - it is better than the alternative of NO De-tunes.

And 10% additional for restrictors.


Let's not calling names here. You don't know who proposed what.

You have any other proposals?


Michael G.

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Just trying to understand that proposed rule makes my head hurt.



Better enforcement of the existing rules to catch cheaters would be better. I am admittedly new to GTS, but I like the simplicity of the rule set.

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So as far as I can tell we're trying to address two issues:


a) people who detune to get a flat powerband still have an advantage over people who have a peaky powerband.


b) people who electronically detune can cheat.


Regarding a): this is true, and we partially addressed it in the 2015 rules. In 2015 we went halfway: we're taking the average of "area under the curve" and "peak hp". What I suggest we do is to complete this transition: switch to "area under the curve" only.


Regarding b): as far as I can tell the proposed rule change won't be effective in preventing cheaters from cheating. The 15-20hp cheats will remain possible. The rule will prevent the 50hp cheats but any such cheat isn't practical anyway: competitors would immediately notice.


So my bottom line: scrap this proposed rule, switch to 100% area-under-the-curve and continue to work on the compliance testing schemes.

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This proposal goes against the roots and what GTS was created on -- simplicity. This simplicity is what has attracted the racers that make up GTS and continues to bring new people to GTS. Many of us have invested so much into this class to race and sharing experiences with other great racers of GTS. Changing rules and not being clear/consistent with current rules is what has ruined classes and series (amateur and pro) too many times - ultimately taking away, not growing the attractiveness.


If there is problem with cheating, ask yourself why the cheating is occurring. It starts with the regulation of rules. Dyno more consistently each weekend and not just the top cars (that may consistently finish on top) but also the back of the field. Continue to use blackbox's and develop superior software to detect outliers. If there is an outlier from 3 data points - he/she will stick out with their acceleration curve.


I fear if this proposal passes, it will kill GTS as a class.


Again, I disagree with this proposal.

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I don't understand what problem this is trying to solve for. If the concern is cheating, updating the rules to unfairly penalize those of us who have _legally_ built cars to comply with the rules and then have stuck to fair competition is just ridiculous. If you want to catch cheaters, run AIM data at all events and do more "random" dyno runs.


This rule reads like a gift to those competitors who have thus far refused to invest in electronic throttle body motors, rather than a rule designed to limit cheating. The cheaters will still find another way to cheat (for example, anyone could still allow RPM overruns in a race condition that are not present on a dyno). Changing the motor rules won't stop cheaters.

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I don;t have a dog in this fight, but I'd like to offer my perspective having spent many years working on rules with other groups.


Here's what I see.


This proposal doesn't make any sense.


You have a good series, with good car counts and level competition and the overwhelming response from the competitors is a resounding NO. That should carry more weight than anything.


What I suggest you consider, is restricting aero and bodywork mods in GTS1 to keep category entry expenses low.


you might also want to consider regulating turbos using a TIR/weight chart, this has proven effective elsewhere. Same with supercharged cars except it would be an SIR/weight chart. That way it doesn't matter what FI unit or what has been done to the internals. The TIR limits the power regardless.


Right now you don't restrict turbos. eventually that will start biting you. same with s/c cars.


Let me know how I can help if wanted/needed.

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I do not sponsor this rule change - Vote No.


My experience has been in GTS2 only, but from what I have seen, a S54 in an e36 GTS2 trim has no effective advantage over a S52 e36 GTS2 Trim. I've seen it first hand in multiple occasions that the acceleration differences (especially with last years rule change taking average HP) are negligible. I mean, hell - some other S52's are quicker than mine down the strait.


I feel this rule change will reduce car count in GTS2 in the Northeast region and if the goal is to improve car attendance and improve "racing". This rule change should not be enforced.



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And another thing that upsets me......where has our voice in these matters gone? There was a bunch of upheaval last year during this process over the new calculator and talk about how gts was over(hell, I was one of them). But you know what, it wasn't b/c of the new calculator. It was b/c our "leaders" decided to completely ignore the masses and force a new rule on us that changed the landscape of the series. I was fine with the new calculator, but not with the fact that NASA basically gave us a big "F you" and let us know that our opinions no longer mattered. Sadly, that is where I see this proposal going. Where are all the supporters of this???? Why will they not speak up? GTS has been growing on the east coast for the last few years. Is that not what NASA wants to see??? The NE has a large group of GTS cars, and the MA region has also seen a lot of growth (we had 13 GTS3 entries at our last race!). I also hear that there are 3 more planned builds for MA gts3 that are in the works. I guess though that since they aren't p-cars nobody (ie.nasa) will care. I'm sure the shop owner that's taking care of those 3 builds will chime in at some point, but I wouldn't be surprised to see those builds put on hold to see what kind of mess our "leaders" make for us this year. So I'll stand by last years statement that this is gonna kill the series! If you guys keep throwing major changes at us year after year then yes, it will ruin the series. I, myself, spent over $60k on my car since last oct to perform an engine swap that maximized the current rule set, so that I could run with my friends in the class that the car was built for. Now, with this change I would no longer be able to race with my friends and be forced into GTS4, which at most had 2 regular attendees in the MA region last year. Screw that! I'll find another place to run before continuing to deal with the people that are running this series!

