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JSG1901

PROPOSED RULE 2015: Prevent de-tuning by more than one class

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JSG1901

Proposed change

Prevent de-tuning any engine by more than one class from its "natural" class.

 

Reason

With the advent of electronic throttles, we are seeing more and more cars being seriously--one might say 'grossly'--detuned to fit into unnaturally low classes for the power normally generated by their engines. This is particularly common among the BMW crowd.

 

By doing this, these cars have none of the peakiness associated with real engines running as they were designed. Instead, cars so modified are able to hit maximum horsepower (or torque) at very low revs and to maintain that level across the entire rev range. This state of affairs creates an artificial situation where these cars have what should be considered an unnatural advantage over other cars that naturally fit into their respective classes by running their engines as designed by the factory.

 

For instance, an E36 driver could conceivably replace his motor with a recent-generation S65 M3 V8--a 444 hp engine--then detune it to, say, 240 hp for GTS3. Compared to a similar E36 running the 240 hp S50 motor it came with, the V8 car would have an enormous advantage.

 

Whereas the unmodified car would have a "normal" power curve, climbing to its 240ish hp peak just short of the redline, the transplanted V8 could have the full 240 horsepower at virtually all useful revs, making it much faster out of turns, after every shift, and in changing traffic situations.

 

My proposal here is to disallow this kind of significant down-tuning of motors, forcing them to run in or near their natural power ranges, as designed by the factory, in an effort to remove the inherent advantage being enjoyed by only a small subset of our drivers.

 

Proposed wording

Engines may not be "de-tuned" by any means--including mechanical or electronic throttle limiters, restrictor plates, or any other technology--by more than one class below that engine's natural class.

 

The term "natural class" as used here is defined as the class into which the vehicle in question would be classified if the engine were run with all limiters of any kind removed.

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UKRBMW

This actually sounds pretty reasonable.

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flink

Will it help much? An S54 in an e36 would be permitted and it can produce a dead flat power band anyway.

 

Switching from peak HP to average HP would fix all this up. I suggest concentrating on that.

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doclouns

What about built motors as opposed to stock motors that are detuned? Take a 300HP S54, built/tune it to say 420HP, then detune it back down to near "natural" levels as built from the factory. So what is the reference point for the "2 levels"? The 420 (built) or the 300 (natural) in this proposal? BTW, im inclined to support this, just need clarification....

Edited by Guest

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With all due respect to OP.

 

What you are describing is a belief that is in direct and complete conflict with the most beautiful aspect of NASA GTS.

 

It is NOT a spec racing series where you have to drive a car as it came from the factory. You are allowed to strip cars to whatever weight you can achieve, add ballast if you want, and pick motors from your brand as you choose, and tune or detune to your heart's content.

 

At the end of the day, if you choose your engine properly, tune or detune it properly, you can prepare a car that NO ONE ELSE in the field should be able to motor away from you as you come out of a turn side by side.

 

A beautiful thing. Don't ruin it!

 

It makes as much sense to limit de-tuning an engine from its "natural state" as to

 

Limit weight reductions from "natural state"

Limit engine building UP from "natural state"

Limit engine choice to "natural" engine the car came with.

 

Don't screw up an awesome set of rules.

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ratchethead

Could not agree more. THANK YOU for proposing this Scott.

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MPower6er

Just mandate cars with V8's must run in classes>GTS3

 

In all seriousness, disagree with this proposal.

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mcdonaldsracing

No way! Who would decide what class a car "should" run in? Would you base it on factory weight and hp? Would you base it on a completely stripped cars weight? This goes completely against the spirit of GTS. I chose this class b/c of the open rule set and freedom to do just about anything to the car you want, so long as you meet your hp/wt ratio. Also, what will happen in the coming years? Cars aren't getting any slower from the manufacturers. Eventually you'll only be able to run newer cars in 4,5, or U. GTS 1-3 will become filled with old and outdated cars

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Brad Waite

I vote NO

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Eric W.

I vote no. Too complicated to determine what is a base/natural class, what weight, etc etc.

 

If the goal is to level the playing field then the other rule suggestion on changing the formula makes more sense in an open class like GTS.

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brant giere

Vote no

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jvanhouten

I vote against.

 

I understand why having a flat tq/hp curve is important--I have one. But the other thing to consider is the "length" of that flat spot and how much of that is actually useful. With the stock 6sp in the E46, the rpm drop from 4th to 3rd is only 2161 rpm. If the flat area of the curve is much longer than that, it isn't really useful.

 

The other question is how do you determine the "base" power of the engine? The difference in RWHP of a stock vs built S54 can be >100hp. Does that mean that with a post race compliance dyno, does the car need to do 3 pulls in the "as raced" condition then all restrictors (mechanical and/or software) be removed and 3 more pulls again to determine the natural/base class of the engine? Seems silly and a lot of work, plus lots of opportunities for shenanigans.

 

If we must do a rule like this, I would propose that we put in a "minimum peak HP" based on the size of the size of the engine. For example, the rule could state the minimum HP/L of an engine is 70, therefore a 3.2L S54 would have a minimum peak HP of 224. This would limit the amount of detuning that could be done while minimizing the complexity around enforcing it.

 

There would of course need to be discussion around what that limit it probably with two limits--one for 2 valve engines and one for 4 valve engines. Similarly, once FI engines show up, they would need a different multiplier.

 

Just my $0.02.

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scottbm3

Against !

 

 

 

 

 

 

 

 

-Scott B.

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jackhaberman

I vote no. Agree that with more focus on "average horsepower" -- this issue would also be addressed.

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cash7c3

Against. What determines a motor's "base" horsepower.

Edited by Guest

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bmwjoon

No.

 

The whole idea of natural hp is too complicated.

 

Also it's a power to weight formula so what about the natural weight?

 

So one BMW with a V8 and little prep is "naturally" in GTS4 and a well prepped chassis with the same motor is naturally in 5 etc. etc.

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7VO-VOM

No. How do you determine natural horsepower? Sure, a V8 M3 has 400-something HP, but they typically dyno in the low-mid 300 range. Do you use the manufacturer's claim or real numbers? Cars can still vary wildly based on wear, carbon build up, or even how hungover the technician was building it. Are you going to dyno each car in stock form to determine its natural HP? What happens if the racer bought the car already modified?

 

It is impossible to do fairly.

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J Smith

No.

Way too much "gray" area here.

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CARVAL Motorsports

Gray, that is 50 shades of gray! Great in spirit, way to difficult to monitor & maintain. NO.

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peter*g

No. It's a power to weight ratio class. This just becomes way too complicated.

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Greg Smith

Absolutely not.

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mmcnw

no- the primary intent of the class was based on a simple power to weight calculation that is reasonably easy to calculate and verify. This type of rule moves away from that intent by dictating how you get the power and will likely require arbitrary line drawing to determine "natural" power.

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mmcnw

no-the intent of the class was a simple power to weight calculation that was reasonably easy to calculate and verify. This rule moves away from that. Also, to determine "natural" class/power will likely require arbitrary line drawing.

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Luke P.

Nope! Can't easily determine a base class.

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Guest
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