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Based on the wording and scope of this rule change I think we can all agree we can all agree that this is not a “GTS person” proposing this change. So the following comments are directed fully at the National Office and whoever is pushing this rock up the hill. I also would respectfully ask that this person get involved in the conversation so the active competitors in the series can understand why and more importantly how this rule change will help the series.


That being said the following are my thoughts:


My first thought is this, if we can’t adequately police the current rule set, so how do we expect a more complicated one to solve the problem?


Currently we are a HP under the curve/ weight formula. This is based on dyno sheets we all turn in. The problem here lies in the inconsistency of the dyno and said operator. This was very succinctly demonstrated at the Eastern Championships. A Dyno Jett dyno can be manipulated to read almost any number you want.


First step in policing the current rule set is to give a set of parameters that the dyno must be set at. Not just smoothing 5. The weather station must be confirmed. The altitude must be confirmed. The base setup of the dyno must be confirmed. All of these points affect the final numbers. Dyno Jett clearly states that if set up correctly all units should be within 1% of each other. The dyno at the Eastern Championships could not do that over the course of a weekend. Our 215 hp car’s dyno numbers varied by over 10 hp, over five different dyno sessions, with ZERO changes to the tune. When we returned to our home dyno, again with zero changes to the tune, there was a 2 hp difference. Well within the 1%. Until you can produce consistent numbers from the dyno it doesn’t matter how complicated the rules are.


My second question is where does this perceived cheating coming from?


Currently there is no consistent method to police ourselves at the regional level. There needs to be a dyno at each event. Period. There is no way to change perception without facts. Reality is, we will never completely loose the cheating accusations. It is part of this sport at all levels.


Third question, how are we going to determine “Natural Horsepower”?


The manufactures are notorious for inflating hp numbers. Does each manufacturer inflate the same amount? The next question is how were the manufacturer’s numbers arrived at? Was the engine run in the same condition as it is in the car? Were all of the parasitic drags (alternator, water pump, power steering pump) on the engine when it when it was tested. What method was used to arrive at the hp numbers? DIN? SAE?


Fourth. How does limiting the amount of de-tune level the playing field?


Horsepower is horsepower whether it comes from an engine that is capable of 50% greater or 20% greater power it doesn’t matter. There will come a point of diminishing returns. A 4 cycle engine is only efficient in roughly a 500 rpm range. Unless you build the engine to work at the hp level you are limiting it to. So, if you continue to chock down an engine that is built to be run at a higher hp you will be putting that engine in a condition of lesser efficiency. Unless you build the engine to work at the hp level you are limiting it to by changing intake, exhaust, and cam. There will come a point where it is not worth it. This is self governing as far as I can see.


Fifth question is as follows. How does changing an internal part make it a “Custom Engine”?


My personal opinion is this was arrived at by someone who has spent too much time in a spec class. The following are changes that will make an engine a custom engine by the wording of the rule: S54 notorious rod bolt problem, notorious rod bearing problem in high RPM use engines. Most people change the bearings for a coated one and at least change the rod bolts to ARP or better, use a forged rod. No real HP advantage. But now a custom engine and subject to the 100 hp/ liter rule. 944/968 has a rod bearing problem, piston pin boss problem. How do you fix this? By putting special baffling in the oil pan and forged pistons. No real HP advantage but now a Custom engine. The M96/97 engine that is in the 911, Cayman, Boxster. The well documented IMS problem. Oil build up in the head under high G turns. Both will destroy the engine in short order. How do you fix? IMS, install special bearing or a bespoke fixture that eliminates the bearing completely. Oil build up? Install special pumps that will evacuate the head of excess oil. Install special Motorsport VOS. No HP advantage, but now a custom engine. The above are all engines that are regularly seen in GTS fields. So what do you do now? Have a huge book of approved mods that do not make it a custom engine? Not what GTS stands for.


Lastly, how can you expect the dyno operator to keep all of these files you expect.


Most if not all dynos are owned and operated by small business. NASA’s expectation that these people just produce data when they want it is ridiculous. Also, what does “serious consequences will follow” mean?


In conclusion, I believe that this all can be answered with one very simple act and unfortunately it is not an easy one to swallow. NASA needs to buy its own dynos at all levels and have staff on hand that are trained to use the equipment properly. GTS is not the only series that uses a HP/WT formula. Until we have the means to police the competitors at all levels it does not matter how many rules we enact.


Sorry this has been so long winded.

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